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Sample records for dental enamel aided

  1. Weaker dental enamel explains dental decay.

    Science.gov (United States)

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  2. Dental Enamel Defects and Celiac Disease

    Science.gov (United States)

    ... Digestive System & How it Works Zollinger-Ellison Syndrome Dental Enamel Defects and Celiac Disease Celiac disease manifestations ... affecting any organ or body system. One manifestation—dental enamel defects—can help dentists and other health ...

  3. Recovery of crystallographic texture in remineralized dental enamel.

    Science.gov (United States)

    Siddiqui, Samera; Anderson, Paul; Al-Jawad, Maisoon

    2014-01-01

    Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain

  4. Recovery of crystallographic texture in remineralized dental enamel.

    Directory of Open Access Journals (Sweden)

    Samera Siddiqui

    Full Text Available Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture and position of the (002 Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected

  5. The fracture behaviour of dental enamel

    OpenAIRE

    Bechtle, Sabine; Habelitz, Stefan; Klocke, Arndt; Fett, Theo; Schneider, Gerold A.

    2009-01-01

    Abstract Enamel is the hardest tissue in the human body covering the crowns of teeth. Whereas the underlying dental material dentin is very well characterised in terms of mechanical and fracture properties, available data for enamel are quite limited and are apart from the most recent investigation mainly based on indentation studies. Within the current study, stable crack-growth experiments in bovine enamel have been performed, to measure fracture resistance curves for enamel. Single edge...

  6. Dental enamel defects in children with coeliac disease

    NARCIS (Netherlands)

    Werink, Claar D.; van Diermen, Denise E.; Aartman, Irene H. A.; Heymans, Hugo S. A.

    2007-01-01

    OBJECTIVE: The aim of this study was to investigate whether Dutch children with proven coeliac disease show specific dental enamel defects, and to asses whether children with the same gastrointestinal complaints, but proved no-coeliac disease, lack these specific dental enamel defects. MATERIALS AND

  7. Evaluation of radiation effects on dental enamel hardness and dental restorative materials

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa; Saiki, Mitiko; Campos, Tomie Nakakuki

    2000-01-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10 12 n cm -2 .s -1 . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  8. The role of mesoscopic modelling in understanding the response of dental enamel to mid-infrared radiation

    Energy Technology Data Exchange (ETDEWEB)

    Verde, A Vila [Department of Chemical Engineering, Fenske Laboratory, Pennsylvania State University, University Park, PA 16802 (United States); Ramos, M M D [Department of Physics, University of Minho, 4710-057 Braga (Portugal); Stoneham, A M [London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2007-05-21

    Human dental enamel has a porous mesostructure at the nanometre to micrometre scales that affects its thermal and mechanical properties relevant to laser treatment. We exploit finite-element models to investigate the response of this mesostructured enamel to mid-infrared lasers (CO{sub 2} at 10.6 {mu}m and Er:YAG at 2.94 {mu}m). Our models might easily be adapted to investigate ablation of other brittle composite materials. The studies clarify the role of pore water in ablation, and lead to an understanding of the different responses of enamel to CO{sub 2} and Er:YAG lasers, even though enamel has very similar average properties at the two wavelengths. We are able to suggest effective operating parameters for dental laser ablation, which should aid the introduction of minimally-invasive laser dentistry. In particular, our results indicate that, if pulses of {approx}10 {mu}s are used, the CO{sub 2} laser can ablate dental enamel without melting, and with minimal damage to the pulp of the tooth. Our results also suggest that pulses with 0.1-1 {mu}s duration can induce high stress transients which may cause unwanted cracking.

  9. The role of mesoscopic modelling in understanding the response of dental enamel to mid-infrared radiation

    Science.gov (United States)

    Vila Verde, A.; Ramos, M. M. D.; Stoneham, A. M.

    2007-05-01

    Human dental enamel has a porous mesostructure at the nanometre to micrometre scales that affects its thermal and mechanical properties relevant to laser treatment. We exploit finite-element models to investigate the response of this mesostructured enamel to mid-infrared lasers (CO2 at 10.6 µm and Er:YAG at 2.94 µm). Our models might easily be adapted to investigate ablation of other brittle composite materials. The studies clarify the role of pore water in ablation, and lead to an understanding of the different responses of enamel to CO2 and Er:YAG lasers, even though enamel has very similar average properties at the two wavelengths. We are able to suggest effective operating parameters for dental laser ablation, which should aid the introduction of minimally-invasive laser dentistry. In particular, our results indicate that, if pulses of ap10 µs are used, the CO2 laser can ablate dental enamel without melting, and with minimal damage to the pulp of the tooth. Our results also suggest that pulses with 0.1-1 µs duration can induce high stress transients which may cause unwanted cracking.

  10. The role of mesoscopic modelling in understanding the response of dental enamel to mid-infrared radiation

    International Nuclear Information System (INIS)

    Verde, A Vila; Ramos, M M D; Stoneham, A M

    2007-01-01

    Human dental enamel has a porous mesostructure at the nanometre to micrometre scales that affects its thermal and mechanical properties relevant to laser treatment. We exploit finite-element models to investigate the response of this mesostructured enamel to mid-infrared lasers (CO 2 at 10.6 μm and Er:YAG at 2.94 μm). Our models might easily be adapted to investigate ablation of other brittle composite materials. The studies clarify the role of pore water in ablation, and lead to an understanding of the different responses of enamel to CO 2 and Er:YAG lasers, even though enamel has very similar average properties at the two wavelengths. We are able to suggest effective operating parameters for dental laser ablation, which should aid the introduction of minimally-invasive laser dentistry. In particular, our results indicate that, if pulses of ∼10 μs are used, the CO 2 laser can ablate dental enamel without melting, and with minimal damage to the pulp of the tooth. Our results also suggest that pulses with 0.1-1 μs duration can induce high stress transients which may cause unwanted cracking

  11. Polymer coated liposomes for dental drug delivery--interactions with parotid saliva and dental enamel.

    Science.gov (United States)

    Nguyen, S; Hiorth, M; Rykke, M; Smistad, G

    2013-09-27

    The interactions between pectin coated liposomes and parotid saliva and dental enamel were studied to investigate their potential to mimic the protective biofilm formed naturally on tooth surfaces. Different pectin coated liposomes with respect to pectin type (LM-, HM- and AM-pectin) and concentration (0.05% and 0.2%) were prepared. Interactions between the pectin coated liposomes and parotid saliva were studied by turbidimetry and imaging by atomic force microscopy. The liposomes were adsorbed to hydroxyapatite (HA) and human dental enamel using phosphate buffer and parotid saliva as adsorption media. A continuous flow was imposed on the enamel surfaces for various time intervals to examine their retention on the dental enamel. The results were compared to uncoated, charged liposomes. No aggregation tendencies for the pectin coated liposomes and parotid saliva were revealed. This makes them promising as drug delivery systems to be used in the oral cavity. In phosphate buffer the adsorption to HA of pectin coated liposomes was significantly lower than the negative liposomes. The difference diminished in parotid saliva. Positive liposomes adsorbed better to the dental enamel than the pectin coated liposomes. However, when subjected to flow for 1h, no significant differences in the retention levels on the enamel were found between the formulations. For all formulations, more than 40% of the liposomes still remained on the enamel surfaces. At time point 20 min the retention of HM-pectin coated and positive liposomes were significantly higher. It was concluded that pectin coated liposomes can adsorb to HA as well as to the dental enamel. Their ability to retain on the enamel surfaces promotes the concept of using them as protective structures for the teeth. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Targeted p120-catenin ablation disrupts dental enamel development

    DEFF Research Database (Denmark)

    Bartlett, John D; Dobeck, Justine M; Tye, Coralee E

    2010-01-01

    Dental enamel development occurs in stages. The ameloblast cell layer is adjacent to, and is responsible for, enamel formation. When rodent pre-ameloblasts become tall columnar secretory-stage ameloblasts, they secrete enamel matrix proteins, and the ameloblasts start moving in rows that slide...... by one another. This movement is necessary to form the characteristic decussating enamel prism pattern. Thus, a dynamic system of intercellular interactions is required for proper enamel development. Cadherins are components of the adherens junction (AJ), and they span the cell membrane to mediate...... attachment to adjacent cells. p120 stabilizes cadherins by preventing their internalization and degradation. So, we asked if p120-mediated cadherin stability is important for dental enamel formation. Targeted p120 ablation in the mouse enamel organ had a striking effect. Secretory stage ameloblasts detached...

  13. Development of fluorapatite cement for dental enamel defects repair.

    Science.gov (United States)

    Wei, Jie; Wang, Jiecheng; Shan, Wenpeng; Liu, Xiaochen; Ma, Jian; Liu, Changsheng; Fang, Jing; Wei, Shicheng

    2011-06-01

    In order to restore the badly carious lesion of human dental enamel, a crystalline paste of fluoride substituted apatite cement was synthesized by using the mixture of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and ammonium fluoride. The apatite cement paste could be directly filled into the enamel defects (cavities) to repair damaged dental enamel. The results indicated that the hardened cement was fluorapatite [Ca(10)(PO(4))(6)F(2), FA] with calcium to phosphorus atom molar ratio (Ca/P) of 1.67 and Ca/F ratio of 5. The solubility of FA cement in Tris-HCl solution (pH = 5) was slightly lower than the natural enamel, indicating the FA cement was much insensitive to the weakly acidic solutions. The FA cement was tightly combined with the enamel surface, and there was no obvious difference of the hardness between the FA cement and natural enamel. The extracts of FA cement caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. In addition, the results showed that the FA cement had good mechanical strength, hydrophilicity, and anti-bacterial adhesion properties. The study suggested that using FA cement was simple and promising approach to effectively and conveniently restore enamel defects.

  14. Targeted p120-catenin ablation disrupts dental enamel development.

    Science.gov (United States)

    Bartlett, John D; Dobeck, Justine M; Tye, Coralee E; Perez-Moreno, Mirna; Stokes, Nicole; Reynolds, Albert B; Fuchs, Elaine; Skobe, Ziedonis

    2010-09-16

    Dental enamel development occurs in stages. The ameloblast cell layer is adjacent to, and is responsible for, enamel formation. When rodent pre-ameloblasts become tall columnar secretory-stage ameloblasts, they secrete enamel matrix proteins, and the ameloblasts start moving in rows that slide by one another. This movement is necessary to form the characteristic decussating enamel prism pattern. Thus, a dynamic system of intercellular interactions is required for proper enamel development. Cadherins are components of the adherens junction (AJ), and they span the cell membrane to mediate attachment to adjacent cells. p120 stabilizes cadherins by preventing their internalization and degradation. So, we asked if p120-mediated cadherin stability is important for dental enamel formation. Targeted p120 ablation in the mouse enamel organ had a striking effect. Secretory stage ameloblasts detached from surrounding tissues, lost polarity, flattened, and ameloblast E- and N-cadherin expression became undetectable by immunostaining. The enamel itself was poorly mineralized and appeared to be composed of a thin layer of merged spheres that abraded from the tooth. Significantly, p120 mosaic mouse teeth were capable of forming normal enamel demonstrating that the enamel defects were not a secondary effect of p120 ablation. Surprisingly, blood-filled sinusoids developed in random locations around the developing teeth. This has not been observed in other p120-ablated tissues and may be due to altered p120-mediated cell signaling. These data reveal a critical role for p120 in tooth and dental enamel development and are consistent with p120 directing the attachment and detachment of the secretory stage ameloblasts as they move in rows.

  15. Error in assessing the absorbed dose from the EPR signal from dental enamel

    International Nuclear Information System (INIS)

    Kleshchenko, E.D.; Kushnereva, K.K.

    1997-01-01

    Dose measurements from EPR signals from dental enamel were analyzed in a random sampling of 100 teeth extracted in liquidators of the Chernobyl accident aftermath and the EPR spectra of dental enamel of 80 intact teeth from children studied. The mean square deviation of enamel sensitivity to ionizing radiation in some teeth is approximately 0.3 of the mean sensitivity value. The variability of the nature EPR spectrum of dental enamel limits in principle the lower threshold of EPR-measured 60 mGy doses. When assessing the individual absorbed doses from the EPR signal from dental enamel without additional exposure it is necessary to bear in mind the extra error of approximately 6-% at a confidence probability P=0.95 caused by the variability of enamel sensitivity to radiation in some teeth. This additional error may be ruled out by graduated additional exposure of the examined enamel samples

  16. Amelogenesis Imperfect, Enamel Hypoplasia and Fluorosis Dental - Literature Review

    Directory of Open Access Journals (Sweden)

    Flávia Magnani Bevilacqua

    2015-12-01

    Full Text Available The developmental disorders of enamel are abnormalities of structure which can affect both dentitions. These abnormalities include amelogenesis imperfecta, enamel hypoplasia and dental fluorosis. The amelogenesis imperfecta is a hereditary change and enamel hypoplasia is a quantitative defect of enamel that occurs as a result of systemic problems, local and also inherited factors, or even the combination of them. Dental fluorosis is a hypoplasia caused by the chronic ingestion of fluoride during odontogenesis. All these anomalies have similar clinical characteristics, and it is necessary to be careful in their assessment. It is extremely important to know these abnormalities to establish a differential diagnosis and, consequently, a treatment plan, which can be set for each situation. Therefore, the purpose of this study was to review the literature regarding these three anomalies: amelogenesis imperfecta, enamel hypoplasia and dental fluorosis. It was concluded that to establish the differential diagnosis of these abnormalities as well as a proper treatment plan, it is indispensable the professional knowledge associated with the clinical examination. The examination has to consist of medical history and physical examination, and in some cases, x-ray examination.

  17. Morphology and structure of polymer layers protecting dental enamel against erosion.

    Science.gov (United States)

    Beyer, Markus; Reichert, Jörg; Sigusch, Bernd W; Watts, David C; Jandt, Klaus D

    2012-10-01

    Human dental erosion caused by acids is a major factor for tooth decay. Adding polymers to acidic soft drinks is one important approach to reduce human dental erosion caused by acids. The aim of this study was to investigate the thickness and the structure of polymer layers adsorbed in vitro on human dental enamel from polymer modified citric acid solutions. The polymers propylene glycol alginate (PGA), highly esterified pectin (HP) and gum arabic (GA) were used to prepare polymer modified citric acids solutions (PMCAS, pH 3.3). With these PMCAS, enamel samples were treated for 30, 60 and 120s respectively to deposit polymer layers on the enamel surface. Profilometer scratches on the enamel surface were used to estimate the thickness of the polymer layers via atomic force microscopy (AFM). The composition of the deposited polymer layers was investigated with X-ray photoelectron spectroscopy (XPS). In addition the polymer-enamel interaction was investigated with zeta-potential measurements and scanning electron microscopy (SEM). It has been shown that the profilometer scratch depth on the enamel with deposited polymers was in the range of 10nm (30s treatment time) up to 25nm (120s treatment time). Compared to this, the unmodified CAS-treated surface showed a greater scratch depth: from nearly 30nm (30s treatment time) up to 60nm (120s treatment time). Based on XPS measurements, scanning electron microscopy (SEM) and zeta-potential measurements, a model was hypothesized which describes the layer deposited on the enamel surface as consisting of two opposing gradients of polymer molecules and hydroxyapatite (HA) particles. In this study, the structure and composition of polymer layers deposited on in vitro dental enamel during treatment with polymer modified citric acid solutions were investigated. Observations are consistent with a layer consisting of two opposing gradients of hydroxyapatite particles and polymer molecules. This leads to reduced erosive effects of

  18. Association of dental enamel lead levels with risk factors for environmental exposure.

    Science.gov (United States)

    Olympio, Kelly Polido Kaneshiro; Naozuka, Juliana; Oliveira, Pedro Vitoriano; Cardoso, Maria Regina Alves; Bechara, Etelvino José Henriques; Günther, Wanda Maria Risso

    2010-10-01

    To analyze household risk factors associated with high lead levels in surface dental enamel. A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

  19. Anisotropic local physical properties of human dental enamel in comparison to properties of some common dental filling materials.

    Science.gov (United States)

    Raue, Lars; Hartmann, Christiane D; Rödiger, Matthias; Bürgers, Ralf; Gersdorff, Nikolaus

    2014-11-01

    A major aspect in evaluating the quality of dental materials is their physical properties. Their properties should be a best fit of the ones of dental hard tissues. Manufacturers give data sheets for each material. The properties listed are characterized by a specific value. This assumes (but does not prove) that there is no direction dependence of the properties. However, dental enamel has direction-dependent properties which additionally vary with location in the tooth. The aim of this paper is to show the local direction dependence of physical properties like the elastic modulus or the thermal expansion in dental hard tissues. With this knowledge the 'perfect filling/dental material' could be characterized. Enamel sections of ∼400-500 μm thickness have been cut with a diamond saw from labial/buccal to palatal/lingual (canine, premolar and molar) and parallel to labial (incisor). Crystallite arrangements have been measured in over 400 data points on all types of teeth with x-ray scattering techniques, known from materials science. X-ray scattering measurements show impressively that dental enamel has a strong direction dependence of its physical properties which also varies with location within the tooth. Dental materials possess only little or no property direction dependence. Therefore, a mismatch was found between enamel and dental materials properties. Since dental materials should possess equal (direction depending) properties, worthwhile properties could be characterized by transferring the directional properties of enamel into a property 'wish list' which future dental materials should fulfil. Hereby the 'perfect dental material' can be characterized.

  20. Prevalence of enamel defects and association with dental caries in preschool children.

    Science.gov (United States)

    Massignan, C; Ximenes, M; da Silva Pereira, C; Dias, L; Bolan, M; Cardoso, M

    2016-12-01

    This was to evaluate the prevalence of the developmental defects of enamel (DDE) in primary teeth and its association with dental caries. A cross-sectional study with a randomised representative sample was carried out with 1101 children aged 2-5 years enrolled in public preschools (50% prevalence of DDE in primary teeth, a standard error of 3%, and a confidence level of 95%). Three calibrated dentists (K > 0.62) performed clinical examination. Data collected were: sex, age, DDE (Modified DDE Index) and dental caries (WHO). Descriptive analysis, Chi-square test and multinomial logistic regression were applied for data analysis. Among children, 565 (51.3%) were boys; mean age was 3.7 (±0.9 years). The prevalence of enamel defect was 39.1%; the prevalence of diffuse opacities, demarcated opacities and enamel hypoplasia was 25.3, 19.1 and 6.1%, respectively. The prevalence of dental caries was 31.0%, with mean def-t 1.14 (±2.44). Primary teeth with enamel hypoplasia had three times the odds of having dental caries than those with absence of enamel defects (OR = 3.10; 95% CI: 1.91, 5.01). The presence of enamel defects was moderate and associated with dental caries.

  1. Quantitative assessment of the enamel machinability in tooth preparation with dental diamond burs.

    Science.gov (United States)

    Song, Xiao-Fei; Jin, Chen-Xin; Yin, Ling

    2015-01-01

    Enamel cutting using dental handpieces is a critical process in tooth preparation for dental restorations and treatment but the machinability of enamel is poorly understood. This paper reports on the first quantitative assessment of the enamel machinability using computer-assisted numerical control, high-speed data acquisition, and force sensing systems. The enamel machinability in terms of cutting forces, force ratio, cutting torque, cutting speed and specific cutting energy were characterized in relation to enamel surface orientation, specific material removal rate and diamond bur grit size. The results show that enamel surface orientation, specific material removal rate and diamond bur grit size critically affected the enamel cutting capability. Cutting buccal/lingual surfaces resulted in significantly higher tangential and normal forces, torques and specific energy (pmachinability for clinical dental practice. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Utilization of radiometric method in evaluation of wear on human dental enamel in vitro by dental porcelain glazed and polished

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa; Campos, Tomie Nakakuki de; Adachi, Eduardo Makoto

    2005-01-01

    The dental porcelain is a material commonly used in prosthesis. Disadvantages of dental porcelain use include possibility to cause tooth or dental materials wear. Before its use in the mouth, surfaces are treated with polishing and/or glazing. This research used the radiometric method to verify the influence of these surface treatments on the porcelains of commercial brands: Ceramco II, Noritake and Finesse. This method was originally developed for dentifrice abrasiveness evaluation. Five specimens of dental enamel and 10 specimens of each porcelain (5 glazed, 5 polished) were used. The dental enamel was flattened and irradiated with neutrons from the IEA-R1 (IPEN/CNEN) nuclear reactor. Then it was weared by each porcelain in sliding motion, with water. After 2,500 cycles for each porcelain specimen, the released enamel residue was measured. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from the irradiated tooth. Results varied from 2.57 to 5.81 μg of enamel /mm 2 weared surface. There was no statistical difference (α=0.05) between dental enamel wear caused by the same porcelains glazed or polished. The results suggest that adequate surface finishing depend on the type of dental porcelain. (author)

  3. Association of dental enamel lead levels with risk factors for environmental exposure

    Directory of Open Access Journals (Sweden)

    Kelly Polido Kaneshiro Olympio

    2010-10-01

    Full Text Available OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97; and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00. Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03 and smoking (OR = 1.66; 95% CI: 0.52;5.28 were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

  4. Proteomic Mapping of Dental Enamel Matrix from Inbred Mouse Strains: Unraveling Potential New Players in Enamel.

    Science.gov (United States)

    Lima Leite, Aline; Silva Fernandes, Mileni; Charone, Senda; Whitford, Gary Milton; Everett, Eric T; Buzalaf, Marília Afonso Rabelo

    2018-01-01

    Enamel formation is a complex 2-step process by which proteins are secreted to form an extracellular matrix, followed by massive protein degradation and subsequent mineralization. Excessive systemic exposure to fluoride can disrupt this process and lead to a condition known as dental fluorosis. The genetic background influences the responses of mineralized tissues to fluoride, such as dental fluorosis, observed in A/J and 129P3/J mice. The aim of the present study was to map the protein profile of enamel matrix from A/J and 129P3/J strains. Enamel matrix samples were obtained from A/J and 129P3/J mice and analyzed by 2-dimensional electrophoresis and liquid chromatography coupled with mass spectrometry. A total of 120 proteins were identified, and 7 of them were classified as putative uncharacterized proteins and analyzed in silico for structural and functional characterization. An interesting finding was the possibility of the uncharacterized sequence Q8BIS2 being an enzyme involved in the degradation of matrix proteins. Thus, the results provide a comprehensive view of the structure and function for putative uncharacterized proteins found in the enamel matrix that could help to elucidate the mechanisms involved in enamel biomineralization and genetic susceptibility to dental fluorosis. © 2018 S. Karger AG, Basel.

  5. Dental enamel defects in Italian children with cystic fibrosis: an observational study.

    Science.gov (United States)

    Ferrazzano, G F; Sangianantoni, G; Cantile, T; Amato, I; Orlando, S; Ingenito, A

    2012-03-01

    The relationship between cystic fibrosis (CF) and caries experience has already been explored, but relatively little information is available on dental enamel defects prevalence among children affected by cystic fibrosis. The aim of this study was to investigate this issue in deciduous and permanent teeth of children with CF resident in southern Italy. This cross sectional observational study was undertaken between October 2009 and March 2010. 88 CF patients and 101 healthy age-matched participated in this study. The prevalence of dental enamel defects was calculated using a modified Developmental Defects of Enamel (DDE) index. The comparison of dental enamel defects prevalence among groups was carried out using regression binary logistic analysis. In the CF subjects there was a higher prevalence (56%) of enamel defects in comparison to the healthy group (22%). The most prevalent enamel defect was hypoplasia with loss of enamel (23% of CF patients vs 1 1/2% of control group) in permanent teeth. This study confirms that children with cystic fibrosis are at increased risk of developing hypoplastic defects on their permanent teeth.

  6. Composition of enamel pellicle from dental erosion patients.

    Science.gov (United States)

    Carpenter, G; Cotroneo, E; Moazzez, R; Rojas-Serrano, M; Donaldson, N; Austin, R; Zaidel, L; Bartlett, D; Proctor, G

    2014-01-01

    Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p erosion patients (p erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth. © 2014 S. Karger AG, Basel.

  7. Oral aspects in celiac disease children: clinical and dental enamel chemical evaluation.

    Science.gov (United States)

    de Carvalho, Fabrício Kitazono; de Queiroz, Alexandra Mussolino; Bezerra da Silva, Raquel Assed; Sawamura, Regina; Bachmann, Luciano; Bezerra da Silva, Léa Assed; Nelson-Filho, Paulo

    2015-06-01

    The aim of this study was to evaluate the oral manifestations of celiac disease (CD), the chemical composition of dental enamel, and the occurrence of CD in children with dental enamel defects (DEDs). In the study, 52 children with CD and 52 controls were examined for DEDs, recurrent aphthous stomatitis (RAS), dental caries experience, and salivary parameters. In addition, 10 exfoliated primary enamel molars from each group were analyzed by energy dispersive x-ray spectroscopy and Fourier transform infrared spectroscopy. Fifty children with DEDs were submitted to CD diagnosis. Among the children with CD, a higher prevalence of DEDs (P = .00001) and RAS (P = .0052), lower caries experience (P = .0024), and reduction of salivary flow (P = .0060) were observed. Dental enamel from the children with CD demonstrated a lower calcium-to-phosphorus ratio (P = .0136), but no difference in the carbonate-to-phosphate ratio (P = .5862) was observed. In the multivariate analysis, CD was a protective factor for caries (OR = 0.74) and a risk factor for RAS (OR3.23). The children with CD presented with more RAS, DEDs, reduction of salivary flow, and chemical alterations in the enamel. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. The fracture behaviour of dental enamel.

    Science.gov (United States)

    Bechtle, Sabine; Habelitz, Stefan; Klocke, Arndt; Fett, Theo; Schneider, Gerold A

    2010-01-01

    Enamel is the hardest tissue in the human body covering the crowns of teeth. Whereas the underlying dental material dentin is very well characterized in terms of mechanical and fracture properties, available data for enamel are quite limited and are apart from the most recent investigation mainly based on indentation studies. Within the current study, stable crack-growth experiments in bovine enamel have been performed, to measure fracture resistance curves for enamel. Single edge notched bending specimens (SENB) prepared out of bovine incisors were tested in 3-point bending and subsequently analysed using optical and environmental scanning electron microscopy. Cracks propagated primarily within the protein-rich rod sheaths and crack propagation occurred under an inclined angle to initial notch direction not only due to enamel rod and hydroxyapatite crystallite orientation but potentially also due to protein shearing. Determined mode I fracture resistance curves ranged from 0.8-1.5 MPa*m(1/2) at the beginning of crack propagation up to 4.4 MPa*m(1/2) at 500 microm crack extension; corresponding mode II values ranged from 0.3 to 1.5 MPa*m(1/2).

  9. An in vitro study of dental enamel wear by restorative materials using radiometric method

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa

    2000-01-01

    There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

  10. Enamel tissue engineering using subcultured enamel organ epithelial cells in combination with dental pulp cells.

    Science.gov (United States)

    Honda, Masaki J; Shinmura, Yuka; Shinohara, Yoshinori

    2009-01-01

    We describe a strategy for the in vitro engineering of enamel tissue using a novel technique for culturing enamel organ epithelial (EOE) cells isolated from the enamel organ using 3T3-J2 cells as a feeder layer. These subcultured EOE cells retain the capacity to produce enamel structures over a period of extended culture. In brief, enamel organs from 6-month-old porcine third molars were dissociated into single cells and subcultured on 3T3-J2 feeder cell layers. These subcultured EOE cells were then seeded onto a collagen sponge in combination with primary dental pulp cells isolated at an early stage of crown formation, and these constructs were transplanted into athymic rats. After 4 weeks, complex enamel-dentin structures were detected in the implants. These results show that our culture technique maintained ameloblast lineage cells that were able to produce enamel in vivo. This novel subculture technique provides an important tool for tooth tissue engineering. Copyright 2008 S. Karger AG, Basel.

  11. Dental enamel cells express functional SOCE channels.

    Science.gov (United States)

    Nurbaeva, Meerim K; Eckstein, Miriam; Concepcion, Axel R; Smith, Charles E; Srikanth, Sonal; Paine, Michael L; Gwack, Yousang; Hubbard, Michael J; Feske, Stefan; Lacruz, Rodrigo S

    2015-10-30

    Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.

  12. Towards enamel biomimetics: Structure, mechanical properties and biomineralization of dental enamel

    Science.gov (United States)

    Fong, Hanson Kwok

    Dental enamel is the most mineralized tissue in the human body. This bioceramic, composed largely of hydroxyapatite (HAp), is also one of the most durable tissues despite a lifetime of masticatory loading and bacterial attack. The biosynthesis of enamel, which occurs in physiological conditions is a complex orchestration of protein assembly and mineral formation. The resulting product is the hardest tissue in the vertebrate body with the longest and most organized arrangement of hydroxyapatite crystals known to biomineralizing systems. Detail understanding of the structure of enamel in relationship to its mechanical function and the biomineralization process will provide a framework for enamel regeneration as well as potential lessons in the design of engineering materials. The objective of this study, therefore, is twofold: (1) establish the structure-function relationship of enamel as well as the dentine-enamel junction (DEJ) and (2) determine the effect of proteins on the enamel biomineralization process. A hierarchy in the enamel structure was established by means of various microscopy techniques (e.g. SEM, TEM, AFM). Mechanical properties (hardness and elastic modulus) associated with the microstructural features were also determined by nanoindentation. Furthermore, the DEJ was found to have a width in the range of micrometers to 10s of micrometers with continuous change in structure and mechanical properties. Indentation tests and contact fatigue tests using a spherical indenter have revealed that the structural features in the enamel and the DEJ played important roles in containing crack propagation emanating from the enamel tissue. To further understand the effect of this protein on the biominerailzation process, we have studied genetically engineered animals that express altered amelogenin which lack the known self-assembly properties. This in vivo study has revealed that, without the proper self-assembly of the amelogenin protein as demonstrated by the

  13. An in vitro investigation of human enamel wear by restorative dental materials

    International Nuclear Information System (INIS)

    Adachi, L.K.; Saiki, M.; De Campos, T.N.

    2001-01-01

    A radiometric method was applied to asses enamel wear by another enamel and by restorative materials. The radioactive enamel was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with the radioactive enamel. The enamel wear was evaluated by measuring the beta-activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another natural enamel or by resin materials. Resin materials caused less enamel wear than another natural enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. (author)

  14. Dental enamel defect diagnosis through different technology-based devices.

    Science.gov (United States)

    Kobayashi, Tatiana Yuriko; Vitor, Luciana Lourenço Ribeiro; Carrara, Cleide Felício Carvalho; Silva, Thiago Cruvinel; Rios, Daniela; Machado, Maria Aparecida Andrade Moreira; Oliveira, Thais Marchini

    2018-06-01

    Dental enamel defects (DEDs) are faulty or deficient enamel formations of primary and permanent teeth. Changes during tooth development result in hypoplasia (a quantitative defect) and/or hypomineralisation (a qualitative defect). To compare technology-based diagnostic methods for detecting DEDs. Two-hundred and nine dental surfaces of anterior permanent teeth were selected in patients, 6-11 years of age, with cleft lip with/without cleft palate. First, a conventional clinical examination was conducted according to the modified Developmental Defects of Enamel Index (DDE Index). Dental surfaces were evaluated using an operating microscope and a fluorescence-based device. Interexaminer reproducibility was determined using the kappa test. To compare groups, McNemar's test was used. Cramer's V test was used for comparing the distribution of index codes obtained after classification of all dental surfaces. Cramer's V test revealed statistically significant differences (P < .0001) in the distribution of index codes obtained using the different methods; the coefficients were 0.365 for conventional clinical examination versus fluorescence, 0.961 for conventional clinical examination versus operating microscope and 0.358 for operating microscope versus fluorescence. The sensitivity of the operating microscope and fluorescence method was statistically significant (P = .008 and P < .0001, respectively). Otherwise, the results did not show statistically significant differences in accuracy and specificity for either the operating microscope or the fluorescence methods. This study suggests that the operating microscope performed better than the fluorescence-based device and could be an auxiliary method for the detection of DEDs. © 2017 FDI World Dental Federation.

  15. Optically stimulated luminescence (OSL) of dental enamel for retrospective assessment of radiation exposure

    International Nuclear Information System (INIS)

    Yukihara, E.G.; Mittani, J.; McKeever, S.W.S.; Simon, S.L.

    2007-01-01

    This paper briefly reviews the optically stimulated luminescence (OSL) properties of dental enamel and discusses the potential and challenges of OSL for filling the technology gap in biodosimetry required for medical triage following a radiological/nuclear accident or terrorist event. The OSL technique uses light to stimulate a radiation-induced luminescence signal from materials previously exposed to ionizing radiation. This luminescence originates from radiation-induced defects in insulating crystals and is proportional to the absorbed dose of ionizing radiation. In our research conducted to date, we focused on fundamental investigations of the OSL properties of dental enamel using extracted teeth and tabletop OSL readers. The objective was to obtain information to support the development of the necessary instrumentation for retrospective dosimetry using dental enamel in laboratory, or for in situ and non-invasive accident dosimetry using dental enamel in emergency triage. An OSL signal from human dental enamel was detected using blue, green, or IR stimulation. Blue/green stimulation associated with UV emission detection seems to be the most appropriate combination in the sense that there is no signal from un-irradiated samples and the shape of the OSL decay is clear. Improvements in the minimum detection level were achieved by incorporating an ellipsoidal mirror in the OSL system to maximize light collection. Other possibilities to improve the sensitivity and research steps necessary to establish the feasibility of the technique for retrospective assessment of radiation exposure are also discussed

  16. Evaluation of radiation effects on dental enamel hardness and dental restorative materials; Avaliacao do efeito da irradiacao na dureza do esmalte dental e de materiais odontologicos

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Lena Katekawa; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica; Campos, Tomie Nakakuki [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Protese

    2000-07-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10{sup 12}n cm{sup -2}.s{sup -1} . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  17. Acids with an equivalent taste lead to different erosion of human dental enamel.

    Science.gov (United States)

    Beyer, Markus; Reichert, Jörg; Bossert, Jörg; Sigusch, Bernd W; Watts, David C; Jandt, Klaus D

    2011-10-01

    The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste. Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic solutions were characterized by pH value and titratable acidity. Atomic force microscopy (AFM) based nanoindentation was used to study the nano mechanical properties and scanning electron microscopy (SEM) was used to study the morphology of the treated enamel samples and the untreated control areas, respectively. The investigated acids fell into two groups. The nano hardnesses of MA, TA and CA treated enamel samples (group I) were statistically significantly greater (penamel samples (group II). Within each group the nano hardness was not statistically significantly different (p>0.05). The SEM micrographs showed different etch prism morphologies depending on the acid used. In vitro, the acids investigated led to different erosion effects on human dental enamel, despite their equivalent sensorial acidic taste. This has not been reported previously. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Wear properties of dental ceramics and porcelains compared with human enamel.

    Science.gov (United States)

    D'Arcangelo, Camillo; Vanini, Lorenzo; Rondoni, Giuseppe D; De Angelis, Francesco

    2016-03-01

    Contemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with human enamel and traditional gold based alloys needs to be better investigated. The purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 different dental ceramics, including a recently introduced zirconia-reinforced lithium silicate ceramic (Celtra Duo). Cylindrical specimens were fabricated from a Type III gold alloy (Aurocast8), 2 hot pressed ceramics (Imagine PressX, IPS e.max Press), 2 CAD/CAM ceramics (IPS e.max CAD, Celtra Duo), and a CAD/CAM feldspathic porcelain (Vitablocs Mark II) (n=10). Celtra Duo was tested both soon after grinding and after a subsequent glaze firing cycle. Ten flat human enamel specimens were used as the control group. All specimens were subjected to a 2-body wear test in a dual axis mastication simulator for 120000 loading cycles against yttria stabilized tetragonal zirconia polycrystal cusps. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed with 1-way ANOVA tests (α=.05). The wear depth (0.223 mm) of gold alloy was the closest to that of human enamel (0.217 mm), with no significant difference (P>.05). The greatest wear was recorded on the milled Celtra Duo (wear depth=0.320 mm), which appeared significantly less wear resistant than gold alloy or human enamel (Pceramics did not statistically differ in comparison with the human enamel. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  19. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE.

    Science.gov (United States)

    Lacruz, Rodrigo S; Habelitz, Stefan; Wright, J Timothy; Paine, Michael L

    2017-07-01

    Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function. Copyright © 2017 the American Physiological Society.

  20. In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel

    International Nuclear Information System (INIS)

    Ebel, Patricia

    2003-01-01

    In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm 2 , 282,84 mJ/cm 2 and 325,38 mJ/cm 2 , respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 μm diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

  1. Size dependent elastic modulus and mechanical resilience of dental enamel.

    Science.gov (United States)

    O'Brien, Simona; Shaw, Jeremy; Zhao, Xiaoli; Abbott, Paul V; Munroe, Paul; Xu, Jiang; Habibi, Daryoush; Xie, Zonghan

    2014-03-21

    Human tooth enamel exhibits a unique microstructure able to sustain repeated mechanical loading during dental function. Although notable advances have been made towards understanding the mechanical characteristics of enamel, challenges remain in the testing and interpretation of its mechanical properties. For example, enamel was often tested under dry conditions, significantly different from its native environment. In addition, constant load, rather than indentation depth, has been used when mapping the mechanical properties of enamel. In this work, tooth specimens are prepared under hydrated conditions and their stiffnesses are measured by depth control across the thickness of enamel. Crystal arrangement is postulated, among other factors, to be responsible for the size dependent indentation modulus of enamel. Supported by a simple structure model, effective crystal orientation angle is calculated and found to facilitate shear sliding in enamel under mechanical contact. In doing so, the stress build-up is eased and structural integrity is maintained. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Association between developmental defects of enamel and dental caries: A systematic review and meta-analysis.

    Science.gov (United States)

    Vargas-Ferreira, F; Salas, M M S; Nascimento, G G; Tarquinio, S B C; Faggion, C M; Peres, M A; Thomson, W M; Demarco, F F

    2015-06-01

    Dental caries is the main problem oral health and it is not well established in the literature if the enamel defects are a risk factor for its development. Studies have reported a potential association between developmental defects enamel (DDE) and dental caries occurrence. We investigated the association between DDE and caries in permanent dentition of children and teenagers. A systematic review was carried out using four databases (Pubmed, Web of Science, Embase, and Science Direct), which were searched from their earliest records until December 31, 2014. Population-based studies assessing differences in dental caries experience according to the presence of enamel defects (and their types) were included. PRISMA guidelines for reporting systematic reviews were followed. Meta-analysis was performed to assess the pooled effect, and meta-regression was carried out to identify heterogeneity sources. From the 2558 initially identified papers, nine studies fulfilled all inclusion criteria after checking the titles, abstracts, references, and complete reading. Seven of them were included in the meta-analysis with random model. A positive association between enamel defects and dental caries was identified; meta-analysis showed that individuals with DDE had higher pooled odds of having dental caries experience [OR 2.21 (95% CI 1.3; 3.54)]. Meta-regression analysis demonstrated that adjustment for sociodemographic factors, countries' socioeconomic status, and bias (quality of studies) explained the high heterogeneity observed. A higher chance of dental caries should be expected among individuals with enamel defects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effects of blue light irradiation on dental enamel remineralization in vitro

    International Nuclear Information System (INIS)

    Kato, Ilka Tiemy

    2009-01-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm 2 e 6.25 mL/mm 2 ). The lesions were irradiated with blue LED (l=455±20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm 2 , radiant exposure of 13.8 J/ c m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  4. Functions of KLK4 and MMP-20 in dental enamel formation

    Science.gov (United States)

    Lu, Yuhe; Papagerakis, Petros; Yamakoshi, Yasuo; Hu, Jan C-C.; Bartlett, John D.; Simmer, James P.

    2009-01-01

    Two proteases are secreted into the enamel matrix of developing teeth. The early protease is enamelysin (MMP-20). The late protease is kallikrein 4 (KLK4). Mutations in MMP20 and KLK4 both cause autosomal recessive amelogenesis imperfecta, a condition featuring soft, porous enamel containing residual protein. MMP-20 is secreted along with enamel proteins by secretory stage ameloblasts. Enamel protein cleavage products accumulate in the space between the crystal ribbons, helping to support them. MMP-20 steadily cleaves accumulated enamel proteins, so their concentration decreases with depth. Kallikrein 4 is secreted by transition and maturation stage ameloblasts. KLK4 aggressively degrades the retained organic matrix following the termination of enamel protein secretion. The principle functions of MMP-20 and KLK4 in dental enamel formation are to facilitate the orderly replacement of organic matrix with mineral, generating an enamel layer that is harder, less porous, and unstained by retained enamel proteins. PMID:18627287

  5. Titanium dioxide in dental enamel as a trace element and its variation with bleaching.

    Science.gov (United States)

    Vargas-Koudriavtsev, Tatiana; Durán-Sedó, Randall; Herrera-Sancho, Óscar-Andrey

    2018-06-01

    Titanium is a less studied trace element in dental enamel. Literature relates an increased Titanium concentration with a decreased enamel crystal domain size, which in turn is related to a higher color value. The aim of our study was to analyze the effect of tooth bleaching agents on its concentration in dental enamel by means of confocal Raman spectroscopy. Human teeth were randomly distributed in six experimental groups (n=10) and submitted to different bleaching protocols according to the manufacturer´s instructions. Confocal Raman spectroscopy was carried out in order to identify and quantify the presence of titanium dioxide molecules in enamel prior to and during whitening. Statistical analysis included repeated measures analysis of variance ( p ≤0.05) and Bonferroni pairwise comparisons. Titanium dioxide concentration was negatively affected by the longer bleaching protocols (at-home bleaching gels). All in-office whitening products increased significantly the studied molecule ( p ≤0,05). All dental specimens depicted the presence of titanium dioxide as a trace element in dental enamel. Bleaching gels that have to be applied at higher concentrations but for shorter periods of time increase the concentration of titanium dioxide, whilst at-home whitening gels used for longer periods of time despite the lower concentration caused a loss in titanium. Key words: Bleaching, whitening, hydrogen peroxide, carbamide peroxide, Raman spectroscopy, titanium dioxide.

  6. Dental enamel, fluorosis and amoxicillin

    Directory of Open Access Journals (Sweden)

    I. Ciarrocchi

    2012-06-01

    Full Text Available Introduction: Amoxicillin is one of the most used antibiotics among pediatric patients for the treatment of upper respiratory tract infections and specially for acute otitis media (AOM, a common diseases of infants and childhood. It has been speculated that the use of amoxicillin during early childhood could be associated with dental enamel fluorosis, also described in literature with the term Molar Incisor Hypomineralization (MIH, because they are generally situated in one or more 1st permanent molars and less frequently in the incisors. The effect of Amoxicillin seems to be independent of other risk factors such as fluoride intake, prematurity, hypoxia, hypocalcaemia, exposure to dioxins, chikenpox, otitis media, high fever and could have a significant impact on oral health for the wide use of this drug in that period of life. Objective: The aim of this work was to review the current literature about the association between amoxicillin and fluorosis. Methods and Results: A literature survey was done by applying the Medline database (Entrez PubMed; the Cochrane Library database of the Cochrane Collaboration (CENTRAL. The databases were searched using the following strategy and keywords: amoxicillin* AND (dental fluorosis* OR dental enamel* AND MIH*. After selecting the studies, only three relevant articles published between 1966 and 2011 were included in the review. Conclusion: The presence of several methodological issues does not allow to draw any evidence-based conclusions. No evidence of association was detected, therefore, there is a need of further well-designed studies to assess the scientific evidence of the relationship between amoxicillin and fluorosis and to restrict the prescription of this drug for recurrent upper respiratory tract infections especially acute otitis media (AOM during the first two years of life. When it is possible can be opportune to use an alternative antibiotic treatment.

  7. Micro energy-dispersive X-ray fluoresence mapping of enamel and dental materials after chemical erosion.

    Science.gov (United States)

    Soares, Luís Eduardo Silva; de Oliveira, Rodrigo; Nahórny, Sídnei; Santo, Ana Maria do Espírito; Martin, Airton Abrahão

    2012-10-01

    Energy-dispersive X-ray fluorescence was employed to test the hypothesis that beverage consumption or mouthwash utilization will change the chemical properties of dental materials and enamel mineral content. Bovine enamel samples (n = 45) each received two cavity preparations (n = 90), each pair filled with one of three dental materials (R: nanofilled composite resin; GIC: glass-ionomer cement; RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: saliva; E: erosion/Pepsi Twist®; or EM: erosion+mouthwash/Colgate Plax®). It was found that mineral loss in enamel was greater in GICE samples than in RE > RMGICE > RMGICEM > REM > GICEM. An increased percentage of Zr was found in REM indicating organic matrix degradation. Dental materials tested (R, GIC, and RMGIC) were not able to protect adjacent enamel from acid erosion by the soft drink tested. The use of mouthwash promoted protection of enamel after erosion by the soft drink. To avoid chemical dissolution by mouthwashes, protection by resin composites with surface sealants is recommended.

  8. Enamel micromorphology of the tribosphenic molar

    OpenAIRE

    Hanousková, Pavla

    2014-01-01

    The tribosphenic molar is an ancestral type of mammalian teeth and a phy- lotypic stage of the mammalian dental evolution. Yet, in contrast to derived teeth types, its enamel microarchitecture attracted only little attention and the information on that subject is often restricted to statements suggesting a simple homogenous arrangement of a primitive radial prismatic enamel. The present paper tests this prediction with aid of comparative study of eight model species representing the orders Ch...

  9. Isotopic study of the comparative uptake and release of ions by deciduous and permanent dental enamel

    International Nuclear Information System (INIS)

    Tetteh, G.K.

    1975-01-01

    A comparative study of the uptake and release of calcium, orthophosphate, strontium and sodium from decidus and permanent dental enamel has been made using radioactive techniques. The rates of uptake and release of orthophosphate, strontium and sodium were observed to be greater in deciduous than in permanent enamel. However, for calcium, the rate of uptake was observed to be greater in the deciduous than in the permanent enamel but the rate of release was observed to be smaller in the deciduous enamel. These results in conjunction with the findings of Tetteh (1974) suggest that most of the calcification in the early stages of development of dental enamel is by a hetero-ionic exchange. (author) [fr

  10. Isotopic study of the comparative uptake and release of ions by deciduous and permanent dental enamel

    Energy Technology Data Exchange (ETDEWEB)

    Tetteh, G K [Department of Physics, University of Ghana,Legon

    1975-04-01

    A comparative study of the uptake and release of calcium, orthophosphate, strontium and sodium from decidus and permanent dental enamel has been made using radioactive techniques. The rates of uptake and release of orthophosphate, strontium and sodium were observed to be greater in deciduous than in permanent enamel. However, for calcium, the rate of uptake was observed to be greater in the deciduous than in the permanent enamel but the rate of release was observed to be smaller in the deciduous enamel. These results in conjunction with the findings of Tetteh (1974) suggest that most of the calcification in the early stages of development of dental enamel is by a hetero-ionic exchange.

  11. Femtosecond laser etching of dental enamel for bracket bonding.

    Science.gov (United States)

    Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk

    2013-09-01

    The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.

  12. Sea otter dental enamel is highly resistant to chipping due to its microstructure.

    Science.gov (United States)

    Ziscovici, Charles; Lucas, Peter W; Constantino, Paul J; Bromage, Timothy G; van Casteren, Adam

    2014-10-01

    Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased fracture resistance correlates with more intense enamel prism decussation, often seen also in some fossil hominins. It is possible therefore that enamel chips in such hominins may have formed at even greater forces than currently envisaged. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  13. Measurement of fluorine total concentration in dental enamel using fast neutron activation

    International Nuclear Information System (INIS)

    Mouadili, A.; Vernais, J.; Isabelle, D.B.

    1988-01-01

    Fluorine which is present in dental enamel, at the level of a few tens to a few hundred ppm, plays an important role in the behaviour of this tissue. Therefore quantitative determination is of interest for particular studies of the dental system. We present a nuclear nondestructive method to determine the total fluorine content in dental enamel by cyclotron-produced fast-neutron activation. The 19 F(n,2n) reaction leads to 18 F which is a β + emitter with a 109.8 min half-life. The irradiated sample activity is measured by detecting in coincidence the annihilation photons. A fluorine standard is used for calibration. The detection limit is of the order of 1 ppm, while the reproducibility is better than 95% [pt

  14. Near-UV laser treatment of extrinsic dental enamel stains.

    Science.gov (United States)

    Schoenly, J E; Seka, W; Featherstone, J D B; Rechmann, P

    2012-04-01

    The selective ablation of extrinsic dental enamel stains using a 400-nm laser is evaluated at several fluences for completely removing stains with minimal damage to the underlying enamel. A frequency-doubled Ti:sapphire laser (400-nm wavelength, 60-nanosecond pulse duration, 10-Hz repetition rate) was used to treat 10 extracted human teeth with extrinsic enamel staining. Each tooth was irradiated perpendicular to the surface in a back-and-forth motion over a 1-mm length using an ∼300-µm-diam 10th-order super-Gaussian beam with fluences ranging from 0.8 to 6.4 J/cm(2) . Laser triangulation determined stain depth and volume removed by measuring 3D surface images before and after irradiation. Scanning electron microscopy evaluated the surface roughness of enamel following stain removal. Fluorescence spectroscopy measured spectra of unbleached and photobleached stains in the spectral range of 600-800 nm. Extrinsic enamel stains are removed with laser fluences between 0.8 and 6.4 J/cm(2) . Stains removed on sound enamel leave behind a smooth enamel surface. Stain removal in areas with signs of earlier cariogenic acid attacks resulted in isolated and randomly located laser-induced, 50-µm-diam enamel pits. These pits contain 0.5-µm diam, smooth craters indicative of heat transfer from the stain to the enamel and subsequent melting and water droplet ejection. Ablation stalling of enamel stains is typically observed at low fluences (Laser ablation of extrinsic enamel stains at 400 nm is observed to be most efficient above 3 J/cm(2) with minimal damage to the underlying enamel. Unsound underlying enamel is also observed to be selectively removed after irradiation. Copyright © 2012 Wiley Periodicals, Inc.

  15. Alaska Dental Health Aide Program.

    Science.gov (United States)

    Shoffstall-Cone, Sarah; Williard, Mary

    2013-01-01

    In 1999, An Oral Health Survey of American Indian and Alaska Native (AI/AN) Dental Patients found that 79% of 2- to 5-year-olds had a history of tooth decay. The Alaska Native Tribal Health Consortium in collaboration with Alaska's Tribal Health Organizations (THO) developed a new and diverse dental workforce model to address AI/AN oral health disparities. This paper describes the workforce model and some experience to date of the Dental Health Aide (DHA) Initiative that was introduced under the federally sanctioned Community Health Aide Program in Alaska. These new dental team members work with THO dentists and hygienists to provide education, prevention and basic restorative services in a culturally appropriate manner. The DHA Initiative introduced 4 new dental provider types to Alaska: the Primary Dental Health Aide, the Expanded Function Dental Health Aide, the Dental Health Aide Hygienist and the Dental Health Aide Therapist. The scope of practice between the 4 different DHA providers varies vastly along with the required training and education requirements. DHAs are certified, not licensed, providers. Recertification occurs every 2 years and requires the completion of 24 hours of continuing education and continual competency evaluation. Dental Health Aides provide evidence-based prevention programs and dental care that improve access to oral health care and help address well-documented oral health disparities.

  16. Alaska Dental Health Aide Program

    Directory of Open Access Journals (Sweden)

    Sarah Shoffstall-Cone

    2013-08-01

    Full Text Available Background. In 1999, An Oral Health Survey of American Indian and Alaska Native (AI/AN Dental Patients found that 79% of 2- to 5-year-olds had a history of tooth decay. The Alaska Native Tribal Health Consortium in collaboration with Alaska’s Tribal Health Organizations (THO developed a new and diverse dental workforce model to address AI/AN oral health disparities. Objectives. This paper describes the workforce model and some experience to date of the Dental Health Aide (DHA Initiative that was introduced under the federally sanctioned Community Health Aide Program in Alaska. These new dental team members work with THO dentists and hygienists to provide education, prevention and basic restorative services in a culturally appropriate manner. Results. The DHA Initiative introduced 4 new dental provider types to Alaska: the Primary Dental Health Aide, the Expanded Function Dental Health Aide, the Dental Health Aide Hygienist and the Dental Health Aide Therapist. The scope of practice between the 4 different DHA providers varies vastly along with the required training and education requirements. DHAs are certified, not licensed, providers. Recertification occurs every 2 years and requires the completion of 24 hours of continuing education and continual competency evaluation. Conclusions. Dental Health Aides provide evidence-based prevention programs and dental care that improve access to oral health care and help address well-documented oral health disparities.

  17. Influence of tooth bleaching on dental enamel microhardness: a systematic review and meta-analysis.

    Science.gov (United States)

    Zanolla, J; Marques, Abc; da Costa, D C; de Souza, A S; Coutinho, M

    2017-09-01

    Several studies have investigated the effect of bleaching on dental tissues. The evaluation of the effect of home bleaching with 10% carbamide peroxide is important for assessing alterations in enamel microhardness that may affect dental health in terms of resistance to masticatory forces. This meta-analysis was performed in order to determine scientific evidence regarding the effects of home vital bleaching with 10% carbamide peroxide gel on the microhardness of human dental enamel. A systematic electronic literature search was conducted in the PubMed and Web of Science databases using search terms. Two independent researchers evaluated the information and methodological quality of the studies. Inclusion and exclusion criteria were established for article selection; further, only studies published in English were selected. Thirteen studies that met all of the inclusion and exclusion criteria were selected and underwent statistical analysis. The results of this meta-analysis showed no significant changes in enamel microhardness when using the 10% carbamide peroxide bleaching gel over periods of 7, 14 and 21 days. © 2016 Australian Dental Association.

  18. Fluoride reactions with dental enamel following different forms of fluoride supply

    International Nuclear Information System (INIS)

    Hellstroem, I.; Ericsson, Y.

    1976-01-01

    The reactions with dental enamel of NaF as tablets dissolved in different beverages or supplied with NaCl, simulating domestic salt fluoridation, were studied in tests with enamel surfaces and enamel powder. It was confirmed that powdered enamel can react quite differently from enamel surfaces under certain conditions. Enamel surfaces took up much more fluoride (F) from orange juice than from water or milk, and neither the low pH nor the citrate content of the juice increased the formation of unstable CaF 2 in the enamel, as judged from a KOH leaching test. The F uptake by enamel surfaces from 0.25 mM NaF in 175 mM NaCl, corresponding to a dish prepared with salt containing 500 parts/10 6 F, was about 80 percent greater than from the same NaF concentration in water. This NaCl concentration did not increase the formation of CaF 2 in the enamel, as judged from the KOH test, while 350 mM NaCl caused a moderate increase. The investigations support the administration of NaF tablets with orange juice and the plans for domestic salt fluoridation. (author)

  19. A comparative study on component volumes from outer to inner dental enamel in relation to enamel tufts.

    Science.gov (United States)

    Setally Azevedo Macena, Marcus; de Alencar e Silva Leite, Maria Luísa; de Lima Gouveia, Cíntia; de Lima, Tamires Alcoforado Sena; Athayde, Priscilla Alves Aguiar; de Sousa, Frederico Barbosa

    2014-06-01

    Dental enamel presents marked mechanical properties gradients from outer to inner enamel, a region lacking component volumes profiles. Tufts, structures of inner enamel, have been shown to play a role in enamel resilience. We aimed at comparing component volumes from inner to outer enamel in relation to enamel tufts. Transversal ground sections from the cervical half of unerupted human third molars (n=10) were prepared and histological points were selected along transversal lines (extending from innermost to outer enamel) traced across tufts and adjacent control areas without tufts. Component volumes were measured at each histological point. Component volumes ranges were: 70.6-98.5% (mineral), 0.02-20.78% (organic), 3.8-9.8% (total water), 3-9% (firmly bound water), and 0.02-3.3% (loosely bound water). Inner enamel presented the lowest mineral volumes and the highest non-mineral volumes. Mineral, water and organic contents differed as a function of the distance from innermost enamel but not between the tuft and control lines. Tufts presented opaqueness in polarizing microscopy (feature of fracture lines). Organic volume gradient correlated with a relatively flat profile of loosely bound water. Inner, but not outer enamel, rehydrated after air-dried enamel was heated to 50°C and re-exposed to room conditions, as predicted by the organic/water gradient profiles. Component volumes vary markedly from outer to inner enamel, but not between areas with or without tufts (that behave like fracture lines under polarizing microscopy). Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. A New Sugarcane Cystatin Strongly Binds to Dental Enamel and Reduces Erosion.

    Science.gov (United States)

    Santiago, A C; Khan, Z N; Miguel, M C; Gironda, C C; Soares-Costa, A; Pelá, V T; Leite, A L; Edwardson, J M; Buzalaf, M A R; Henrique-Silva, F

    2017-08-01

    Cystatin B was recently identified as an acid-resistant protein in acquired enamel pellicle; it could therefore be included in oral products to protect against caries and erosion. However, human recombinant cystatin is very expensive, and alternatives to its use are necessary. Phytocystatins are reversible inhibitors of cysteine peptidases that are found naturally in plants. In plants, they have several biological and physiological functions, such as the regulation of endogenous processes, defense against pathogens, and response to abiotic stress. Previous studies performed by our research group have reported high inhibitory activity and potential agricultural and medical applications of several sugarcane cystatins, including CaneCPI-1, CaneCPI-2, CaneCPI-3, and CaneCPI-4. In the present study, we report the characterization of a novel sugarcane cystatin, named CaneCPI-5. This cystatin was efficiently expressed in Escherichia coli, and inhibitory assays demonstrated that it was a potent inhibitor of human cathepsins B, K, and L ( K i = 6.87, 0.49, and 0.34 nM, respectively). The ability of CaneCPI-5 to bind to dental enamel was evaluated using atomic force microscopy. Its capacity to protect against initial enamel erosion was also tested in vitro via changes in surface hardness. CaneCPI-5 showed a very large force of interaction with enamel (e.g., compared with mucin and casein) and significantly reduced initial enamel erosion. These results suggest that the inclusion of CaneCPIs in dental products might confer protection against enamel erosion.

  1. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Science.gov (United States)

    Lacruz, Rodrigo S; Nakayama, Yohei; Holcroft, James; Nguyen, Van; Somogyi-Ganss, Eszter; Snead, Malcolm L; White, Shane N; Paine, Michael L; Ganss, Bernhard

    2012-01-01

    We have previously identified amelotin (AMTN) as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel) gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL) and ameloblastin (AMBN) was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM) was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  2. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Directory of Open Access Journals (Sweden)

    Rodrigo S Lacruz

    Full Text Available We have previously identified amelotin (AMTN as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL and ameloblastin (AMBN was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  3. Effect of moisture on dental enamel in the interaction of two orthodontic bonding systems.

    Science.gov (United States)

    Bertoz, André Pinheiro de Magalhães; de Oliveira, Derly Tescaro Narcizo; Gimenez, Carla Maria Melleiro; Briso, André Luiz Fraga; Bertoz, Francisco Antonio; Santos, Eduardo César Almada

    2013-01-01

    The purpose of this study was to assess by means of scanning electron microscopy (SEM) the remaining adhesive interface after debonding orthodontic attachments bonded to bovine teeth with the use of hydrophilic and hydrophobic primers under different dental substrate moisture conditions. Twenty mandibular incisors were divided into four groups (n = 5). In Group I, bracket bonding was performed with Transbond MIP hydrophilic primer and Transbond XT adhesive paste applied to moist substrate, and in Group II a bonding system comprising Transbond XT hydrophobic primer and adhesive paste was applied to moist substrate. Brackets were bonded to the specimens in Groups III and IV using the same adhesive systems, but on dry dental enamel. The images were qualitatively assessed by SEM. The absence of moisture in etched enamel enabled better interaction between bonding materials and the adamantine structure. The hydrophobic primer achieved the worst micromechanical interlocking results when applied to a moist dental structure, whereas the hydrophilic system proved versatile, yielding acceptable results in moist conditions and excellent interaction in the absence of contamination. The authors assert that the best condition for the application of primers to dental enamel occurs in the absence of moisture.

  4. An in vitro study of dental enamel wear by restorative materials using radiometric method; Estudo in vitro do desgaste do esmalte dental pelos materiais restauradores utilizando metodo radiometrico

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Lena Katekawa

    2000-07-01

    There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of {sup 32}P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

  5. [The effects of topical fluoridation of enamel on the growth of cariogenic bacteria contained in the dental plaque].

    Science.gov (United States)

    Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

    2013-01-01

    Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Fluoride can inhibit metabolism and bacterial growth in the dental plaque. The aim of the study was to evaluate the effect of topical fluoridation of the enamel on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom three-day dental plaque from the enamel was examined. Next, fluoride was rubbed on the same surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.475) in the amounts of Lactobacillus spp. in the plaque collected prior to and after the topical fluoridation were revealed. Fluoride rubbed in the enamel, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

  6. Utilization of radiometric method in evaluation of wear on human dental enamel in vitro by dental porcelain glazed and polished; Utilizacao do metodo radiometrico na avaliacao in vitro do desgaste provocado ao esmalte dental humano por porcelanas dentais glazeadas e polidas

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Lena Katekawa; Campos, Tomie Nakakuki de; Adachi, Eduardo Makoto [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Protese]. E-mail: katekawa@usp.br; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: mitiko@curiango.ipen.br

    2005-07-01

    The dental porcelain is a material commonly used in prosthesis. Disadvantages of dental porcelain use include possibility to cause tooth or dental materials wear. Before its use in the mouth, surfaces are treated with polishing and/or glazing. This research used the radiometric method to verify the influence of these surface treatments on the porcelains of commercial brands: Ceramco II, Noritake and Finesse. This method was originally developed for dentifrice abrasiveness evaluation. Five specimens of dental enamel and 10 specimens of each porcelain (5 glazed, 5 polished) were used. The dental enamel was flattened and irradiated with neutrons from the IEA-R1 (IPEN/CNEN) nuclear reactor. Then it was weared by each porcelain in sliding motion, with water. After 2,500 cycles for each porcelain specimen, the released enamel residue was measured. The enamel wear was evaluated by measuring beta activity of {sup 32}P transferred to water from the irradiated tooth. Results varied from 2.57 to 5.81 {mu}g of enamel /mm{sup 2} weared surface. There was no statistical difference ({alpha}=0.05) between dental enamel wear caused by the same porcelains glazed or polished. The results suggest that adequate surface finishing depend on the type of dental porcelain. (author)

  7. Influence of bleaching agents on surface roughness of sound or eroded dental enamel specimens.

    Science.gov (United States)

    Azrak, Birgül; Callaway, Angelika; Kurth, Petra; Willershausen, Brita

    2010-12-01

    The aim of the present in vitro study was to assess the effect of bleaching agents on eroded and sound enamel specimens. Enamel specimens prepared from human permanent anterior teeth were incubated with different bleaching agents containing active ingredients as 7.5 or 13.5% hydrogen peroxide or 35% carbamide peroxide, ranging in pH from 4.9 to 10.8. The effect of the tooth whitening agents on surface roughness was tested for sound enamel surfaces as well as for eroded enamel specimens. To provoke erosive damage, the enamel specimens were incubated for 10 hours with apple juice (pH = 3.4). Afterwards, pretreated and untreated dental slices were incubated with one of the bleaching agents for 10 hours. The surface roughness (R(a)) of all enamel specimens (N = 80) was measured using an optical profilometric device. A descriptive statistical analysis of the R(a) values was performed. The study demonstrated that exposure to an acidic bleaching agent (pH = 4.9) resulted in a higher surface roughness (p = 0.043) than treatment with a high peroxide concentration (pH = 6.15). If the enamel surface was previously exposed to erosive beverages, subsequent bleaching may enhance damage to the dental hard tissue. Bleaching agents with a high concentration of peroxide or an acidic pH can influence the surface roughness of sound or eroded enamel. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  8. Laser investigation of the non-uniformity of fluorescent species in dental enamel

    Science.gov (United States)

    Tran, Stephanie U.; Ridge, Jeremy S.; Nelson, Leonard Y.; Seibel, Eric J.

    In the present study, artificial type I and type II erosions were created on dental specimen using acetic acid and EDTA respectively. Specimens were prepared by etching extracted teeth samples in acid to varying degrees, after which the absolute fluorescence intensity ratio of the etched enamel relative to sound enamel was recorded for each specimen using 405 and 532 nm laser excitation. Results showed differences in the fluorescence ratio of etched to sound enamel for type I and II erosions. These findings suggest a non-uniform distribution of fluorescent species in the interprismatic region as compared to the prismatic region.

  9. High Radiation Doses from Radiotherapy Measured by Electron Spin Resonance in Dental Enamel

    International Nuclear Information System (INIS)

    Pass, B.; Wood, R.E.; Liu, F.; McLean, M.; Aldrich, J.E.

    1998-01-01

    For radiotherapy, an error in the complicated treatment planning or treatment procedure is a possibility, however remote. Thus, in the present study electron spin resonance (ESR) in dental enamel was investigated for the first time as a means of retrospective dosimetry for validating applied radiotherapy doses to the head and neck regions. Total absorbed radiation doses measured by ESR in dental enamel were compared to the doses determined by treatment planning for 19 patients who received radiotherapy for intra-oral, pharyngeal or laryngeal malignancies, or total-body irradiation prior to bone marrow transplants (BMT). For the 15 tumour irradiations there was, within the framework of the tooth positions as presented, general agreement between the treatment planned and ESR dose determinations. There were, however, both significant and minor discrepancies. For the BMT patients there were major discrepancies for two of the four patients investigated. This study indicates that ESR in dental enamel may be useful as the only means of retrospective dosimetry for validating applied radiotherapy doses after treatment. However, further research must be carried out before this technique can be accepted as accurate and reliable. (author)

  10. Enamel formation and amelogenesis imperfecta.

    Science.gov (United States)

    Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

    2007-01-01

    Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel. Copyright 2007 S. Karger AG, Basel.

  11. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    Science.gov (United States)

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-09-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (pmeasurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

  12. Comparative study of dental enamel loss after debonding braces by analytical scanning electron microscopy (SEM).

    Science.gov (United States)

    Rodríguez-Chávez, Jacqueline Adelina; Arenas-Alatorre, Jesús; Belio-Reyes, Irma Araceli

    2017-07-01

    Clinical procedures when shear forces are applied to brackets suggest adhesion forces between 2.8 and 10.0 MPa as appropriate. In this study dental enamel was evaluated by scanning electron microscopy (SEM) before and after removing the brackets. Thirty bicuspids (previous prophylaxis) with metallic brackets (Roth Inovation 0.022 GAC), Transbond Plus SEP 3M Unitek adhesive and Transbond XT 3M resin were used. The samples were preserved to 37°C during 24 hr and submited to tangential forces with the Instron Universal machine 1.0 mm/min speed load strength resistance debonding. Also the Adhesive Remanent Index (ARI) test was made, evaluating the bracket base and the bicuspid surface. All the bracket SEM images were processed with AutoCAD to determine the enamel detached area. The average value was 6.86 MPa (SD ± 3.2 MPa). ARI value 1= 63.3%, value 2= 20%, value 3= 13.3% and 33% presented value 0. All those samples with dental enamel loss, presented different situations as fractures, ledges, horizontal, and vertical loss in some cases, and some scratch lines. There is no association between the debonding resistance and enamel presence. Less than half of the remanent adhesive on the dental enamel was present in most of the samples when the ARI test was applied. When the resin area increases, the debonding resistance also increases, and when the enamel loss increases, the resin free metallic area of the bracket base decreases in the debonding. © 2017 Wiley Periodicals, Inc.

  13. Dental enamel defects in adult coeliac disease: prevalence and correlation with symptoms and age at diagnosis.

    Science.gov (United States)

    Trotta, Lucia; Biagi, Federico; Bianchi, Paola I; Marchese, Alessandra; Vattiato, Claudia; Balduzzi, Davide; Collesano, Vittorio; Corazza, Gino R

    2013-12-01

    Coeliac disease is a condition characterized by a wide spectrum of clinical manifestations. Any organ can be affected and, among others, dental enamel defects have been described. Our aims were to study the prevalence of dental enamel defects in adults with coeliac disease and to investigate a correlation between the grade of teeth lesion and clinical parameters present at the time of diagnosis of coeliac disease. A dental examination was performed in 54 coeliac disease patients (41 F, mean age 37 ± 13 years, mean age at diagnosis 31 ± 14 years). Symptoms leading to diagnosis were diarrhoea/weight loss (32 pts.), anaemia (19 pts.), familiarity (3 pts.); none of the patients was diagnosed because of enamel defects. At the time of evaluation, they were all on a gluten-free diet. Enamel defects were classified from grade 0 to 4 according to its severity. Enamel defects were observed in 46/54 patients (85.2%): grade 1 defects were seen in 18 patients (33.3%) grade 2 in 16 (29.6%), grade 3 in 8 (14.8%), and grade 4 in 4 (7.4%). We also observed that grades 3 and 4 were more frequent in patients diagnosed with classical rather than non-classical coeliac disease (10/32 vs. 2/20). However, this was not statistically significant. This study confirms that enamel defects are common in adult coeliac disease. Observation of enamel defects is an opportunity to diagnose coeliac disease. Copyright © 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  14. Function and repair of dental enamel - Potential role of epithelial transport processes of ameloblasts.

    Science.gov (United States)

    Varga, Gábor; Kerémi, Beáta; Bori, Erzsébet; Földes, Anna

    2015-07-01

    The hardest mammalian tissue, dental enamel is produced by ameloblasts, which are electrolyte-transporting epithelial cells. Although the end product is very different, they show many similarities to transporting epithelia of the pancreas, salivary glands and kidney. Enamel is produced in a multi-step epithelial secretory process that features biomineralization which is an interplay of secreted ameloblast specific proteins and the time-specific transport of minerals, protons and bicarbonate. First, "secretory" ameloblasts form the entire thickness of the enamel layer, but with low mineral content. Then they differentiate into "maturation" ameloblasts, which remove organic matrix from the enamel and in turn further build up hydroxyapatite crystals. The protons generated by hydroxyapatite formation need to be buffered, otherwise enamel will not attain full mineralization. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. The whole process has been the focus of many immunohistochemical and gene knock-out studies, but, perhaps surprisingly, no functional data existed for mineral ion transport by ameloblasts. However, recent studies including ours provided a better insight for molecular mechanism of mineral formation. The secretory regulation is not completely known as yet, but its significance is crucial. Impairing regulation retards or prevents completion of enamel mineralization and results in the development of hypomineralized enamel that easily erodes after dental eruption. Factors that impair this function are fluoride and disruption of pH regulators. Revealing these factors may eventually lead to the treatment of enamel hypomineralization related to genetic or environmentally induced malformation. Copyright © 2015 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  15. Prenatal effects by exposing to amoxicillin on dental enamel in Wistar rats.

    Science.gov (United States)

    Gottberg, Beatriz; Berné, Jeanily; Quiñónez, Belkis; Solórzano, Eduvigis

    2014-01-01

    Amoxicillin is an antibiotic widely prescribed; its most frequent side effects are gastrointestinal disorders and hypersensitivity reactions. Over the last 10 years studies have been published which suggest that amoxicillin may cause dental alterations similar to dental fluorosis. Never the less, the results are not conclusive, this is why it was planned the need to make controlled studies on test animals. The purpose of this study was to determine the effect produced by amoxicillin prenatal administration on dental enamel in Wistar rats. 12 pregnant adult rats were used distributed into five different groups: witness control (n=2) didn't get any treatment; negative control (n=2) they were prescribed with saline solution; positive control (n=3) they were prescribed with tetracycline 130 mg/kg, and two groups (n=3 and n=2) treated with amoxicillin doses of 50 and 100 mg/kg respectively. The treatments were daily administered by mouth, from the 6th gestation day to the end of gestation. Twenty five days after they were born, the offspring were sacrificed with a sodium pentobarbital overdose, the mandible was dissected and the first lower molars were gotten. The samples were fixed in 10% formaldehyde solution and clinically and histologically observed to determine any enamel disorders. hypomineralization was observed in every single sample of the tetracyclic and amoxicillin treated group 100 mg/kg, meanwhile only 50% from the group administered with 50 mg/kg amoxicillin showed this histological disorder. the side effect caused by amoxicillin on dental enamel was doses dependent.

  16. Spectrally enhanced image resolution of tooth enamel surfaces

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2012-01-01

    Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged with 405 nm, 444 nm, 532 nm, or 635 nm illumination lasers. The obtained images were then processed offline to compensate for any differences in the illumination beam diameters between the different lasers. Scattering and absorption coefficients for a Monte Carlo model of light propagation in dental enamel for 405 nm were scaled from published data at 532 nm and 633 nm. The value of the scattering coefficient used in the model was scaled from the coefficients at 532 nm and 633 nm by the inverse third power of wavelength. Simulations showed that the penetration depth of short-wavelength illumination is localized close to the enamel surface, while long-wavelength illumination travels much further and is backscattered from greater depths. Therefore, images obtained using short wavelength laser are not contaminated by the superposition of light reflected from enamel tissue at greater depths. Hence, the SFE with short-wavelength illumination may make it possible to visualize surface manifestations of phenomena such as demineralization, thus better aiding the clinician in the detection of early caries.

  17. Prevalence of dental anomalies and enamel hypoplasia in primary dentition among preschool children of West Godavari District, Andhra Pradesh -A cross - sectional study

    Directory of Open Access Journals (Sweden)

    Suzan Sahana

    2013-01-01

    Full Text Available Background: It is axiomatic that Pediatric dental anomalies and enamel hypoplasia (E.H are routinely encountered in primary dentition and early detection and prudent management of the condition facilitates normal occlusal development. Objectives: To determine the prevalence of various dental anomalies and enamel hypoplasia in preschool children between two to six years of age. Materials & Method: A total of 1898 children, between two to six years were randomly selected and screened for dental anomalies and enamel hypoplasia The chi square test was used to analyze the data statistically. Results: The overall prevalence rate of dental anomalies and enamel hypoplasia in this study was 0.63% and 8.95% respectively. Double teeth were the most frequently reported dental anomaly while supernumerary teeth were least reported. None of them reported with hypodontia.

  18. Dental stigmata and enamel thickness in a probable case of congenital syphilis from XVI century Croatia.

    Science.gov (United States)

    Lauc, Tomislav; Fornai, Cinzia; Premužić, Zrinka; Vodanović, Marin; Weber, Gerhard W; Mašić, Boris; Rajić Šikanjić, Petra

    2015-10-01

    To analyse the dental remains of an individual with signs of congenital syphilis by using macroscopic observation, CBCT and micro-CT images, and the analysis of the enamel thickness. Anthropological analysis of human skeletal remains from the 16th century archaeological site Park Grič in Zagreb, Croatia discovered a female, 17-20 years old at the time of death, with dental signs supportive of congenital syphilis: mulberry molars and canine defects, as well as non-specific hypoplastic changes on incisors. The focus of the analysis was on three aspects: gross morphology, hypoplastic defects of the molars, canines and incisors, as well as enamel thickness of the upper first and second molars. The observed morphology of the first molars corresponds to the typical aspect of mulberry molars, while that of the canines is characterised by hypomineralisation. Hypoplastic grooves were observed on the incisal edges of all incisors. The enamel of the first molars is underdeveloped while in the second molars a thick-enamelled condition is observed. Our observations for the dental and skeletal evidence are supportive to a diagnosis of congenital syphilis for this specimen from XVI century Croatia. The use of CT imaging helped documenting the diagnostic features and quantifying the effect of the dental stigmata on first molars. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Evaluation of enamel by scanning electron microscopy green LED associated to hydrogen peroxide 35% for dental bleaching

    Science.gov (United States)

    Monteiro, Juliana S. C.; de Oliveira, Susana C. P. S.; Zanin, Fátima A. A.; Santos, Gustavo M. P.; Sampaio, Fernando J. P.; Gomes Júnior, Rafael Araújo; Gesteira, Maria F. M.; Vannier-Santos, Marcos A.; Pinheiro, Antônio Luiz B.

    2014-02-01

    Dental bleaching is a frequently requested procedure in clinical dental practice. The literature is contradictory regarding the effects of bleaching agents on both morphology and demineralization of enamel after bleaching. The aim of this study was to analyze by SEM the effect of 35% neutral hydrogen peroxide cured by green LED. Buccal surfaces of 15 pre-molars were sectioned and marked with a central groove to allow experimental and control groups on the same specimen. For SEM, 75 electron micrographs were evaluated by tree observers at 43X, 220X and 1000X. Quantitative analysis for the determination of the surface elemental composition of the samples through X-ray microanalysis by SEM was also performed. The protocol tested neither showed significant changes in mineral composition of the samples nor to dental enamel structure when compared to controls. SEM analysis allowed inferring that there were marked morphological differences between the enamel samples highlighting the need for the use of the same tooth in comparative morphological studies. The tested protocol did not cause morphological damage the enamel surface when compared to their respective controls.

  20. Distribution patterns of elements in dental enamel of G. blacki: a preliminary dietary investigation using SRXRF

    International Nuclear Information System (INIS)

    Qu, Yating; Hu, Yaowu; Shang, Xue; Wang, Changsui; Jin, Changzhu; Zhang, Yingqi

    2013-01-01

    We measured the elemental mappings in dental enamel of Gigantopithecus blacki (n=3) using synchrotron radiation X-ray fluorescence (SRXRF) to understand the dietary variation during the time of tooth eruption. In order to account for the effects of diagenesis on the variation of elements in these fossil teeth, we compared the Fe and Mn elemental distribution and levels in dental enamel of G. blacki with that of a single modern pig tooth and found no differences. The observation of the variations of Sr, Ca and RE (rare earth elements) distribution in the incremental lines reveals that the plant foods utilized by G. blacki from the early Pleistocene or the middle Pleistocene had varied during the formation of dental enamel, possibly caused by the change of living environment or food resources. The variations of elemental distribution in different incremental lines are very promising to understand the nutritional and physical stress of G. blacki during the tooth eruption and environmental adaptations. (orig.)

  1. Distribution patterns of elements in dental enamel of G. blacki: a preliminary dietary investigation using SRXRF

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Yating; Hu, Yaowu; Shang, Xue; Wang, Changsui [Chinese Academy of Sciences, Lab of Human Evolution, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing (China); University of Chinese Academy of Sciences, Department of Scientific History and Archaeometry, School of Humanities, Beijing (China); Jin, Changzhu; Zhang, Yingqi [Chinese Academy of Sciences, Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing (China)

    2013-04-15

    We measured the elemental mappings in dental enamel of Gigantopithecus blacki (n=3) using synchrotron radiation X-ray fluorescence (SRXRF) to understand the dietary variation during the time of tooth eruption. In order to account for the effects of diagenesis on the variation of elements in these fossil teeth, we compared the Fe and Mn elemental distribution and levels in dental enamel of G. blacki with that of a single modern pig tooth and found no differences. The observation of the variations of Sr, Ca and RE (rare earth elements) distribution in the incremental lines reveals that the plant foods utilized by G. blacki from the early Pleistocene or the middle Pleistocene had varied during the formation of dental enamel, possibly caused by the change of living environment or food resources. The variations of elemental distribution in different incremental lines are very promising to understand the nutritional and physical stress of G. blacki during the tooth eruption and environmental adaptations. (orig.)

  2. Distribution patterns of elements in dental enamel of G. blacki: a preliminary dietary investigation using SRXRF

    Science.gov (United States)

    Qu, Yating; Jin, Changzhu; Zhang, Yingqi; Hu, Yaowu; Shang, Xue; Wang, Changsui

    2013-04-01

    We measured the elemental mappings in dental enamel of Gigantopithecus blacki ( n=3) using synchrotron radiation X-ray fluorescence (SRXRF) to understand the dietary variation during the time of tooth eruption. In order to account for the effects of diagenesis on the variation of elements in these fossil teeth, we compared the Fe and Mn elemental distribution and levels in dental enamel of G. blacki with that of a single modern pig tooth and found no differences. The observation of the variations of Sr, Ca and RE (rare earth elements) distribution in the incremental lines reveals that the plant foods utilized by G. blacki from the early Pleistocene or the middle Pleistocene had varied during the formation of dental enamel, possibly caused by the change of living environment or food resources. The variations of elemental distribution in different incremental lines are very promising to understand the nutritional and physical stress of G. blacki during the tooth eruption and environmental adaptations.

  3. Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

    Science.gov (United States)

    Lubarsky, Gennady V.; Lemoine, Patrick; Meenan, Brian J.; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

    2014-04-01

    A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix.

  4. Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

    International Nuclear Information System (INIS)

    Lubarsky, Gennady V; Lemoine, Patrick; Meenan, Brian J; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

    2014-01-01

    A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix. (papers)

  5. Developmental defects of enamel and dental caries in the primary dentition: A systematic review and meta-analysis.

    Science.gov (United States)

    Costa, Francine S; Silveira, Ethieli R; Pinto, Gabriela S; Nascimento, Gustavo G; Thomson, William Murray; Demarco, Flávio F

    2017-05-01

    This systematic review and meta-analysis evaluated the association between developmental defects of enamel and dental caries in the primary dentition. Electronic searches were performed in PubMed, Web of Knowledge, Scopus and Scielo for the identification of relevant studies. Observational studies that examined the association between developmental defects of enamel and dental caries in the deciduous dentition were included. Additionally, meta-analysis, funnel plots and sensitivity analysis were employed to synthesize the available evidence. Multivariable meta-regression analysis was performed to explore heterogeneity among studies. A total of 318 articles were identified in the electronic searches. Of those, 16 studies were included in the meta-analysis. Pooled estimates revealed that children with developmental defects of enamel had higher odds of having dental caries (OR 3.32; 95%CI 2.41-4.57), with high heterogeneity between studies (I 2 80%). Methodological characteristic of the studies, such as where it was conducted, the examined teeth and the quality of the study explained about 30% of the variability. Concerning type of defect, children with hypoplasia and diffuse opacities had higher odds of having dental caries (OR 4.28; 95%CI 2.24-8.15; OR1.42; 95%CI 1.15-1.76, respectively). This systematic review and meta-analysis demonstrates a clear association between developmental defects of enamel and dental caries in the primary dentition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Signal processing for radiation dosimetry using EPR in dental enamel: comparison of three methods

    International Nuclear Information System (INIS)

    Pass, B. Barry.; Shames, A.I. Alexander I.

    2000-01-01

    We are reporting an alternative method of extracting useful dose information from complex EPR spectra of dental enamel. Digital differentiation of the initial first derivative spectrum followed by filtering is used to clearly distinguish the radiation-induced signal from the native background signal. The peak-to-peak height of the resulting second derivative of the signal is then measured as an indication of absorbed dose. This method does not require preliminary elimination of the native background signal, and is not effected by any uncertainty in the determination of the background signal or by errors resulting from the subtraction of two signals of comparable magnitude. Ten enamel samples were irradiated with known doses in the range of 250-10 5 mGy. There was agreement for all the samples, within the typical experimental error of ±10% for EPR dosimetry in dental enamel, between the doses determined by two common techniques using native signal subtraction and the doses determined by the new second derivative method proposed here

  7. Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges.

    Science.gov (United States)

    Oliveira, Gabriela Cristina de; Tereza, Guida Paola Genovez; Boteon, Ana Paula; Ferrairo, Brunna Mota; Gonçalves, Priscilla Santana Pinto; Silva, Thiago Cruvinel da; Honório, Heitor Marques; Rios, Daniela

    2017-01-01

    This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15): GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3) for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (perosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

  8. Enamel protein regulation and dental and periodontal physiopathology in MSX2 mutant mice.

    Science.gov (United States)

    Molla, Muriel; Descroix, Vianney; Aïoub, Muhanad; Simon, Stéphane; Castañeda, Beatriz; Hotton, Dominique; Bolaños, Alba; Simon, Yohann; Lezot, Frédéric; Goubin, Gérard; Berdal, Ariane

    2010-11-01

    Signaling pathways that underlie postnatal dental and periodontal physiopathology are less studied than those of early tooth development. Members of the muscle segment homeobox gene (Msx) family encode homeoproteins that show functional redundancy during development and are known to be involved in epithelial-mesenchymal interactions that lead to crown morphogenesis and ameloblast cell differentiation. This study analyzed the MSX2 protein during mouse postnatal growth as well as in the adult. The analysis focused on enamel and periodontal defects and enamel proteins in Msx2-null mutant mice. In the epithelial lifecycle, the levels of MSX2 expression and enamel protein secretion were inversely related. Msx2+/- mice showed increased amelogenin expression, enamel thickness, and rod size. Msx2-/- mice displayed compound phenotypic characteristics of enamel defects, related to both enamel-specific gene mutations (amelogenin and enamelin) in isolated amelogenesis imperfecta, and cell-cell junction elements (laminin 5 and cytokeratin 5) in other syndromes. These effects were also related to ameloblast disappearance, which differed between incisors and molars. In Msx2-/- roots, Malassez cells formed giant islands that overexpressed amelogenin and ameloblastin that grew over months. Aberrant expression of enamel proteins is proposed to underlie the regional osteopetrosis and hyperproduction of cellular cementum. These enamel and periodontal phenotypes of Msx2 mutants constitute the first case report of structural and signaling defects associated with enamel protein overexpression in a postnatal context.

  9. Amelogenin and Enamel Biomimetics

    Science.gov (United States)

    Ruan, Qichao; Moradian-Oldak, Janet

    2015-01-01

    Mature tooth enamel is acellular and does not regenerate itself. Developing technologies that rebuild tooth enamel and preserve tooth structure is therefore of great interest. Considering the importance of amelogenin protein in dental enamel formation, its ability to control apatite mineralization in vitro, and its potential to be applied in fabrication of future bio-inspired dental material this review focuses on two major subjects: amelogenin and enamel biomimetics. We review the most recent findings on amelogenin secondary and tertiary structural properties with a focus on its interactions with different targets including other enamel proteins, apatite mineral, and phospholipids. Following a brief overview of enamel hierarchical structure and its mechanical properties we will present the state-of-the-art strategies in the biomimetic reconstruction of human enamel. PMID:26251723

  10. In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel; Estudo in vitro do efeito do laser diodo sobre a superficie de esmalte dental humano desmineralizado artificialmente

    Energy Technology Data Exchange (ETDEWEB)

    Ebel, Patricia

    2003-07-01

    In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm{sup 2}, 282,84 mJ/cm{sup 2} and 325,38 mJ/cm{sup 2}, respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 {mu}m diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

  11. Retrospective dosimetry by electronic paramagnetic resonance (EPR) in dental enamel

    International Nuclear Information System (INIS)

    Dubner, D.; Gisone, P.; Perez, M.R.; Davila, F.A.; Boveris, A.; Puntarulo, S.

    1998-01-01

    Biophysical dosimetry based on EPR in biological solid samples (like bone and teeth) or in organic materials (like textile fibres, sugar, etc.) is a complementary technique that could contribute, along with the biological dosimetry, to the retrospective evaluation of the absorbed dose in accidental situations. Dental enamel could be considered as the only tissue with structure and composition essentially constant over time: this characteristic feature allows its use as an index of radiation exposure since tooth retains indefinitely its radiation history. Samples of human molars were exposed to gamma-Rays (Co 60) with doses between 0,5 Gy to 10 Gy. After a chemical treatment of samples, enamel was removed by grinding with a dental drill and reduced to a fine powder. A characteristic EPR signal was detected at g=2.002. The dose effect curves were done using 20 mw of microwave power. Measurements were done both, with flat cells and disposable Pasteur pipettes allowing the use of lower amounts of sample. The intensity of the signal was proportional to the dose and linearity was verified in both cases. We discuss the applicability of this technique in evaluating radiation dose in accidental overexposures. (author) [es

  12. Trace elementary concentration in enamel after dental bleaching using HI-ERDA

    International Nuclear Information System (INIS)

    Added, N.; Rizzutto, M.A.; Curado, J.F.; Francci, C.; Markarian, R.; Mori, M.

    2006-01-01

    Changes of elementary concentrations in dental enamel after a bleaching treatment with different products, is presented, with special focus on the oxygen contribution. Concentrations for Ca, P, O and C and some other trace elements were obtained for enamel of bovine incisor teeth by HI-ERDA measurements using a 35 Cl incident beam and an ionization chamber. Five groups of teeth with five samples each were treated with a different bleaching agents. Each tooth had its crown sectioned in two halves, one for bleaching test and one the other used as a control. Average values of C/Ca, O/Ca, F/Ca enrichment factors were found. The comparison between bleached and non-bleached halves indicates that bleaching treatment did not affect the mineral structure when low-concentration whitening systems were used. The almost constant oxygen concentration in enamel, suggests little changes due to whitening therapy

  13. Trace elementary concentration in enamel after dental bleaching using HI-ERDA

    Science.gov (United States)

    Added, N.; Rizzutto, M. A.; Curado, J. F.; Francci, C.; Markarian, R.; Mori, M.

    2006-08-01

    Changes of elementary concentrations in dental enamel after a bleaching treatment with different products, is presented, with special focus on the oxygen contribution. Concentrations for Ca, P, O and C and some other trace elements were obtained for enamel of bovine incisor teeth by HI-ERDA measurements using a 35Cl incident beam and an ionization chamber. Five groups of teeth with five samples each were treated with a different bleaching agents. Each tooth had its crown sectioned in two halves, one for bleaching test and one the other used as a control. Average values of C/Ca, O/Ca, F/Ca enrichment factors were found. The comparison between bleached and non-bleached halves indicates that bleaching treatment did not affect the mineral structure when low-concentration whitening systems were used. The almost constant oxygen concentration in enamel, suggests little changes due to whitening therapy.

  14. Trace elementary concentration in enamel after dental bleaching using HI-ERDA

    Energy Technology Data Exchange (ETDEWEB)

    Added, N [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil); Rizzutto, M A [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil); Curado, J F [GFAA, Depto de Fisica Nuclear, IFUSP, University of Sao Paulo, Travessa R da rua do Matao 187, Cidade Universitaria, Caixa Postal 66318, CEP 05508-970 Sao Paulo, SP (Brazil); Francci, C [School of Dentistry, University of Sao Paulo (Brazil); Markarian, R [School of Dentistry, University of Sao Paulo (Brazil); Mori, M [School of Dentistry, University of Sao Paulo (Brazil)

    2006-08-15

    Changes of elementary concentrations in dental enamel after a bleaching treatment with different products, is presented, with special focus on the oxygen contribution. Concentrations for Ca, P, O and C and some other trace elements were obtained for enamel of bovine incisor teeth by HI-ERDA measurements using a {sup 35}Cl incident beam and an ionization chamber. Five groups of teeth with five samples each were treated with a different bleaching agents. Each tooth had its crown sectioned in two halves, one for bleaching test and one the other used as a control. Average values of C/Ca, O/Ca, F/Ca enrichment factors were found. The comparison between bleached and non-bleached halves indicates that bleaching treatment did not affect the mineral structure when low-concentration whitening systems were used. The almost constant oxygen concentration in enamel, suggests little changes due to whitening therapy.

  15. Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates

    Science.gov (United States)

    Bartlett, John D.

    2013-01-01

    This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389

  16. Matching the optical properties of direct esthetic dental restorative materials to those of human enamel and dentin

    Science.gov (United States)

    Ragain, James Carlton, Jr.

    One of the goals of the restorative dentist is to restore the appearance of the natural dentition. Clinical matching of teeth and restorative materials are seldom accurate and shade selection techniques are subjective. The first specific aim of this research was to characterize the optical absorption and scattering that occurs within enamel, dentin, and composite resin and compomer restorative materials and to relate those phenomena to translucency and color. The second aim was to evaluate small color differences among composite restorative materials which would be detectable by humans. The last aim was to lay the foundation for developing an improved model of specifying layers of dental restorative materials in order to match the translucency and color to those of human enamel. The Kubelka-Munk theory was validated for enamel, dentin, and the restorative materials. These tissues and materials were then characterized in terms of their color parameters. Tooth cores were also characterized in terms of color space parameters. Human subjects were evaluated for their abilities to discriminate small color differences in the dental composite resin materials. The following conclusions were derived from this study: (1) Kubelka-Munk theory accurately predicts the diffuse reflectance spectra of enamel, dentin, and the direct esthetic dental restorative materials studied. (2) Scattering and absorption coefficients of the dental tissues and esthetic restorative materials can be directly calculated from diffuse reflectance measurements of a uniformly thick slab of tissue/material using black and white backings and the appropriate refractive index. (3) For tooth cores, there is a positive correlation between L* and b* and a negative correlation between L* and a*. (4) The range of translucency parameters for the restorative materials studied does not match those of enamel and dentin. (5) None of the shades of the dental composite resin restorative materials studied fit into the

  17. Randomized clinical study of alterations in the color and surface roughness of dental enamel brushed with whitening toothpaste.

    Science.gov (United States)

    de Moraes Rego Roselino, Lourenço; Tirapelli, Camila; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2018-03-30

    This clinical study evaluated the influence of whitening toothpaste on color and surface roughness of dental enamel. Initially, the abrasiveness of the toothpastes used (Sorriso Dentes Brancos [SDB]; Colgate Luminous White and Close up White Now) was tested on 30 (n = 10) plexiglass acrylic plates that were submitted to mechanical tooth brushing totalizing 29,200 cycles. Subsequently, 30 participants were selected, and received a toothbrush and nonwhitening toothpaste (SDB). The participants used these products for 7 days and initial color readouts (Spectrophotometer) and surface roughness of one maxillary central incisors was performed after this period of time. For surface roughness readouts, one replica of the maxillary central incisor was obtained by a polyvinyl siloxane impression material (Express) and polyurethane resin. After baseline measurements, participants were separated into three groups (n = 10), according to the toothpaste used. The participants returned after 7, 30, and 90 days when new color readouts and surface roughness were recorded. The measured values were statistically analyzed (2-way-ANOVA, repeated measures, Tukey, P Whitening toothpastes did not promote significant (P > .05) color alteration and nor increased the surface roughness of the dental enamel in brushing time of the study. The abrasiveness of whitening toothpaste and the brushing trial period did not affect the surface roughness of dental enamel. However, color changes observed on enamel were above the perceptibility and acceptability thresholds reported in the literature. The over-the-counter toothpastes tested had an effect on dental enamel color above the perceptibility and acceptability thresholds but did not change the surface roughness of the teeth. © 2018 Wiley Periodicals, Inc.

  18. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    International Nuclear Information System (INIS)

    Aragno, D.; Fattibene, P.; Onori, S.

    2000-01-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO 2 -signal of intensity similar to that induced by a dose of about 2 mGy of 60 Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60 Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined. (author)

  19. Quantitative study of fluoride transport during subsurface dissolution of dental enamel

    International Nuclear Information System (INIS)

    Chu, J.S.; Fox, J.L.; Higuchi, W.I.

    1989-01-01

    Previous studies using bovine dental enamel as a model have shown that surface and subsurface dissolution of enamel may be governed by micro-environmental solution conditions. We have now investigated the demineralization phenomenon more rigorously with the primary objective of developing a method for deducing solution species concentration profiles as a function of time from appropriate experimental data. More specifically, in this report, a model-independent method is described for determination of the pore solution fluoride gradients in bovine enamel during subsurface demineralization. Microradiography was used to determine the mineral density profiles, and an electron microprobe technique to determine total fluoride (F) profiles associated with the enamel. In each case, matched sections of bovine enamel were exposed to partially saturated acetate buffers at pH = 4.5 containing 0.5 ppm F for various periods of time (from six to 24 hours). The treated enamel was found to have an intact surface layer and subsurface demineralization. The extent of the demineralization and the depths of the lesions increased with time in all cases. The data were first used to calculate (a) the total F gradients in the enamel at various times, and (b) the local uptake rate of F as a function of time and position. Then, by manipulation of the equations describing the uptake and transport of F, we calculated the pore diffusion rate of F and the micro-environmental solution F concentration in the aqueous pores as a function of time and of distance from the enamel surface. It was also possible to calculate an intrinsic F diffusion coefficient in the pores, which was about 1.0 X 10(-5) cm2/sec, in good agreement with reported values

  20. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report

    Directory of Open Access Journals (Sweden)

    Tae-Young Park

    2016-08-01

    Full Text Available Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results.

  1. Susceptibility of bovine dental enamel with initial erosion lesion to new erosive challenges.

    Directory of Open Access Journals (Sweden)

    Gabriela Cristina de Oliveira

    Full Text Available This in vitro study evaluated the impact of initial erosion on the susceptibility of enamel to further erosive challenge. Thirty bovine enamel blocks were selected by surface hardness and randomized into two groups (n = 15: GC- group composed by enamel blocks without erosion lesion and GT- group composed by enamel blocks with initial erosion lesion. The baseline profile of each block was determined using the profilometer. The initial erosion was produced by immersing the blocks into HCl 0.01 M, pH 2.3 for 30 seconds, under stirring. The erosive cycling consisted of blocks immersion in hydrochloric acid (0.01 M, pH 2.3 for 2 minutes, followed by immersion in artificial saliva for 120 minutes. This procedure was repeated 4 times a day for 5 days, and the blocks were kept in artificial saliva overnight. After erosive cycling, final profile measurement was performed. Profilometry measured the enamel loss by the superposition of initial and final profiles. Data were analyzed by t-test (p<0.05. The result showed no statistically significant difference between groups (GS = 14.60±2.86 and GE = .14.69±2.21 μm. The presence of initial erosion on bovine dental enamel does not enhance its susceptibility to new erosive challenges.

  2. Protection of enamel surfaces in the oral cavity

    DEFF Research Database (Denmark)

    Lazovic, Maja Bruvo

    The two main diseases that can affect the tooth enamel are dental caries and dental erosion, which both are caused by exposure of the enamel surfaces to acids. In the case of dental caries, acids from bacterial metabolism cause chemical dissolution of the tooth surface, whereas acids from drinks...... and foodstuffs or gastric juice can cause dental erosion. During a lifetime the enamel surface is also exposed to fluids that can have protective effects against dental caries and erosion such as saliva, various foodstuffs, drinking water and many types of drinks. However, little is still known about simple...... inorganic interactions between different fluids and dental caries and little is also known about which saliva proteins are able to protect the enamel surface against dental erosion. Therefore, the overall aim of this thesis was to examine simple inorganic and protein related protective effects with dental...

  3. Research on optical properties of dental enamel for early caries diagnostics using a He-Ne laser

    Science.gov (United States)

    Tang, Jing; Liu, Li; Li, Song-zhan

    2008-12-01

    A new and non-invasive method adapted for optical diagnosis of early caries is proposed by researching on the interaction mechanism of laser with dental tissue and relations of remitted light with optical properties of the tissue. This method is based on simultaneous analyses of the following parameters: probing radiation, backscattering and auto-fluorescence. Investigation was performed on 104 dental samples in vitro by using He-Ne laser (λ=632.8nm, 2.0+/-0.1mW) as the probing. Spectrums of all samples were obtained. Characteristic spectrums of dental caries in various stages (intact, initial, moderate and deep) were given. Using the back-reflected light to normalize the intensity of back-scattering and fluorescence, a quantitative diagnosis standard for different stages of caries is proposed. In order to verify the test, comparison research was conducted among artificial caries, morphological damaged enamel, dental calculus and intact tooth. Results show that variations in backscattering characteristic changes in bio-tissue morphological and the quantity of auto-fluorescence is correlated with concentration of anaerobic microflora in hearth of caries lesion. This method poses a high potential of diagnosing various stages of dental caries, and is more reliability to detect early caries, surface damage of health enamel and dental calculus.

  4. Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel.

    Science.gov (United States)

    Manuela Díaz-Monroy, Jennifer; Contreras-Bulnes, Rosalía; Fernando Olea-Mejía, Oscar; Emma Rodríguez-Vilchis, Laura; Sanchez-Flores, Ignacio

    2014-06-01

    Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects. © 2014 Wiley Periodicals, Inc.

  5. Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser.

    Science.gov (United States)

    Pires, Patrícia T; Ferreira, João C; Oliveira, Sofia A; Azevedo, Alvaro F; Dias, Walter R; Melo, Paulo R

    2013-01-01

    Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA)+ ExciTE(®); Group II - ExciTE(®); Group III - AdheSE(®) self-etching; Group IV - FuturaBond(®) no-rinse. NR; Group V - Xeno(®) V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. One-way ANOVA and post-hoc tests (P adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE(®) and ExciTE(®) without condition with PA. FuturaBond(®) NR and Xeno(®) V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

  6. Alteration of dentin-enamel mechanical properties due to dental whitening treatments.

    Science.gov (United States)

    Zimmerman, B; Datko, L; Cupelli, M; Alapati, S; Dean, D; Kennedy, M

    2010-05-01

    The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 GPa versus 113.4 GPa), while smaller increases were observed in the dentin (17.9 GPa versus 27.9 GPa). Likewise, there was an increase in the hardness of enamel (2.0 GPa versus 4.3 GPa) and dentin (0.5 GPa versus 0.7 GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips, Opalescence or UltraEtch caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips showed a reduction in the elastic modulus of enamel (55.3 GPa to 32.7 GPa) and increase in the elastic modulus of dentin (17.2 GPa to 24.3 GPa). Opalescence treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 GPa to 15.1 GPa). Additionally, as expected, UltraEtch treatment decreased the modulus and hardness of enamel (48.7 GPa to 38.0 GPa and 1.9 GPa to 1.5 GPa, respectively) and dentin (21.4 GPa to 15.0 GPa and 1.9 GPa to 1.5 GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. Published by Elsevier Ltd.

  7. Enamel microabrasion for aesthetic management of dental fluorosis.

    Science.gov (United States)

    Pandey, Pallavi; Ansari, Afroz Alam; Moda, Preeti; Yadav, Madhulika

    2013-10-11

    Fluorosis has increased in recent times due to fluoridation of drinking water and addition of fluoride to various edible items, which leads to unaesthetic appearance of teeth visible at close quarters. The enamel microabrasion technique is a conservative method that improves the appearance of the teeth by restoring bright and superficial smoothness, without causing significant structural loss. The aim of this article is to describe an easy technique for managing mild to moderate dental fluorosis using Opalustre (Ultradent Products) microabrasion slurry. This conservative approach may be considered an interesting alternative to more invasive prosthetic techniques like composite resin restorations, ceramic veneers or crown fabrications.

  8. Threshold value of enamel mineral solubility and dental erosion after consuming acidic soft drinks

    Directory of Open Access Journals (Sweden)

    Muhammad Ilyas

    2011-09-01

    Full Text Available Background: Dental erosion is irreversible and can caused by acidic soft drink consumption. Dental erosion prevention had already been done, but it still has not been satisfying since the consumption of acidic soft drink is still high. There is still no explanation about the threshold value of enamel mineral solubility and the occurance of dental erosion after consuming acidic soft drink. Purpose: This research is aimed to find the threshold value of enamel mineral solubility and dental erosion before and after consuming acidic soft drinks. Methods: Subjects of the research are saliva and enamel of 12 rabbits, which have some criteria such as age > 70 days, body weight > 600 grams, and teeth considered to be healthy. The sample devided equally into 4 groups. Each of those marmooths was given a drink as much as 2.5 cc/consumption (there are 1, 2 and 3× per day by using syringe without injection needle. Salivary minerals then were examined by using atomic absorption spectrophotometric (ASS, while dental erosion was examined using scanning electron microscop (SEM. The data were analyzed by using Paired t-test. Results: It is known that the threshold value of enamel mineral solubility (K, Na, Fe, Mg, Cl, P, Ca, F, C has significant difference (p < 0.05 after being exposed to folic acid. Meanwhile, Fe did not have significant difference (p = 0.090 after being exposed to citric acid. Similarly, C did not have significant difference (p = 0.063 after being exposed to bicarbonate acid. Furthermore, it is also known that the threshold time value of dental erosion are on the 105th day for folic acid, on the 111th day for citric acid, and on the 117th day for bicarbonate acid. Conclusion: Threshold value of enamel mineral solubility before and after consuming soft drinks containing acid is different. Based on the threshold value of dental erosion, it is known that folic acid is the most erosive acid.Latar belakang: Erosi gigi bersifat irreversible

  9. Efficacy and cytotoxicity of a bleaching gel after short application times on dental enamel.

    Science.gov (United States)

    Soares, Diana Gabriela; Ribeiro, Ana Paula Dias; da Silveira Vargas, Fernanda; Hebling, Josimeri; de Souza Costa, Carlos Alberto

    2013-11-01

    This study aimed to evaluate and correlate the efficacy and cytotoxicity of a 35 % hydrogen peroxide (HP) bleaching gel after different application times on dental enamel. Enamel/dentin disks in artificial pulp chambers were placed in wells containing culture medium. The following groups were formed: G1, control (no bleaching); G2 and G3, three or one 15-min bleaching applications, respectively; and G4 and G5, three or one 5-min bleaching applications, respectively. Extracts (culture medium with bleaching gel components) were applied for 60 min on cultured odontoblast-like MDPC-23 cells. Cell metabolism (methyl tetrazolium assay) (Kruskal-Wallis/Mann-Whitney; α = 5 %) and cell morphology (scanning electron microscopy) were analyzed immediately after the bleaching procedures and the trans-enamel and trans-dentinal HP diffusion quantified (one-way analysis of variance/Tukey's test; α = 5 %). The alkaline phosphatase (ALP) activity was evaluated 24 h after the contact time of the extracts with the cells (Kruskal-Wallis/Mann-Whitney; α = 5 %). Tooth color was analyzed before and 24 h after bleaching using a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system (Kruskal-Wallis/Mann-Whitney; α = 0.05). Significant difference (p 0.05). The lowest amount of HP diffusion was observed in G5 (p 0.05). HP diffusion through dental tissues and its cytotoxic effects were proportional to the contact time of the bleaching gel with enamel. However, shorter bleaching times reduced bleaching efficacy. Shortening the in-office tooth bleaching time could be an alternative to minimize the cytotoxic effects of this clinical procedure to pulp tissue. However, the reduced time of bleaching agent application on enamel may not provide adequate esthetic outcome.

  10. Theobromine Effects on Enamel Surface Microhardness: In Vitro

    OpenAIRE

    Grace Syafira; Rina Permatasari; Nina Wardani

    2013-01-01

    Dental caries is still a dental health problem in Indonesia. Fluoride, one of the dental caries prevention material, but its safety and the danger of fluorosis is still debated. Theobromine is an alkaloid compound contained in cocoa beans. Theobromine is believed to increase enamel microhardness with mineral changes in the enamel superficial layer. Objectives: To determine the influence of theobromine on the enamel surface microhardness. Methods: This study used 40 premolar tooth crown pieces...

  11. Ph-activated nano-amorphous calcium phosphate-based cement to reduce dental enamel demineralization.

    Science.gov (United States)

    Melo, Mary A S; Weir, Michael D; Passos, Vanara F; Powers, Michael; Xu, Hockin H K

    2017-12-01

    Enamel demineralization is destructive, esthetically compromised, and costly complications for orthodontic patients. Nano-sized amorphous calcium phosphate (NACP) has been explored to address this challenge. The 20% NACP-loaded ortho-cement notably exhibited favorable behavior on reducing demineralization of enamel around brackets in a caries model designed to simulate the carious attack. The 20% NACP-loaded ortho-cement markedly promotes higher calcium and phosphate release at a low pH, and the mineral loss was almost two fold lower and carious lesion depth decreased the by 1/3. This novel approach is promising co-adjuvant route for prevention of dental caries dissemination in millions of patients under orthodontic treatment.

  12. Effect of beverages on bovine dental enamel subjected to erosive challenge with hydrochloric acid.

    Science.gov (United States)

    Amoras, Dinah Ribeiro; Corona, Silmara Aparecida Milori; Rodrigues, Antonio Luiz; Serra, Mônica Campos

    2012-01-01

    This study evaluated by an in vitro model the effect of beverages on dental enamel previously subjected to erosive challenge with hydrochloric acid. The factor under study was the type of beverage, in five levels: Sprite® Zero Low-calorie Soda Lime (positive control), Parmalat® ultra high temperature (UHT) milk, Ades® Original soymilk, Leão® Ice Tea Zero ready-to-drink low-calorie peach-flavored black teaand Prata® natural mineral water (negative control). Seventy-five bovine enamel specimens were distributed among the five types of beverages (n=15), according to a randomized complete block design. For the formation of erosive wear lesions, the specimens were immersed in 10 mL aqueous solution of hydrochloric acid 0.01 M for 2 min. Subsequently, the specimens were immersed in 20 mL of the beverages for 1 min, twice daily for 2 days at room temperature. In between, the specimens were kept in 20 mL of artificial saliva at 37ºC. The response variable was the quantitative enamel microhardness. ANOVA and Tukey's test showed highly significant differences (penamel exposed to hydrochloric acid and beverages. The soft drink caused a significantly higher decrease in microhardness compared with the other beverages. The black tea caused a significantly higher reduction in microhardness than the mineral water, UHT milk and soymilk, but lower than the soft drink. Among the analyzed beverages, the soft drink and the black tea caused the most deleterious effects on dental enamel microhardness.

  13. Dental enamel defects, caries experience and oral health-related quality of life: a cohort study.

    Science.gov (United States)

    Arrow, P

    2017-06-01

    The impact of enamel defects of the first permanent molars on caries experience and child oral health-related quality of life was evaluated in a cohort study. Children who participated in a study of enamel defects of the first permanent molars 8 years earlier were invited for a follow-up assessment. Consenting children completed the Child Perception Questionnaire and the faces Modified Child Dental Anxiety Scale, and were examined by two calibrated examiners. ANOVA, Kruskal-Wallis, negative binomial and logistic regression were used for data analyses. One hundred and eleven children returned a completed questionnaire and 91 were clinically examined. Negative binomial regression found that oral health impacts were associated with gender (boys, risk ratio (RR) = 0.73, P = 0.03) and decayed, missing or filled permanent teeth (DMFT) (RR = 1.1, P = 0.04). The mean DMFT of children were sound (0.9, standard deviation (SD) = 1.4), diffuse defects (0.8, SD = 1.7), demarcated defects (1.5, SD = 1.4) and pit defects (1.3, SD = 2.3) (Kruskal-Wallis, P = 0.05). Logistic regression of first permanent molar caries found higher odds of caries experience with baseline primary tooth caries experience (odds ratio (OR) = 1.5, P = 0.01), the number of teeth affected by enamel defects (OR = 1.9, P = 0.05) and lower odds with the presence of diffuse enamel defects (OR = 0.1, P = 0.04). The presence of diffuse enamel defects was associated with lower odds of caries experience. © 2016 Australian Dental Association.

  14. Adherence inhibition of Streptococcus mutans on dental enamel surface using silver nanoparticles

    International Nuclear Information System (INIS)

    Espinosa-Cristóbal, L.F.; Martínez-Castañón, G.A.; Téllez-Déctor, E.J.

    2013-01-01

    The aim of this ex vivo study was to evaluate the adherence capacity of Streptococcus mutans after being exposed to three different sizes of silver nanoparticles on healthy human dental enamel. Three different sizes of silver nanoparticles (9.3, 21.3 and 98 nm) were prepared, characterized and an adherence testing was performed to evaluate their anti-adherence activity on a reference strain of S. mutans on healthy dental enamel surfaces. Colony-Forming Unit count was made for adherence test and light microscopy, atomic force microscopy and scanning electron microscopy were used to compare qualitative characteristics of S. mutans. 9.3 nm and 21.3 nm groups did not show differences between them but statistical differences were found when 9.3 nm and 21.3 nm groups were compared with 98 nm and negative control groups (p < 0.05). Microscopy analysis shows a better inhibition of S. mutans adherence in 9.3 nm and 21.3 nm groups than the 98 nm group when compared with control group. Silver nanoparticles showed an adherence inhibition on S. mutans and the anti-adherence capacity was better when silver nanoparticles were smaller. Highlights: ► We examined how SNP can affect cellular adhesion from S. mutans. ► Several techniques were applied to analyzed S. mutans biofilm on enamel. ► All SNP sizes had an adhesion inhibition of S. mutans. ► Smaller SNP showed a better adhesion inhibition than larger SNP. ► Inhibition effect of SNP could be related with adhesion inhibition from S. mutans

  15. Adherence inhibition of Streptococcus mutans on dental enamel surface using silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Cristóbal, L.F. [Doctorado Institucional en Ingeniería y Ciencia de Materiales, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava S/N, Zona Universitaria, C.P. 78290 San Luis Potosí, S.L.P. (Mexico); Maestría en Ciencias Odontológicas en el Área de Odontología Integral Avanzada, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava S/N, Zona Universitaria, C.P. 78290 San Luis Potosí, S.L.P. (Mexico); Martínez-Castañón, G.A., E-mail: mtzcastanon@fciencias.uaslp.mx [Doctorado Institucional en Ingeniería y Ciencia de Materiales, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava S/N, Zona Universitaria, C.P. 78290 San Luis Potosí, S.L.P. (Mexico); Maestría en Ciencias Odontológicas en el Área de Odontología Integral Avanzada, Universidad Autónoma de San Luis Potosí, Av. Salvador Nava S/N, Zona Universitaria, C.P. 78290 San Luis Potosí, S.L.P. (Mexico); Téllez-Déctor, E.J. [Facultad de Odontología de la Universidad Veracruzana campus Río Blanco, Mariano Abasolo S/N. Col. Centro. Río Blanco, Veracruz (Mexico); and others

    2013-05-01

    The aim of this ex vivo study was to evaluate the adherence capacity of Streptococcus mutans after being exposed to three different sizes of silver nanoparticles on healthy human dental enamel. Three different sizes of silver nanoparticles (9.3, 21.3 and 98 nm) were prepared, characterized and an adherence testing was performed to evaluate their anti-adherence activity on a reference strain of S. mutans on healthy dental enamel surfaces. Colony-Forming Unit count was made for adherence test and light microscopy, atomic force microscopy and scanning electron microscopy were used to compare qualitative characteristics of S. mutans. 9.3 nm and 21.3 nm groups did not show differences between them but statistical differences were found when 9.3 nm and 21.3 nm groups were compared with 98 nm and negative control groups (p < 0.05). Microscopy analysis shows a better inhibition of S. mutans adherence in 9.3 nm and 21.3 nm groups than the 98 nm group when compared with control group. Silver nanoparticles showed an adherence inhibition on S. mutans and the anti-adherence capacity was better when silver nanoparticles were smaller. Highlights: ► We examined how SNP can affect cellular adhesion from S. mutans. ► Several techniques were applied to analyzed S. mutans biofilm on enamel. ► All SNP sizes had an adhesion inhibition of S. mutans. ► Smaller SNP showed a better adhesion inhibition than larger SNP. ► Inhibition effect of SNP could be related with adhesion inhibition from S. mutans.

  16. Matrix metalloproteinase-20 mediates dental enamel biomineralization by preventing protein occlusion inside apatite crystals.

    Science.gov (United States)

    Prajapati, Saumya; Tao, Jinhui; Ruan, Qichao; De Yoreo, James J; Moradian-Oldak, Janet

    2016-01-01

    Reconstruction of enamel-like materials is a central topic of research in dentistry and material sciences. The importance of precise proteolytic mechanisms in amelogenesis to form a hard tissue with more than 95% mineral content has already been reported. A mutation in the Matrix Metalloproteinase-20 (MMP-20) gene results in hypomineralized enamel that is thin, disorganized and breaks from the underlying dentin. We hypothesized that the absence of MMP-20 during amelogenesis results in the occlusion of amelogenin in the enamel hydroxyapatite crystals. We used spectroscopy and electron microscopy techniques to qualitatively and quantitatively analyze occluded proteins within the isolated enamel crystals from MMP-20 null and Wild type (WT) mice. Our results showed that the isolated enamel crystals of MMP-20 null mice had more organic macromolecules occluded inside them than enamel crystals from the WT. The crystal lattice arrangements of MMP-20 null enamel crystals analyzed by High Resolution Transmission Electron Microscopy (HRTEM) were found to be significantly different from those of the WT. Raman studies indicated that the crystallinity of the MMP-20 null enamel crystals was lower than that of the WT. In conclusion, we present a novel functional mechanism of MMP-20, specifically prevention of unwanted organic material entrapped in the forming enamel crystals, which occurs as the result of precise amelogenin cleavage. MMP-20 action guides the growth morphology of the forming hydroxyapatite crystals and enhances their crystallinity. Elucidating such molecular mechanisms can be applied in the design of novel biomaterials for future clinical applications in dental restoration or repair. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Effect of Toothpaste Application Prior to Dental Bleaching on Whitening Effectiveness and Enamel Properties.

    Science.gov (United States)

    Vieira-Junior, W F; Lima, D A N L; Tabchoury, C P M; Ambrosano, G M B; Aguiar, F H B; Lovadino, J R

    2016-01-01

    The purpose of this study was to investigate the effects on the enamel properties and effectiveness of bleaching using 35% hydrogen peroxide (HP) when applying toothpastes with different active agents prior to dental bleaching. Seventy enamel blocks (4 × 4 × 2 mm) were submitted to in vitro treatment protocols in a tooth-brushing machine (n=10): with distilled water and exposure to placebo gel (negative control [NC]) or HP bleaching (positive control [PC]); and brushing with differing toothpastes prior to HP bleaching, including potassium nitrate toothpaste (PN) containing NaF, conventional sodium monofluorophosphate toothpaste (FT), arginine-based toothpastes (PA and SAN), or a toothpaste containing bioactive glass (NM). Color changes were determined using the CIE L*a*b* system (ΔE, ΔL, Δa, and Δb), and a roughness (Ra) analysis was performed before and after treatments. Surface microhardness (SMH) and cross-sectional microhardness (CSMH) were analyzed after treatment. Data were analyzed with repeated measures ANOVA for Ra, one-way ANOVA (SMH, ΔE, ΔL, Δa, and Δb), split-plot ANOVA (CSMH), and Tukey post hoc test (α PA = SAN > all other groups) or decreased HP effects (CSMH). Ra increased in all bleached groups, with the exception of NM, which did not differ from the NC. The variation in the color variables (ΔL, Δa, and Δb) explained 21% of the variation in the physical surface variables (Ra and SMH). The application of toothpaste prior to dental bleaching did not interfere with the effectiveness of treatment. The bioactive glass based toothpaste protected the enamel against the deleterious effects of dental bleaching.

  18. Dental prostheses mimic the natural enamel behavior under functional loading: A review article

    Directory of Open Access Journals (Sweden)

    Ahmed A. Madfa

    2016-02-01

    Full Text Available Alumina- and zirconia-based ceramic dental restorations are designed to repair functionality as well as esthetics of the failed teeth. However, these materials exhibited several performance deficiencies such as fracture, poor esthetic properties of ceramic cores (particularly zirconia cores, and difficulty in accomplishing a strong ceramic–resin-based cement bond. Therefore, improving the mechanical properties of these ceramic materials is of great interest in a wide range of disciplines. Consequently, spatial gradients in surface composition and structure can improve the mechanical integrity of ceramic dental restorations. Thus, this article reviews the current status of the functionally graded dental prostheses inspired by the dentino-enamel junction (DEJ structures and the linear gradation in Young's modulus of the DEJ, as a new material design approach, to improve the performance compared to traditional dental prostheses. This is a remarkable example of nature's ability to engineer functionally graded dental prostheses. The current article opens a new avenue for recent researches aimed at the further development of new ceramic dental restorations for improving their clinical durability.

  19. Theobromine Effects on Enamel Surface Microhardness: In Vitro

    Directory of Open Access Journals (Sweden)

    Grace Syafira

    2013-07-01

    Full Text Available Dental caries is still a dental health problem in Indonesia. Fluoride, one of the dental caries prevention material, but its safety and the danger of fluorosis is still debated. Theobromine is an alkaloid compound contained in cocoa beans. Theobromine is believed to increase enamel microhardness with mineral changes in the enamel superficial layer. Objectives: To determine the influence of theobromine on the enamel surface microhardness. Methods: This study used 40 premolar tooth crown pieces that were embedded in epoxy resin. Furthermore specimens were randomly divided into 4 groups, which were control (distilled water, theobromine 100 mg/L (T100, theobromine 500 mg/L (T500 and theobromine 1000 mg/L (T1000. Specimens were immersed for 15 minutes and microhardness test was performed using Knoop microhardness tester. Results: Increasing enamel microhardness was observed after treatment with four different theobromine concentrations. The highest icreased of enamel microhardness was shown in T1000 group and difference compared to other groups were statistically significant (p<0.05. Conclusion: theobromine is a potential dental caries prevention material due to its effect in improving the microhardness of tooth enamel.

  20. Interactions between dodecyl phosphates and hydroxyapatite or tooth enamel: relevance to inhibition of dental erosion.

    Science.gov (United States)

    Jones, Siân B; Barbour, Michele E; Shellis, R Peter; Rees, Gareth D

    2014-05-01

    Tooth surface modification is a potential method of preventing dental erosion, a form of excessive tooth wear facilitated by softening of tooth surfaces through the direct action of acids, mainly of dietary origin. We have previously shown that dodecyl phosphates (DPs) effectively inhibit dissolution of native surfaces of hydroxyapatite (the type mineral for dental enamel) and show good substantivity. However, adsorbed saliva also inhibits dissolution and DPs did not augment this effect, which suggests that DPs and saliva interact at the hydroxyapatite surface. In the present study the adsorption and desorption of potassium and sodium dodecyl phosphates or sodium dodecyl sulphate (SDS) to hydroxyapatite and human tooth enamel powder, both native and pre-treated with saliva, were studied by high performance liquid chromatography-mass Spectrometry. Thermo gravimetric analysis was used to analyse residual saliva and surfactant on the substrates. Both DPs showed a higher affinity than SDS for both hydroxyapatite and enamel, and little DP was desorbed by washing with water. SDS was readily desorbed from hydroxyapatite, suggesting that the phosphate head group is essential for strong binding to this substrate. However, SDS was not desorbed from enamel, so that this substrate has surface properties different from those of hydroxyapatite. The presence of a salivary coating had little or no effect on adsorption of the DPs, but treatment with DPs partly desorbed saliva; this could account for the failure of DPs to increase the dissolution inhibition due to adsorbed saliva. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Morphological and mineral analysis of dental enamel after erosive challenge in gastric juice and orange juice.

    Science.gov (United States)

    Braga, Sheila Regina Maia; De Faria, Dalva Lúcia Araújo; De Oliveira, Elisabeth; Sobral, Maria Angela Pita

    2011-12-01

    This study evaluated and compared in vitro the morphology and mineral composition of dental enamel after erosive challenge in gastric juice and orange juice. Human enamel specimens were submitted to erosive challenge using gastric juice (from endoscopy exam) (n = 10), and orange juice (commercially-available) (n = 10), as follows: 5 min in 3 mL of demineralization solution, rinse with distilled water, and store in artificial saliva for 3 h. This cycle was repeated four times a day for 14 days. Calcium (Ca) loss after acid exposure was determined by atomic emission spectroscopy. The presence of carbonate (CO) and phosphate (PO) in the specimens was evaluated before and after the erosive challenge by FT-Raman spectroscopy. Data were tested using t-tests (P enamel was observed in scanning electron microscopy (SEM). The mean loss of Ca was: 12.74 ± 3.33 mg/L Ca (gastric juice) and 7.07 ± 1.44 mg/L Ca (orange juice). The analysis by atomic emission spectroscopy showed statistically significant difference between erosive potential of juices (P = 0.0003). FT-Raman spectroscopy found no statistically significant difference in the ratio CO/PO after the erosive challenge. The CO/PO ratios values before and after the challenge were: 0.16/0.17 (gastric juice) (P = 0.37) and 0.18/0.14 (orange juice) (P = 0.16). Qualitative analysis by SEM showed intense alterations of enamel surface. The gastric juice caused more changes in morphology and mineral composition of dental enamel than orange juice. The atomic emission spectroscopy showed to be more suitable to analyze small mineral loss after erosive challenge than FT-Raman. Copyright © 2011 Wiley Periodicals, Inc.

  2. The staining effect of different mouthwashes containing nanoparticles on dental enamel.

    OpenAIRE

    Eslami, Neda; Ahrari, Farzaneh; Rajabi, Omid; Zamani, Roya

    2015-01-01

    Background This study aimed to evaluate the effects of several mouthwashes containing nanoparticles on discoloration of dental enamel, and compare the results with that of 0.2% chlorhexidine (CHX). Material and Methods Sixty intact premolars were randomly assigned to six groups. A spectrophotometer was used to measure the color of the teeth (T1) according to the CIELAB system. The specimens in groups 1 to 4 were then immersed in colloidal solutions containing nanoTiO2 (Group 1), nanoZnO (Grou...

  3. First-Aid Algorithms in Dental Avulsion

    Science.gov (United States)

    Baginska, Joanna; Wilczynska-Borawska, Magdalena

    2012-01-01

    Almost one fourth of traumatic dental injuries occur at schools or in their surroundings. Prevalence of tooth avulsion varies from 0.5% to 16% of all cases of dental trauma. Children with dental avulsion may seek help from school nurses so they should be able to provide first-aid treatment. However, many studies showed that the general level of…

  4. Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

    Science.gov (United States)

    Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

    2014-06-01

    To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (penamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (penamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

  5. In vitro study of 960 nm high power diode laser applications in dental enamel, aided by the presence of a photoinitiator dye: scanning electron microscopy analysis

    International Nuclear Information System (INIS)

    Oliveira, Marcelo Vinicius de

    2002-06-01

    The objective of this study is to verify if a high power diode laser can effectively modify the morphology of an enamel surface, and if this can be done in a controlled fashion by changing the lasers parameters. Previous studies using SEM demonstrated that through irradiation with Nd:YAG laser (1064 nm) it is possible to modify the morphology of the dental surface in such way as to increase its resistance against caries decays. The desired procedures that should achieve a decrease of the index of caries decays and of its sequels are on a primary level, which means that action is necessary before the disease installs itself. In this study it was used for the first time a prototype of a high power diode laser operating at 960 nm, produced by the Laboratory of Development of Lasers of the Center for Lasers and Applications of the IPEN. This equipment can present several advantages as reliability, reduced size and low cost. The aim was establish parameters of laser irradiation that produce the desired effects wanted in the enamel and protocols that guarantee its safety during application in dental hard tissues, protecting it of heating effects such as fissures and carbonization. (author)

  6. Tooth enamel hypoplasia in PHACE syndrome.

    Science.gov (United States)

    Chiu, Yvonne E; Siegel, Dawn H; Drolet, Beth A; Hodgson, Brian D

    2014-01-01

    Individuals with PHACE syndrome (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal cleft, and supraumbilical raphe syndrome) have reported dental abnormalities to their healthcare providers and in online forums, but dental involvement has not been comprehensively studied. A study was conducted at the third PHACE Family Conference, held in Milwaukee, Wisconsin, in July 2012. A pediatric dentist examined subjects at enrollment. Eighteen subjects were enrolled. The median age was 4.2 years (range 9 mos-9 yrs; 14 girls, 4 boys). Eleven of 18 patients had intraoral hemangiomas and five of these (50%) had hypomature enamel hypoplasia. None of the seven patients without intraoral hemangiomas had enamel hypoplasia. No other dental abnormalities were seen. Enamel hypoplasia may be a feature of PHACE syndrome when an intraoral hemangioma is present. Enamel hypoplasia increases the risk of caries, and clinicians should refer children with PHACE syndrome to a pediatric dentist by 1 year of age. © 2014 Wiley Periodicals, Inc.

  7. Mesoscopic modeling of the response of human dental enamel to mid-infrared radiation

    Science.gov (United States)

    Vila Verde, Ana; Ramos, Marta; Stoneham, A. M.

    2006-03-01

    Ablation of human dental enamel, a composite biomaterial with water pores, is of significant importance in minimally invasive laser dentistry but progress in the area is hampered by the lack of optimal laser parameters. We use mesoscopic finite element models of this material to study its response to mid-infrared radiation. Our results indicate that the cost-effective, off-the-shelf CO2 laser at λ = 10.6 μm may in fact ablate enamel precisely, reproducibly and with limited unwanted side effects such as cracking or heating, provided that a pulse duration of 10 μs is used. Furthermore, our results also indicate that the Er:YAG laser (λ = 2.94 μm), currently popular for laser dentistry, may in fact cause unwanted deep cracking in the enamel when regions with unusually high water content are irradiated, and also provide an explanation for the large range of ablation threshold values observed for this material. The model may be easily adapted to study the response of any composite material to infrared radiation and thus may be useful for the scientific community.

  8. ON THE EROSIVE EFFECT OF SOME BEVERAGES FOR SPORTSMEN UPON DENTAL ENAMEL

    Directory of Open Access Journals (Sweden)

    Cosmin ARNAUTEANU

    2015-06-01

    Full Text Available The aim of the study was to compare the surface morphology of enamel and the variation of the mineral ions concentration after the manifestation of the erosive effect determined by various commercial beverages for athletes. 14 premolars extracted from orthodontic reasons have been cut in two halves. On each section, an enamel surface of 3x3 mm was preserved for investigations. The samples have been divided into 4 groups. In the control group, the 7 sections were kept in artificial saliva while, in the other 3 groups, the sections were introduced in 3 beverages for athletes: Gatorade Citron (Pepsi Cola Co., 5-hour Energy (Living Essentials, Powerade Cherry (Coca Cola Co.. The samples were analyzed on an electronic microscope with Vega II LSH scanning device, coupled with EDX Quantax QX2 detector. SEM analysis evidenced erosion zones at the level of enamel, which appears pinched in the samples subjected to the action of acid beverages. A decreasing tendency of the average values of calcium ion concentrations was observed in the batches in which the enamel samples had been subjected to the action of beverages for athletes. The highest relative variations of calcium and phosphorous ions (10%, respectively 8% were recorded for Gatorade, followed, in decreasing order, by Powerade, for which variations of 9%, respectively 6%, were noticed, and by the 5-hour Energy beverage, in which the relative losses were of 5%, respectively 3%. All beverages for athletes tested in the present study showed erosion potential upon the dental enamel. Gatorade appeared as the most aggressive beverage for athletes followed by Powerade and 5-hour Energy.

  9. First aid in the dental practice: an overview.

    Science.gov (United States)

    Jevon, P

    2016-06-24

    First aid encompasses a wide range of scenarios ranging from simple reassurance following a minor mishap to dealing with a life-threatening emergency. Dentists may need to provide first aid in their dental practice to a patient, relative or member of staff. This article provides an overview to first aid in the dental practice, including priorities, responsibilities when providing first aid, assessment of the environment and the casualty (primary survey &secondary survey). The new A3 'First Aid in the Workplace' poster is now available and is included as an insert in this issue (BDJ Vol. 220, Issue 12).

  10. Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

    Directory of Open Access Journals (Sweden)

    Patrícia T Pires

    2013-01-01

    Full Text Available Context: Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Aims: Evaluate shear bond strength (SBS values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. Subjects and Methods: One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15 and to enamel morphology analysis ( n = 5 after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA+ ExciTE® ; Group II - ExciTE® ; Group III - AdheSE® self-etching; Group IV - FuturaBond® no-rinse. NR; Group V - Xeno® V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. Statistical Analysis Used: One-way ANOVA and post-hoc tests (p < 0.05. For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA and the etching pattern analyzed under Scanning Electron Microscope (SEM. Results: Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern; Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern; Group V - 24.43 MPa ± 1.55 (type II etching pattern. Conclusions: Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE® and ExciTE® without condition with PA. FuturaBond® NR and Xeno® V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

  11. Remineralization potential of nano-hydroxyapatite on enamel and cementum surrounding margin of computer-aided design and computer-aided manufacturing ceramic restoration

    Science.gov (United States)

    Juntavee, Niwut; Juntavee, Apa; Plongniras, Preeyarat

    2018-01-01

    Objective This study investigates the effects of nano-hydroxyapatite (NHA) gel and Clinpro (CP) on remineralization potential of enamel and cementum at the cavosurface area of computer-aided design and computer-aided manufacturing ceramic restoration. Materials and methods Thirty extracted human mandibular third molars were sectioned at 1 mm above and below the cemento–enamel junction to remove the cemento–enamel junction portions and replaced them with zirconia ceramic disks by bonding them to the crown and root portions with resin cement. The enamel and cementum with an area of 4×4 mm2 surrounding the ceramic disk was demineralized with carbopol. The demineralized surfaces were treated with either NHA or CP, while 1 group was left with no treatment. Vickers microhardness of enamel and cementum were determined before demineralization, after demineralization, and after remineralization. Analysis of variance and Tukey multiple comparisons were used to determine statistically significant differences at 95% level of confidence. Scanning electron microscopy and X-ray diffraction were used to evaluate for surface alterations. Results The mean ± SD of Vickers microhardness for before demineralization, after demineralization, and after remineralization for enamel and cementum were 377.37±22.99, 161.95±10.54, 161.70±5.92 and 60.37±3.81, 17.65±0.91, 17.04±1.00 for the no treatment group; 378.20±18.76, 160.72±8.38, 200.08±8.29 and 62.58±3.37, 18.38±1.33, 27.99±2.68 for the NHA groups; and 380.53±25.14, 161.94±5.66, 193.16±7.54 and 62.78±4.75, 19.07±1.30, 24.46±2.02 for the CP groups. Analysis of variance indicated significant increase in microhardness of demineralized enamel and cementum upon the application of either NHA or CP (pmanufacturing ceramic. PMID:29780246

  12. 'In vitro' assessment to instrumented indentation hardness tests in enamel of bovine teeth, before and after dental bleaching by laser

    International Nuclear Information System (INIS)

    Britto Junior, Francisco Meira

    2004-01-01

    The laser enamel bleaching is a common used procedure due to its satisfactory esthetic results. The possible changes on the dental structures caused by the bleaching technique are of great importance. The enamel superficial microhardness changes through instrumented indentation hardness on bovine teeth were analyzed in this present study. The samples were divided in two halves, one being the control and the other irradiated with a diode laser (808 nm) or with a Nd:YAG laser (1064 nm) to activate the Whiteness HP bleaching gel (hydrogen peroxide at 35%). It was possible to conclude that there was a statistical significant increase on the enamel superficial microhardness (Group I, sample 1 and Group II, sample 1) despite this increase did not seem to indicate a concern regarding the enamel surface resistance change. There was not a significant statistical change on the enamel microhardness on the other samples. The final conclusion is that there was no superficial enamel morphological change after these treatments. (author)

  13. Regulation of Dental Enamel Shape and Hardness

    Science.gov (United States)

    Simmer, J.P.; Papagerakis, P.; Smith, C.E.; Fisher, D.C.; Rountrey, A.N.; Zheng, L.; Hu, J.C.-C.

    2010-01-01

    Epithelial-mesenchymal interactions guide tooth development through its early stages and establish the morphology of the dentin surface upon which enamel will be deposited. Starting with the onset of amelogenesis beneath the future cusp tips, the shape of the enamel layer covering the crown is determined by five growth parameters: the (1) appositional growth rate, (2) duration of appositional growth (at the cusp tip), (3) ameloblast extension rate, (4) duration of ameloblast extension, and (5) spreading rate of appositional termination. Appositional growth occurs at a mineralization front along the ameloblast distal membrane in which amorphous calcium phosphate (ACP) ribbons form and lengthen. The ACP ribbons convert into hydroxyapatite crystallites as the ribbons elongate. Appositional growth involves a secretory cycle that is reflected in a series of incremental lines. A potentially important function of enamel proteins is to ensure alignment of successive mineral increments on the tips of enamel ribbons deposited in the previous cycle, causing the crystallites to lengthen with each cycle. Enamel hardens in a maturation process that involves mineral deposition onto the sides of existing crystallites until they interlock with adjacent crystallites. Neutralization of acidity generated by hydroxyapatite formation is a key part of the mechanism. Here we review the growth parameters that determine the shape of the enamel crown as well as the mechanisms of enamel appositional growth and maturation. PMID:20675598

  14. Ceramic-like wear behaviour of human dental enamel.

    Science.gov (United States)

    Arsecularatne, J A; Hoffman, M

    2012-04-01

    This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Selective ablation of dental enamel and dentin using femtosecond laser pulses

    International Nuclear Information System (INIS)

    Lizarelli, R F Z; Costa, M M; Carvalho-Filho, E; Bagnato, V S; Nunes, F D

    2008-01-01

    The study of the interaction of intense laser light with matter, as well as transient response of atoms and molecules is very appropriated because of the laser energy concentration in a femtosecond optical pulses. The fundamental problem to be solved is to find tools and techniques which allow us to observe and manipulate on a femtosecond time scale the photonics events on and into the matter. Six third human extracted molars were exposed to a femtosecond Ti:Sapphire Q-switched and mode locked laser (Libra-S, Coherent, Palo Alto, CA, USA), emitting pulses with 70 fs width, radiation wavelength of 801 nm, at a constant pulse repetition rate of 1 KHz. The laser was operated at different power levels (70 to 400 mW) with constant exposition time of 10 seconds, at focused and defocused mode. Enamel and dentin surfaces were evaluated concerned ablation rate and morphological aspects under scanning electron microscopic. The results in this present experiment suggest that at the focused mode and under higher average power, enamel tissues present microcavities with higher depth and very precise edges, but, while dentin shows a larger melt-flushing, lower depth and melting and solidification aspect. In conclusion, it is possible to choose hard or soft ablation, under lower and higher average power, respectively, revealing different aspects of dental enamel and dentin, depending on the average power, fluence and distance from the focal point of the ultra-short pulse laser on the tooth surface

  16. Analysis of the Early Stages and Evolution of Dental Enamel Erosion.

    Science.gov (United States)

    Derceli, Juliana Dos Reis; Faraoni, Juliana Jendiroba; Pereira-da-Silva, Marcelo Assumpção; Palma-Dibb, Regina Guenka

    2016-01-01

    The aim of this study was to evaluate by atomic force microscopy (AFM) the early phases and evolution of dental enamel erosion caused by hydrochloric acid exposure, simulating gastroesophageal reflux episodes. Polished bovine enamel slabs (4x4x2 mm) were selected and exposed to 0.1 mL of 0.01 M hydrochloric acid (pH=2) at 37 ?#61472;?#61616;C using five different exposure intervals (n=1): no acid exposure (control), 10 s, 20 s, 30 s and 40 s. The exposed area was analyzed by AFM in 3 regions to measure the roughness, surface area and morphological surface. The data were analyzed qualitatively. Roughness started as low as that of the control sample, Rrms=3.5 nm, and gradually increased at a rate of 0.3 nm/s, until reaching Rrms=12.5 nm at 30 s. After 40 s, the roughness presented increment of 0.40 nm only. Surface area (SA) increased until 20 s, and for longer exposures, the surface area was constant (at 30 s, SA=4.40 μm2 and at 40 s, SA=4.43 μm2). As regards surface morphology, the control sample presented smaller hydroxyapatite crystals (22 nm) and after 40 s the crystal size was approximately 60 nm. Short periods of exposure were sufficient to produce enamel demineralization in different patterns and the morphological structure was less affected by exposure to hydrochloric acid over 30 s.

  17. Dental Calculus Arrest of Dental Caries.

    Science.gov (United States)

    Keyes, Paul H; Rams, Thomas E

    An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. These observations further document the potential protective effects of dental calculus mineralization against dental caries.

  18. Dental Calculus Arrest of Dental Caries

    Science.gov (United States)

    Keyes, Paul H.; Rams, Thomas E.

    2016-01-01

    Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

  19. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    Science.gov (United States)

    Han, Xianglong; Liu, Xiaolin; Bai, Ding; Meng, Yao; Huang, Lan

    2008-11-01

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.

  20. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    International Nuclear Information System (INIS)

    Han Xianglong; Liu Xiaolin; Bai Ding; Meng Yao; Huang Lan

    2008-01-01

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure

  1. Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface

    Energy Technology Data Exchange (ETDEWEB)

    Han Xianglong [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Liu Xiaolin [Department of Orthodontics, Stomatology Hospital, Dalian University, Dalian 116021 (China); Bai Ding [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China); Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)], E-mail: baiding88@hotmail.com; Meng Yao; Huang Lan [Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

    2008-11-15

    In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.

  2. The effects of acid erosion and remineralization on enamel and three different dental materials: FT-Raman spectroscopy and scanning electron microscopy analysis.

    Science.gov (United States)

    Soares, Luís Eduardo Silva; Soares, Ana Lúcia Silva; De Oliveira, Rodrigo; Nahórny, Sidnei

    2016-07-01

    FT-Raman spectroscopy and scanning electron microscopy (SEM) were employed to test the hypothesis that the beverage consumption or mouthwash utilization would change the chemistry of dental materials and enamel inorganic content. Bovine enamel samples (n = 36) each received two cavity preparations (n = 72), each pair filled with one of three dental materials (R: nanofilled composite resin, GIC: glass-ionomer cement, RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: artificial saliva, E: erosion/Pepsi Twist or EM: erosion + mouthwash/Colgate Plax). Reduction of carbonate content of enamel was greater in RE than RS (P erosion. Material degradation was greater after E and EM than S. GIC and RMGIC materials had a positive effect against acid erosion in the adjacent enamel after remineralization with mouthwash. The beverage and mouthwash utilization would change R and GIC chemical properties. A professional should periodically monitor the glass-ionomer and resin restorations, as they degrade over time under erosive challenges and mouthwash utilization. Microsc. Res. Tech., 2016. © 2016 Wiley Periodicals, Inc. Microsc. Res. Tech. 79:646-656, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Identification of novel candidate genes involved in mineralization of dental enamel by genome-wide transcript profiling.

    Science.gov (United States)

    Lacruz, Rodrigo S; Smith, Charles E; Bringas, Pablo; Chen, Yi-Bu; Smith, Susan M; Snead, Malcolm L; Kurtz, Ira; Hacia, Joseph G; Hubbard, Michael J; Paine, Michael L

    2012-05-01

    The gene repertoire regulating vertebrate biomineralization is poorly understood. Dental enamel, the most highly mineralized tissue in mammals, differs from other calcifying systems in that the formative cells (ameloblasts) lack remodeling activity and largely degrade and resorb the initial extracellular matrix. Enamel mineralization requires that ameloblasts undergo a profound functional switch from matrix-secreting to maturational (calcium transport, protein resorption) roles as mineralization progresses. During the maturation stage, extracellular pH decreases markedly, placing high demands on ameloblasts to regulate acidic environments present around the growing hydroxyapatite crystals. To identify the genetic events driving enamel mineralization, we conducted genome-wide transcript profiling of the developing enamel organ from rat incisors and highlight over 300 genes differentially expressed during maturation. Using multiple bioinformatics analyses, we identified groups of maturation-associated genes whose functions are linked to key mineralization processes including pH regulation, calcium handling, and matrix turnover. Subsequent qPCR and Western blot analyses revealed that a number of solute carrier (SLC) gene family members were up-regulated during maturation, including the novel protein Slc24a4 involved in calcium handling as well as other proteins of similar function (Stim1). By providing the first global overview of the cellular machinery required for enamel maturation, this study provide a strong foundation for improving basic understanding of biomineralization and its practical applications in healthcare. Copyright © 2011 Wiley Periodicals, Inc.

  4. Residual heat deposition in dental enamel during IR laser ablation at 2.79, 2.94, 9.6, and 10.6 microm.

    Science.gov (United States)

    Fried, D; Ragadio, J; Champion, A

    2001-01-01

    The principal factor limiting the rate of laser ablation of dental hard tissue is the risk of excessive heat accumulation in the tooth. Excessive heat deposition or accumulation may result in unacceptable damage to the pulp. The objective of this study was to measure the residual heat deposition during the laser ablation of dental enamel at those IR laser wavelengths well suited for the removal of dental caries. Optimal laser ablation systems minimize the residual heat deposition in the tooth by efficiently transferring the deposited laser energy to kinetic and internal energy of ejected tissue components. The residual heat deposition in dental enamel was measured at laser wavelengths of 2.79, 2.94, 9.6, and 10.6 microm and pulse widths of 150 nsec -150 microsec using bovine block "calorimeters." Water droplets were applied to the surface before ablation with 150 microsec Er:YAG laser pulses to determine the influence of an optically thick water layer on reducing heat deposition. The residual heat was at a minimum for fluences well above the ablation threshold where measured values ranged from 25-70% depending on pulse duration and wavelength for the systems investigated. The lowest values of the residual heat were measured for short (heat deposition during ablation with 150 microsec Er:YAG laser pulses. Residual heat deposition can be markedly reduced by using CO(2) laser pulses of less than 20 microsec duration and shorter Q-switched Er:YAG and Er:YSGG laser pulses for enamel ablation. Copyright 2001 Wiley-Liss, Inc.

  5. Maryland residents' attitudes toward AIDS and the use of dental services.

    Science.gov (United States)

    Cohen, L A; Grace, E G; Ward, M A

    1992-01-01

    This project was conducted to examine the impact of Maryland residents' attitudes about AIDS on dental services utilization. A telephone survey of 1,477 households was conducted (response rate 68.9%). Less than 7 percent of the respondents volunteered a concern about contracting AIDS in the dental office. When asked directly, approximately 35 percent stated they would change dentists if their dentist were treating AIDS patients. Respondents who were most aware of the wide-spread treatment of AIDS patients by dentists were more likely to believe their dentist was treating AIDS patients. Also, they were less likely to report that they would leave the practice of dentists with AIDS or those who treated AIDS patients. It is critical for the public to be educated properly about the continued safety of the dental office and to receive accurate information about AIDS.

  6. Exogenous mineralization of hard tissues using photo-absorptive minerals and femto-second lasers; the case of dental enamel.

    Science.gov (United States)

    Anastasiou, A D; Strafford, S; Thomson, C L; Gardy, J; Edwards, T J; Malinowski, M; Hussain, S A; Metzger, N K; Hassanpour, A; Brown, C T A; Brown, A P; Duggal, M S; Jha, A

    2018-04-15

    A radical new methodology for the exogenous mineralization of hard tissues is demonstrated in the context of laser-biomaterials interaction. The proposed approach is based on the use of femtosecond pulsed lasers (fs) and Fe 3+ -doped calcium phosphate minerals (specifically in this work fluorapatite powder containing Fe 2 O 3 nanoparticles (NP)). A layer of the synthetic powder is applied to the surface of eroded bovine enamel and is irradiated with a fs laser (1040 nm wavelength, 1 GHz repetition rate, 150 fs pulse duration and 0.4 W average power). The Fe 2 O 3 NPs absorb the light and may act as thermal antennae, dissipating energy to the vicinal mineral phase. Such a photothermal process triggers the sintering and densification of the surrounding calcium phosphate crystals thereby forming a new, dense layer of typically ∼20 μm in thickness, which is bonded to the underlying surface of the natural enamel. The dispersed iron oxide NPs, ensure the localization of temperature excursion, minimizing collateral thermal damage to the surrounding natural tissue during laser irradiation. Simulated brushing trials (pH cycle and mechanical force) on the synthetic layer show that the sintered material is more acid resistant than the natural mineral of enamel. Furthermore, nano-indentation confirms that the hardness and Young's modulus of the new layers are significantly more closely matched to enamel than current restorative materials used in clinical dentistry. Although the results presented herein are exemplified in the context of bovine enamel restoration, the methodology may be more widely applicable to human enamel and other hard-tissue regenerative engineering. In this work we provide a new methodology for the mineralisation of dental hard tissues using femtosecond lasers and iron doped biomaterials. In particular, we demonstrate selective laser sintering of an iron doped fluorapatite on the surface of eroded enamel under low average power and mid

  7. Modelling of micromachining of human tooth enamel by erbium laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Belikov, A V; Skrypnik, A V; Shatilova, K V [St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg (Russian Federation)

    2014-08-31

    We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

  8. Modelling of micromachining of human tooth enamel by erbium laser radiation

    International Nuclear Information System (INIS)

    Belikov, A V; Skrypnik, A V; Shatilova, K V

    2014-01-01

    We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

  9. Effect of tooth-bleaching on the carbonate concentration in dental enamel by Raman spectroscopy

    OpenAIRE

    Vargas-Koudriavtsev, Tatiana; Herrera-Sancho, ?scar-Andrey

    2017-01-01

    Background There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. Material and Methods Sixty human teeth were randomly divided into six groups and exposed to three different home bleaching gels (Day White) and three in-office whitening agents (Zoom! Whitespeed and Pol...

  10. Fluoride uptake from restorative dental materials by human enamel

    International Nuclear Information System (INIS)

    Forsten, L.; Rytoemaa, I.; Anttila, A.; Keinonen, J.

    1976-01-01

    The purpose of the study was to determine the uptake in vitro of fluoride from restorative materials by tooth enamel and whether prior etching of the enamel causes a change of uptake. The outermost layer of the labial surface of extracted canines was removed by grinding and the enamel was covered with five different fluoride-containing materials ; a silicate, a composite resin, an amalgam, a silicophosphate, and a polycarboxylate luting cement. The material was either removed immediately or after storing the tooth in distilled water. The fluoride content was determined using a sensitive physical method based on the 19 F (p, αγ) 16 O reaction. In addition, the fluoride content of enamel after etching for different periods of time and of etched enamel which had been in contact with silicate cement was determined. The mean fluoride content of uncovered interior enamel was 226 parts 10 6 . All materials, except the composite, increased clearly the fluoride content of the underlying enamel. Etching of interior enamel also increased the fluoride values. No difference could be shown in fluoride uptake from silicate and composite resin between etched and unetched enamel. (author)

  11. Effect of carbonated beverages, coffee, sports and high energy drinks, and bottled water on the in vitro erosion characteristics of dental enamel.

    Science.gov (United States)

    Kitchens, Michael; Owens, Barry M

    2007-01-01

    This study evaluated the effect of carbonated and non-carbonated beverages, bottled and tap water, on the erosive potential of dental enamel with and without fluoride varnish protection. Beverages used in this study included: Coca Cola Classic, Diet Coke, Gatorade sports drink, Red Bull high-energy drink, Starbucks Frappuccino coffee drink, Dasani water (bottled), and tap water (control). Enamel surfaces were coated with Cavity Shield 5% sodium fluoride treatment varnish. Twenty-eight previously extracted human posterior teeth free of hypocalcification and caries were used in this study. The coronal portion of each tooth was removed and then sectioned transverse from the buccal to lingual surface using a diamond coated saw blade. The crown sections were embedded in acrylic resin blocks leaving the enamel surfaces exposed. The enamel surfaces were polished using 600 to 2000 grit abrasive paper and diamond paste. Test specimens were randomly distributed to seven beverage groups and comprised 4 specimens per group. Two specimens per beverage group were treated with a fluoride varnish while 2 specimens did not receive fluoride coating. Surface roughness (profilometer) readings were performed at baseline (prior to fluoride treatment and immersion in the beverage) and again, following immersion for 14 days (24 hours/day). The test beverages were changed daily and the enamel specimens were immersed at 37 degrees C. Surface roughness data was evaluated using multiple factor ANOVA at a significance level of pStarBucks coffee, Dasani water, and tap water. Fluoride varnish was not a significant impact factor; however, beverage (type) and exposure time were significant impact variables. Both carbonated and non-carbonated beverages displayed a significant erosive effect on dental enamel; however, fluoride varnish treatments did not demonstrate a significant protective influence on enamel surfaces.

  12. The Role of Na:K:2Cl Cotransporter 1 (NKCC1/SLC12A2) in Dental Epithelium during Enamel Formation in Mice

    Science.gov (United States)

    Jalali, Rozita; Lodder, Johannes C.; Zandieh-Doulabi, Behrouz; Micha, Dimitra; Melvin, James E.; Catalan, Marcelo A.; Mansvelder, Huibert D.; DenBesten, Pamela; Bronckers, Antonius

    2017-01-01

    Na+:K+:2Cl− cotransporters (NKCCs) belong to the SLC12A family of cation-coupled Cl− transporters. We investigated whether enamel-producing mouse ameloblasts express NKCCs. Transcripts for Nkcc1 were identified in the mouse dental epithelium by RT-qPCR and NKCC1 protein was immunolocalized in outer enamel epithelium and in the papillary layer but not the ameloblast layer. In incisors of Nkcc1-null mice late maturation ameloblasts were disorganized, shorter and the mineral density of the enamel was reduced by 10% compared to wild-type controls. Protein levels of gap junction protein connexin 43, Na+-dependent bicarbonate cotransporter e1 (NBCe1), and the Cl−-dependent bicarbonate exchangers SLC26A3 and SLC26A6 were upregulated in Nkcc1-null enamel organs while the level of NCKX4/SLC24A4, the major K+, Na+ dependent Ca2+ transporter in maturation ameloblasts, was slightly downregulated. Whole-cell voltage clamp studies on rat ameloblast-like HAT-7 cells indicated that bumetanide increased ion-channel activity conducting outward currents. Bumetanide also reduced cell volume of HAT-7 cells. We concluded that non-ameloblast dental epithelium expresses NKCC1 to regulate cell volume in enamel organ and provide ameloblasts with Na+, K+ and Cl− ions required for the transport of mineral- and bicarbonate-ions into enamel. Absence of functional Nkcc1 likely is compensated by other types of ion channels and ion transporters. The increased amount of Cx43 in enamel organ cells in Nkcc1-null mice suggests that these cells display a higher number of gap junctions to increase intercellular communication. PMID:29209227

  13. Detection sensitivity of fluorine in dental enamel through the 19F(p,psup(')γ)19F reaction

    International Nuclear Information System (INIS)

    Papper, C.S.; Chittleborough, G.; Kennett, S.R.; Chaudhri, M.A.

    1978-01-01

    The total cross sections for production of 109 and 197 keV gamma rays in the reaction 19 F(p,psup(')γ) 19 F have been measured, over a range of energies up to 4.3 MeV. From these cross sections, the thick detection sensitivities for a uniform distribution of fluorine in dental enamel have been calculated

  14. Efficacy of microtensile versus microshear bond testing for evaluation of bond strength of dental adhesive systems to enamel

    NARCIS (Netherlands)

    El Zohairy, A.A.; Saber, M.H.; Abdalla, A.I.; Feilzer, A.J.

    2010-01-01

    Objective The aim of the study was to evaluate the efficacy of the microtensile bond test (μTBS) and the microshear bond test (μSBS) in ranking four dental adhesives according to bond strength to enamel and identify the modes of failure involved. Materials and methods Forty-four caries-free human

  15. Genes expressed in dental enamel development are associated with molar-incisor hypomineralization.

    Science.gov (United States)

    Jeremias, Fabiano; Koruyucu, Mine; Küchler, Erika C; Bayram, Merve; Tuna, Elif B; Deeley, Kathleen; Pierri, Ricardo A; Souza, Juliana F; Fragelli, Camila M B; Paschoal, Marco A B; Gencay, Koray; Seymen, Figen; Caminaga, Raquel M S; dos Santos-Pinto, Lourdes; Vieira, Alexandre R

    2013-10-01

    Genetic disturbances during dental development influence variation of number and shape of the dentition. In this study, we tested if genetic variation in enamel formation genes is associated with molar-incisor hypomineralization (MIH), also taking into consideration caries experience. DNA samples from 163 cases with MIH and 82 unaffected controls from Turkey, and 71 cases with MIH and 89 unaffected controls from Brazil were studied. Eleven markers in five genes [ameloblastin (AMBN), amelogenin (AMELX), enamelin (ENAM), tuftelin (TUFT1), and tuftelin-interacting protein 11 (TFIP11)] were genotyped by the TaqMan method. Chi-square was used to compare allele and genotype frequencies between cases with MIH and controls. In the Brazilian data, distinct caries experience within the MIH group was also tested for association with genetic variation in enamel formation genes. The ENAM rs3796704 marker was associated with MIH in both populations (Brazil: p=0.03; OR=0.28; 95% C.I.=0.06-1.0; Turkey: p=1.22e-012; OR=17.36; 95% C.I.=5.98-56.78). Associations between TFIP11 (p=0.02), ENAM (p=0.00001), and AMELX (p=0.01) could be seen with caries independent of having MIH or genomic DNA copies of Streptococcus mutans detected by real time PCR in the Brazilian sample. Several genes involved in enamel formation appear to contribute to MIH. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Penetration of Streptococcus sobrinus and Streptococcus sanguinis into dental enamel.

    Science.gov (United States)

    Kneist, Susanne; Nietzsche, Sandor; Küpper, Harald; Raser, Gerhard; Willershausen, Brita; Callaway, Angelika

    2015-10-01

    The aim of this pilot study was to assess the difference in virulence of acidogenic and aciduric oral streptococci in an in vitro caries model using their penetration depths into dental enamel. 30 caries-free extracted molars from 11- to 16-year-olds were cleaned ultrasonically for 1 min with de-ionized water and, after air-drying, embedded in epoxy resin. After 8-h of setting at room temperature, the specimens were ground on the buccal side with SiC-paper 1200 (particle size 13-16 μm). Enamel was removed in circular areas sized 3 mm in diameter; the mean depth of removed enamel was 230 ± 60 μm. 15 specimens each were incubated anaerobically under standardized conditions with 24 h-cultures of Streptococcus sanguinis 9S or Streptococcus sobrinus OMZ 176 in Balmelli broth at 37 ± 2 °C; the pH-values of the broths were measured at the beginning and end of each incubation cycle. After 2, 4, 6, 8, and 10 weeks 3 teeth each were fixed in 2.5% glutaraldehyde in cacodylate buffer for 24 h, washed 3× and dehydrated 30-60min by sequential washes through a series of 30-100% graded ethanol. The teeth were cut in half longitudinally; afterward, two slits were made to obtain fracture surfaces in the infected area. After critical-point-drying the fragments were gold-sputtered and viewed in a scanning electron microscope at magnifications of ×20-20,000. After 10 weeks of incubation, penetration of S. sanguinis of 11.13 ± 24.04 μm below the break edges into the enamel was observed. The invasion of S. sobrinus reached depths of 87.53 ± 76.34 μm. The difference was statistically significant (paired t test: p = 0.033). The experimental penetration depths emphasize the importance of S. sanguinis versus S. sobrinus in the context of the extended ecological plaque hypothesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Real-time near-IR imaging of laser-ablation crater evolution in dental enamel

    Science.gov (United States)

    Darling, Cynthia L.; Fried, Daniel

    2007-02-01

    We have shown that the enamel of the tooth is almost completely transparent near 1310-nm in the near-infrared and that near-IR (NIR) imaging has considerable potential for the optical discrimination of sound and demineralized tissue and for observing defects in the interior of the tooth. Lasers are now routinely used for many applications in dentistry including the ablation of dental caries. The objective of this study was to test the hypothesis that real-time NIR imaging can be used to monitor laser-ablation under varying conditions to assess peripheral thermal and transient-stress induced damage and to measure the rate and efficiency of ablation. Moreover, NIR imaging may have considerable potential for monitoring the removal of demineralized areas of the tooth during cavity preparations. Sound human tooth sections of approximately 3-mm thickness were irradiated by a CO II laser under varying conditions with and without a water spray. The incision area in the interior of each sample was imaged using a tungsten-halogen lamp with band-pass filter centered at 131--nm combined with an InGaAs focal plane array with a NIR zoom microscope in transillumination. Due to the high transparency of enamel at 1310-nm, laser-incisions were clearly visible to the dentin-enamel junction and crack formation, dehydration and irreversible thermal changes were observed during ablation. This study showed that there is great potential for near-IR imaging to monitor laser-ablation events in real-time to: assess safe laser operating parameters by imaging thermal and stress-induced damage, elaborate the mechanisms involved in ablation such as dehydration, and monitor the removal of demineralized enamel.

  18. Effect of tooth-bleaching on the carbonate concentration in dental enamel by Raman spectroscopy.

    Science.gov (United States)

    Vargas-Koudriavtsev, Tatiana; Herrera-Sancho, Óscar-Andrey

    2017-01-01

    There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. Sixty human teeth were randomly divided into six groups and exposed to three different home bleaching gels (Day White) and three in-office whitening agents (Zoom! Whitespeed and PolaOffice) according to the manufacturer´s instructions. The concentration of carbonate molecules in enamel was measured prior to and during the treatment by means of Raman spectroscopy. Statistical analysis included repeated measures analysis of variance ( p ≤0.05) and Bonferroni pairwise comparisons. At home bleaching agents depicted a decrease in the carbonate molecule. This decrease was statistically significant for the bleaching gel with the highest hydrogen peroxide concentration ( p ≤0,05). In-office whitening agents caused an increase in carbonate, which was significant for all three groups ( p ≤0,05). In-office bleaching gels seem to cause a gain in carbonate of the enamel structure, whilst at-home whitening gels caused a loss in carbonate. Key words: Bleaching, whitening, hydrogen peroxide, carbamide peroxide, Raman spectroscopy, carbonate.

  19. Effect of different dental ceramic systems on the wear of human enamel: An in vitro study.

    Science.gov (United States)

    Zandparsa, Roya; El Huni, Rabie M; Hirayama, Hiroshi; Johnson, Marc I

    2016-02-01

    The wear of tooth structure opposing different advanced dental ceramic systems requires investigation. The purpose of this in vitro study was to compare the wear of advanced ceramic systems against human enamel antagonists. Four ceramic systems (IPS e.max Press, IPS e.max CAD, Noritake Super Porcelain EX-3, and LAVA Plus Zirconia) and 1 control group containing human enamel specimens were used in this study (n = 12). All specimens were fabricated as disks 11 mm in diameter and 3 mm thick. The mesiopalatal cusps of the maxillary third molars were prepared to serve as the enamel styluses. All specimens were embedded individually in 25 mm(3) autopolymerizing acrylic resin blocks. Wear was measured with a cyclic loading machine and a newly designed wear simulator. All enamel styluses (cusps) were scanned using the Activity 880 digital scanner (SmartOptics). Data from the base line and follow-up scans were collected and compared with Qualify 2012 3-dimensional (3D) and 2D digital inspection software (Geomagic), which aligned the models and detected the geometric changes and the wear caused by the antagonist specimen. One-way ANOVA was used to analyze the collected data. After 125,000 bidirectional loading cycles, the mean loss of opposing enamel volume for the enamel disks in the control group was 37.08 μm(3), the lowest mean value for IPS e.max Press system was 39.75 μm(3); 40.58 μm(3) for IPS e.max CAD; 45.08 μm(3) for Noritake Super Porcelain EX-3 system; and 48.66 μm(3) for the Lava Plus Zirconia system. No statically significant differences were found among the groups in opposing enamel volume loss (P=.225) or opposing enamel height loss (P=.149). In terms of opposing enamel height loss, Lava Plus Zirconia system showed the lowest mean value of 27.5 μm. The mean value for the IPS e.max CAD system was 27.91 μm; 29.08 μm for the control enamel; 33.25 μm for the IPS e.max Press system; and 34.75 μm for the Noritake Super Porcelain EX-3 system. Within the

  20. Effects of blue light irradiation on dental enamel remineralization in vitro; Avaliacao dos efeitos promovidos pela radiacao azul na remineralizacao do esmalte dentario in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ilka Tiemy

    2009-07-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm{sup 2} e 6.25 mL/mm{sup 2}). The lesions were irradiated with blue LED (l=455{+-}20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm{sup 2}, radiant exposure of 13.8 J/{sup c}m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  1. Qualitative and quantitative evaluation of human dental enamel after bracket debonding: a noncontact three-dimensional optical profilometry analysis.

    Science.gov (United States)

    Ferreira, Fabiano G; Nouer, Darcy F; Silva, Nelson P; Garbui, Ivana U; Correr-Sobrinho, Lourenço; Nouer, Paulo R A

    2014-09-01

    The aim of this study was to undertake a qualitative and quantitative evaluation of changes on enamel surfaces after debonding of brackets followed by finishing procedures, using a high-resolution three-dimensional optical profiler and to investigate the accuracy of the technique. The labial surfaces of 36 extracted upper central incisors were examined. Before bonding, the enamel surfaces were subjected to profilometry, recording four amplitude parameters. Brackets were then bonded using two types of light-cured orthodontic adhesive: composite resin and resin-modified glass ionomer cement. Finishing was performed by three different methods: pumice on a rubber cup, fine and ultrafine aluminum oxide discs, and microfine diamond cups followed by silicon carbide brushes. The samples were subsequently re-analyzed by profilometry. Wilcoxon signed-rank test, Kruskal-Wallis test (p enamel roughness when diamond cups followed by silicon carbide brushes were used to finish surfaces that had remnants of resin-modified glass ionomer adhesive and when pumice was used to finish surfaces that had traces of composite resin. Enamel loss was minimal. The 3D optical profilometry technique was able to provide accurate qualitative and quantitative assessment of changes on the enamel surface after debonding. Morphological changes in the topography of dental surfaces, especially if related to enamel loss and roughness, are of considerable clinical importance. The quantitative evaluation method used herein enables a more comprehensive understanding of the effects of orthodontic bonding on teeth.

  2. Oriented and Ordered Biomimetic Remineralization of the Surface of Demineralized Dental Enamel Using HAP@ACP Nanoparticles Guided by Glycine

    Science.gov (United States)

    Wang, Haorong; Xiao, Zuohui; Yang, Jie; Lu, Danyang; Kishen, Anil; Li, Yanqiu; Chen, Zhen; Que, Kehua; Zhang, Qian; Deng, Xuliang; Yang, Xiaoping; Cai, Qing; Chen, Ning; Cong, Changhong; Guan, Binbin; Li, Ting; Zhang, Xu

    2017-01-01

    Achieving oriented and ordered remineralization on the surface of demineralized dental enamel, thereby restoring the satisfactory mechanical properties approaching those of sound enamel, is still a challenge for dentists. To mimic the natural biomineralization approach for enamel remineralization, the biological process of enamel development proteins, such as amelogenin, was simulated in this study. In this work, carboxymethyl chitosan (CMC) conjugated with alendronate (ALN) was applied to stabilize amorphous calcium phosphate (ACP) to form CMC/ACP nanoparticles. Sodium hypochlorite (NaClO) functioned as the protease which decompose amelogenin in vivo to degrade the CMC-ALN matrix and generate HAP@ACP core-shell nanoparticles. Finally, when guided by 10 mM glycine (Gly), HAP@ACP nanoparticles can arrange orderly and subsequently transform from an amorphous phase to well-ordered rod-like apatite crystals to achieve oriented and ordered biomimetic remineralization on acid-etched enamel surfaces. This biomimetic remineralization process is achieved through the oriented attachment (OA) of nanoparticles based on non-classical crystallization theory. These results indicate that finding and developing analogues of natural proteins such as amelogenin involved in the biomineralization by natural macromolecular polymers and imitating the process of biomineralization would be an effective strategy for enamel remineralization. Furthermore, this method represents a promising method for the management of early caries in minimal invasive dentistry (MID).

  3. Refining enamel thickness measurements from B-mode ultrasound images.

    Science.gov (United States)

    Hua, Jeremy; Chen, Ssu-Kuang; Kim, Yongmin

    2009-01-01

    Dental erosion has been growing increasingly prevalent with the rise in consumption of heavy starches, sugars, coffee, and acidic beverages. In addition, various disorders, such as Gastroenterological Reflux Disease (GERD), have symptoms of rapid rates of tooth erosion. The measurement of enamel thickness would be important for dentists to assess the progression of enamel loss from all forms of erosion, attrition, and abrasion. Characterizing enamel loss is currently done with various subjective indexes that can be interpreted in different ways by different dentists. Ultrasound has been utilized since the 1960s to determine internal tooth structure, but with mixed results. Via image processing and enhancement, we were able to refine B-mode dental ultrasound images for more accurate enamel thickness measurements. The mean difference between the measured thickness of the occlusal enamel from ultrasound images and corresponding gold standard CT images improved from 0.55 mm to 0.32 mm with image processing (p = 0.033). The difference also improved from 0.62 to 0.53 mm at the buccal/lingual enamel surfaces, but not significantly (p = 0.38).

  4. The impact of stannous, fluoride ions and its combination on enamel pellicle proteome and dental erosion prevention.

    Directory of Open Access Journals (Sweden)

    A A Algarni

    Full Text Available To compare the effects of stannous (Sn and fluoride (F ions and their combination on acquired enamel pellicle (AEP protein composition (proteome experiment, and protection against dental erosion (functional experiment.In the proteome experiment, bovine enamel specimens were incubated in whole saliva supernatant for 24h for AEP formation. They were randomly assigned to 4 groups (n=10, according to the rinse treatment: Sn (800ppm/6.7mM, SnCl2, F (225ppm/13mM, NaF, Sn and F combination (Sn+F and deionized water (DIW, negative control. The specimens were immersed 3× in the test rinses for 2min, 2h apart. Pellicles were collected, digested, and analyzed for protein content using liquid chromatography electrospray ionization tandem mass spectrometry. In the functional experiment, bovine enamel specimens (n=10 were similarly treated for pellicle formation. Then, they were subjected to a five-day erosion cycling model, consisting of 5min erosive challenges (15.6 mM citric acid, pH 2.6, 6×/d and 2min treatment with the rinses containing Sn, F or Sn+F (3×/d. Between the treatments, all specimens were incubated in whole saliva supernatant. Surface loss was determined by profilometry.Our proteome approach on bovine enamel identified 72 proteins that were common to all groups. AEP of enamel treated with Sn+F demonstrated higher abundance for most of the identified proteins than the other groups. The functional experiment showed reduction of enamel surface loss for Sn+F (89%, Sn (67% and F (42% compared to DIW (all significantly different, p<0.05.This study highlighted that anti-erosion rinses (e.g. Sn+F can modify quantitatively and qualitatively the AEP formed on bovine enamel. Moreover, our study demonstrated a combinatory effect that amplified the anti-erosive protection on tooth surface.

  5. Dental Pulp Defence and Repair Mechanisms in Dental Caries

    OpenAIRE

    Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J.; Cooper, Paul R.

    2015-01-01

    Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and red...

  6. Dental enamel Hypoplasia. Investigations on the Bones Exhumed from the Medieval Necropole of Lozova (Republic of Moldova, XIVth–XVth Centuries

    Directory of Open Access Journals (Sweden)

    Robert Daniel Simalcsik

    2014-10-01

    Full Text Available Dental hypoplasia is a developmental anomaly based on perturbations of amelogenesis. Hypoplasia defects are part of the unspecific quantitative indicators for the state of health and / or nutritional state during the formation of the dental buds. It is a response of the human organism to physiological stress. The incidence of this dysplasia in a past population can indicate its biological frailty in its attempt to adapt to the environmental changes. The osteological material was excavated in the interval 2010 – 2011 by archaeologists from the Archaeology Centre in Chisinau, from the Medieval cemetery of Lozova (Straseni County, Republic of Moldova, dated for the XIVth and XVth centuries. Fifty one skeletons from 50 inhumation graves have been excavated and analyzed so far. Only 40 individuals had most of their teeth present. The enamel hypoplasia is of linear transversal type, located on the labial surface of the dental crowns, in the median third. The canine is the most affected tooth, followed by the incisors. The incidence of dental enamel hypoplasia at population level (based on the data collected and on the number of graves excavates so far, which does not illustrate the entire population of the cemetery is 7.5%. The incidence of dental caries is 23.53%, of cribra orbitalia – 11.75%, and of cribra cranii externa – 1.96%. The results obtained for a relatively small rural community illustrate a good adaptation to the stressing environmental factors. The possible malnutrition and illness episodes suffered during early childhood were recovered along the growth and development processes.

  7. Chromatographic separation of alkaline phosphatase from dental enamel

    DEFF Research Database (Denmark)

    Moe, D; Kirkeby, S; Salling, E

    1989-01-01

    Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4.......4. Three enzyme peaks were eluted using low pressure chromatography with a Bio-gel column. With a HPLC gel filtration column the separation of the enamel extract resulted in only one peak with AP activity. The fractions of this peak were used to produce an antibody against bovine AP....

  8. A quantitative light microscopic study of the odontoblast and subodontoblastic reactions to active and arrested enamel caries without cavitation

    DEFF Research Database (Denmark)

    Bjørndal, L.; Darvann, T.A.; Thylstrup, Anders

    1998-01-01

    Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast......Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast...

  9. Indirect veneer treatment of anterior maxillary teeth with enamel hypoplasia

    OpenAIRE

    Juniarti, Devi Eka

    2010-01-01

    Background: Nowadays, aesthetic rehabilitation becomes a necessity. It is affected by patient’s background, especially career, social and economic status. The aesthetic abnormality of anterior teeth i.e discoloration, malposition and malformation can affect patient’s appearance, especially during smile. These dental abnormalities, as a result, can decrease patient’s performance. Dental malformation, for instance, can be caused by developmental tooth defect, such as enamel hypoplasia. Enamel h...

  10. Dental caries: Strategies to control this preventable disease

    Directory of Open Access Journals (Sweden)

    Andrew Rugg-Gunn

    2013-11-01

    Full Text Available Objective. To provide a brief commentary review of strategies to control dental caries. Dental decay is one of man’s most prevalent diseases. In many counties, severity increased in parallel with importation of sugar, reaching its zenith about 1950s and 1960s. Since then, severity has declined in many countries, due to the wide use of fluoride especially in toothpaste, but dental caries remains a disease of medical, social and economic importance. Within the EU in 2011, the cost of dental treatment was estimated to be €79 billion. The pathogenesis is well understood: bacteria in dental plaque (biofilm metabolise dietary sugars to acids which then dissolve dental enamel and dentine. Possible approaches to control caries development, therefore, involve: removal of plaque, reducing the acidogenic potential of plaque, reduction in sugar consumption, increasing the tooth’s resistance to acid attack, and coating the tooth surface to form a barrier between plaque and enamel. At the present time, only three approaches are of practical importance: sugar control, fluoride, and fissure sealing. The evidence that dietary sugars are the main cause of dental caries is extensive, and comes from six types of study. Without sugar, caries would be negligible. Fluoride acts in several ways to aid caries prevention. Ways of delivering fluoride can be classed as: ‘automatic’, ‘home care’ and ‘professional care’: the most important of these are discussed in detail in four articles in this issue of the Acta Medica Academica. Conclusion. Dental caries is preventable – individuals, communities and countries need strategies to achieve this.

  11. A simple, sensitive and non-destructive technique for characterizing bovine dental enamel erosion: attenuated total reflection Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Kim, In-Hye; Son, Jun Sik; Min, Bong Ki; Kim, Young Kyoung; Kim, Kyo-Han; Kwon, Tae-Yub

    2016-03-30

    Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Deionized water (control) and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth (110) were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 °C. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers' microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ν1, ν3 phosphate contour: the ratio of the height amplitude of ν3 PO4 to that of ν1 PO4 (Method 1) and the shift of the ν3 PO4 peak to a higher wavenumber (Method 2). The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy (Perosion.

  12. Deformation behavior of human enamel and dentin-enamel junction under compression.

    Science.gov (United States)

    Zaytsev, Dmitry; Panfilov, Peter

    2014-01-01

    Deformation behavior under uniaxial compression of human enamel and dentin-enamel junction (DEJ) is considered in comparison with human dentin. This deformation scheme allows estimating the total response from all levels of the hierarchical composite material in contrast with the indentation, which are limited by the mesoscopic and microscopic scales. It was shown for the first time that dental enamel is the strength (up to 1850MPa) hard tissue, which is able to consider some elastic (up to 8%) and plastic (up to 5%) deformation under compression. In so doing, it is almost undeformable substance under the creep condition. Mechanical properties of human enamel depend on the geometry of sample. Human dentin exhibits the similar deformation behavior under compression, but the values of its elasticity (up to 40%) and plasticity (up to 18%) are much more, while its strength (up to 800MPa) is less in two times. Despite the difference in mechanical properties, human enamel is able to suppress the cracking alike dentin. Deformation behavior under the compression of the samples contained DEJ as the same to dentin. This feature allows a tooth to be elastic-plastic (as dentin) and wear resistible (as enamel), simultaneously. © 2013 Elsevier B.V. All rights reserved.

  13. Enamel formation and growth in non-mammalian cynodonts

    Science.gov (United States)

    Dirks, Wendy; Martinelli, Agustín G.

    2018-01-01

    The early evolution of mammals is associated with the linked evolutionary origin of diphyodont tooth replacement, rapid juvenile growth and determinate adult growth. However, specific relationships among these characters during non-mammalian cynodont evolution require further exploration. Here, polarized light microscopy revealed incremental lines, resembling daily laminations of extant mammals, in histological sections of enamel in eight non-mammalian cynodont species. In the more basal non-probainognathian group, enamel extends extremely rapidly from cusp to cervix. By contrast, the enamel of mammaliamorphs is gradually accreted, with slow rates of crown extension, more typical of the majority of non-hypsodont crown mammals. These results are consistent with the reduction in dental replacement rate across the non-mammalian cynodont lineage, with greater rates of crown extension required in most non-probainognathians, and slower crown extension rates permitted in mammaliamorphs, which have reduced patterns of dental replacement in comparison with many non-probainognathians. The evolution of mammal-like growth patterns, with faster juvenile growth and more abruptly terminating adult growth, is linked with this reduction in dental replacement rates and may provide an additional explanation for the observed pattern in enamel growth rates. It is possible that the reduction in enamel extension rates in mammaliamorphs reflects an underlying reduction in skeletal growth rates at the time of postcanine formation, due to a more abruptly terminating pattern of adult growth in these more mammal-like, crownward species. PMID:29892415

  14. Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography.

    Science.gov (United States)

    Maia, Ana Marly Araújo; de Freitas, Anderson Zanardi; de L Campello, Sergio; Gomes, Anderson Stevens Leônidas; Karlsson, Lena

    2016-06-01

    An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light-Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System. QLF versus OCT imaging of enamel caries: a photonics assessment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Indirect veneer treatment of anterior maxillary teeth with enamel hypoplasia

    Directory of Open Access Journals (Sweden)

    Devi Eka Juniarti

    2010-09-01

    Full Text Available Background: Nowadays, aesthetic rehabilitation becomes a necessity. It is affected by patient’s background, especially career, social and economic status. The aesthetic abnormality of anterior teeth i.e discoloration, malposition and malformation can affect patient’s appearance, especially during smile. These dental abnormalities, as a result, can decrease patient’s performance. Dental malformation, for instance, can be caused by developmental tooth defect, such as enamel hypoplasia. Enamel hypoplasia is a developmental defect caused by the lack of matrix amount which leads to thin and porous enamel. Enamel hypoplasia can also be caused by matrix calcification disturbance starting from the formation and development of enamel matrix causing defect and permanent changes which can occur on one or more tooth. Purpose: The aim of the study is to improve dental discoloration and tooth surface texture on anterior maxillary teeth with enamel hypoplasia by using indirect veneer with porcelain material. Case: A 20 years-old woman with enamel hypoplasia came to the Dental Hospital, Faculty of Dentistry Airlangga University. The patient wanted to improve her anterior maxillary teeth. It is clinically known that there were some opaque white spots (chalky spotted and porous on anterior teeth’s surface. Case management: Indirect veneer with porcelain material had been chosen as a restoration treatment which has excellent aesthetics and strength, and did not cause gingival irritation. As a result, the treatment could improve the confidence of the patient, and could also make their function normal. Conclusion: Indirect veneer is an effective treatment, which can improve patient’s appearance and self confidence.Latar belakang: Saat ini perbaikan estetik menjadi suatu kebutuhan. Kebutuhan akan estetik dipengaruhi latar belakang penderita, terutama karir, status sosial dan ekonomi. Hal ini disebabkan, kelainan estetik seperti diskolorasi, malposisi

  16. Store-operated Ca2+ Entry Modulates the Expression of Enamel Genes.

    Science.gov (United States)

    Nurbaeva, M K; Eckstein, M; Snead, M L; Feske, S; Lacruz, R S

    2015-10-01

    Dental enamel formation is an intricate process tightly regulated by ameloblast cells. The correct spatiotemporal patterning of enamel matrix protein (EMP) expression is fundamental to orchestrate the formation of enamel crystals, which depend on a robust supply of Ca2+. In the extracellular milieu, Ca2+ -EMP interactions occur at different levels. Despite its recognized role in enamel development, the molecular machinery involved in Ca2+ homeostasis in ameloblasts remains poorly understood. A common mechanism for Ca2+ influx is store-operated Ca2+ entry (SOCE). We evaluated the possibility that Ca2+ influx in enamel cells might be mediated by SOCE and the Ca2+ release-activated Ca2+ (CRAC) channel, the prototypical SOCE channel. Using ameloblast-like LS8 cells, we demonstrate that these cells express Ca2+ -handling molecules and mediate Ca2+ influx through SOCE. As a rise in the cytosolic Ca2+ concentration is a versatile signal that can modulate gene expression, we assessed whether SOCE in enamel cells had any effect on the expression of EMPs. Our results demonstrate that stimulating LS8 cells or murine primary enamel organ cells with thapsigargin to activate SOCE leads to increased expression of Amelx, Ambn, Enam, Mmp20. This effect is reversed when cells are treated with a CRAC channel inhibitor. These data indicate that Ca2+ influx in LS8 cells and enamel organ cells is mediated by CRAC channels and that Ca2+ signals enhance the expression of EMPs. Ca2+ plays an important role not only in mineralizing dental enamel but also in regulating the expression of EMPs. © International & American Associations for Dental Research 2015.

  17. Enamel Regeneration - Current Progress and Challenges

    Science.gov (United States)

    Baswaraj; H.K, Navin; K.B, Prasanna

    2014-01-01

    Dental Enamel is the outermost covering of teeth. It is hardest mineralized tissue present in the human body. Enamel faces the challenge of maintaining its integrity in a constant demineralization and remineralization within the oral environment and it is vulnerable to wear, damage, and decay. It cannot regenerate itself, because it is formed by a layer of cells that are lost after the tooth eruption. Conventional treatment relies on synthetic materials to restore lost enamel that cannot mimic natural enamel. With advances in material science and understanding of basic principles of organic matrix mediated mineralization paves a way for formation of synthetic enamel. The knowledge of enamel formation and understanding of protein interactions and their gene products function along with the isolation of postnatal stem cells from various sources in the oral cavity, and the development of smart materials for cell and growth factor delivery, makes possibility for biological based enamel regeneration. This article will review the recent endeavor on biomimetic synthesis and cell based strategies for enamel regeneration. PMID:25386548

  18. Bonding strategies for MIH-affected enamel and dentin.

    Science.gov (United States)

    Krämer, Norbert; Bui Khac, Ngoc-Han Nana; Lücker, Susanne; Stachniss, Vitus; Frankenberger, Roland

    2018-02-01

    Aim of the present study was to evaluate resin composite adhesion to dental hard tissues affected by molar incisor hypomineralisation (MIH). 94 freshly extracted human molars and incisors (53 suffering MIH) were used. 68 teeth (35 with MIH) were used for μ-TBS tests in enamel and dentin, 26 (18 with MIH) for qualitative evaluation. Specimens were bonded with Clearfil SE Bond, Scotchbond Universal, and OptiBond FL. For MIH affected enamel, additional OptiBond FL groups with NaOCl and NaOCl+Icon were investigated. Beside fractographic analysis, also qualitative evaluations were performed using SEM at different magnifications as well as histological sectioning. Highest μ-TBS values were recorded with dentin specimens (ANOVA, mod. LSD, p0.05). Pre-test failures did not occur in dentin specimens. Sound enamel specimens exhibited significantly higher μ-TBS values than MIH enamel (p0.05), however, it caused less pre-test failures (pMIH enamel is the limiting factor in adhesion to MIH teeth. MIH-affected dentin may be bonded conventionally. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  19. The molecular basis of hereditary enamel defects in humans.

    Science.gov (United States)

    Wright, J T; Carrion, I A; Morris, C

    2015-01-01

    The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. © International & American Associations for

  20. Acid demineralization susceptibility of dental enamel submitted to different bleaching techniques and fluoridation regimens.

    Science.gov (United States)

    Salomão, Dlf; Santos, Dm; Nogueira, Rd; Palma-Dibb, Rg; Geraldo-Martins, Vr

    2014-01-01

    The aim of the current study was to assess the acid demineralization susceptibility of bleached dental enamel submitted to different fluoride regimens. One hundred bovine enamel blocks (6×6×3 mm) were randomly divided into 10 groups (n=10). Groups 1 and 2 received no bleaching. Groups 3 to 6 were submitted to an at-home bleaching technique using 6% hydrogen peroxide (HP; G3 and G4) or 10% carbamide peroxide (CP; G5 and G6). Groups 7 to 10 were submitted to an in-office bleaching technique using 35% HP (G7 and G8) or 35% CP (G9 and G10). During bleaching, a daily fluoridation regimen of 0.05% sodium fluoride (NaF) solution was performed on groups 3, 5, 7, and 9, while weekly fluoridation with a 2% NaF gel was performed on groups 4, 6, 8, and 10. The samples in groups 2 to 10 were pH cycled for 14 consecutive days. The samples from all groups were then assessed by cross-sectional Knoop microhardness at different depths from the outer enamel surface. The average Knoop hardness numbers (KHNs) were compared using one-way analysis of variance and Tukey tests (α=0.05). The comparison between groups 1 and 2 showed that the demineralization method was effective. The comparison among groups 2 to 6 showed the same susceptibility to acid demineralization, regardless of the fluoridation method used. However, the samples from groups 8 and 10 showed more susceptibility to acid demineralization when compared with group 2 (penamel to acid demineralization. However, the use of 35% HP and 35% CP must be associated with a daily fluoridation regimen, otherwise the in-office bleaching makes the bleached enamel more susceptible to acid demineralization.

  1. Computer-aided dental prostheses construction using reverse engineering.

    Science.gov (United States)

    Solaberrieta, E; Minguez, R; Barrenetxea, L; Sierra, E; Etxaniz, O

    2014-01-01

    The implementation of computer-aided design/computer-aided manufacturing (CAD/CAM) systems with virtual articulators, which take into account the kinematics, constitutes a breakthrough in the construction of customised dental prostheses. This paper presents a multidisciplinary protocol involving CAM techniques to produce dental prostheses. This protocol includes a step-by-step procedure using innovative reverse engineering technologies to transform completely virtual design processes into customised prostheses. A special emphasis is placed on a novel method that permits a virtual location of the models. The complete workflow includes the optical scanning of the patient, the use of reverse engineering software and, if necessary, the use of rapid prototyping to produce CAD temporary prostheses.

  2. Measurement of opalescence of tooth enamel.

    Science.gov (United States)

    Lee, Yong-Keun; Yu, Bin

    2007-08-01

    Opalescent dental esthetic restoratives look natural and esthetic in any light, react to light in the same manner as the natural tooth and show improved masking effect. The objective of this study was to determine the opalescence of tooth enamel with reflection spectrophotometers. Color of intact bovine and human enamel was measured in the reflectance and transmittance modes. Two kinds of spectrophotometers were used for bovine and one kind was used for human enamel. The opalescence parameter (OP) was calculated as the difference in yellow-blue color coordinate (CIE Deltab(*)) and red-green color coordinate (CIE Deltaa(*)) between the reflected and transmitted colors. Mean OP value of bovine enamel was 10.6 (+/-1.4) to 19.0 (+/-2.1), and varied by the configuration of spectrophotometers. Mean OP value of human enamel was 22.9 (+/-1.9). Opalescence varied by the configuration of measuring spectrophotometer and the species of enamel. These values could be used in the development of esthetic restorative materials.

  3. Attitudes of Dental Hygiene Students toward Individuals with AIDS.

    Science.gov (United States)

    Haring, Joen Iannucci; Lind, Laura J.

    1992-01-01

    At Ohio State University, 81 dental hygiene students' attitudes toward homosexual and heterosexual patients with acquired immune deficiency syndrome (AIDS) or leukemia were assessed using ratings of prejudice, social interaction, and interpersonal interaction. Negative bias toward individuals with AIDS and unwillingness to engage in everyday…

  4. Enamel hypoplasia and its role in identification of individuals: A review of literature

    Science.gov (United States)

    Kanchan, Tanuj; Machado, Meghna; Rao, Ashwin; Krishan, Kewal; Garg, Arun K.

    2015-01-01

    Identification of individuals is the mainstay of any forensic investigation especially in cases of mass disasters when mutilated remains are brought for examination. Dental examination helps in establishing the identity of an individual and thus, has played a vital role in forensic investigation process since long. In this regard, description on the role of enamel hypoplasia is limited in the literature. The present article reviews the literature on the enamel hypoplasia and discusses its utility in forensic identification. Enamel hypoplasia is a surface defect of the tooth crown caused by disturbance of enamel matrix secretion. Enamel defects can be congenital or acquired. In cases of mass disasters, or when the body is completely charred, putrefied and mutilated beyond recognition, the unique dental features can help in identification of the victims. PMID:26097340

  5. β-pyrophosphate: A potential biomaterial for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Anastasiou, A.D., E-mail: a.anastasiou@leeds.ac.uk [School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Strafford, S. [Leeds Dental School, Worsley Building, University of Leeds, Leeds LS2 9JT (United Kingdom); Posada-Estefan, O. [Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, LS2 9JT (United Kingdom); Thomson, C.L. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Hussain, S.A. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Cambridge Graphene Centre, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Edwards, T.J. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Malinowski, M. [Leeds Dental School, Worsley Building, University of Leeds, Leeds LS2 9JT (United Kingdom); Hondow, N. [School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Metzger, N.K.; Brown, C.T.A. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Routledge, M.N. [Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, LS2 9JT (United Kingdom); Brown, A.P. [School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Duggal, M.S. [Leeds Dental School, Worsley Building, University of Leeds, Leeds LS2 9JT (United Kingdom); Jha, A. [School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2017-06-01

    Tooth hypersensitivity is a growing problem affecting both the young and ageing population worldwide. Since an effective and permanent solution is not yet available, we propose a new methodology for the restoration of dental enamel using femtosecond lasers and novel calcium phosphate biomaterials. During this procedure the irradiated mineral transforms into a densified layer of acid resistant iron doped β-pyrophosphate, bonded with the surface of eroded enamel. Our aim therefore is to evaluate this densified mineral as a potential replacement material for dental hard tissue. To this end, we have tested the hardness of β-pyrophosphate pellets (sintered at 1000 °C) and its mineral precursor (brushite), the wear rate during simulated tooth-brushing trials and the cytocompatibility of these minerals in powder form. It was found that the hardness of the β-pyrophosphate pellets is comparable with that of dental enamel and significantly higher than dentine while, the brushing trials prove that the wear rate of β-pyrophosphate is much slower than that of natural enamel. Finally, cytotoxicity and genotoxicity tests suggest that iron doped β-pyrophosphate is cytocompatible and therefore could be used in dental applications. Taken together and with the previously reported results on laser irradiation of these materials we conclude that iron doped β-pyrophosphate may be a promising material for restoring acid eroded and worn enamel. - Highlights: • A novel procedure for the restoration of dental enamel is introduced. • Fe-doped ß-pyrophosphate is evaluated as potential biomaterial for enamel restoration. • Fe-doped ß-pyrophosphate found to have the same hardness as natural enamel and dramatically lower wear rate. • Cytotoxicity and genotoxicity tests suggest that Fe-doped ß-pyrophosphate is safe for dental applications.

  6. β-pyrophosphate: A potential biomaterial for dental applications

    International Nuclear Information System (INIS)

    Anastasiou, A.D.; Strafford, S.; Posada-Estefan, O.; Thomson, C.L.; Hussain, S.A.; Edwards, T.J.; Malinowski, M.; Hondow, N.; Metzger, N.K.; Brown, C.T.A.; Routledge, M.N.; Brown, A.P.; Duggal, M.S.; Jha, A.

    2017-01-01

    Tooth hypersensitivity is a growing problem affecting both the young and ageing population worldwide. Since an effective and permanent solution is not yet available, we propose a new methodology for the restoration of dental enamel using femtosecond lasers and novel calcium phosphate biomaterials. During this procedure the irradiated mineral transforms into a densified layer of acid resistant iron doped β-pyrophosphate, bonded with the surface of eroded enamel. Our aim therefore is to evaluate this densified mineral as a potential replacement material for dental hard tissue. To this end, we have tested the hardness of β-pyrophosphate pellets (sintered at 1000 °C) and its mineral precursor (brushite), the wear rate during simulated tooth-brushing trials and the cytocompatibility of these minerals in powder form. It was found that the hardness of the β-pyrophosphate pellets is comparable with that of dental enamel and significantly higher than dentine while, the brushing trials prove that the wear rate of β-pyrophosphate is much slower than that of natural enamel. Finally, cytotoxicity and genotoxicity tests suggest that iron doped β-pyrophosphate is cytocompatible and therefore could be used in dental applications. Taken together and with the previously reported results on laser irradiation of these materials we conclude that iron doped β-pyrophosphate may be a promising material for restoring acid eroded and worn enamel. - Highlights: • A novel procedure for the restoration of dental enamel is introduced. • Fe-doped ß-pyrophosphate is evaluated as potential biomaterial for enamel restoration. • Fe-doped ß-pyrophosphate found to have the same hardness as natural enamel and dramatically lower wear rate. • Cytotoxicity and genotoxicity tests suggest that Fe-doped ß-pyrophosphate is safe for dental applications.

  7. MMP20 Promotes a Smooth Enamel Surface, a Strong DEJ, and a Decussating Enamel Rod Pattern

    Science.gov (United States)

    Bartlett, John D.; Skobe, Ziedonis; Nanci, Antonio; Smith, Charles E.

    2012-01-01

    Mutations of the Matrix metalloproteinase-20 (MMP20, enamelysin) gene cause autosomal recessive amelogenesis imperfecta and Mmp20 ablated mice also have malformed dental enamel. Here we show that Mmp20 null mouse secretory stage ameloblasts maintained a columnar shape and were present as a single layer of cells. However, the null maturation stage ameloblasts covered extraneous nodules of ectopic calcified material formed at the enamel surface. Remarkably, nodule formation occurs in null mouse enamel when MMP20 is normally no longer expressed. The malformed enamel in Mmp20 null teeth was loosely attached to the dentin and the entire enamel layer tended to separate from the dentin indicative of a faulty DEJ. The enamel rod pattern was also altered in Mmp20 null mice. Each enamel rod is formed by a single ameloblast and is a mineralized record of the migration path of the ameloblast that formed it. The Mmp20 null mouse enamel rods were grossly malformed or were absent indicating that the ameloblasts do not migrate properly when backing away from the DEJ. Thus, MMP20 is required for ameloblast cell movement necessary to form the decussating enamel rod patterns, for the prevention of ectopic mineral formation, and to maintain a functional DEJ. PMID:22243247

  8. Human dental enamel and dentin structural effects after Er:YAG laser irradiation.

    Science.gov (United States)

    Lima, Darlon Martíns; Tonetto, Mateus Rodrigues; de Mendonça, Adriano Augusto Melo; Elossais, André Afif; Saad, José Roberto Cury; de Andrade, Marcelo Ferrarezi; Pinto, Shelon Cristina Souza; Bandéca, Matheus Coelho

    2014-05-01

    Ideally projected to be applied on soft tissues, infrared lasers were improved by restorative dentistry to be used in hard dental tissues cavity preparations--namely enamel and dentin. This paper evidentiates the relevant aspects of infrared Erbium laser's action mechanism and its effects, and characterizes the different effects deriving from the laser's beams emission. The criteria for use and selection of optimal parameters for the correct application of laser systems and influence of supporting factors on the process, such as water amount and its presence in the ablation process, protection exerted by the plasma shielding and structural factors, which are indispensable in dental tissues cavity preparation related to restorative technique, are subordinated to optical modifications caused by the interaction of the energy dissipated by these laser light emission systems in the targeted tissue substrate. Differences in the action of infrared Erbium laser system in regard to the nature of the ablation process and variations on the morphological aspects observed in the superficial structure of the target tissue irradiated, may be correlated to the structural optical modifications of the substrate produced by an interaction of the energy propagated by laser systems.

  9. Fractography of clinically fractured, implant-supported dental computer-aided design and computer-aided manufacturing crowns

    NARCIS (Netherlands)

    Lohbauer, Ulrich; Belli, Renan; Cune, Marco S; Schepke, Ulf

    2017-01-01

    Today, a substantial part of the dental crown production uses computer-aided design and computer-aided manufacturing (CAD/CAM) technology. A recent step in restorative dentistry is the replacement of natural tooth structure with pre-polymerized and machined resin-based methacrylic polymers.

  10. Dental wear, wear rate, and dental disease in the African apes.

    Science.gov (United States)

    Elgart, Alison A

    2010-06-01

    The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

  11. Structural changes in fluorosed dental enamel of red deer (Cervus elaphus L.) from a region with severe environmental pollution by fluorides

    International Nuclear Information System (INIS)

    Kierdorf, U.; Kierdorf, H.; Sedlacek, F.; Fejerskov, O.

    1996-01-01

    A macroscopic, microradiographic and scanning electron microscope study was performed on the structure of fluorosed dental enamel in red deer from a fluoride polluted region (North Bohemia, Czech Republic). As was revealed by analysis of mandibular bone fluoride content, the rate of skeletal fluoride accumulation in the fluorotic deer was about 6 times that in controls taken from a region not exposed to excessive fluoride deposition. In all fluorosed mandibles, the 1st molar was consistently less fluorotic than the other permanent teeth. This was related to the fact that crown formation in the M1 takes place prenatally and during the lactation period. Fluorosed teeth exhibited opaque and posteruptively stained enamel, reduction or loss of enamel ridges, moderately to grossly increased wear and, in more severe cases, also enamel surface lesions of partly posteruptive, partly developmental origin. Microradiographically, fluorosed enamel was characterised by subsurface hypomineralisation, interpreted as a result of fluoride interference with the process of enamel maturation. In addition, an accentuation of the incremental pattern due to the occurrence of alternating bands with highly varying mineral content was observed in severely fluorosed teeth, denoting fluoride disturbance during the secretory stage of amelogenesis. A corresponding enhancement of the incremental pattern was also seen in the dentine. The enamel along the more pronounced hypoplasias consisted of stacked, thin layers of crystals arranged in parallel, indicating that the ameloblasts in these locations had lost the distal (prism-forming) portions of their Tomes processes. The findings of the present study indicate that red deer are highly sensitive bioindicators of environmental pollution by fluorides

  12. Effects of fluoride and epigallocatechin gallate on soft-drink-induced dental erosion of enamel and root dentin.

    Science.gov (United States)

    Wang, Yin-Lin; Chang, Hao-Hueng; Chiang, Yu-Chih; Lu, Yu-Chen; Lin, Chun-Pin

    2018-04-01

    Fluoride and epigallocatechin gallate (EGCG) have been proven to prevent dental caries. The purpose of this study was to evaluate the effects of fluoride and EGCG on soft-drink-induced dental erosion in vitro. Forty enamel and dentin specimens were prepared from extracted human teeth. The specimens were divided into 4 groups and treated separately with distilled water (as control), 0.5 M sodium fluoride (NF), 400 μM EGCG (EG), and a solution containing 0.5 M NaF and 400 μM EGCG (FG). Cyclic erosive treatment was performed according to the experimental procedures. The specimens were analyzed using laser scanning confocal microscopy, scanning electron microscopy, and a microhardness tester. The data were analyzed using ANOVA and Bonferroni's post hoc test. The significance level was set at 5%. The amount of substance loss was lower in the NF and EG groups than in the control group (p erosion-caused substance loss was more pronounced in the dentin than in the enamel specimens. Surface microhardness loss was lower in the NF and EG groups than in the control group (p erosion compared with the control group. Fluoride and EGCG may interfere with each other. The mechanisms of the anti-erosive effect need to be explored in the future. Copyright © 2018. Published by Elsevier B.V.

  13. Knowledge and attitude of Indian clinical dental students towards the dental treatment of patients with human immunodeficiency virus (HIV)/acquired immune-deficiency syndrome (AIDS).

    Science.gov (United States)

    Oberoi, Sukhvinder Singh; Marya, Charu Mohan; Sharma, Nilima; Mohanty, Vikrant; Marwah, Mohita; Oberoi, Avneet

    2014-12-01

    Oral health care of patients with human immunodeficiency virus (HIV)/acquired immune-deficiency syndrome (AIDS) is a growing area of concern. Information on HIV- and AIDS-related knowledge among dental students provides a crucial foundation for efforts aimed at developing an appropriate dental curriculum on HIV and AIDS. The purpose of this study was to assess the knowledge and attitude of Indian clinical dental students towards the treatment of patients with HIV/AIDS and perceived sources of information regarding HIV-related issues. Data were collected from clinical dental students (third year, fourth year and internship) from three dental institutions in Delhi National Capital Region (NCR). The questions assessed the knowledge and attitude towards treatment of patients with HIV and the perceived source of information related to HIV. The willingness to treat HIV-positive patients among dental students was 67.0%, and 74.20% were confident of treating a patient with HIV/AIDS. The potential problems in rendering treatment to these patients were effect on the attitude of other patients (49.90%) and staff fears (52.50%). The correct knowledge regarding the infection-control practice (barrier technique) was found among only 15.50% of respondents. The respondents had sufficient knowledge regarding the oral manifestations of HIV/AIDS. There was no correlation between the knowledge and attitude score, demonstrating a gap between knowledge and attitude among dental students regarding treatment of HIV-infected patients. Appropriate knowledge has to be delivered through the dental education curriculum, which can instil confidence in students about their ability to manage HIV-positive patients. © 2014 FDI World Dental Federation.

  14. Stress Response Pathways in Ameloblasts: Implications for Amelogenesis and Dental Fluorosis

    Directory of Open Access Journals (Sweden)

    John D. Bartlett

    2012-08-01

    Full Text Available Human enamel development of the permanent teeth takes place during childhood and stresses encountered during this period can have lasting effects on the appearance and structural integrity of the enamel. One of the most common examples of this is the development of dental fluorosis after childhood exposure to excess fluoride, an elemental agent used to increase enamel hardness and prevent dental caries. Currently the molecular mechanism responsible for dental fluorosis remains unknown; however, recent work suggests dental fluorosis may be the result of activated stress response pathways in ameloblasts during the development of permanent teeth. Using fluorosis as an example, the role of stress response pathways during enamel maturation is discussed.

  15. In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel.

    Science.gov (United States)

    Shadman, Niloofar; Ebrahimi, Shahram Farzin; Shoul, Maryam Azizi; Sattari, Hasti

    2015-01-01

    Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel. Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to create a flat enamel surface. Adhesives used were Tetric N-Bond, AdheSE and AdheSE One F. In three subgroups, before applying adhesives, enamel surfaces were treated with Tooth Mousse CPP-ACP for one hour, rinsed and stored in 37°C temperature with 100% humidity. This procedure was repeated for 5 days and then adhesives were applied and Tetric N-Ceram composite was adhered to the enamel. This procedure was also fulfilled for the other three subgroups without CPP-ACP treatment. After 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. Failure modes were determined by stereomicroscope. Data were analyzed by t-test and one-way analysis of variance with P enamel only in Tetric N-Bond (P > 0.05). In non-applied CPP-ACP subgroups, there were statistically significant differences among all subgroups. Tetric N-Bond had the highest and AdheSE One F had the lowest shear bond strength. CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.

  16. Prevalence of enamel defects and MIH in non-fluoridated and fluoridated communities.

    Science.gov (United States)

    Balmer, R C; Laskey, D; Mahoney, E; Toumba, K J

    2005-12-01

    This was to study the prevalence of enamel defects and molar incisor hypomineralisation (MIH) in children attending Leeds Dental Institute (UK) and Westmead Dental Hospital, Sydney (Australia). Prospective dental examinations were carried out on 25 children referred to two orthodontic departments. A questionnaire was completed to obtain background information and about previous fluoride (F) exposure followed by an oral examination. First permanent molars and permanent incisors were examined for presence, type and severity of enamel defects using the modified DDE screening index. Chi square tests were used to compare results. Data for 24 children in Sydney and 20 in Leeds presented with at least one enamel defect. Of 300 teeth examined, 155 in Sydney and 82 in Leeds had a defect (p MIH was the same supporting the view that F is not associated with the aetiology of MIH.

  17. Enamel hypoplasia in the deciduous teeth of great apes: variation in prevalence and timing of defects.

    Science.gov (United States)

    Lukacs, J R

    2001-11-01

    The prevalence of enamel hypoplasia in the deciduous teeth of great apes has the potential to reveal episodes of physiological stress in early stages of ontogenetic development. However, little is known about enamel defects of deciduous teeth in great apes. Unresolved questions addressed in this study are: Do hypoplastic enamel defects occur with equal frequency in different groups of great apes? Are enamel hypoplasias more prevalent in the deciduous teeth of male or female apes? During what phase of dental development do enamel defects tend to form? And, what part of the dental crown is most commonly affected? To answer these questions, infant and juvenile skulls of two sympatric genera of great apes (Gorilla and Pan) were examined for dental enamel hypoplasias. Specimens from the Powell-Cotton Museum (Quex Park, UK; n = 107) are reported here, and compared with prior findings based on my examination of juvenile apes at the Cleveland Museum of Natural History (Hamman-Todd Collection; n = 100) and Smithsonian Institution (National Museum of Natural History; n = 36). All deciduous teeth were examined by the author with a x10 hand lens, in oblique incandescent light. Defects were classified using Fédération Dentaire International (FDI)/Defects of Dental Enamel (DDE) standards; defect size and location on the tooth crown were measured and marked on dental outline charts. Enamel defects of ape deciduous teeth are most common on the labial surface of canine teeth. While deciduous incisor and molar teeth consistently exhibit similar defects with prevalences of approximately 10%, canines average between 70-75%. Position of enamel defects on the canine crown was analyzed by dividing it into three zones (apical, middle, and cervical) and calculating defect prevalence by zone. Among gorillas, enamel hypoplasia prevalence increases progressively from the apical zone (low) to the middle zone to the cervical zone (highest), in both maxillary and mandibular canine teeth

  18. The developmental clock of dental enamel: a test for the periodicity of prism cross-striations in modern humans and an evaluation of the most likely sources of error in histological studies of this kind

    Science.gov (United States)

    Antoine, Daniel; Hillson, Simon; Dean, M Christopher

    2009-01-01

    Dental tissues contain regular microscopic structures believed to result from periodic variations in the secretion of matrix by enamel- and dentine-forming cells. Counts of these structures are an important tool for reconstructing the chronology of dental development in both modern and fossil hominids. Most studies rely on the periodicity of the regular cross-banding that occurs along the long axis of enamel prisms. These prism cross-striations are widely thought to reflect a circadian rhythm of enamel matrix secretion and are generally regarded as representing daily increments of tissue. Previously, some researchers have argued against the circadian periodicity of these structures and questioned their use in reconstructing dental development. Here we tested the periodicity of enamel cross-striations – and the accuracy to which they can be used – in the developing permanent dentition of five children, excavated from a 19th century crypt in London, whose age-at-death was independently known. The interruption of crown formation by death was used to calibrate cross-striation counts. All five individuals produced counts that were strongly consistent with those expected from the independently known ages, taking into account the position of the neonatal line and factors of preservation. These results confirm that cross-striations do indeed reflect a circadian rhythm in enamel matrix secretion. They further validate their use in reconstructing dental development and in determining the age-at-death of the remains of children whose dentitions are still forming at the time of death. Significantly they identify the most likely source of error and the common difficulties encountered in histological studies of this kind. PMID:19166472

  19. Retrospective radiation dosimetry using electron paramagnetic resonance in canine dental enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.; Pekar, J.; Rink, W.J.; Boreham, D.R.

    2005-01-01

    Electron paramagnetic resonance (EPR) biodosimetry of human tooth enamel has been widely used for measuring radiation doses in various scenarios. We have now developed EPR dosimetry in tooth enamel extracted from canines. Molars and incisors from canines were cleaned by processing in supersaturated aqueous potassium hydroxide solution. The dosimetric signal in canine tooth enamel was found to increase linearly as a function of laboratory added dose from 0.44±0.02 to 4.42±0.22 Gy. The gamma radiation sensitivity of the canine molar enamel was found to be comparable to that of human tooth enamel. The dosimetric signal in canine enamel has been found to be stable up to at least 6 weeks after in vitro irradiation. A dosimetric signal variation of 10-25% was observed for canines ranging from in age 3 years to 16 year old

  20. Nanostructured synthetic hydroxyapatite and dental enamel heated and irradiated by ER,CR:YSGG: characterized by FTIR and XRD

    International Nuclear Information System (INIS)

    Rabelo Neto, Jose da Silva

    2009-01-01

    The study evaluate the physical changes and/or chemical that occurs in synthetic hydroxyapatite (HAP) and in enamel under action of thermal heating in oven or laser irradiation of Er,Cr:YSGG that may cause changes in its structure to make them more resistant to demineralization aiming the formation of dental caries. The synthetic HAP was produced by reaction of solutions of Ca(NO 3 ) and (NH 4 ) 2 HPO 4 with controlled temperature and pH. The enamel powder was collected from the bovine teeth. Samples of powder enamel and synthetic HAP were subjected to thermal heating in oven at temperatures of 200 deg C, 400 deg C, 600 deg C, 800 deg C and 1000 deg C. For the laser irradiation of materials, were made with 5,79 J/cm 2 of irradiation, 7,65 J/cm 2 , 10,55 J/cm 2 and 13,84 J/cm 2 for synthetic HAP and 7,53 J/cm 2 , 10,95 J/cm 2 , and 13,74 J/cm 2 for the enamel. The samples were evaluated by X-ray diffraction (XRD) for analysis of crystallographic phases and analysis by the Rietveld method, to determine their respective proportions in the material, as well as results of changes of the lattice unit cell parameters (axis-a, axis-c and volume), crystallites sizes and the occupation rate of sites of Ca and P atoms. The samples were analyzed by Fourier transform infrared spectroscopy (FTIR), which should compositional changes due to treatment related to carbonate, phosphate, adsorbed water and hydroxyl radicals content. The infrared was used to measure the surface temperature generated by the laser beam in the solid samples of enamel. Besides the major hydroxyapatite crystallographic phases, there was formations of octa calcium phosphate (OCP) and phase β of tricalcium phosphate (β-TCP ) in enamel heated at 800 deg C. There was reduction of the axis-a, volume and size of crystallites to the temperatures between 400 degree C and 600 deg C and also on laser irradiated samples. Above the temperature of 600 degree C it is observed the effect in the lattice parameters. The Ca

  1. [Evaluation of shear bond strengths of self-etching and total-etching dental adhesives to enamel and dentin].

    Science.gov (United States)

    Yu, Ling; Liu, Jing-Ming; Wang, Xiao-Yan; Gao, Xue-Jun

    2009-03-01

    To evaluate the shear bond strengths of four dental adhesives in vitro. The facial surfaces of 20 human maxillary incisors were prepared to expose fresh enamel and randomly divided into four groups, in each group 5 teeth were bonded with one adhesives: group A (Clearfil Protect Bond, self-etching two steps), group B (Adper( Prompt, self-etching one step), group C (SwissTEC SL Bond, total-etching two steps), group D (Single Bond, total-etching two steps). Shear bond strengths were determined using an universal testing machine after being stored in distilled water for 24 h at 37 degrees C. The bond strengths to enamel and dentin were (25.33 +/- 2.84) and (26.07 +/- 5.56) MPa in group A, (17.08 +/- 5.13) and (17.93 +/- 4.70) MPa in group B, (33.14 +/- 6.05) and (41.92 +/- 6.25) MPa in group C, (22.51 +/- 6.25) and (21.45 +/- 7.34) MPa in group D. Group C showed the highest and group B the lowest shear bond strength to enamel and dentin among the four groups. The two-step self-etching adhesive showed comparable shear bond strength to some of the total-etching adhesives and higher shear bond strength than one-step self-etching adhesive.

  2. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    International Nuclear Information System (INIS)

    Wei Jie; Wang Jiecheng; Liu Xiaochen; Ma Jian; Liu Changsheng; Fang Jing; Wei Shicheng

    2011-01-01

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H 3 PO 4 ) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  3. Enamel lesions in development, classification in Costa Rican families

    International Nuclear Information System (INIS)

    Murillo Knudsen, Gina; Berrocal Salazar, Cristina

    2013-01-01

    Enamel lesions in development were identified and classified in patients of Llano Grande de Cartago, examined at the Facultad de Odontologia of the Universidad de Costa Rica. A guide is provided over the topic. 15 children and 2 Costa Rican adults were selected. Clinical examinations, radiographs and clinical photographs were used as data collection method. Dental defects of the enamel were classified according to the possible genetic causes and without genetic causes. Imperfect Amelogenesis (IA) was diagnosed in 10 of patients. Hypoplastic IA was determined in 3 siblings with autosomal recessive inheritance, for 16% of the total sample. Hypomineralized IA was identified in an adult and two of his sons, with autosomal dominant inheritance. The remaining 4 cases of IA have been sporadic. Lesions of dental fluorosis were determined in the Horowitz index in 4 individuals, from 2 unrelated families. Other defects unspecified of the enamel or hypoplasias were found in 3 individuals. Enamel lesions in development should be classified with precision, for the purpose to inform to patients affected about their condition, origin, prognosis and appropriate treatment. The basis are established to implement reliability in the construction of family genealogy, identification and classification of enamel lesions, as well as the probabilities of future generations to express the lesions in the enamel of temporary or permanent dentition [es

  4. Novel Dental Cement to Combat Biofilms and Reduce Acids for Orthodontic Applications to Avoid Enamel Demineralization

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2016-05-01

    Full Text Available Orthodontic treatments often lead to biofilm buildup and white spot lesions due to enamel demineralization. The objectives of this study were to develop a novel bioactive orthodontic cement to prevent white spot lesions, and to determine the effects of cement compositions on biofilm growth and acid production. 2-methacryloyloxyethyl phosphorylcholine (MPC, nanoparticles of silver (NAg, and dimethylaminohexadecyl methacrylate (DMAHDM were incorporated into a resin-modified glass ionomer cement (RMGI. Enamel shear bond strength (SBS was determined. Protein adsorption was determined using a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU and lactic acid production. Incorporating 3% of MPC, 1.5% of DMAHDM, and 0.1% of NAg into RMGI, and immersing in distilled water at 37 °C for 30 days, did not decrease the SBS, compared to control (p > 0.1. RMGI with 3% MPC + 1.5% DMAHDM + 0.1% NAg had protein amount that was 1/10 that of control. RMGI with triple agents (MPC + DMAHDM + NAg had much stronger antibacterial property than using a single agent or double agents (p < 0.05. Biofilm CFU on RMGI with triple agents was reduced by more than 3 orders of magnitude, compared to commercial control. Biofilm metabolic activity and acid production were also greatly reduced. In conclusion, adding MPC + DMAHDM + NAg in RMGI substantially inhibited biofilm viability and acid production, without compromising the orthodontic bracket bond strength to enamel. The novel bioactive cement is promising for orthodontic applications to hinder biofilms and plaque buildup and enamel demineralization.

  5. Effect of pretreatment with an Er:YAG laser and fluoride on the prevention of dental enamel erosion.

    Science.gov (United States)

    dos Reis Derceli, Juliana; Faraoni-Romano, Juliana Jendiroba; Azevedo, Danielle Torres; Wang, Linda; Bataglion, César; Palma-Dibb, Regina Guenka

    2015-02-01

    The aim of this study was to evaluate the effect of the Er:YAG laser and its association with fluoride (1.23% acidulate phosphate fluoride gel) on the prevention of enamel erosion. Sixty specimens were obtained from bovine enamel (4 × 4 mm), which were ground flat, polished, and randomly divided into five groups according to the preventive treatments: control-fluoride application; L--Er:YAG laser; L+F--laser + fluoride; F+L--fluoride + laser; L/F--laser/fluoride simultaneously. Half of the enamel surface was covered with nail varnish (control area), and the other half was pretreated with one of the preventive strategies to subsequently be submitted to erosive challenge. When the laser was applied, it was irradiated for 10 s with a focal length of 4 mm and 60 mJ/2 Hz. Fluoride gel was applied for 4 min. Each specimen was individually exposed to regular Coca-Cola® for 1 min, four times/day, for 5 days. Wear analysis was performed with a profilometer, and demineralization was assessed with an optical microscope. Data were analyzed using the Kruskal-Wallis test (wear)/Dunn test and ANOVA/Fisher's exact tests. The group L/F was similar to control group. The other groups showed higher wear, which did not present differences among them. In the demineralization assessment, the groups F+L and L/F showed lower demineralization in relation to the other groups. It can be concluded that none preventive method was able to inhibit dental wear. The treatments L/F and F+L showed lower enamel demineralization.

  6. Effects of fluoride and epigallocatechin gallate on soft-drink-induced dental erosion of enamel and root dentin

    Directory of Open Access Journals (Sweden)

    Yin-Lin Wang

    2018-04-01

    Full Text Available Background/Purpose: Fluoride and epigallocatechin gallate (EGCG have been proven to prevent dental caries. The purpose of this study was to evaluate the effects of fluoride and EGCG on soft-drink-induced dental erosion in vitro. Methods: Forty enamel and dentin specimens were prepared from extracted human teeth. The specimens were divided into 4 groups and treated separately with distilled water (as control, 0.5 M sodium fluoride (NF, 400 μM EGCG (EG, and a solution containing 0.5 M NaF and 400 μM EGCG (FG. Cyclic erosive treatment was performed according to the experimental procedures. The specimens were analyzed using laser scanning confocal microscopy, scanning electron microscopy, and a microhardness tester. The data were analyzed using ANOVA and Bonferroni's post hoc test. The significance level was set at 5%. Results: The amount of substance loss was lower in the NF and EG groups than in the control group (p < 0.05. The erosion-caused substance loss was more pronounced in the dentin than in the enamel specimens. Surface microhardness loss was lower in the NF and EG groups than in the control group (p < 0.05. The diameter of the dentinal tubule was wider in the control group than in the NF and EG groups (p < 0.05. No combined effects were observed in the FG group. Conclusion: Both fluoride and EGCG are effective in preventing soft-drink-induced erosion compared with the control group. Fluoride and EGCG may interfere with each other. The mechanisms of the anti-erosive effect need to be explored in the future. Keywords: Dental erosion, Fluoride, Epigallocatechin gallate, Soft drinks, Laser scanning confocal microscopy

  7. Chronic fluoride toxicity: dental fluorosis.

    Science.gov (United States)

    Denbesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2-3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface. With more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the dose-related decrease in cycles of ameloblast modulation from ruffle-ended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further

  8. Child Care Providers' Knowledge About Dental Injury First Aid in Preschool-age Children.

    Science.gov (United States)

    Sienkiewicz, Kristine L; Rainchuso, Lori; Boyd, Linda D; Giblin, Lori

    2017-06-01

    Purpose: The aim of this study was to assess child care providers' level of knowledge of first aid management and attitudes towards dental injuries among preschool-age children within Fairfield County, Connecticut and Boston, Massachusetts. Methods: This descriptive cross-sectional study used a web-based, validated questionnaire adapted from several studies with permission from authors. A panel of 5 dental experts determined the relevance of the questions and overall content (I-CVI range 0.8-1; S-CVI = 0.95). The 28 question survey included demographics, level of knowledge, attitudes about traumatic dental injuries, emergency management, and 2 case study questions on management of luxation and tooth fracture. Survey data was coded and analyzed for associations and trends using STATA® statistics/data analysis software v. 11.2. Results: A total of 100 child care providers completed the online questionnaire. Eighty-four percent self-reported little to no knowledge about dental injury management. Sixty percent of child care providers agreed that they are responsible for managing dental injuries. Approximately two-thirds of child care providers reported not feeling adequately informed about dental injuries, with 77% expressing interest in receiving more information. Conclusions: The majority of child care providers' do not have the knowledge to perform adequate first aid following a dental injury. Professional development on first aid for dental injuries is recommended among this workforce population. Copyright © 2017 The American Dental Hygienists’ Association.

  9. Enamel renal syndrome with associated amelogenesis imperfecta, nephrolithiasis, and hypocitraturia: A case report

    International Nuclear Information System (INIS)

    Bhesania, Dhvani; Arora, Ankit; Kapoor, Sonali

    2015-01-01

    Numerous cases of enamel renal syndrome have been previously reported. Various terms, such as enamel renal syndrome, amelogenesis imperfecta and gingival fibromatosis syndrome, and enamel-renal-gingival syndrome, have been used for patients presenting with the dental phenotype characteristic of this condition, nephrocalcinosis or nephrolithiasis, and gingival findings. This report describes a case of amelogenesis imperfecta of the enamel agenesis variety with nephrolithiasis in a 21-year-old male patient who complained of small teeth. The imaging modalities employed were conventional radiography, cone-beam computed tomography, and renal sonography. Such cases are first encountered by dentists, as other organ or metabolic diseases are generally hidden. Hence, cases of amelogenesis imperfecta should be subjected to advanced diagnostic modalities, incorporating both dental and medical criteria, in order to facilitate comprehensive long-term management

  10. Enamel renal syndrome with associated amelogenesis imperfecta, nephrolithiasis, and hypocitraturia: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Bhesania, Dhvani; Arora, Ankit; Kapoor, Sonali [Dept. of Conservative Dentistry and Endodontics, Manubhai Patel Dental College, Maharaja Krishnakumarsinhji Bhavnagar University, Vadodara (India)

    2015-09-15

    Numerous cases of enamel renal syndrome have been previously reported. Various terms, such as enamel renal syndrome, amelogenesis imperfecta and gingival fibromatosis syndrome, and enamel-renal-gingival syndrome, have been used for patients presenting with the dental phenotype characteristic of this condition, nephrocalcinosis or nephrolithiasis, and gingival findings. This report describes a case of amelogenesis imperfecta of the enamel agenesis variety with nephrolithiasis in a 21-year-old male patient who complained of small teeth. The imaging modalities employed were conventional radiography, cone-beam computed tomography, and renal sonography. Such cases are first encountered by dentists, as other organ or metabolic diseases are generally hidden. Hence, cases of amelogenesis imperfecta should be subjected to advanced diagnostic modalities, incorporating both dental and medical criteria, in order to facilitate comprehensive long-term management.

  11. Enamel renal syndrome with associated amelogenesis imperfecta, nephrolithiasis, and hypocitraturia: A case report.

    Science.gov (United States)

    Bhesania, Dhvani; Arora, Ankit; Kapoor, Sonali

    2015-09-01

    Numerous cases of enamel renal syndrome have been previously reported. Various terms, such as enamel renal syndrome, amelogenesis imperfecta and gingival fibromatosis syndrome, and enamel-renal-gingival syndrome, have been used for patients presenting with the dental phenotype characteristic of this condition, nephrocalcinosis or nephrolithiasis, and gingival findings. This report describes a case of amelogenesis imperfecta of the enamel agenesis variety with nephrolithiasis in a 21-year-old male patient who complained of small teeth. The imaging modalities employed were conventional radiography, cone-beam computed tomography, and renal sonography. Such cases are first encountered by dentists, as other organ or metabolic diseases are generally hidden. Hence, cases of amelogenesis imperfecta should be subjected to advanced diagnostic modalities, incorporating both dental and medical criteria, in order to facilitate comprehensive long-term management.

  12. Year of birth determination using radiocarbon dating of dental enamel.

    Science.gov (United States)

    Buchholz, B A; Spalding, K L

    2010-05-01

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ((14)C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, (14)C levels in the enamel represent (14)C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  13. Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A; Spalding, K L

    2009-03-10

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  14. Natural enamel caries in polarized light microscopy: differences in histopathological features derived from a qualitative versus a quantitative approach to interpret enamel birefringence.

    Science.gov (United States)

    De Medeiros, R C G; Soares, J D; De Sousa, F B

    2012-05-01

    Lesion area measurement of enamel caries using polarized light microscopy (PLM) is currently performed in a large number of studies, but measurements are based mainly on a mislead qualitative interpretation of enamel birefringence in a single immersion medium. Here, five natural enamel caries lesions are analysed by microradiography and in PLM, and the differences in their histopathological features derived from a qualitative versus a quantitative interpretation of enamel birefringence are described. Enamel birefringence in different immersion media (air, water and quinoline) is interpreted by both qualitative and quantitative approaches, the former leading to an underestimation of the depth of enamel caries mainly when the criterion of validating sound enamel as a negatively birefringent area in immersion in water is used (a current common practice in dental research). Procedures to avoid the shortcomings of a qualitative interpretation of enamel birefringence are presented and discussed. © 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.

  15. 'In vitro' assessment to instrumented indentation hardness tests in enamel of bovine teeth, before and after dental bleaching by laser; Avaliacao in vitro' de ensaios instrumentados de dureza em esmalte de dente bovino, antes e apos clareamento dental a laser

    Energy Technology Data Exchange (ETDEWEB)

    Britto Junior, Francisco Meira

    2004-07-01

    The laser enamel bleaching is a common used procedure due to its satisfactory esthetic results. The possible changes on the dental structures caused by the bleaching technique are of great importance. The enamel superficial microhardness changes through instrumented indentation hardness on bovine teeth were analyzed in this present study. The samples were divided in two halves, one being the control and the other irradiated with a diode laser (808 nm) or with a Nd:YAG laser (1064 nm) to activate the Whiteness HP bleaching gel (hydrogen peroxide at 35%). It was possible to conclude that there was a statistical significant increase on the enamel superficial microhardness (Group I, sample 1 and Group II, sample 1) despite this increase did not seem to indicate a concern regarding the enamel surface resistance change. There was not a significant statistical change on the enamel microhardness on the other samples. The final conclusion is that there was no superficial enamel morphological change after these treatments. (author)

  16. Fine structure and development of the collar enamel in gars, Lepisosteus oculatus, Actinopterygii

    Science.gov (United States)

    Sasagawa, Ichiro; Ishiyama, Mikio; Yokosuka, Hiroyuki; Mikami, Masato

    2008-06-01

    The fine structure of collar enamel and the cells constituting the enamel organ during amelogenesis in Lepisosteus oculatus was observed by light, scanning electron and transmission electron microscopy. In the enamel, slender crystals were arranged perpendicular to the surface and the stripes that were parallel to the surface were observed, suggesting that the enamel in Lepisosteus shares common morphological features with that in sarcopterygian fish and amphibians. Ameloblasts containing developed Golgi apparatus, rough endoplasmic reticulum (rER) and secretory granules were found in the secretory stage. In the maturation stage, a ruffled border was not seen at the distal end of the ameloblasts, while many mitochondria and lysosome-like granules were obvious in the distal cytoplasm. The enamel organ consisted of the outer dental epithelial cells, stratum reticulum cells and ameloblasts, but there was no stratum intermedium. It is likely that the ameloblasts have less absorptive function in comparison with the inner dental epithelial cells facing cap enameloid.

  17. Vanadium content of human dental enamel and its relationship to caries

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, A R [Institut Jozef Stefan, Ljubljana (Yugoslavia); Vrbic, V [Ljubljana Univ. (Yugoslavia)

    1979-01-01

    A method for the determination of vanadium in dental enamel based on neutron activation analysis is described. After rapid dissolution of the irradiated sample in perchloric acid, /sup 52/V is quickly separated by solvent extraction from mixed perchloric-hydrochloric medium with N-benzoyl-N-phenyl hydroxylamine (BPHA) reagent in toluene in 95% yield. The technique was applied to samples from a low caries area of Dalmatia, Zemunik (DMFT < 2), and a normal area, Novigrad (DMFT > 5), in the same region. No significant differences in vanadium content were found between the two areas, nor between deciduous and permanent teeth. The levels in other areas of Yugoslavia were found to be similar, with a mean concentration of 3.7 +- 1.5 ngxg/sup -1/ for 37 samples, with a nearly normal distribution; a few impacted teeth gave lower values. The method can also be adapted to the analysis of bone and biological materials generally.

  18. Influence of the number of cycles on shear fatigue strength of resin composite bonded to enamel and dentin using dental adhesives in self-etching mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Erickson, Robert L; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2018-01-30

    The influence of the number of cycles on shear fatigue strength to enamel and dentin using dental adhesives in self-etch mode was investigated. A two-step self-etch adhesive and two universal adhesives were used to bond to enamel and dentin in self-etch mode. Initial shear bond strength and shear fatigue strength to enamel and dentin using the adhesive in self-etch mode were determined. Fatigue testing was used with 20 Hz frequency and cycling periods of 50,000, 100,000 and 1,000,000 cycles, or until failure occurred. For each of the cycling periods, there was no significant difference in shear fatigue strength across the cycling periods for the individual adhesives. Differences in shear fatigue strength were found between the adhesives within the cycling periods. Regardless of the adhesive used in self-etch mode for bonding to enamel or dentin, shear fatigue strength was not influenced by the number of cycles used for shear fatigue strength testing.

  19. AIDS in dentistry | Muya | Tanzania Dental Journal

    African Journals Online (AJOL)

    Tanzania Dental Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 4, No 1 (1989) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. AIDS in dentistry. RJ Muya. Abstract. No Abstract. Full Text:.

  20. Assessment of Dental Fluorosis in Mmp20+/− Mice

    OpenAIRE

    Sharma, R.; Tye, C.E.; Arun, A.; MacDonald, D.; Chatterjee, A.; Abrazinski, T.; Everett, E.T.; Whitford, G.M.; Bartlett, J.D.

    2011-01-01

    The molecular mechanisms that underlie dental fluorosis are poorly understood. The retention of enamel proteins hallmarking fluorotic enamel may result from impaired hydrolysis and/or removal of enamel proteins. Previous studies have suggested that partial inhibition of Mmp20 expression is involved in the etiology of dental fluorosis. Here we ask if mice expressing only one functional Mmp20 allele are more susceptible to fluorosis. We demonstrate that Mmp20+/− mice express approximately half ...

  1. Photoacoustic imaging of teeth for dentine imaging and enamel characterization

    Science.gov (United States)

    Periyasamy, Vijitha; Rangaraj, Mani; Pramanik, Manojit

    2018-02-01

    Early detection of dental caries, cracks and lesions is needed to prevent complicated root canal treatment and tooth extraction procedures. Resolution of clinically used x-ray imaging is low, hence optical imaging techniques such as optical coherence tomography, fluorescence imaging, and Raman imaging are widely experimented for imaging dental structures. Photoacoustic effect is used in photon induced photoacoustic streaming technique to debride the root canal. In this study, the extracted teeth were imaged using photoacoustic tomography system at 1064 nm. The degradation of enamel and dentine is an indicator of onset of dental caries. Photoacoustic microscopy (PAM) was used to study the tooth enamel. Images were acquired using acoustic resolution PAM system. This was done to identify microscopic cracks and dental lesion at different anatomical sites (crown and cementum). The PAM tooth profile is an indicator of calcium distribution which is essential for demineralization studies.

  2. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Energy Technology Data Exchange (ETDEWEB)

    Wei Jie [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang Jiecheng; Liu Xiaochen [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Ma Jian [Hospital of Stomatology, Tongji University, Shanghai 200072 (China); Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Fang Jing, E-mail: biomater2006@yahoo.com.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China); Wei Shicheng, E-mail: nic7505@263.net [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Inter-disciplinary Studies, Peking University, Beijing 100871 (China) and School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2011-06-15

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H{sub 3}PO{sub 4}) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC paste was changed into fluorapatite crystals with the atom molar ratio for calcium to phosphorus of 1.66 and the F ion amount of 3 wt% after self-hardening for 2 days. The solubility of fs-AC in Tris-HCl solution (pH 6) was slightly lower than hydroxyapatite cement (HAC) that was similar to the apatite in enamel, indicating the fs-AC was much insensitive to the weakly acidic solution than the apatite in enamel. The fs-AC was tightly combined with the enamel surface because of the chemical reaction between the fs-AC and the apatite in enamel after the caries cavities was filled with fs-AC. The extracts of fs-AC caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. The fs-AC had potential prospect for the reconstitution of carious lesion of dental enamel.

  3. Antibacterial activity against Streptococcus mutans and inhibition of bacterial induced enamel demineralization of propolis, miswak, and chitosan nanoparticles based dental varnishes.

    Science.gov (United States)

    Wassel, Mariem O; Khattab, Mona A

    2017-07-01

    Using natural products can be a cost-effective approach for caries prevention especially in low income countries where dental caries is highly prevalent and the resources are limited. Specially prepared dental varnishes containing propolis, miswak, and chitosan nanoparticles (CS-NPs) with or without sodium fluoride (NaF) were assessed for antibacterial effect against Streptococcus mutans ( S. mutans ) using disk diffusion test. In addition, the protective effect of a single pretreatment of primary teeth enamel specimens against in vitro bacterial induced enamel demineralization was assessed for 3 days. All natural products containing varnishes inhibited bacterial growth significantly better than 5% NaF varnish, with NaF loaded CS-NPs (CSF-NPs) showing the highest antibacterial effect, though it didn't significantly differ than those of other varnishes except miswak ethanolic extract (M) varnish. Greater inhibitory effect was noted with varnish containing freeze dried aqueous miswak extract compared to that containing ethanolic miswak extract, possibly due to concentration of antimicrobial substances by freeze drying. Adding natural products to NaF in a dental varnish showed an additive effect especially compared to fluoride containing varnish. 5% NaF varnish showed the best inhibition of demineralization effect. Fluoride containing miswak varnish (MF) and CSF-NPs varnish inhibited demineralization significantly better than all experimental varnishes, especially during the first 2 days, though CSF-NPs varnish had a low fluoride concentration, probably due to better availability of fluoride ions and the smaller size of nanoparticles. Incorporating natural products with fluoride into dental varnishes can be an effective approach for caries prevention, especially miswak and propolis when financial resources are limited.

  4. Concentração de chumbo, defeitos de esmalte e cárie em dentes decíduos Lead level, enamel defects and dental caries in deciduous teeth

    Directory of Open Access Journals (Sweden)

    Viviane Elisângela Gomes

    2004-10-01

    Full Text Available OBJETIVO: Verificar a relação da concentração de chumbo no esmalte de dentes decíduos com a presença de defeitos de esmalte e sua relação com cárie dental em pré-escolares. MÉTODOS: A amostra foi de 329 crianças de pré-escolas municipais de uma área próxima de indústrias (N=132 e outra não industrial (N=197 da cidade de Piracicaba, Estado de São Paulo. Essa amostra pertencente a um estudo inicial realizado entre 2000 e 2001 no qual o chumbo foi analisado por meio de biópsia de esmalte. Foram realizados exames clínicos bucais para verificação da prevalência de defeitos de esmalte (Developmental Defects of Enamel Index - DDE, da Federação Dentária Internacional - FDI e cárie (Índice ceos, Organização Mundial da Saúde, em ambas regiões. Foram utilizados teste de qui-quadrado e cálculo do risco relativo ao nível de significância de 5%, considerando cada região separadamente. RESULTADOS: Houve maior proporção de crianças com cárie entre aquelas com maiores concentrações de chumbo nos decíduos na região não industrial (p=0,02, o que não se observou na região industrial (p=0,89. Houve risco relativo (RR aumentado de cárie nas crianças da região não industrial o que não foi verificado nas crianças da região industrial. Não se observou relação entre a presença de chumbo e os defeitos de esmalte. CONCLUSÕES: Não foram encontados dados que evidenciassem a relação entre concentração de chumbo e defeitos no esmalte em nenhuma das regiões pesquisadas. Não foi encontrada relação entre chumbo e cárie na região industrial, ressaltando a necessidade de mais estudos dessas relações.OBJECTIVE: To verify the relationship between lead concentration in the enamel of deciduous teeth and the presence of enamel defects and, consequently, with dental caries among preschool children. METHODS: The sample consisted of 329 preschool children in Piracicaba, State of São Paulo: 132 attending municipal

  5. Fluorine uptake into human enamel around a fluoride-containing dental material during cariogenic pH cycling

    International Nuclear Information System (INIS)

    Komatsu, H.; Yamamoto, H.; Nomachi, M.; Yasuda, K.; Matsuda, Y.; Murata, Y.; Kijimura, T.; Sano, H.; Sakai, T.; Kamiya, T.

    2007-01-01

    the enamel adjacent to the material remained a caries inhibition zone due to low rate of demineralization. With caries progression, fluorine accumulated in the subsurface of the caries lesion, while the outermost surface of the caries lesion gradually dissolved under increasing pH cycling. The data obtained using PIGE (TIARA, JAPAN) technique were useful to understand the fluorine benefit for preventing dental caries by means of fluoride-containing dental materials

  6. Fluorine uptake into human enamel around a fluoride-containing dental material during cariogenic pH cycling

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, H. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan)]. E-mail: kom@den.hokudai.ac.jp; Yamamoto, H. [Graduate School of Dentistry, Osaka University, 1-8 Yamada-Oka, Suita 565-0871 (Japan); Nomachi, M. [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043 (Japan); Yasuda, K. [Wakasa wan Energy Research Center, 64-52-1 Hase, Tsuruga 914-0192 (Japan); Matsuda, Y. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan); Murata, Y. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan); Kijimura, T. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan); Sano, H. [Graduate School of Dental Medicine, Hokkaido University, Kita-13, Nishi-7, Kita-ku, Sapporo 060-8586 (Japan); Sakai, T. [Takasaki Advanced Radiation Research Institute, JAEA, 1233 Watanuki-machi, Takasaki 370-1292 (Japan); Kamiya, T. [Takasaki Advanced Radiation Research Institute, JAEA, 1233 Watanuki-machi, Takasaki 370-1292 (Japan)

    2007-07-15

    duration of pH cycling, although the enamel adjacent to the material remained a caries inhibition zone due to low rate of demineralization. With caries progression, fluorine accumulated in the subsurface of the caries lesion, while the outermost surface of the caries lesion gradually dissolved under increasing pH cycling. The data obtained using PIGE (TIARA, JAPAN) technique were useful to understand the fluorine benefit for preventing dental caries by means of fluoride-containing dental materials.

  7. In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

    Directory of Open Access Journals (Sweden)

    Niloofar Shadman

    2015-01-01

    Full Text Available Background: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel. Materials and Methods: Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to create a flat enamel surface. Adhesives used were Tetric N-Bond, AdheSE and AdheSE One F. In three subgroups, before applying adhesives, enamel surfaces were treated with Tooth Mousse CPP-ACP for one hour, rinsed and stored in 37°C temperature with 100% humidity. This procedure was repeated for 5 days and then adhesives were applied and Tetric N-Ceram composite was adhered to the enamel. This procedure was also fulfilled for the other three subgroups without CPP-ACP treatment. After 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. Failure modes were determined by stereomicroscope. Data were analyzed by t-test and one-way analysis of variance with P 0.05. In non-applied CPP-ACP subgroups, there were statistically significant differences among all subgroups. Tetric N-Bond had the highest and AdheSE One F had the lowest shear bond strength. Conclusion: CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.

  8. The vanadium content of human dental enamel and its relationship to caries

    International Nuclear Information System (INIS)

    Byrne, A.R.; Vrbic, V.

    1979-01-01

    A method for the determination of vanadium in dental enamel based on neutron activation analysis is described. After rapid dissolution of the irradiated sample in perchloric acid, 52 V is quickly separated by solvent extraction from mixed perchloric-hydrochloric medium with N-benzoyl-N-phenyl hydroxylamine (BPHA) reagent in toluene in 95% yield. The technique was applied to samples from a low caries area of Dalmatia, Zemunik (DMFT 5), in the same region. No significant differences in vanadium content were found between the two areas, nor between deciduous and permanent teeth. The levels in other areas of Yugoslavia were found to be similar, with a mean concentration of 3.7 +- 1.5 ngxg -1 for 37 samples, with a nearly normal distribution; a few impacted teeth gave lower values. The method can also be adapted to the analysis of bone and biological materials generally. (author)

  9. The CuHBr laser in hard dental tissues

    International Nuclear Information System (INIS)

    Miyakawa, Walter

    2004-01-01

    In this work, it was verified the viability of characterization of laser-irradiated dental tissues in two extreme conditions: high and low absorption by the dental tissue. Comparison with light microscopy and scanning electronic microscopy revealed that these techniques are complementary each other: quantitative topographic information is directly extracted from the atomic force microscopy, while morphological aspects can be imaged by light microscopy or scanning electronic microscopy. A cavity generated by Cu-HyBrID laser in human dental enamel was also evaluated by atomic force microscopy. Structural and morphological differences between the fused and resolidified enamel from the cavity walls and the enamel from the natural tis sue were analyzed. A model, based on the Monte Carlo method described the propagation of CuHBr laser radiation and the absorbed energy distribution in dental tissues. Experimental measures with a CCD camera were used to semiquantitatively characterize the scattered light distribution in the tooth and they corroborated the model. It was observed that Rayleigh scattering and diffuse scattered radiation is predominant. The absorbed energy distribution map and the temperature variation along the beam propagation axis presented strong dependence with the absorption coefficient of the dental enamel and they cannot be deduced from the light distribution profile. The exposure time threshold for dental enamel melting and evaporation, irradiated by a specific condition of the green line of the Cu-HyBrID laser, was determined and a phenomenological model was discussed for the laser-matter interaction, based on pulse accumulation effect. Theoretical temperature calculations associated with experimental evidences strongly suggest that optical and thermal parameters should vary with temperature. The obtained exposure time threshold should correspond to the time necessary to the sample reach the critical temperature, at which the increase of absorption

  10. [Differential diagnosis of dental enamel focal demineralization and fluorosis by means of spectrophotometry].

    Science.gov (United States)

    Makarova, N E; Vinnichenko, Yu A

    2018-01-01

    The article presents the results of spectrophotometric tooth enamel scanning for differential diagnosis of focal enamel demineralization and fluorosis. Research was conducted in vivo on teeth affected by these diseases. VITA EasyShade spectrophotometer measurements were made on the affected area and on the visually healthy part of enamel. The lightness appeared as the only one differential significant optical characteristics of tooth enamel. Lightness metrics were higher in the case of initial caries than on the healthy part of enamel when these metrics were lower in the case of fluorosis than on the healthy part of enamel.

  11. Cutting efficiency of a mid-infrared laser on human enamel.

    Science.gov (United States)

    Levy, G; Koubi, G F; Miserendino, L J

    1998-02-01

    In this study, the cutting ability of a newly developed dental laser was compared with a dental high-speed handpiece and rotary bur for removal of enamel. Measurements of the volume of tissue removed, energy emitted, and time of exposure were used to quantify the ablation rate (rate of tissue removal) for each test group and compared. Cutting efficiency (mm3/s) of the laser was calculated based on the mean volume of tissue removed per pulse (mm3/pulse) and unit energy expended (mm3/J) over the range of applied powers (2, 4, 6, and 8 W). The specimens were then examined by light microscopy and scanning electron micrographs for qualitative analysis of the amount of remaining debris and the presence of the smear layer on the prepared enamel surface. Calculations of the cutting efficiency of the laser over the range of powers tested revealed a linear relationship with the level of applied power. The maximum average rate of tissue removal by the laser was 0.256 mm3/s at 8 W, compared with 0.945 mm3/s by the dental handpiece. Light microscopy and scanning electron micrograph examinations revealed a reduction in the amount of remaining debris and smear layer in the laser-prepared enamel surfaces, compared with the conventional method. Based on the results of this study, the cutting efficiency of the high-speed handpiece and dental bur was 3.7 times greater than the laser over the range of powers tested, but the laser appeared to create a cleaner enamel surface with minimal thermal damage. Further modifications of the laser system are suggested for improvement of laser cutting efficiency.

  12. Comparison of hydroxyapatite and dental enamel for testing shear bond strengths.

    Science.gov (United States)

    Imthiaz, Nishat; Georgiou, George; Moles, David R; Jones, Steven P

    2008-05-01

    To investigate the feasibility of using artificial hydroxyapatite as a future biomimetic laboratory substitute for human enamel in orthodontic bond strength testing by comparing the shear bond strengths and nature of failure of brackets bonded to samples of hydroxyapatite and enamel. One hundred and fifty hydroxyapatite discs were prepared by compression at 20 tons and fired in a furnace at 1300 degrees C. One hundred and five enamel samples were prepared from the buccal and palatal/lingual surfaces of healthy premolars extracted for orthodontic purposes. Orthodontic brackets were bonded to each sample and these were subjected to shear bond strength testing using a custom-made jig mounted in an Instron Universal Testing Machine. The force value at bond failure was obtained, together with the nature of failure which was assessed using the Adhesive Remnant Index. The mean shear bond strength for the enamel samples was 16.62 MPa (95 per cent CI: 15.26, 17.98) and for the hydroxyapatite samples 20.83 MPa (95 per cent CI: 19.68, 21.98). The difference between the two samples was statistically significant (p enamel samples scored 2 or 3, while 49 per cent of the hydroxyapatite samples scored 0 or 1. Hydroxyapatite was an effective biomimetic substrate for bond strength testing with a mean shear bond strength value (20.83 MPa) at the upper end of the normal range attributed to enamel (15-20 MPa). Although the difference between the shear bond strengths for hydroxyapatite and enamel was statistically significant, hydroxyapatite could be used as an alternative to enamel for comparative laboratory studies until a closer alternative is found. This would eliminate the need for extracted teeth to be collected. However, it should be used with caution for quantitative studies where true bond strengths are to be investigated.

  13. Automated dental identification system: An aid to forensic odontology

    Directory of Open Access Journals (Sweden)

    Parvathi Devi

    2011-01-01

    Full Text Available Automated dental identification system is computer-aided software for the postmortem identification of deceased individuals based on dental characteristics specifically radiographs. This system is receiving increased attention because of the large number of victims encountered in the mass disasters and it is 90% more time saving and accurate than the conventional radiographic methods. This technique is based on the intensity of the overall region of tooth image and therefore it does not necessitate the presence of sharp boundary between the teeth. It provides automated search and matching capabilities for digitized radiographs and photographic dental images and compares the teeth present in multiple digitized dental records in order to access their similarity. This paper highlights the functionality of its components and techniques used in realizing these components.

  14. Nanoindentation mapping of the mechanical properties of human molar tooth enamel.

    Science.gov (United States)

    Cuy, J L; Mann, A B; Livi, K J; Teaford, M F; Weihs, T P

    2002-04-01

    The mechanical behavior of dental enamel has been the subject of many investigations. Initial studies assumed that it was a more or less homogeneous material with uniform mechanical properties. Now it is generally recognized that the mechanical response of enamel depends upon location, chemical composition, and prism orientation. This study used nanoindentation to map out the properties of dental enamel over the axial cross-section of a maxillary second molar (M(2)). Local variations in mechanical characteristics were correlated with changes in chemical content and microstructure across the entire depth and span of a sample. Microprobe techniques were used to examine changes in chemical composition and scanning electron microscopy was used to examine the microstructure. The range of hardness (H) and Young's modulus (E) observed over an individual tooth was found to be far greater than previously reported. At the enamel surface H>6GPa and E>115GPa, while at the enamel-dentine junction H<3GPa and E<70GPa. These variations corresponded to the changes in chemistry, microstructure, and prism alignment but showed the strongest correlations with changes in the average chemistry of enamel. For example, the concentrations of the constituents of hydroxyapatite (P(2)O(5) and CaO) were highest at the hard occlusal surface and decreased on moving toward the softer enamel-dentine junction. Na(2)O and MgO showed the opposite trend. The mechanical properties of the enamel were also found to differ from the lingual to the buccal side of the molar. At the occlusal surface the enamel was harder and stiffer on the lingual side than on the buccal side. The interior enamel, however, was softer and more compliant on the lingual than on the buccal side, a variation that also correlated with differences in average chemistry and might be related to differences in function.

  15. p38α MAPK Is Required for Tooth Morphogenesis and Enamel Secretion*

    Science.gov (United States)

    Greenblatt, Matthew B.; Kim, Jung-Min; Oh, Hwanhee; Park, Kwang Hwan; Choo, Min-Kyung; Sano, Yasuyo; Tye, Coralee E.; Skobe, Ziedonis; Davis, Roger J.; Park, Jin Mo; Bei, Marianna; Glimcher, Laurie H.; Shim, Jae-Hyuck

    2015-01-01

    An improved understanding of the molecular pathways that drive tooth morphogenesis and enamel secretion is needed to generate teeth from organ cultures for therapeutic implantation or to determine the pathogenesis of primary disorders of dentition (Abdollah, S., Macias-Silva, M., Tsukazaki, T., Hayashi, H., Attisano, L., and Wrana, J. L. (1997) J. Biol. Chem. 272, 27678–27685). Here we present a novel ectodermal dysplasia phenotype associated with conditional deletion of p38α MAPK in ectodermal appendages using K14-cre mice (p38αK14 mice). These mice display impaired patterning of dental cusps and a profound defect in the production and biomechanical strength of dental enamel because of defects in ameloblast differentiation and activity. In the absence of p38α, expression of amelogenin and β4-integrin in ameloblasts and p21 in the enamel knot was significantly reduced. Mice lacking the MAP2K MKK6, but not mice lacking MAP2K MKK3, also show the enamel defects, implying that MKK6 functions as an upstream kinase of p38α in ectodermal appendages. Lastly, stimulation with BMP2/7 in both explant culture and an ameloblast cell line confirm that p38α functions downstream of BMPs in this context. Thus, BMP-induced activation of the p38α MAPK pathway is critical for the morphogenesis of tooth cusps and the secretion of dental enamel. PMID:25406311

  16. Colour Change of Enamel after Application of Averrhoa bilimbi

    Directory of Open Access Journals (Sweden)

    Cut Fauziah

    2013-07-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Teeth discoloration is mainly treated with dental bleaching. Use of chemical bleaching has side effects, so it is important to find an alternative natural dental bleaching agent. Averrhoa bilimbi contains peroxide and oxalate acid that possess tooth whitening properties. Objective: To determine the change in color of dental enamel after the application of Averrhoa bilimbi and 10% carbamide peroxide. Methods: Samples were 20 post-extracted of the two tested materials premolars (10 specimens each for Averrhoa bilimbi and carbamide peroxide application. After the application, the specimens were incubated at 37ºC for 2 hours, washed and soaked in aquadest before further incubated for another 14 days. The colour changed was observed by 5 independent observers using shade guide. Results: Quantitative and qualitative analyzes were performed. Qualitatively, A3 color has changed into C1, A2, D2, B2 and B1 in the Averrhoa bilimbi group. A more significant color change in the 10% carbamide peroxide group (p=0.005 compared to Averrhoa bilimbi group (p=0.005 were observed. The difference of resulted enamel colour change was statistically significant (p=0.002. Conclusion: Averrhoa bilimbi had a good prospect as dental bleaching agent since its application effectively resulted in a slight enamel colour change although its whitening properties was still lower than 10% carbamide peroxide.DOI: 10.14693/jdi.v19i3.134

  17. Algorithm of first-aid management of dental trauma for medics and corpsmen.

    Science.gov (United States)

    Zadik, Yehuda

    2008-12-01

    In order to fill the discrepancy between the necessity of providing prompt and proper treatment to dental trauma patients, and the inadequate knowledge among medics and corpsmen, as well as the lack of instructions in first-aid textbook and manuals, and after reviewing the dental literature, a simple algorithm for non-professional first-aid management for various injuries to hard (teeth) and soft oral tissues, is presented. The recommended management of tooth avulsion, subluxation and luxation, crown fracture and lip, tongue or gingival laceration included in the algorithm. Along with a list of after-hour dental clinics, this symptoms- and clinical-appearance-based algorithm is suited to tuck easily into a pocket for quick utilization by medics/corpsmen in an emergency situation. Although the algorithm was developed for the usage of military non-dental health-care providers, this method could be adjusted and employed in the civilian environment as well.

  18. Computer-aided navigation in dental implantology: 7 years of clinical experience.

    Science.gov (United States)

    Ewers, Rolf; Schicho, Kurt; Truppe, Michael; Seemann, Rudolf; Reichwein, Astrid; Figl, Michael; Wagner, Arne

    2004-03-01

    This long-term study gives a review over 7 years of research, development, and routine clinical application of computer-aided navigation technology in dental implantology. Benefits and disadvantages of up-to-date technologies are discussed. In the course of the current advancement, various hardware and software configurations are used. In the initial phase, universally applicable navigation software is adapted for implantology. Since 2001, a special software module for dental implantology is available. Preoperative planning is performed on the basis of prosthetic aspects and requirements. In clinical routine use, patient and drill positions are intraoperatively registered by means of optoelectronic tracking systems; during preclinical tests, electromagnetic trackers are also used. In 7 years (1995 to 2002), 55 patients with 327 dental implants were successfully positioned with computer-aided navigation technology. The mean number of implants per patient was 6 (minimum, 1; maximum, 11). No complications were observed; the preoperative planning could be exactly realized. The average expenditure of time for the preparation of a surgical intervention with navigation decreased from 2 to 3 days in the initial phase to one-half day in clinical routine use with software that is optimized for dental implantology. The use of computer-aided navigation technology can contribute to considerable quality improvement. Preoperative planning is exactly realized and intraoperative safety is increased, because damage to nerves or neighboring teeth can be avoided.

  19. Study in vitro of dental enamel irradiated with a high power diode laser operating at 960 nm: morphological analysis of post-irradiation dental surface and thermal effect analysis in pulp chamber due to laser application

    International Nuclear Information System (INIS)

    Quinto Junior, Jose

    2001-01-01

    Objectives: This study examines the structural and thermal modifications induced in dental enamel under dye assisted diode laser irradiation. The aim of this study is to verify if this laser-assisted treatment is capable to modify the enamel surface by causing fusion of the enamel surface layer. At the same time, the pulpal temperature rise must be kept low enough in order not to cause pulpar necrosis. To achieve this target, it is necessary to determine suitable laser parameters. As is known, fusion of the enamel surface followed by re-solidification produce a more acid resistant layer. This surface treatment is being researched as a new method for caries prevention. Method and Materials: A series of fourteen identically prepared enamel samples of human teeth were irradiated with a high power diode laser operating at 960 nm and using fiber delivery. Prior to irradiation, a fine layer of cromophorous ink was applied to the enamel surface. In the first part of the experiment the best parameter for pulse duration was determined. In the second part of the experimental phase the same energy density was used but with different repetition rates. During irradiation we monitored the temperature rise in the pulpal cavity. The morphology of the treated samples was analysed under SEM. Results: The morphology of the treated samples showed a homogeneously re-solidified enamel layer. The results of the temperature analysis showed a decrease of the pulpal temperature rise with decreasing repetition rate. Conclusion: With the diode laser it is possible to cause morphological alterations of the enamel surface, which is known to increase the enamel resistance against acid attack, and still maintain the temperature rise in the pulpar chamber below damage threshold. (author)

  20. [Effects of surface treatment and adhesive application on shear bond strength between zirconia and enamel].

    Science.gov (United States)

    Li, Yinghui; Wu, Buling; Sun, Fengyang

    2013-03-01

    To evaluate the effects of sandblasting and different orthodontic adhesives on shear bond strength between zirconia and enamel. Zirconia ceramic samples were designed and manufactured for 40 extracted human maxillary first premolars with CAD/CAM system. The samples were randomized into 4 groups for surface treatment with sandblasting and non-treated with adhesives of 3M Transbond XT or Jingjin dental enamel bonding resin. After 24 h of bonded fixation, the shear bond strengths were measured by universal mechanical testing machine and analyzed with factorial variance analysis. The shear bond strength was significantly higher in sandblasting group than in untreated group (Padhesives of Transbond XT and dental enamel bonding resin (P>0.05). The shear bond strength between zirconia and enamel is sufficient after sandblasting regardless of the application of either adhesive.

  1. Effects of probiotic fermented milk on biofilms, oral microbiota, and enamel

    OpenAIRE

    Lodi, Carolina Simonetti; Oliveira, Lidiane Viana; Brighenti, Fernanda Lourenção [UNESP; Delbem, Alberto Carlos Botazzo; Martinhon, Cleide Cristina Rodrigues

    2015-01-01

    The aim of this study was to evaluate in vitro and in vivo the effects of 2 brands of probiotic fermented milk on biofilms, oral microbiota, and enamel. For the in situ experiment, ten volunteers wore palatine devices containing four blocks of bovine dental enamel over 3 phases, during which 20% sucrose solution, Yakult® (Treatment A), and Batavito® (Treatment B) were dropped on the enamel blocks. Salivary microbial counts were obtained and biofilm samples were analyzed after each phase. For ...

  2. Further morphological evidence on South African earliest Homo lower postcanine dentition: Enamel thickness and enamel dentine junction.

    Science.gov (United States)

    Pan, Lei; Dumoncel, Jean; de Beer, Frikkie; Hoffman, Jakobus; Thackeray, John Francis; Duployer, Benjamin; Tenailleau, Christophe; Braga, José

    2016-07-01

    The appearance of the earliest members of the genus Homo in South Africa represents a key event in human evolution. Although enamel thickness and enamel dentine junction (EDJ) morphology preserve important information about hominin systematics and dietary adaptation, these features have not been sufficiently studied with regard to early Homo. We used micro-CT to compare enamel thickness and EDJ morphology among the mandibular postcanine dentitions of South African early hominins (N = 30) and extant Homo sapiens (N = 26), with special reference to early members of the genus Homo. We found that South African early Homo shows a similar enamel thickness distribution pattern to modern humans, although three-dimensional average and relative enamel thicknesses do not distinguish australopiths, early Homo, and modern humans particularly well. Based on enamel thickness distributions, our study suggests that a dietary shift occurred between australopiths and the origin of the Homo lineage. We also observed that South African early Homo postcanine EDJ combined primitive traits seen in australopith molars with derived features observed in modern human premolars. Our results confirm that some dental morphological patterns in later Homo actually occurred early in the Homo lineage, and highlight the taxonomic value of premolar EDJ morphology in hominin species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Morphology of the cemento-enamel junction in premolar teeth.

    Science.gov (United States)

    Arambawatta, Kapila; Peiris, Roshan; Nanayakkara, Deepthi

    2009-12-01

    The present study attempted to describe the distribution of the mineralized tissues that compose the cemento-enamel junction, with respect to both the different types of permanent premolars of males and females and the various surfaces of individual teeth. The cervical region of ground sections of 67 premolars that had been extracted for orthodontic reasons were analyzed using transmitted light microscopy to identify which of the following tissue interrelationships was present at the cemento-enamel junction: cementum overlapping enamel; enamel overlapping cementum; edge-to-edge relationship between cementum and enamel; or the presence of gaps between the enamel and cementum with exposed dentin. An edge-to-edge interrelation between root cementum and enamel was predominant (55.1%). In approximately one-third of the sample, gaps between cementum and enamel with exposed dentin were observed. Cementum overlapping enamel was less prevalent than previously reported, and enamel overlapping cementum was seen in a very small proportion of the sample. In any one tooth, the distribution of mineralized tissues at the cemento-enamel junction was irregular and unpredictable. The frequency of gaps between enamel and cementum with exposure of dentin was higher than previously reported, which suggests that this region is fragile and strongly predisposed to pathological changes. Hence, this region should be protected and carefully managed during routine clinical procedures such as dental bleaching, orthodontic treatment, and placement of restorative materials.

  4. Effect of acidity upon attrition-corrosion of human dental enamel.

    Science.gov (United States)

    Wu, Yun-Qi; Arsecularatne, Joseph A; Hoffman, Mark

    2015-04-01

    Attrition-corrosion is a synthesized human enamel wear process combined mechanical effects (attrition) with corrosion. With the rising consumption of acidic food and beverages, attrition-corrosion is becoming increasingly common. Yet, research is limited and the underlying mechanism remains unclear. In this study, in vitro wear loss of human enamel was investigated and the attrition-corrosion process and wear mechanism were elucidated by the analysis of the wear scar and its subsurface using focused ion beam (FIB) sectioning and scanning electron microscopy (SEM). Human enamel flat-surface samples were prepared with enamel cusps as the wear antagonists. Reciprocating wear testing was undertaken under load of 5N at the speed of 66 cycle/min for 2250 cycles with lubricants including citric acid (at pH 3.2 and 5.5), acetic acid (at pH 3.2 and 5.5) and distilled water. All lubricants were used at 37°C. Similar human enamel flat-surface samples were also exposed to the same solutions as a control group. The substance loss of enamel during wear can be linked to the corrosion potential of a lubricant used. Using a lubricant with very low corrosion potential (such as distilled water), the wear mechanism was dominated by delamination with high wear loss. Conversely, the wear mechanism changed to shaving of the softened layer with less material loss in an environment with medium corrosion potential such as citric acid at pH 3.2 and 5.5 and acetic acid at pH 5.5. However, a highly corrosive environment (e.g., acetic acid at pH 3.2) caused the greatest loss of substance during wear. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Micro-structural integrity of dental enamel subjected to two tooth whitening regimes.

    Science.gov (United States)

    Tanaka, Reina; Shibata, Yo; Manabe, Atsufumi; Miyazaki, Takashi

    2010-04-01

    Colour modification of tooth enamel has proven successful, but it is unclear how various bleaching applications affect micro-structural integrity of the whitened enamel. To investigate the internal structural integrity of human intact tooth enamel with the application of two commonly used whitening regimes (in-office power bleaching with 35% hydrogen peroxide and home bleaching with 10% carbamide peroxide), evaluations were performed on teeth of identical colour classification. After the bleaching applications, the enamel mineral density was quantified and visualised with micro-computed tomography. The micro-structural differences between the whitened tooth enamel samples were distinctive, though the colour parameter changes within the samples were equivalent. Home bleaching achieved colour modification by demineralisation, whereas in-office bleaching depended on redistribution of the minerals after treatment and subsequent enhanced mineralisation.

  6. Effect of thickener agents on dental enamel microhardness submitted to at-home bleaching Efeito de agentes espessantes na microdureza do esmalte submetido ao clareamento dental caseiro

    Directory of Open Access Journals (Sweden)

    José Augusto Rodrigues

    2007-06-01

    Full Text Available Dental bleaching occurs due to an oxidation reaction between the bleaching agents and the macromolecules of pigments in the teeth. This reaction is unspecific and the peroxides can also affect the dental matrix causing mineral loss. On the other hand, recent studies have suggested that the thickener agent carbopol can also cause mineral loss. Thus, the objective of this study was to evaluate in vitro the effect of at-home dental bleaching on dental enamel microhardness after the use of bleaching agents with and without carbopol as a thickener agent. Bovine dental slabs with 3 x 3 x 3 mm were obtained, sequentially polished, and randomly divided into 4 groups according to the experimental treatment: G1: 2% carbopol; G2: 10% carbamide peroxide with carbopol; G3: carbowax; G4: 10% carbamide peroxide with poloxamer. Bleaching was performed daily for 4 weeks, immersed in artificial saliva. Enamel microhardness values were obtained before the treatment (T0 and 7 (T1, 14 (T2, 21 (T3, 28 (T4, and 42 (T5 days after the beginning of the treatment. ANOVA and Tukey's test revealed statistically significant differences only for the factor Time (F = 5.48; p O clareamento dental ocorre devido a uma reação de oxidação entre o agente clareador e as macromoléculas de pigmentos presentes nos dentes. Esta reação é inespecífica e o peróxido pode agir na matriz dental causando perdas de mineral. Por outro lado, estudos recentes sugerem que o agente espessante carbopol também pode causar perda mineral. Assim, o objetivo deste trabalho foi avaliar in vitro o efeito do clareamento caseiro sobre a microdureza do esmalte após o uso de agentes clareadores com e sem carbopol como espessante. Fragmentos de esmalte bovino de 3 x 3 x 3 mm foram obtidos, polidos seqüencialmente e aleatoriamente divididos em 4 grupos de acordo com o tratamento experimental: G1: carbopol a 2%; G2: peróxido de carbamida a 10% com carbopol; G3: carbowax; G4: peróxido de carbamida a

  7. Sub-10-micrometer toughening and crack tip toughness of dental enamel

    OpenAIRE

    Ang, Siang Fung; Schulz, Anja; Pacher Fernandes, Rodrigo; Schneider, Gerold A.

    2011-01-01

    In previous studies, enamel showed indications to occlude small cracks in-vivo and exhibited R-curve behaviors for bigger cracks ex-vivo. This study quantifies the crack tip toughness (KI0, KIII0), the crack closure stress and the cohesive zone size at the crack tip of enamel and investigates the toughening mechanisms near the crack tip down to the length scale of a single enamel crystallite. The crack-opening-displacement (COD) profile of cracks induced by Vickers indents on mature bovine en...

  8. Crystallite size and lattice distortion of human dental enamel estimated from the integral width of x-ray diffraction peak profile

    International Nuclear Information System (INIS)

    Maruyama, Fumiaki; Sakae, Toshiro

    2000-01-01

    Crystallite size and lattice distortion of human dental enamel were estimated by peak profile analysis using x-ray diffraction pattern. Firstly, noises were removed from x-ray diffraction pattern, and deconvolution of overlapping peaks and determination of baseline level were carried out. Then, the instrumental peak broadening and effect of overlapping Kα1 and Kα2 were eliminated to obtain pure peak profile using the Stokes's Fourier method. The integral width method was applied for estimation of crystallite size and 'upper-limit of distortion', assuming the peak profile as Cauchy function. The estimated crystallite size and distortion were ca. 210 A and ca. 0.4% in the a-axis direction and ca. 550 A and ca. 0.7% in the c-axis direction, respectively. The crystallite size value along the a-axis was almost the same to the previously reported values, but the value for along the c-axis was nearly half of the reported values. The crystallite size in this study means the size of coherent domain in contrast to the size of particle which may contain several domains in the case of enamel crystals. The results suggest that human enamel crystals grow in their size along the c-axis by multiplication, fusion of crystallites. It was notable that the distortion value was larger in the c-axis direction. The phenomenon may partly be due to the high carbonate ion content of enamel crystals and partly due to crystal growth mechanism. (author)

  9. Mammalian enamel maturation: Crystallographic changes prior to tooth eruption

    Czech Academy of Sciences Publication Activity Database

    Kallistová, Anna; Horáček, I.; Šlouf, Miroslav; Skála, Roman; Fridrichová, Michaela

    2017-01-01

    Roč. 12, č. 2 (2017), č. článku e0171424. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:67985831 ; RVO:61389013 Keywords : resolution electron-microscopy * atomic-force microscopy * dental enamel * vertebrate dentition * rat enamel * protein * evolution * crystals * shape * ameloblastin Subject RIV: EH - Ecology, Behaviour; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Other biological topics; Polymer science (UMCH-V) Impact factor: 2.806, year: 2016

  10. COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

    Directory of Open Access Journals (Sweden)

    EDUARDO Carlos de Paula

    1997-01-01

    Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

  11. On the critical parameters that regulate the deformation behaviour of tooth enamel.

    Science.gov (United States)

    Xie, Zonghan; Swain, Michael; Munroe, Paul; Hoffman, Mark

    2008-06-01

    Tooth enamel is the hardest tissue in the human body with a complex hierarchical structure. Enamel hypomineralisation--a developmental defect--has been reported to cause a marked reduction in the mechanical properties of enamel and loss of dental function. We discover a distinctive difference in the inelastic deformation mechanism between sound and hypomineralised enamels that is apparently controlled by microstructural variation. For sound enamel, when subjected to mechanical forces the controlling deformation mechanism was distributed shearing within nanometre thick protein layer between its constituent mineral crystals; whereas for hypomineralised enamel microcracking and subsequent crack growth were more evident in its less densely packed microstructure. We develop a mechanical model that not only identifies the critical parameters, i.e., the thickness and shear properties of enamels, that regulate the mechanical behaviour of enamel, but also explains the degradation of hypomineralised enamel as manifested by its lower resistance to deformation and propensity for catastrophic failure. With support of experimental data, we conclude that for sound enamel an optimal microstructure has been developed that endows enamel with remarkable structural integrity for durable mechanical function.

  12. Critiquing the Computer-Aided Design of Dental Prostheses.

    Science.gov (United States)

    Fitzpatrick, F. J.; And Others

    This paper describes RaPiD, a computer-aided assistant for the design of dental prostheses called removable partial dentures. The user manipulates icons directly to indicate the desired design solution to a given clinical situation. A developing design is represented as a logic database of components in a design; expert rules are applied as…

  13. The Chernobyl accident: EPR dosimetry on dental enamel of children

    International Nuclear Information System (INIS)

    Gualtieri, G.; Colacicchi, S.; Sgattoni, R.; Giannoni, M.

    2001-01-01

    The radiation dose on tooth enamel of children living close to Chernobyl has been evaluated by EPR. The sample preparation was reduced to a minimum of mechanical steps to remove a piece of enamel. A standard X-ray tube at low energy was used for additive irradiation. The filtration effect of facial soft tissue was taken into account. The radiation dose for a group of teeth slightly exceeds the annual dose, whereas for another group the dose very much exceeds the annual dose. Since the higher dose is found in teeth whose enamel have much lower EPR sensitivity to the radiation, it can be suggested that for these teeth the native signal could alter the evaluation of the smaller radiation signal

  14. Matching 4.7-Å XRD spacing in amelogenin nanoribbons and enamel matrix.

    Science.gov (United States)

    Sanii, B; Martinez-Avila, O; Simpliciano, C; Zuckermann, R N; Habelitz, S

    2014-09-01

    The recent discovery of conditions that induce nanoribbon structures of amelogenin protein in vitro raises questions about their role in enamel formation. Nanoribbons of recombinant human full-length amelogenin (rH174) are about 17 nm wide and self-align into parallel bundles; thus, they could act as templates for crystallization of nanofibrous apatite comprising dental enamel. Here we analyzed the secondary structures of nanoribbon amelogenin by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and tested if the structural motif matches previous data on the organic matrix of enamel. XRD analysis showed that a peak corresponding to 4.7 Å is present in nanoribbons of amelogenin. In addition, FTIR analysis showed that amelogenin in the form of nanoribbons was comprised of β-sheets by up to 75%, while amelogenin nanospheres had predominantly random-coil structure. The observation of a 4.7-Å XRD spacing confirms the presence of β-sheets and illustrates structural parallels between the in vitro assemblies and structural motifs in developing enamel. © International & American Associations for Dental Research.

  15. Application of the ultrashort pulses in bovine dental enamel

    International Nuclear Information System (INIS)

    Todescan, Carla de Rago

    2003-01-01

    The interaction of lasers with the hard structures of the teeth, has found the excess of heat as a problem for its utilization. This study analyzes, in vitro, the interaction of the ultrashort pulse laser of Ti:safire (830 nm) with the bovine dental enamel. The system consisted in one main oscillator integrated with an amplifier (CPA). The pulses extracted before the temporal compression inside the amplifier had 30 ps, 1000 Hz and ∼1 mJ. The pulses extracted after the compression had 60 fs, 1000 Hz and ∼0,7 mJ. The M 2 was 1,3, the focal lens 2,5 cm, the focal distance 29,7 and a computerized translation stage x,y,z. We evaluated the amount of tissue removed per pulse,the resulting cavities and the surrounding tissues not irradiated, under OM and SEM. The fluency was the major factor for differentiating the two regimens studied, therefore, the intensity was not so important as we expected in this process. We found: one ablation region in 'cat tongue', one ablation length, one fluency ∼0,7 J/cm 2 for 30 ps and ∼0,5 J/cm 2 for 60 fs (50% of high speed burr), smooth edge for 30 ps and high precision of the sharp edge cut of submicrometric order for 60 fs. (author)

  16. Evaluation of microshear bond strength of resin composites to enamel of dental adhesive systems associated with Er,Cr:YSGG laser

    Science.gov (United States)

    Cassimiro-Silva, Patricia F.; Zezell, Denise M.; Monteiro, Gabriela Q. d. M.; Benetti, Carolina; de Paula Eduardo, Carlos; Gomes, Anderson S. L.

    2016-02-01

    The aim of this in vitro study was to evaluate the microshear bond strength (μSBS) of resin composite to enamel etching by Er,Cr:YSGG laser with the use of two differents adhesives systems. Fifty freshly extracted human molars halves were embedded in acrylic resin before preparation for the study, making a total of up to 100 available samples. The specimens were randomly assigned into six groups (η=10) according to substrate pre-treatment and adhesive system on the enamel. A two-step self-etching primer system (Clearfil SE Bond) and a universal adhesive used as an etch-andrinse adhesive (Adper Single Bond Universal) were applied to the nonirradiated enamel surface according to manufacturer's instructions, as control groups (Control CF and Control SB, respectively). For the other groups, enamel surfaces were previously irradiated with the Er,Cr:YSGG laser with 0.5 W, 75 mJ and 66 J/cm2 (CF 5 Hz and SB 5 Hz) and 1.25 W, 50 mJ and 44 J/cm2 (CF 15 Hz and SB 15 Hz). Irradiation was performed under air (50%) and water (50%) cooling. An independent t-test was performed to compare the adhesive systems. Mean μSBS ± sd (MPa) for each group was 16.857 +/- 2.61, 17.87 +/- 5.83, 12.23 +/- 2.02, 9.88 +/- 2.26, 15.94 +/- 1.98, 17.62 +/- 2.10, respectively. The control groups and the 50 mJ laser groups showed no statistically significant differences, regardless of the adhesive system used. The results obtained lead us to affirm that the bonding interaction of adhesives to enamel depends not only on the morphological aspects of the dental surface, but also on the characteristics of the adhesive employed and the parameters of the laser.

  17. Knowledge and attitudes about HIV/AIDS of dental students from Kuwait and Sri Lanka.

    Science.gov (United States)

    Ellepola, Arjuna N B; Sundaram, Devipriya B; Jayathilake, Sumedha; Joseph, Bobby K; Sharma, Prem N

    2011-04-01

    Several studies regarding knowledge and attitudes of dental students towards HIV/AIDS have been reported from various countries. However, to the best of our knowledge, an international comparison between countries with diverse cultural and educational backgrounds has not been reported in the literature. The aim of this study was to compare the knowledge and attitudes towards HIV/AIDS of dental students of Kuwait University (KU), Kuwait and the University of Peradeniya (UP), Sri Lanka, the only dental schools in the respective countries. A cross-sectional survey was conducted among a total of 258 dental students, representing the clinical years of both universities, using a similar structured questionnaire with sixty questions to examine their knowledge of various aspects of HIV/AIDS and thirteen questions to examine their attitudes towards the disease. The mean knowledge and attitude scores were calculated and compared between students from the two universities using t-test with SPSS 17.0. A total of 215 questionnaires were completed and returned, giving a total response rate of 83.3 percent. The KU students were significantly more knowledgeable (p=0.018) regarding HIV/AIDS than the UP students. However, the UP students demonstrated a more highly significant positive attitude (peducation in these countries.

  18. Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus) Exposed to High Environmental Levels of Fluoride

    Science.gov (United States)

    Kierdorf, Uwe; Death, Clare; Hufschmid, Jasmin; Witzel, Carsten; Kierdorf, Horst

    2016-01-01

    Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface) enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species. PMID:26895178

  19. Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus Exposed to High Environmental Levels of Fluoride.

    Directory of Open Access Journals (Sweden)

    Uwe Kierdorf

    Full Text Available Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species.

  20. Sub-10-micrometer toughening and crack tip toughness of dental enamel.

    Science.gov (United States)

    Ang, Siang Fung; Schulz, Anja; Pacher Fernandes, Rodrigo; Schneider, Gerold A

    2011-04-01

    In previous studies, enamel showed indications to occlude small cracks in-vivo and exhibited R-curve behaviors for bigger cracks ex-vivo. This study quantifies the crack tip's toughness (K(I0),K(III0)), the crack's closure stress and the cohesive zone size at the crack tip of enamel and investigates the toughening mechanisms near the crack tip down to the length scale of a single enamel crystallite. The crack-opening-displacement (COD) profile of cracks induced by Vickers indents on mature bovine enamel was studied using atomic force microscopy (AFM). The mode I crack tip toughness K(I0) of cracks along enamel rod boundaries and across enamel rods exhibit a similar range of values: K(I0,Ir)=0.5-1.6MPa m(0.5) (based on Irwin's 'near-field' solution) and K(I0,cz)=0.8-1.5MPa m(0.5) (based on the cohesive zone solution of the Dugdale-Muskhelishvili (DM) crack model). The mode III crack tip toughness K(III0,Ir) was computed as 0.02-0.15MPa m(0.5). The crack-closure stress at the crack tip was computed as 163-770 MPa with a cohesive zone length and width 1.6-10.1μm and 24-44 nm utilizing the cohesive zone solution. Toughening elements were observed under AFM and SEM: crack bridging due to protein ligament and hydroxyapatite fibres (micro- and nanometer scale) as well as microcracks were identified. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

  1. Controlling dental enamel-cavity ablation depth with optimized stepping parameters along the focal plane normal using a three axis, numerically controlled picosecond laser.

    Science.gov (United States)

    Yuan, Fusong; Lv, Peijun; Wang, Dangxiao; Wang, Lei; Sun, Yuchun; Wang, Yong

    2015-02-01

    The purpose of this study was to establish a depth-control method in enamel-cavity ablation by optimizing the timing of the focal-plane-normal stepping and the single-step size of a three axis, numerically controlled picosecond laser. Although it has been proposed that picosecond lasers may be used to ablate dental hard tissue, the viability of such a depth-control method in enamel-cavity ablation remains uncertain. Forty-two enamel slices with approximately level surfaces were prepared and subjected to two-dimensional ablation by a picosecond laser. The additive-pulse layer, n, was set to 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70. A three-dimensional microscope was then used to measure the ablation depth, d, to obtain a quantitative function relating n and d. Six enamel slices were then subjected to three dimensional ablation to produce 10 cavities, respectively, with additive-pulse layer and single-step size set to corresponding values. The difference between the theoretical and measured values was calculated for both the cavity depth and the ablation depth of a single step. These were used to determine minimum-difference values for both the additive-pulse layer (n) and single-step size (d). When the additive-pulse layer and the single-step size were set 5 and 45, respectively, the depth error had a minimum of 2.25 μm, and 450 μm deep enamel cavities were produced. When performing three-dimensional ablating of enamel with a picosecond laser, adjusting the timing of the focal-plane-normal stepping and the single-step size allows for the control of ablation-depth error to the order of micrometers.

  2. Enamel softening with Coca-Cola and rehardening with milk or saliva.

    Science.gov (United States)

    Gedalia, I; Dakuar, A; Shapira, L; Lewinstein, I; Goultschin, J; Rahamim, E

    1991-06-01

    Rehardening effects by cow's milk and by secreted saliva were investigated, in situ, following softening of human enamel with an acidic beverage (Coca-Cola). Volunteers wearing orthodontic removable appliances participated in the study. The intra-oral test was chosen for measuring microhardness of enamel slabs inserted into the dental appliance. The softening and the rehardening degrees were defined as the alterations between initial- and experimental-microhardness value at the enamel surface. In addition, SEM photos were prepared from the initial and experimental stages. Exposure of enamel slabs to the acidic beverage during 1 hour had a softening effect as expressed by the hardness decrease and visualized by the SEM photo. Rehardening effects following milk or saliva exposures respectively were evident, presumably due to deposited organic and mineral material on the enamel surface.

  3. Effects of moisture conditions of dental enamel surface on bond strength of brackets bonded with moisture-insensitive primer adhesive system.

    Science.gov (United States)

    Endo, Toshiya; Ozoe, Rieko; Sanpei, Sugako; Shinkai, Koichi; Katoh, Yoshiroh; Shimooka, Shohachi

    2008-07-01

    The purposes of this study were to evaluate the effects of different degrees of water contamination on the shear bond strength of orthodontic brackets bonded to dental enamel with a moisture-insensitive primer (MIP) adhesive system and to compare the modes of bracket/adhesive failure. A total of 68 human premolars were divided into four groups by primers and enamel surface conditions (desiccated, blot dry, and overwet). In group I, the hydrophobic Transbond XT primer adhesive system was used under desiccated conditions for bonding the brackets; in group II, the hydrophilic Transbond MIP adhesive system was used under desiccated conditions; in group III, the hydrophilic Transbond MIP adhesive system was used under blot dry conditions; and in group IV, the hydrophilic Transbond MIP adhesive system was used under overwet conditions. Shear bond strength was measured with a universal testing machine, and the mode of bracket/adhesive failure was determined according to the adhesive remnant index. The mean shear bond strengths were not significantly different among groups I, II, and III, and were higher than the clinically required range of 6 to 8 MPa. The mean shear bond strength achieved in group IV was significantly lower than that achieved in groups I, II, and III, and also lower than the clinically required values. Bond failure occurred at the enamel-adhesive interface more frequently in group IV than in groups I and III. To achieve clinically sufficient bond strengths with the hydrophilic MIP adhesive system, excess water should be blotted from the water-contaminated enamel surface.

  4. Trace Elements in Human Tooth Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Nixon, G. S. [Turner Dental School, University Of Manchester, Manchester (United Kingdom); Smith, H.; Livingston, H. D. [Department of Forensic Medicine, University Of Glasgow, Glasgow (United Kingdom)

    1967-10-15

    The trace elements are considered to play a role in the resistance of teeth to dental caries. The exact mechanism by which they act has not yet been fully established. Estimations of trace elements have been undertaken in sound human teeth. By means of activation analysis it has been possible to determine trace element concentrations in different layers of enamel in the same tooth. The concentrations of the following elements have been determined: arsenic, antimony, copper, zinc, manganese, mercury, molybdenum and vanadium. The distribution of trace elements in enamel varies from those with a narrow range, such as manganese, to those with a broad range, such as antimony. The elements present in the broad range are considered to be non-essential and their presence is thought to result from a chance incorporation into the enamel. Those in the narrow range appear to be essential trace elements and are present in amounts which do not vary unduly from other body tissues. Only manganese and zinc were found in higher concentrations in the surface layer of enamel compared with the inner layers. The importance of the concentration of trace elements on this surface layer of enamel is emphasized as this layer is the site of the first attack by the carious process. (author)

  5. EFFECT OF SURFACE CONDTIONINGON BOND STRENGTH TO ENAMEL AND DENTIN

    Directory of Open Access Journals (Sweden)

    M MOUSAVINASAB

    2002-09-01

    Full Text Available Introduction. Compoglass is a trade mark of dental compomers and because of its partially resinus structure, surface conditioning of dental surfaces is needed for a better bonding process. In this study, the effect of enamel and dentin conditioning procedure on shear bond strength (SBS of compoglass to tooth surfaces was studied. Methods. four groups each one including 11 sound premolars were chosen and their surfaces were prepared as following groups: group1, unconitioned dentin; group 2, dentin conditioning with phosphoric acid 35%; group 3, dentin conditioning with polyacrylic acid 20% group 4, unconditioning enamel; group 5, enamel conditioning with phosphoric acid 35%; and group 6, enamel conditioning with polyacrylic acid 20%. Compoglass was bonded to prepared surfaces and after fixation of the samples in acrylic molds, all samples were tested under shear force of instron testing machine at a rate of 1 mm/min speed. Results. The mean SBS obtained in these 6 groups were 6.207, 8.057, 10.146, 25.939 and 11.827 mpa. the mode of fracture also studied using a streomicroscope. Statistical analysis of the results showed that the maximum SBS obtained in group 5 and the lowest SBS about 6.207 mpa obtained in group 1. Despite increase in SBS group 2 and 3, there was no statistical differncies between group 1, 2 and 3. Discussion. Based on results of this study, conditioning of enamel and dentin surface due to improve SBS is recommeneded.

  6. Enamel subsurface damage due to tooth preparation with diamonds.

    Science.gov (United States)

    Xu, H H; Kelly, J R; Jahanmir, S; Thompson, V P; Rekow, E D

    1997-10-01

    In clinical tooth preparation with diamond burs, sharp diamond particles indent and scratch the enamel, causing material removal. Such operations may produce subsurface damage in enamel. However, little information is available on the mechanisms and the extent of subsurface damage in enamel produced during clinical tooth preparation. The aim of this study, therefore, was to investigate the mechanisms of subsurface damage produced in enamel during tooth preparation by means of diamond burs, and to examine the dependence of such damage on enamel rod orientation, diamond particle size, and removal rate. Subsurface damage was evaluated by a bonded-interface technique. Tooth preparation was carried out on two enamel rod orientations, with four clinical diamond burs (coarse, medium, fine, and superfine) used in a dental handpiece. The results of this study showed that subsurface damage in enamel took the form of median-type cracks and distributed microcracks, extending preferentially along the boundaries between the enamel rods. Microcracks within individual enamel rods were also observed. The median-type cracks were significantly longer in the direction parallel to the enamel rods than perpendicular to the rods. Preparation with the coarse diamond bur produced cracks as deep as 84 +/- 30 microns in enamel. Finishing with fine diamond burs was effective in crack removal. The crack lengths in enamel were not significantly different when the removal rate was varied. Based on these results, it is concluded that subsurface damage in enamel induced by tooth preparation takes the form of median-type cracks as well as inter- and intra-rod microcracks, and that the lengths of these cracks are sensitive to diamond particle size and enamel rod orientation, but insensitive to removal rate.

  7. [In vivo retention of KOH soluble and firmly bound fluoride in demineralized dental enamel].

    Science.gov (United States)

    Hellwig, E; Klimek, J; Albert, G

    1989-03-01

    Cylindrical enamel blocks with initial carious lesions were treated for one hour with Duraphat or Fluor-Protector. After removal of the fluoride varnishes the enamel blocks were kept in the mouths of 3 probands for 5 days. Plaque was allowed to accumulate on half of the enamel cylinders, while the other half was kept clean. Part of the enamel cylinders were retained as fluoridated controls. Compared with Duraphat the application of Fluor-Protector resulted in a significantly higher uptake of KOH soluble and firmly bound fluoride. During the 5 days of the experiment the amount of KOH soluble fluorides decreased in both groups. In the presence of plaque the fluoride loss was higher. The amount of firmly bound fluoride increased both in the plaque covered and in the clean enamel. The durable cariostatic effect of fluoridated varnishes seems to be due to the slow dissolution of Ca F2-like precipitates on the enamel surface and the concomitant fluoride uptake in the underlying demineralized enamel.

  8. Effect of a New Surface Treatment Solution on the Bond Strength of Composite to Enamel

    Science.gov (United States)

    2016-06-01

    Bond Strength of Composite to Enamel " is appropriately acknowledged and, beyond brief excerpts, is with the permission of the copyright owner...Solution on the Bond Strength of Composite to Enamel ABSTRACT Clean & Boost (Apex Dental Materials) is a novel surface treatment solution...designed to be used in place of phosphoric acid to increase the bond strength of self-etch adhesives to enamel and more effectively remove contaminants

  9. Microwave processing of a dental ceramic used in computer-aided design/computer-aided manufacturing.

    Science.gov (United States)

    Pendola, Martin; Saha, Subrata

    2015-01-01

    Because of their favorable mechanical properties and natural esthetics, ceramics are widely used in restorative dentistry. The conventional ceramic sintering process required for their use is usually slow, however, and the equipment has an elevated energy consumption. Sintering processes that use microwaves have several advantages compared to regular sintering: shorter processing times, lower energy consumption, and the capacity for volumetric heating. The objective of this study was to test the mechanical properties of a dental ceramic used in computer-aided design/computer-aided manufacturing (CAD/CAM) after the specimens were processed with microwave hybrid sintering. Density, hardness, and bending strength were measured. When ceramic specimens were sintered with microwaves, the processing times were reduced and protocols were simplified. Hardness was improved almost 20% compared to regular sintering, and flexural strength measurements suggested that specimens were approximately 50% stronger than specimens sintered in a conventional system. Microwave hybrid sintering may preserve or improve the mechanical properties of dental ceramics designed for CAD/CAM processing systems, reducing processing and waiting times.

  10. Determination of thermal diffusivity of dental enamel and dentin as a function of temperature, using infrared thermography

    International Nuclear Information System (INIS)

    Pereira, Thiago Martini

    2009-01-01

    In this work it was developed a software that calculates automatically, the thermal diffusivity value as a function of temperature in materials. The infrared thermography technique was used for data acquisition of temperature distribution as a function of time. These data were used to adjust a temperature function obtained from the homogeneous heat equation with specific boundary conditions. For that, an infrared camera (detecting from 8 μm to 9 μm) was calibrated to detect temperature ranging from 185 degree C up to 1300 degree C at an acquisition rate of 300 Hz. It was used, 10 samples of dental enamel and 10 samples of dentin, with 4 mm x 4 mm x 2 mm, which were obtained from bovine lower incisor teeth. These samples were irradiated with an Er:Cr:YSGG pulsed laser (λ = 2,78 μm). The resulting temperature was recorded 2 s prior, 10 s during irradiation and continuing for 2 more seconds after it. After each irradiation, all obtained thermal images were processed in the software, creating a file with the data of thermal diffusivity as a function of temperature. Another file with the thermal diffusivity values was also calculated after each laser pulse. The mean result of thermal diffusivity obtained for dental enamel was 0,0084 ± 0,001 cm2/s for the temperature interval of 220-550 degree C. The mean value for thermal diffusivity obtained for dentin was 0,0015 0,0004 cm2/s in temperatures up to 360 degree C; however, this value increases for higher temperatures. According to these results, it was possible to conclude that the use of infrared thermography, associated with the software developed in this work, is an efficient method to determine the thermal diffusivity values as a function of temperature in different materials. (author)

  11. AFM analysis of bleaching effects on dental enamel microtopography

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira de Freitas, Ana Carolina, E-mail: anacarolfreitas@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Cardoso Espejo, Luciana, E-mail: luespejo@hotmail.com [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Brossi Botta, Sergio, E-mail: sbbotta@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Sa Teixeira, Fernanda de, E-mail: nandast@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil); Cerqueira, Luz Maria Aparecida A., E-mail: maacluz@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Garone-Netto, Narciso, E-mail: ngarone@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Bona Matos, Adriana, E-mail: bona@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Barbosa da Silveira Salvadori, Maria Cecilia, E-mail: mcsalva@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil)

    2010-02-15

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 {mu}m x 15 {mu}m area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  12. AFM analysis of bleaching effects on dental enamel microtopography

    International Nuclear Information System (INIS)

    Pedreira de Freitas, Ana Carolina; Cardoso Espejo, Luciana; Brossi Botta, Sergio; Sa Teixeira, Fernanda de; Cerqueira, Luz Maria Aparecida A.; Garone-Netto, Narciso; Bona Matos, Adriana; Barbosa da Silveira Salvadori, Maria Cecilia

    2010-01-01

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 μm x 15 μm area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  13. Effect of 10% Strontium Chloride and 5% Potassium Nitrate with Fluoride on Bleached Bovine Enamel.

    Science.gov (United States)

    Alencar, Cristiane de Melo; Pedrinha, Victor Feliz; Araújo, Jesuína Lamartine Nogueira; Esteves, Renata Antunes; Silva da Silveira, Ana Daniela; Silva, Cecy Martins

    2017-01-01

    Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. This study evaluated in vitro the effect of 10% strontium chloride and 5% potassium nitrate with fluoride on bovine enamel, through tristimulus colorimetry, Knoop microhardness (KHN), and roughness after bleaching with 35% hydrogen peroxide (HP). The specimens were divided into three groups (n=15): GControl received bleaching treatment with 35% HP; GNitrate received bleaching with 35% HP followed by the application of 5% potassium nitrate with 2% sodium fluoride; and GStrontium received bleaching with 35% HP followed by the application of 10% strontium chloride on the enamel. Next, five specimens of each experimental group were subjected to KHN and tristimulus colorimetry tests, and 10 specimens were subjected to surface roughness (SR) tests. The values obtained for the different groups were compared through analysis of variance (ANOVA) followed by a post-hoc Tukey-Kramer test in addition to Student's T-test for paired data. In the intergroup comparison, KHN final differed statistically ( p 0.05). 10% strontium chloride and 5% potassium nitrate combined with 2% fluoride downplayed morphological changes to the enamel, without interfering with the effectiveness of the bleaching process.

  14. Bonding efficacy of new self-etching, self-adhesive dual-curing resin cements to dental enamel.

    Science.gov (United States)

    Benetti, Paula; Fernandes, Virgílio Vilas; Torres, Carlos Rocha; Pagani, Clovis

    2011-06-01

    This study evaluated the efficacy of the union between two new self-etching self-adhesive resin cements and enamel using the microtensile bond strength test. Buccal enamel of 80 bovine teeth was submitted to finishing and polishing with metallographic paper to a refinement of #600, in order to obtain a 5-mm2 flat area. Blocks (2 x 4 x 4 mm) of laboratory composite resin were cemented to enamel according to different protocols: (1) untreated enamel + RelyX Unicem cement (RX group); (2) untreated enamel + Bifix SE cement (BF group); (3) enamel acid etching and application of resin adhesive Single Bond + RelyX Unicem (RXA group); (4) enamel acid etching and application of resin adhesive Solobond M + Bifix SE (BFA group). After 7 days of storage in distillated water at 37°C, the blocks were sectioned for obtaining microbar specimens with an adhesive area of 1 mm2 (n = 120). Specimens were submitted to the microtensile bond strength test at a crosshead speed of 0.5 mm/min. The results (in MPa) were analyzed statistically by ANOVA and Tukey's test. Enamel pre-treatment with phosphoric acid and resin adhesive (27.9 and 30.3 for RXA and BFA groups) significantly improved (p ≤ 0.05) the adhesion of both cements to enamel compared to the union achieved with as-polished enamel (9.9 and 6.0 for RX and BF). Enamel pre-treatment with acid etching and the application of resin adhesive significantly improved the bond efficacy of both luting agents compared to the union achieved with as-polished enamel.

  15. Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

    2015-07-01

    This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Ca2+ transport and signalling in enamel cells

    Science.gov (United States)

    Nurbaeva, Meerim K.; Eckstein, Miriam; Feske, Stefan

    2016-01-01

    Abstract Dental enamel is one of the most remarkable examples of matrix‐mediated biomineralization. Enamel crystals form de novo in a rich extracellular environment in a stage‐dependent manner producing complex microstructural patterns that are visually stunning. This process is orchestrated by specialized epithelial cells known as ameloblasts which themselves undergo striking morphological changes, switching function from a secretory role to a cell primarily engaged in ionic transport. Ameloblasts are supported by a host of cell types which combined represent the enamel organ. Fully mineralized enamel is the hardest tissue found in vertebrates owing its properties partly to the unique mixture of ionic species represented and their highly organized assembly in the crystal lattice. Among the main elements found in enamel, Ca2+ is the most abundant ion, yet how ameloblasts modulate Ca2+ dynamics remains poorly known. This review describes previously proposed models for passive and active Ca2+ transport, the intracellular Ca2+ buffering systems expressed in ameloblasts and provides an up‐dated view of current models concerning Ca2+ influx and extrusion mechanisms, where most of the recent advances have been made. We also advance a new model for Ca2+ transport by the enamel organ. PMID:27510811

  17. Bio-inspired dental fillings

    Science.gov (United States)

    Deyhle, Hans; Bunk, Oliver; Buser, Stefan; Krastl, Gabriel; Zitzmann, Nicola U.; Ilgenstein, Bernd; Beckmann, Felix; Pfeiffer, Franz; Weiger, Roland; Müller, Bert

    2009-08-01

    Human teeth are anisotropic composites. Dentin as the core material of the tooth consists of nanometer-sized calcium phosphate crystallites embedded in collagen fiber networks. It shows its anisotropy on the micrometer scale by its well-oriented microtubules. The detailed three-dimensional nanostructure of the hard tissues namely dentin and enamel, however, is not understood, although numerous studies on the anisotropic mechanical properties have been performed and evaluated to explain the tooth function including the enamel-dentin junction acting as effective crack barrier. Small angle X-ray scattering (SAXS) with a spatial resolution in the 10 μm range allows determining the size and orientation of the constituents on the nanometer scale with reasonable precision. So far, only some dental materials, i.e. the fiber reinforced posts exhibit anisotropic properties related to the micrometer-size glass fibers. Dental fillings, composed of nanostructures oriented similar to the natural hard tissues of teeth, however, do not exist at all. The current X-ray-based investigations of extracted human teeth provide evidence for oriented micro- and nanostructures in dentin and enamel. These fundamental quantitative findings result in profound knowledge to develop biologically inspired dental fillings with superior resistance to thermal and mechanical shocks.

  18. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-10-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r2 >= -0.86) as well as calcium release (r2 >= -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r2 = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

  19. Osteogenic differentiation of dental pulp stem cells under the influence of three different materials

    DEFF Research Database (Denmark)

    Ajlan, S. A.; Ashri, N. Y.; Aldahmash, Abdullah M.

    2015-01-01

    Background: Regeneration of periodontal tissues is a major goal of periodontal therapy. Dental pulp stem cells (DPSCs) show mesenchymal cell properties with the potential for dental tissue engineering. Enamel matrix derivative (EMD) and platelet-derived growth factor (PDGF) are examples of materi......Background: Regeneration of periodontal tissues is a major goal of periodontal therapy. Dental pulp stem cells (DPSCs) show mesenchymal cell properties with the potential for dental tissue engineering. Enamel matrix derivative (EMD) and platelet-derived growth factor (PDGF) are examples...

  20. Surface variations affecting human dental enamel studied using nanomechanical and chemical analysis

    Science.gov (United States)

    Dickinson, Michelle Emma

    The enamel surface is the interface between the tooth and its ever changing oral environment. Cavity (caries) formation and extrinsic tooth staining are due, respectively, to degradation of the enamel structure under low pH conditions and interactions between salivary pellicle and dietary elements. Both of these occur at the enamel surface and are caused by the local environment changing the chemistry of the surface. The results can be detrimental to the enamel's mechanical integrity and aesthetics. Incipient carious lesions are the precursor to caries and form due to demineralisation of enamel. These carious lesions are a reversible structure where ions (e.g. Ca2+, F -) can diffuse in (remineralisation) to preserve the tooth's structural integrity. This investigation used controlled in vitro demineralisation and remineralisation to study artificial carious lesion formation and repair. The carious lesions were cross-sectioned and characterised using nanoindentation, electron probe micro-analysis and time of flight secondary ion mass spectrometry. Mechanical and chemical maps showed the carious lesion had a significantly reduced hardness and elastic modulus, and the calcium and phosphate content was lower than in sound enamel. Fluoride based remineralisation treatments gave a new phase (possibly fluorohydroxyapatite) within the lesion with mechanical properties higher than sound enamel. The acquired salivary pellicle is a protein-rich film formed by the physisorption of organic molecules in saliva onto the enamel surface. Its functions include lubrication during mastication and chemical protection. However, pellicle proteins react with dietary elements such as polyphenols (tannins in tea) causing a brown stain. This study has used in vitro dynamic nanoindentation and atomic force microscopy to examine normal and stained pellicles formed in vivo. The effects of polyphenols on the pellicle's mechanical properties and morphology have been studied. It was found that the

  1. Mediator 1 contributes to enamel mineralization as a coactivator for Notch1 signaling and stimulates transcription of the alkaline phosphatase gene.

    Science.gov (United States)

    Yoshizaki, Keigo; Hu, Lizhi; Nguyen, Thai; Sakai, Kiyoshi; Ishikawa, Masaki; Takahashi, Ichiro; Fukumoto, Satoshi; DenBesten, Pamela K; Bikle, Daniel D; Oda, Yuko; Yamada, Yoshihiko

    2017-08-18

    Tooth enamel is mineralized through the differentiation of multiple dental epithelia including ameloblasts and the stratum intermedium (SI), and this differentiation is controlled by several signaling pathways. Previously, we demonstrated that the transcriptional coactivator Mediator 1 (MED1) plays a critical role in enamel formation. For instance, conditional ablation of Med1 in dental epithelia causes functional changes in incisor-specific dental epithelial stem cells, resulting in mineralization defects in the adult incisors. However, the molecular mechanism by which Med1 deficiency causes these abnormalities is not clear. Here, we demonstrated that Med1 ablation causes early SI differentiation defects resulting in enamel hypoplasia of the Med1 -deficient molars. Med1 deletion prevented Notch1-mediated differentiation of the SI cells resulting in decreased alkaline phosphatase (ALPL), which is essential for mineralization. However, it does not affect the ability of ameloblasts to produce enamel matrix proteins. Using the dental epithelial SF2 cell line, we demonstrated that MED1 directly activates transcription of the Alpl gene through the stimulation of Notch1 signaling by forming a complex with cleaved Notch1-RBP-Jk on the Alpl promoter. These results suggest that MED1 may be essential for enamel matrix mineralization by serving as a coactivator for Notch1 signaling regulating transcription of the Alpl gene.

  2. The Molecular Basis of Hereditary Enamel Defects in Humans

    Science.gov (United States)

    Carrion, I.A.; Morris, C.

    2015-01-01

    The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. PMID:25389004

  3. Development of a decision aid for children faced with the decision to undergo dental treatment with sedation or general anaesthesia.

    Science.gov (United States)

    Hulin, Joe; Baker, Sarah R; Marshman, Zoe; Albadri, Sondos; Rodd, Helen D

    2017-09-01

    Decision aids are tools used to help individuals faced with difficult healthcare decisions. They help patients further understand the treatment options available and encourage the sharing of information between patients and clinicians. To develop a decision aid for young patients faced with the decision to undergo dental treatment with inhalation sedation, intravenous sedation, or general anaesthesia (GA). Qualitative interviews with dental patients (aged 10-16 years), and their parents/guardians were used to inform the content of a draft decision aid. Following further revisions, a pilot evaluation of the decision aid was conducted. Patients referred for dental treatment with sedation or GA were recruited from a UK dental hospital. Patients (n = 15) and parents/guardians (n = 13) assigned to the intervention group received the decision aid and routine clinical counselling, whereas patients (n = 17) and parents/guardians (n = 13) in the control group only received routine clinical counselling. Participants completed measures of knowledge, decisional conflict, and dental anxiety. Knowledge scores were significantly higher for participants who received the decision aid when compared to standard care. There were no other significant differences between groups. A decision aid was successfully developed, and initial findings suggest such tools could be beneficial to dental sedation or GA patients and their parents/guardians. Further research is required on the use of such tools in primary care settings, with particular attention to the impact of the decision aid on attendance and completion rates of treatment. © 2016 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Dental calculus image based on optical coherence tomography

    Science.gov (United States)

    Hsieh, Yao-Sheng; Ho, Yi-Ching; Lee, Shyh-Yuan; Chuang, Ching-Cheng; Wang, Chun-Yang; Sun, Chia-Wei

    2011-03-01

    In this study, the dental calculus was characterized and imaged by means of swept-source optical coherence tomography (SSOCT). The refractive indices of enamel, dentin, cementum and calculus were measured as 1.625+/-0.024, 1.534+/-0.029, 1.570+/-0.021 and 1.896+/-0.085, respectively. The dental calculus lead strong scattering property and thus the region can be identified under enamel with SSOCT imaging. An extracted human tooth with calculus was covered by gingiva tissue as in vitro sample for SSOCT imaging.

  5. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser

    International Nuclear Information System (INIS)

    Eduardo, Patricia Lerro de Paula

    2001-01-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm 2 and 450 J/cm 2 were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous researches developed at

  6. Wear of human enamel opposing monolithic zirconia, glass ceramic, and composite resin: an in vitro study.

    Science.gov (United States)

    Sripetchdanond, Jeerapa; Leevailoj, Chalermpol

    2014-11-01

    Demand is increasing for ceramic and composite resin posterior restorations. However, ceramics are recognized for their high abrasiveness to opposing dental structure. The purpose of this study was to investigate the wear of enamel as opposed to dental ceramics and composite resin. Twenty-four test specimens (antagonists), 6 each of monolithic zirconia, glass ceramic, composite resin, and enamel, were prepared into cylindrical rods. Enamel specimens were prepared from 24 extracted human permanent molar teeth. Enamel specimens were abraded against each type of antagonist with a pin-on-disk wear tester under a constant load of 25 N at 20 rpm for 4800 cycles. The maximum depth of wear (Dmax), mean depth of wear (Da), and mean surface roughness (Ra) of the enamel specimens were measured with a profilometer. All data were statistically analyzed by 1-way ANOVA, followed by the Tukey test (α=.05). A paired t test was used to compare the Ra of enamel at baseline and after testing. The wear of both the enamel and antagonists was evaluated qualitatively with scanning electron microscopic images. No significant differences were found in enamel wear depth (Dmax, Da) between monolithic zirconia (2.17 ±0.80, 1.83 ±0.75 μm) and composite resin (1.70 ±0.92, 1.37 ±0.81 μm) or between glass ceramic (8.54 ±2.31, 7.32 ±2.06 μm) and enamel (10.72 ±6.31, 8.81 ±5.16 μm). Significant differences were found when the enamel wear depth caused by monolithic zirconia and composite resin was compared with that of glass ceramic and enamel (Pglass ceramic, and enamel (Pglass ceramic and enamel. All test materials except composite resin similarly increased the enamel surface roughness after wear testing. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. Dentist and practice characteristics associated with restorative treatment of enamel caries in permanent teeth

    DEFF Research Database (Denmark)

    Fellows, Jeffrey L; Gordan, Valeria V; Gilbert, Gregg H

    2014-01-01

    PURPOSE: Current evidence in dentistry recommends non-surgical treatment to manage enamel caries lesions. However, surveyed practitioners report they would restore enamel lesions that are confined to the enamel. Actual clinical data were used to evaluate patient, dentist, and practice...... characteristics associated with restoration of enamel caries, while accounting for other factors. METHODS: Data from a National Dental Practice-Based Research Network observational study of consecutive restorations placed in previously unrestored permanent tooth surfaces and practice/demographic data from 229...... participating network dentists were combined. ANOVA and logistic regression, using generalized estimating equations (GEE) and variable selection within blocks, were used to test the hypothesis that patient, dentist, and practice characteristics were associated with variations in enamel restorations of occlusal...

  8. NBCe1 (SLC4A4) a potential pH regulator in enamel organ cells during enamel development in the mouse

    NARCIS (Netherlands)

    Jalali, R.; Guo, J.; Zandieh-Doulabi, B.; Bervoets, T.J.M.; Paine, M.L.; Boron, W.F.; Parker, M.D.; Bijvelds, M.J.C.; Medina, J.F.; DenBesten, P.K.; Bronckers, A.L.J.J.

    2014-01-01

    During the formation of dental enamel, maturation-stage ameloblasts express ion-transporting transmembrane proteins. The SLC4 family of ion-transporters regulates intra- and extracellular pH in eukaryotic cells by cotransporting HCO3 − with Na+. Mutation in SLC4A4 (coding for the sodium-bicarbonate

  9. Keratins as components of the enamel organic matrix

    Science.gov (United States)

    Duverger, Olivier; Beniash, Elia; Morasso, Maria I.

    2016-01-01

    Dental enamel is a hardest tissue in the human body, and although it starts as a tissue rich in proteins, by the time of eruption of the tooth in the oral cavity only a small fraction of the protein remains. While this organic matrix of enamel represents less than 1% by weight it plays essential roles in improving both toughness and resilience to chemical attacks. Despite the fact that the first studies of the enamel matrix began in the 19th century its exact composition and mechanisms of its function remain poorly understood. It was proposed that keratin or a keratin-like primitive epithelial component exists in mature enamel, however due to the extreme insolubility of its organic matrix the presence of keratins there was never clearly established. We have recently identified expression of a number of hair keratins in ameloblasts, the enamel secreting cells, and demonstrated their incorporation into mature enamel. Mutation in epithelial hair keratin KRT75 leads to a skin condition called pseudofollicularis barbae. Carriers of this mutation have an altered enamel structure and mechanical properties. Importantly, these individuals have a much higher prevalence of caries. To the best of our knowledge, this is the first study showing a direct link between a mutation in a protein-coding region of a gene and increased caries rates. In this paper we present an overview of the evidence of keratin-like material in enamel that has accumulated over the last 150 years. Furthermore, we propose potential mechanisms of action of KTR75 in enamel and highlight the clinical implications of the link between mutations in KRT75 and caries. Finally, we discuss the potential use of keratins for enamel repair. PMID:26709044

  10. Hen's teeth with enamel cap: from dream to impossibility

    Directory of Open Access Journals (Sweden)

    Girondot Marc

    2008-09-01

    Full Text Available Abstract Background The ability to form teeth was lost in an ancestor of all modern birds, approximately 100-80 million years ago. However, experiments in chicken have revealed that the oral epithelium can respond to inductive signals from mouse mesenchyme, leading to reactivation of the odontogenic pathway. Recently, tooth germs similar to crocodile rudimentary teeth were found in a chicken mutant. These "chicken teeth" did not develop further, but the question remains whether functional teeth with enamel cap would have been obtained if the experiments had been carried out over a longer time period or if the chicken mutants had survived. The next odontogenetic step would have been tooth differentiation, involving deposition of dental proteins. Results Using bioinformatics, we assessed the fate of the four dental proteins thought to be specific to enamel (amelogenin, AMEL; ameloblastin, AMBN; enamelin, ENAM and to dentin (dentin sialophosphoprotein, DSPP in the chicken genome. Conservation of gene synteny in amniotes allowed definition of target DNA regions in which we searched for sequence similarity. We found the full-length chicken AMEL and the only N-terminal region of DSPP, and both are invalidated genes. AMBN and ENAM disappeared after chromosomal rearrangements occurred in the candidate region in a bird ancestor. Conclusion These findings not only imply that functional teeth with enamel covering, as present in ancestral Aves, will never be obtained in birds, but they also indicate that these four protein genes were dental specific, at least in the last toothed ancestor of modern birds, a specificity which has been questioned in recent years.

  11. Developmental enamel and anatomical tooth defects in dogs – Experience from veterinary dental referral practice and review of the literature

    Directory of Open Access Journals (Sweden)

    Sonja Catharina Boy

    2016-02-01

    Full Text Available Developmental tooth abnormalities in dogs are uncommon in general veterinary practice but understanding thereof is important for optimal management in order to maintain gnathic function through conservation of the dentition. The purpose of this review is to discuss abnormalities of enamel structure and macroscopic tooth anatomy in dogs encountered in veterinary dental referral practice in South Africa and the United Kingdom. The basis of the pathogenesis, resultant clinical appearance and the management principles of each anomaly will be considered. Future research should aim to provide a detailed individual tooth mineralization schedule for dogs.

  12. Management of dental trauma in primary care: a postal survey of general dental practitioners.

    Science.gov (United States)

    Jackson, N G; Waterhouse, P J; Maguire, A

    2005-03-12

    To determine the self-perceived knowledge and attitudes of general dental practitioners (GDPs) concerning management of dental trauma in primary care. To identify potential barriers to the management of dental trauma in primary care. A self-completion postal questionnaire survey of 417 GDPs in six local health authority districts in northeast England. Likert scale responses to 20 statements designed to test self-perceived knowledge and attitudes. Following descriptive statistical analysis. Factor analysis with principle components analysis was undertaken to identify areas of correlation in questionnaire responses, followed by Chi squared test, Spearman's Rank Correlation and analysis of variance (ANOVA) to measure association between variables. The response rate was 74%. Enamel and dentine fractures were the most common injury, with 45% of GDPs responding seeing more than 10 cases of dental trauma in the preceding year and 53% of respondents seeing one to three cases of complicated crown fracture. Seventy-eight per cent believed that NHS remuneration was inadequate, but only 8% would refer patients with dental trauma to secondary care for this reason. Half of the GDPs believed that trauma could be treated more effectively in practice if NHS payments were greater. GDPs were significantly more likely to agree with this statement if they had previously undertaken a postgraduate course in the treatment of dental trauma (p=0.002). Single handed GDPs were statistically significantly more likely to agree with the statements 'I would not treat dental trauma cases at my practice because the NHS payment is inadequate' (p=0.008) and 'Treating dental trauma at my practice requires too much of my clinical time to be worthwhile' (p=0.002). Ninety-six per cent of GDPs disagreed that treatment of dental trauma rested solely within secondary care. Ninety-six per cent of GDPs agreed that they had a responsibility to provide initial emergency treatment for trauma patients prior to

  13. Enamel microabrasion: An overview of clinical and scientific considerations

    Science.gov (United States)

    Pini, Núbia Inocencya Pavesi; Sundfeld-Neto, Daniel; Aguiar, Flavio Henrique Baggio; Sundfeld, Renato Herman; Martins, Luis Roberto Marcondes; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

    2015-01-01

    Superficial stains and irregularities of the enamel are generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a low-rotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations. PMID:25610848

  14. Type 1 diabetes mellitus effects on dental enamel formation revealed by microscopy and microanalysis.

    Science.gov (United States)

    Silva, Bruna Larissa Lago; Medeiros, Danila Lima; Soares, Ana Prates; Line, Sérgio Roberto Peres; Pinto, Maria das Graças Farias; Soares, Telma de Jesus; do Espírito Santo, Alexandre Ribeiro

    2018-03-01

    Type 1 diabetes mellitus (T1DM) largely affects children, occurring therefore at the same period of deciduous and permanent teeth development. The aim of this work was to investigate birefringence and morphology of the secretory stage enamel organic extracellular matrix (EOECM), and structural and mechanical features of mature enamel from T1DM rats. Adult Wistar rats were maintained alive for a period of 56 days after the induction of experimental T1DM with a single dose of streptozotocin (60 mg/kg). After proper euthanasia of the animals, fixed upper incisors were accurately processed, and secretory stage EOECM and mature enamel were analyzed by transmitted polarizing and bright field light microscopies (TPLM and BFLM), energy-dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and microhardness testing. Bright field light microscopies and transmitted polarizing light microscopies showed slight morphological changes in the secretory stage EOECM from diabetic rats, which also did not exhibit statistically significant alterations in birefringence brightness when compared to control animals (P > .05). EDX analysis showed that T1DM induced statistically significant little increases in the amount of calcium and phosphorus in outer mature enamel (P  .05). T1DM also caused important ultrastructural alterations in mature enamel as revealed by SEM and induced a statistically significant reduction of about 13.67% in its microhardness at 80 μm from dentin-enamel junction (P enamel development, leading to alterations in mature enamel ultrastructure and in its mechanical features. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts in the deciduous and permanent teeth

    International Nuclear Information System (INIS)

    Takahashi, Masashi; Zheng, Jinhua; Mori, Kazuhisa; Mataga, Izumi; Kobayashi, Kan

    2006-01-01

    The purpose of this study is to compare the histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts between the deciduous molars and permanent molars. They were observed by the polarizing and scanning electron microscopies. The enamel rods were less made slender by EDTA etching and the outlines of the apatite crystals, constituting the enamel rods, were clearer at the occlusal pit part of the deciduous molar than that of the permanent molar in reverse of that at the cusp part. It is thought that the enamel at the occlusal pit part of the permanent molar is more easily decayed by the dental caries than that of the deciduous molar because the former is more easily decayed by the acidic etching than the latter in reverse at the cusp part. It is considered that the thin superficialmost layer of the enamel at the occlusal pit part of the permanent molar has originally higher degree of resistance to the dental caries

  16. Histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts in the deciduous and permanent teeth

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Masashi [Department of Dental Hygiene, Nippon Dental University College at Niigata, Niigata 951-8580 (Japan)]. E-mail: masashi@ngt.ndu.ac.jp; Zheng, Jinhua [Department of Oral Anatomy, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Mori, Kazuhisa [Department of Oral Surgery, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Mataga, Izumi [Department of Oral Surgery, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Kobayashi, Kan [Department of Oral Anatomy, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan)

    2006-05-15

    The purpose of this study is to compare the histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts between the deciduous molars and permanent molars. They were observed by the polarizing and scanning electron microscopies. The enamel rods were less made slender by EDTA etching and the outlines of the apatite crystals, constituting the enamel rods, were clearer at the occlusal pit part of the deciduous molar than that of the permanent molar in reverse of that at the cusp part. It is thought that the enamel at the occlusal pit part of the permanent molar is more easily decayed by the dental caries than that of the deciduous molar because the former is more easily decayed by the acidic etching than the latter in reverse at the cusp part. It is considered that the thin superficialmost layer of the enamel at the occlusal pit part of the permanent molar has originally higher degree of resistance to the dental caries.

  17. A tissue-dependent hypothesis of dental caries.

    Science.gov (United States)

    Simón-Soro, A; Belda-Ferre, P; Cabrera-Rubio, R; Alcaraz, L D; Mira, A

    2013-01-01

    Current understanding of dental caries considers this disease a demineralization of the tooth tissues due to the acid produced by sugar-fermenting microorganisms. Thus, caries is considered a diet- and pH-dependent process. We present here the first metagenomic analysis of the bacterial communities present at different stages of caries development, with the aim of determining whether the bacterial composition and biochemical profile are specific to the tissue affected. The data show that microbial composition at the initial, enamel-affecting stage of caries is significantly different from that found at subsequent stages, as well as from dental plaque of sound tooth surfaces. Although the relative proportion of Streptococcus mutans increased from 0.12% in dental plaque to 0.72% in enamel caries, Streptococcus mitis and Streptococcus sanguinis were the dominant streptococci in these lesions. The functional profile of caries-associated bacterial communities indicates that genes involved in acid stress tolerance and dietary sugar fermentation are overrepresented only at the initial stage (enamel caries), whereas other genes coding for osmotic stress tolerance as well as collagenases and other proteases enabling dentin degradation are significantly overrepresented in dentin cavities. The results support a scenario in which pH and diet are determinants of the disease during the degradation of enamel, but in dentin caries lesions not only acidogenic but also proteolytic bacteria are involved. We propose that caries disease is a process of varying etiology, in which acid-producing bacteria are the vehicle to penetrate enamel and allow dentin degrading microorganisms to expand the cavity. © 2013 S. Karger AG, Basel.

  18. The effect of acidulated phosphate fluoride application on dental enamel surfaces hardness

    Directory of Open Access Journals (Sweden)

    Edhie Arief P

    2007-09-01

    Full Text Available Enamel demineralization by acid is the first step of caries process. It has recently been shown that acidulated phosphate fluoride (APF can maintain the hardness of enamel surface. The aim of this study was examine the effect of APF application in the hardest of enamel surface. Fifty extracted teeth were cut at their crown, 40 teeth were taken randomly then divided into 4 groups, group 1 as the control, group 2 was treated with APF for 1 minute, group 3 for 4 minutes and group 4 for 7 minutes, then all the samples were washed with demineralized water. To see the effect of APF, all of the samples were soaked in lactic acid demineralization solution with pH 4,5 for 72 hours., the hardness of the surfaces of those samples before and after the treatment was measured by Micro Vickers Hardness Tester. The data were analyzed using One-Way ANOVA and LSD tests. In conclusion, 1.23% APF gel can reduce higher enamel demineralization.

  19. Use of radioisotopes in the study of permeability of hard dental tissue

    International Nuclear Information System (INIS)

    Tarjan, I.

    1978-01-01

    A literature survey. According to in vivo experiments 32 P, 131 I and 45 Ca penetrate dental enamel and dentine. In vitro studies revealed that the healthy enamel and that damaged by caries and dentine are penetrable by 22 Na and 24 Na both in centripetal and in centrifugal directions. 32 P, 18 F and urea, labelled with 14 C penetrate healthy hard dental tissue. 45 CaCl 2 , 110 AgNO 3 , 111 AgNO 3 , 103 PdCl 2 , 64 Cu(NO 3 ) 2 , 63 ZnCl 2 , 65 ZnCl 2 and glucose, labelled with 14 C penetrate enamel defects, lamellas and caries areas. 239 Pu citrate complex links to the surface of enamel and cement, but does not penetrate them. (author)

  20. Near-IR imaging of thermal changes in enamel during laser ablation

    Science.gov (United States)

    Maung, Linn H.; Lee, Chulsung; Fried, Daniel

    2010-02-01

    The objective of this work was to observe the various thermal-induced optical changes that occur in the near-infrared (NIR) during drilling in dentin and enamel with the laser and the high-speed dental handpiece. Tooth sections of ~ 3 mm-thickness were prepared from extracted human incisors (N=60). Samples were ablated with a mechanically scanned CO2 laser operating at a wavelength of 9.3-μm, a 300-Hz laser pulse repetition rate, and a laser pulse duration of 10-20 μs. An InGaAs imaging camera was used to acquire real-time NIR images at 1300-nm of thermal and mechanical changes (cracks). Enamel was rapidly removed by the CO2 laser without peripheral thermal damage by mechanically scanning the laser beam while a water spray was used to cool the sample. Comparison of the peripheral thermal and mechanical changes produced while cutting with the laser and the high-speed hand-piece suggest that enamel and dentin can be removed at high speed by the CO2 laser without excessive peripheral thermal or mechanical damage. Only 2 of the 15 samples ablated with the laser showed the formation of small cracks while 9 out of 15 samples exhibited crack formation with the dental hand-piece. The first indication of thermal change is a decrease in transparency due to loss of the mobile water from pores in the enamel which increase lightscattering. To test the hypothesis that peripheral thermal changes were caused by loss of mobile water in the enamel, thermal changes were intentionally induced by heating the surface. The mean attenuation coefficient of enamel increased significantly from 2.12 +/- 0.82 to 5.08 +/- 0.98 with loss of mobile water due to heating.

  1. Effect of white tea and xylitol on structure and properties of demineralized enamel and jawbone

    Science.gov (United States)

    Auerkari, EI; Kiranahayu, R.; Emerita, D.; Sumariningsih, P.; Sarita, D.; Adiwirya, MS; Suhartono, AW

    2018-05-01

    White tea and xylitol have been suggested as potential agents to combat dental caries and osteoporosis through enhanced remineralization. This investigation aimed to determine the effects of exposure to white tea with and without xylitol on the structure, composition and hardness of demineralized human dental enamel. For control, samples of untreated and demineralized enamel and samples of untreated rat jawbone were subjected to similar measurements. For demineralization, the enamel samples were immersed for two days at 50°C in an acetate solution (pH 4.0). All samples were then soaked for two weeks at 37°C in a solution containing three different concentrations of white tea, xylitol or both, and an optional addition of the remineralization ingredients including Ca, P and F. For enamel samples without preceding demineralization and without added remineralization ingredients, the results showed highest mean hardness after immersion in a solution containing both white tea and xylitol, practically independently of their applied concentration level. However, for demineralized enamel samples with added remineralization ingredients, the resulting mean hardness was also dependent on concentration of white tea and xylitol. With sufficient concentration, hardness was again higher for combined white tea and xylitol than for either of these used alone.

  2. Dental Anomalies: An Update

    Directory of Open Access Journals (Sweden)

    Fatemeh Jahanimoghadam

    2016-01-01

    Full Text Available Dental anomalies are usual congenital malformation that can happen either as isolated findings or as a part of a syndrome. Developmental anomalies influencing the morphology exists in both deciduous and permanent dentition and shows different forms such as gemination, fusion, concrescence, dilaceration, dens evaginatus (DE, enamel pearls, taurodontism or peg-shaped laterals. All These anomalies have clinical significance concerning aesthetics, malocclusion and more necessary preparing of the development of dental decays and oral diseases. Through a search in PubMed, Google, Scopus and Medline, a total of eighty original research papers during 1928-2016 were found with the keywords such as dental anomaly, syndrome, tooth and hypodontia. One hundred review titles were identified, eighty reviews were retrieved that were finally included as being relevant and of sufficient quality. In this review, dental anomalies including gemination, fusion, concrescence, dilaceration, dens invaginatus, DE, taurodontism, enamel pearls, fluorosis, peg-shaped laterals, dentinal dysplasia, regional odontodysplasia and hypodontia are discussed. Diagnosing dental abnormality needs a thorough evaluation of the patient, involving a medical, dental, familial and clinical history. Clinical examination and radiographic evaluation and in some of the cases, specific laboratory tests are also needed. Developmental dental anomalies require careful examination and treatment planning. Where one anomaly is present, clinicians should suspect that other anomalies may also be present. Moreover, careful clinical and radiographical examination is required. Furthermore, more complex cases need multidisciplinary planning and treatment.

  3. General characteristics of dental morbidity in children against orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Kovach I.V.

    2016-03-01

    Full Text Available A wide spread of orthodontic treatment showed a fairly high risk of complications developed from the use of various devices. The aim of our study was to determine the general characteristics of dental morbidity in children with orthodontic treatment. According to the survey the most common pathologies in children with orthodontic problems are dental caries (87,8-92,9% and chronic catarrhal gingivitis (81.2-84.1%. The prevalence of different types of diseases of the mucous membrane and soft tissues of the oral cavity in children surveyed was 30.5-32.9%. Non-caries lesions of dental hard tissues occurred in 39.5-40.9% of the children surveyed, local enamel hypoplasia was observed in 42.9%, systemic enamel hypoplasia made up 17.8%, signs of hypersensitivity of enamel were found in 9.6%, and the wedge defects – in two children.

  4. Potential of sub-ablative pulsed CO2 laser irradiation on inhibition of artificial caries-like lesion progress in bovine dental enamel

    International Nuclear Information System (INIS)

    Oliveira, Marcella Esteves

    2005-01-01

    The aim of this study was to investigate whether sub-ablative pulsed C0 2 laser (1 0,6 μm) irradiation is capable of reducing the susceptibility of the dental enamel to demineralization, and thus achieving a potential caries-protective effect. The crowns of 51 bovine front teeth, embedded in acrylic resin and polished until exposure of flat enamel surface, were used. The samples were cut in cubes of 10x10 mm, and totally coated with acid-resistant nail varnish, except for an enamel exposed window of 16 mm square. Three groups (n=17) were obtained: control group (CG) not irradiated; group laser A (LA) and group laser B (LB) where the samples were irradiated. The conditions were 60 mJ, 100 Hz, 0,3 J/cm 2 for LA and 135 mJ, 10 Hz, 0,7 J/cm 2 for LB. Two samples of each group were submitted to SEM analysis and fifteen to demineralization in 3 ml acetate buffer solution (0,1 mol/L) with pH 4,5 for 24h at 37 deg C, with regular agitation. After the specimens were removed from the solution, the calcium and phosphorous content were measured with an inductively coupled plasma optical emission spectrometer and 2 more samples of each were submitted to SEM analysis. The obtained Ca and P means in μg/ml and the calculated Ca/P molar ratio were: CG (367,88 ± 33,47; 168,91 ± 14,55; 1,70 ± 0,07) ; LA (372,70 ± 41,70; 161,46 ± 15,26; 1,79 ± 0,07) and LB (328,87 ± 24,91; 145,02 ± 11,04; 1,77 ± 0,05). The ANOVA statistical test revealed statistically significant difference for [Ca], [P] e Ca/P content between the groups (p 2 pulsed CO 2 laser irradiation of bovine enamel was capable of reducing the enamel acid solubility without causing damage to the surface and therefore is a potential method of caries prevention. (author)

  5. Effects of ultrasonic instrumentation on enamel surfaces with various defects.

    Science.gov (United States)

    Kim, S-Y; Kang, M-K; Kang, S-M; Kim, H-E

    2018-05-01

    The aim of this study was to analyse the enamel damage caused by ultrasonic scaling of teeth with various enamel conditions that are difficult to identify by visual inspection, such as enamel cracks, early caries and resin restorations. In total, 120 tooth surfaces were divided into 4 experimental groups using a quantitative light-induced fluorescence-digital system: sound enamel group, enamel cracks group, early caries group and resin restoration group. A skilled dental hygienist performed ultrasonic scaling under a standardized set of conditions: a ≤ 15° angle between the scaler tip and tooth surface and 40-80 g of lateral pressure at the rate of 12 times/10 s. Following scaling, the depth of enamel damage was measured using a surface profilometer and observed using scanning electron microscopy (SEM). The damage depth was the greatest in the enamel cracks group (37.63 ± 34.42 μm), followed by the early caries group (26.81 ± 8.67 μm), resin restoration group (19.63 ± 6.73 μm) and the sound enamel group (17.00 ± 5.66 μm). The damage depth was significantly deeper in the enamel cracks and early caries groups than in the sound enamel group (P enamel loss in the enamel cracks, early caries and resin restoration groups. The results of this study suggest that ultrasonic scaling can cause further damage to teeth with enamel cracks, early caries and resin restorations. Therefore, accurate identification of tooth conditions and calculus before the initiation of ultrasonic scaling is necessary to minimize damage. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Comparative evaluation of enamel abrasivity of different commercially available dentifrices – An In vitro Study

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    Rupali Athawale

    2018-01-01

    Full Text Available Background: Toothbrushing with toothpaste is a major contributor to dental abrasion. A number of factors such as abrasivity and concentration of the toothpaste, brushing frequency, brushing duration, force of brushing, and toothbrush bristle stiffness have a potential impact on the abrasion process of dental hard tissue. However, the abrasivity of the toothpaste is the most important parameter that affects the abrasion process of dental hard tissue. Aims: This study aims to evaluate the maximum and mean enamel abrasivity of commercially available dentifrices such as Colgate total®, Pepsodent whitening®, Vicco vajradanti®, Dabur red® in primary and permanent teeth. Materials and Methods: Human extracted 60 primary and 60 permanent teeth were randomly selected based on the inclusion criteria. Teeth were sectioned at cementoenamel junction using diamond disc and mounted in an acrylic resin blocks. Baseline profilometric measurements were recorded for all the samples. Four commonly used dentifrices were selected and labeled as Group A (Colgate Total®, B (Pepsodent Whitening®, C (Vicco Vajradanti®, and D (Dabur Red®. Toothpaste slurry was prepared. Tooth specimens were brushed in vitro using a customized brushing machine. After toothbrushing, profilometric measurements were obtained, and the differences in readings served as proxy measure to assess surface abrasion. Data were collected and analyzed using student t-test and ANOVA test. Student t-test was used to compare the enamel abrasivity prebrushing and postbrushing, and ANOVA was used to compare the enamel abrasivity among the four different commercially available toothpastes. Results: In permanent teeth, all the toothpastes were found to cause significant enamel abrasion (P = 0.000 and a significant variation was observed when maximum (P = 0.008 and mean (P = 0.036 enamel abrasivity of these toothpastes were compared. In primary teeth also, all the toothpastes caused significant abrasion

  7. Diagnóstico y epidemiología de erosión dental Diagnosis and epidemiology of dental erosion

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    Maria Claudia Fajardo Santacruz

    2011-08-01

    Full Text Available La erosión dental es la pérdida localizada, crónica y patológica de tejido duro dental. Ésta es causada por soluciones químicas las cuales entran en contacto con los dientes. La apariencia de los dientes erosionados es suave, sedosa y brillante, a veces mate, la superficie del esmalte tiene una ausencia de periquimatíes y esmalte intacto en el margen gingival. Se ha hipotetizado que la banda de esmalte preservado a lo largo del margen vestibular y lingual pudiera ser debido a que algunos remanentes de placa podían actuar como una barrera de difusión para los ácidos. Un diagnóstico temprano de este daño del tejido duro dental es de importancia clínica. El objetivo de este artículo es mostrar algunos aspectos básicos de erosión dental en términos de diagnóstico y epidemiología. Este documento enfatiza sobre factores de riesgo extrínsecos los cuales son discutidos con respecto a su relevancia para el desarrollo de erosión dental. Salud UIS 2011; 43 (2: 179-189Dental erosion is a pathologic, chronic, localized loss of dental hard tissue. It is caused by chemical solutions which come into contact with the teeth. The appearance of eroded teeth is smoothing, silky-glazed, sometimes dull, the enamel surface has an absence of perikymata and intact enamel on the gingival margin. It has been hypothesized that the preserved enamel band along the oral and facial gingival margin could be due to some plaque remnants could act as a diffusion barrier for acids. Early diagnosis of this damage of dental hard tissue is of clinical importance. The aim of this article is to show some basic aspects of dental erosion in terms of diagnosis and epidemiology. This paper emphasize on extrinsic risk factors which are discussed with respect to their relevance for the development of dental erosion. Salud UIS 2011; 43 (2: 179-189

  8. Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

    Science.gov (United States)

    Rakhmatullina, Ekaterina; Bossen, Anke; Höschele, Christoph; Wang, Xiaojie; Beyeler, Barbara; Meier, Christoph; Lussi, Adrian

    2011-01-01

    We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r2 ≥ −0.86) as well as calcium release (r2 ≥ −0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r2 = 0.42–0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo. PMID:22029364

  9. Mathematical model governing laser-produced dental cavity

    Science.gov (United States)

    Yilbas, Bekir S.; Karatoy, M.; Yilbas, Z.; Karakas, Eyup S.; Bilge, A.; Ustunbas, Hasan B.; Ceyhan, O.

    1990-06-01

    Formation of dental cavity may be improved by using a laser beam. This provides nonmechanical contact, precise location of cavity, rapid processing and increased hygienity. Further examination of interaction mechanism is needed to improve the application of lasers in density. Present study examines the tenperature rise and thermal stress development in the enamel during Nd YAG laser irradiation. It is found that the stresses developed in the enamel is not sufficiently high enough to cause crack developed in the enamel.

  10. The influence of the Nd:YAG laser bleaching on physical and mechanical properties of the dental enamel.

    Science.gov (United States)

    Marcondes, Maurem; Paranhos, Maria Paula Gandolfi; Spohr, Ana Maria; Mota, Eduardo Gonçalves; da Silva, Isaac Newton Lima; Souto, André Arigony; Burnett, Luiz Henrique

    2009-07-01

    The Nd:YAG laser can be used in Dentistry to remove soft tissue, disinfect canals in endodontic procedures and prevent caries. However, there is no protocol for Nd:YAG laser application in dental bleaching. The aims of this in vitro study were: (a) to observe the tooth shade alteration when hydrogen peroxide whitening procedures are associated with dyes with different wavelengths and irradiated with Nd:YAG laser or halogen light; (b) to measure the Vickers (VHN) enamel microhardness before and after the whitening procedure; (c) to evaluate the tensile bond strength of two types of adhesive systems applied on bleached enamel; (d) to observe the failure pattern after bond strength testing; (e) to evaluate the pulpal temperature during the bleaching procedures with halogen light or laser; (f) to measure the kinetic reaction of hydrogen peroxide. Extracted sound human molar crowns were sectioned in the mesiodistal direction to obtain 150 fragments that were divided into five groups for each adhesive system: WL (H(2)O(2) + thickener and Nd:YAG), WH (H(2)O(2) + thickener and halogen light), QL (H(2)O(2) + carbopol + Q-switch and Nd:YAG), QH (H(2)O(2) + carbopol + Q-switch and halogen light), and C (Control, without whitening agent). Shade assessment was made with a shade guide and the microhardness tests were performed before and after the bleaching procedures. Immediately afterwards, the groups were restored with the adhesive systems Adper Single Bond 2 or Solobond M plus composite resin, and the tensile bond strength test was performed. The temperature was measured by thermocouples placed on the enamel surface and intrapulpal chamber. The kinetics of hydrogen peroxide was observed by ultraviolet analysis. The shade changed seven levels for Nd:YAG laser groups and eight levels for halogen light. According to the student's t-test, there was no statistical difference between the VHN before and after the whitening protocols (p > 0.05). The tensile bond strength showed no

  11. Synthetic tooth enamel: SEM characterization of a fluoride hydroxyapatite coating for dentistry applications

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    Marise Oliveira

    2007-06-01

    Full Text Available An alternative to etching enamel for retention of an adhesive is to grow crystals on the enamel surface. The potential advantages of crystal growth include easy procedure and less damage to the enamel. These crystals retain the adhesive or are the actual dental restoration. In this work, a paste of synthetic enamel was used to grow crystals of fluoride hydroxyapatite (F-HA onto the human tooth surface. This technique can be used for several dentistry applications like enamel whitening, strengthening and restoration of early carie lesions. The low cost of reagents and simplicity of the technique along with the biocompatibility of the paste render possible the utilization on the market. The samples were prepared through the application of the paste by the incremental technique. The results obtained by scanning electron microscope (SEM/EDX have indicated the deposition of a homogeneous layer of calcium phosphate that was grown onto the enamel substrate. The average thickness of the deposited film was in the range of 50-100 µm and with a similar density from the natural enamel observed by radiographic images.

  12. Characterization of enamel caries lesions in rat molars using synchrotron X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Free, R.D.; DeRocher, K.; Stock, S.R.; Keane, D.; Scott-Anne, K.; Bowen, W.H.; Joester, D. (Rochester); (NWU)

    2017-08-18

    Dental caries is a ubiquitous infectious disease with a nearly 100% lifetime prevalence. Rodent caries models are widely used to investigate the etiology, progression and potential prevention or treatment of the disease. To explore the suitability of these models for deeper investigations of intact surface zones during enamel caries, the structures of early-stage carious lesions in rats were characterized and compared with previous reports on white spot enamel lesions in humans. Synchrotron X-ray microcomputed tomography non-destructively mapped demineralization in carious rat molar specimens across a range of caries severity, identifying 52 lesions across the 30 teeth imaged. Of these lesions, 13 were shown to have intact surface zones. Depth profiles of fractional mineral density were qualitatively similar to lesions in human teeth. However, the thickness of the surface zone in the rat model ranges from 10 to 58 µm, and is therefore significantly thinner than in human enamel. These results indicate that a fraction of lesions in rat caries possess an intact surface zone and are qualitatively similar to human lesions at the micrometer scale. This suggests that rat caries models may be a suitable analog through which to investigate the structure of surface zone enamel and its role during dental caries.

  13. Dental OCT

    Science.gov (United States)

    Wilder-Smith, Petra; Otis, Linda; Zhang, Jun; Chen, Zhongping

    This chapter describes the applications of OCT for imaging in vivo dental and oral tissue. The oral cavity is a diverse environment that includes oral mucosa, gingival tissues, teeth and their supporting structures. Because OCT can image both hard and soft tissues of the oral cavity at high resolution, it offers the unique capacity to identity dental disease before destructive changes have progressed. OCT images depict clinically important anatomical features such as the location of soft tissue attachments, morphological changes in gingival tissue, tooth decay, enamel thickness and decay, as well as the structural integrity of dental restorations. OCT imaging allows for earlier intervention than is possible with current diagnostic modalities.

  14. Evaluation of temperature variation in pulp chamber after high power diode laser irradiation (λ=830 nm) on dental enamel: 'in vitro' study

    International Nuclear Information System (INIS)

    Macri, Rodrigo Teixeira

    2001-01-01

    The aim of this study was to observe the variation of temperature in the pulp chamber caused by irradiation of a commercial diode laser operating in continuous wave with wavelength 830 nm over the dental enamel. In the first part of this study, two types of tooth models were tested: 3,5 mm slice and whole tooth. In the second part, we irradiated the buccal si de of the enamel in 2 primary lower incisors from cattle with Opus 10 diode laser for 10 s with power levels of 1 W and 2 W, always using an absorber. Two thermocouples were used. The first one was inserted in the dentin wall closest to the irradiation site, while the second was inserted in the middle of the pulp chamber. It was observed that the thermocouples registered different temperatures. Always, the dentin thermocouple registered higher temperatures. Considering the dentin records, the irradiation of 1 W for 10 s can be safe for the pulp. Further studies must be developed related to the correct positioning of the thermocouples inside the pulp chamber. This was a first step of using diode laser in enamel, and in this study, we concluded that the Opus 10 diode laser shown to be safe for this use, with 1 W power for 10 S. (author)

  15. New developments in understanding development defects of enamel: optimizing clinical outcomes.

    Science.gov (United States)

    Kilpatrick, Nicky

    2009-12-01

    Developmental defects of enamel appear to be presenting with increasing frequency and with this comes significant clinical challenges. Affected teeth, in particular first permanent molars, are susceptible to dental caries as they are not only more porous but also very sensitive making effective oral hygiene difficult. Affected children require more dental treatment than their unaffected peers while also suffering greater pain and anxiety. Current clinical approaches focus on the placement of contemporary adhesive restorative materials onto the compromised tooth which in turn, fail, leading to premature loss of permanent molars with associated repercussions. Incomplete understanding of the structure, composition and behaviour of affected enamel means that clinical protocols are, as yet, empiric rather than evidence based. This review summarises contemporary evidence regarding this condition and identifies potential areas for future research which would assist in improving clinical outcomes.

  16. Radiographic technique and brackets affect measurements of proximal enamel thickness on mandibular incisors

    NARCIS (Netherlands)

    Ang, Amy Giok Phing; Steegmans, Pauline Antoinette Josephine; Kerdijk, Wouter; Livas, Christos; Ren, Yijin

    2017-01-01

    Objective: To investigate the influence of radiographic film and tube positioning, the presence and the size of brackets on in vitro measurements of proximal enamel thickness of mandibular incisors on periapical radiographs aimed to aid planning of interproximal enamel reduction procedures in

  17. Effects of different black mediators on the shear strength of orthodontic bracket to the enamel treated with Nd-Yag laser

    Science.gov (United States)

    Huang, Shun-Te; Lin, I.-Shueng; Tsai, Chi-Cheng

    1995-04-01

    The Nd:YAG laser has ablation, crack, and crater effects on the dental enamel through black mediators which are very similar to the acid etching effects of phosphoric acid. This study was designed for searching how the different black mediators influence the shear strengths of the brackets bound to the enamel surfaces which were treated with the Nd:YAG laser. 90 bovine enamels divided into 5 groups were painted with 5 kinds of black mediators including Chinese ink, oil ink, black ball pen, water ink and black transfer paper. The enamel surfaces painted with black mediators were then radiated by Nd:YAG laser (ADL; American Dental Laser 300dl, power: 20 pps, 87.5 mj). Orthodontic brackets were bonded to the radiated surfaces. Then the shear strengths of the brackets to the enamels were measured by Instron. The results showed that the Chinese ink group and oil ink group has the strongest shear strength, ball pen group and water ink group showed the second strength, and the transfer paper group has the lowest shear strength. In addition, scanning electronic microscope also was used to observe the topographic changes of the enamel surfaces induced by the laser ablation.

  18. In Vitro Inhibition of Enamel Demineralisation by Fluoride-releasing Restorative Materials and Dental Adhesives.

    Science.gov (United States)

    Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

    2016-01-01

    To determine the ability of 5 contemporary fluoride-releasing restoratives and 3 fluoride-releasing adhesives to inhibit enamel demineralisation surrounding restorations, and the associations between inhibition and the levels of fluoride released from these materials. Five fluoride-releasing restoratives (Fuji IX GP, Ketac N100, Dyract Extra, Beautifil II and Wave) and 3 fluoride-releasing adhesives (Stae, Prime & Bond NT and Fluoro Bond II) were investigated. Eight disks of each material were prepared. Fluoride release was measured daily using a fluoride-ion-selective electrode for 15 days. Twenty-four cavities for each group were restored with a restorative and an adhesive. Specimens were subjected to thermal stress and stored for 30 days in saline solution. After a 15-day pH-cycling regimen, two 150-μm-thick sections were derived from each specimen. Enamel lesion depth was measured at 0, 100, and 200 μm from each restoration's margin via polarised light microscopy. Of the restoratives investigated, Fuji IX GP released the most fluoride. The fluoride-releasing restoratives tested exhibited shallower enamel lesions than did the control group at all distances tested (p < 0.05). Fuji IX GP yielded significantly lower enamel lesion depth than did the other experimental materials. The depths of enamel lesions did not differ significantly when comparing restoratives applied with a fluoride-releasing adhesive with those applied with a non-fluoride-releasing adhesive. The fluoride-releasing materials tested reduced enamel demineralisation but to different extents, depending on their levels of fluoride release. Fluoride-releasing adhesives did not influence enamel lesion formation.

  19. A laser-abrasive method for the cutting of enamel and dentin.

    Science.gov (United States)

    Altshuler, G B; Belikov, A V; Sinelnik, Y A

    2001-01-01

    This paper introduced a new method for the removal of hard dental tissue based upon the use of particles accelerated by laser irradiation, which the authors have called the laser-abrasive method. The particles used were sapphire as powder or an aqueous suspension. The effect of the products of enamel ablation was also investigated. The particles were accelerated using submillisecond pulses of Er:YAG and Nd:YAG lasers. A strobing CCD camera was used to measure the speed of the ejected particles. The additional contribution of these particles to the efficiency of laser ablation of enamel and dentin was also investigated. The results showed that the enamel particles produced by the beam-tissue interaction were also accelerated by this process of ablation and were effective in the removal of enamel and dentin. The use of an aqueous suspension of sapphire particles increased the efficiency of enamel removal threefold when compared with the use of an Er:YAG laser with water spray. The laser-abrasive method allowed for the removal of enamel and dentin at speeds approaching those of the high-speed turbine. Copyright 2001 Wiley-Liss, Inc.

  20. Effects of enamel fluorosis and dental caries on quality of life.

    Science.gov (United States)

    Onoriobe, U; Rozier, R G; Cantrell, J; King, R S

    2014-10-01

    The objectives of this study were to determine the impact of enamel fluorosis and dental caries on oral health-related quality of life (OHRQoL) in North Carolina schoolchildren and their families. Students (n = 7,686) enrolled in 398 classrooms in grades K-12 were recruited for a onetime survey. Parents of students in grades K-3 and 4-12 completed the Early Childhood Oral Health Impact Scale (ECOHIS) and Family Impact Scale (FIS), respectively. Students in grades 4-12 completed the Child Perceptions Questionnaire (CPQ8-10 in grades 4-5; CPQ11-14 in grades 6-12). All students were examined for fluorosis (Dean's index) and caries experience (d2-3fs or D2-3MFS indices). OHRQoL scores (sum response codes) were analyzed for their association with fluorosis categories and sum of d2-3fs and D2-3MFS according to ordinary least squares regression with SAS procedures for multiple imputation and analysis of complex survey data. Differences in OHRQoL scores were evaluated against statistical and minimal important difference (MID) thresholds. Of 5,484 examined students, 71.8% had no fluorosis; 24.4%, questionable to very mild fluorosis; and 3.7%, mild, moderate, or severe fluorosis. Caries categories were as follows: none (43.1%), low (28.6%), and moderate to high (28.2%). No associations between fluorosis and any OHRQoL scales met statistical or MID thresholds. The difference (5.8 points) in unadjusted mean ECOHIS scores for the no-caries and moderate-to-high caries groups exceeded the MID estimate (2.7 points) for that scale. The difference in mean FIS scores (1.5 points) for the no-caries and moderate-to-high groups exceeded the MID value (1.2 points). The sum of d2-3fs and D2-3MFS scores was positively associated with CPQ11-14 (B = 0.240, p caries experience negatively affects OHRQoL, while fluorosis has little impact. © International & American Associations for Dental Research.

  1. Evaluation of crystalline changes and resistance to demineralization of the surface of human dental enamel treated with Er:YAG laser and fluoride using x-ray diffraction analysis and Vickers microhardness

    Science.gov (United States)

    Behroozibakhsh, Marjan; Shahabi, Sima; Ghavami-Lahiji, Mehrsima; Sadeghian, Safura; Sadat Faal Nazari, Neda

    2018-06-01

    This study aimed to investigate the changes in crystalline structure and resistance to demineralization of human dental surface enamel treated with erbium-doped yttrium aluminium garnet laser (Er:YAG) laser and fluoride. The enamel surfaces were divided into four groups according to the treatment process including, (L): irradiated with Er:YAG; (F): treated with acidulated phosphate fluoride gel (LF): Pre-irradiated surfaces with Er:YAG subjected to acidulated phosphate fluoride gel and (FL): laser irradiation was performed on the fluoridated enamel surface. Before and after the treatment procedure, the samples were evaluated using X-ray diffraction, scanning electron microscope (SEM) and the Vickers microhardness test. The surface microhardness values also were measured after a pH-cycling regime and acid challenge. The a-axis of all lased groups was contracted after treatment procedure. Measurement of the area under the peaks showed the highest crysallinity in the FL group. The hardness values of all laser treated samples significantly reduced after treatment procedure compared to the F group (p  ⩽  0.001). The morphological observations showed remarkable changes on the lased enamel surfaces including cracks, craters and exposed prisms. These findings suggest, irradiation of the Er:YAG laser accompanying with fluoride application can induce some beneficial crystalline changes regarding the acid-resistance properties of enamel, however, the craters and cracks produced by laser irradiation can promote enamel demineralization and consequently the positive effects of the Er:YAG laser will be eliminated.

  2. Effects of tooth whitening and orange juice on surface properties of dental enamel.

    Science.gov (United States)

    Ren, Yan-Fang; Amin, Azadeh; Malmstrom, Hans

    2009-06-01

    To study the effects of 6% H2O2 activated with LED light on surface enamel as compared to orange juice challenges in vitro. A total of 40 human enamel discs were incubated in saliva overnight to allow pellicle formation and then divided into three groups: 15 for whitening treatments, 15 for orange juice immersions and 10 for normal saline controls. Baseline microhardness was measured with a microhardness Knoop indenter (50g, 10s) and surface topography was evaluated with a focus-variation 3D scanning microscopy. Enamel discs were treated with H2O2 or orange juice for 20 min each cycle for five cycles to simulate daily treatment with the products for 5 days. The discs were stored in saliva between treatment cycles. Microhardness and surface topography were evaluated again after treatments. Changes in microhardness and in surface area roughness (Sa), mean maximum peak-to-valley distance (Sz) and the developed surface area ratio (Sdr) were compared before and after treatments (t-test) and among groups (ANOVA). Enamel surface hardness decreased by 84% after orange juice immersion but no statistically significant changes were observed in the whitening and control groups. Surface topography changed significantly only in the orange juice group as shown by increased Sa (1.2 microm vs. 2.0 microm), Sz (7.7 microm vs. 10.2 microm) and Sdr (2.8% vs. 6.0%). No such changes were observed in the whitening and control groups. In comparison to orange juice challenges, the effects of 6% H2O2 on surface enamel are insignificant. Orange juice erosion markedly decreased hardness and increased roughness of enamel.

  3. Micro-indentation fracture behavior of human enamel.

    Science.gov (United States)

    Padmanabhan, Sanosh Kunjalukkal; Balakrishnan, Avinash; Chu, Min-Cheol; Kim, Taik Nam; Cho, Seong Jai

    2010-01-01

    The purpose of this study was to determine the crack resistance behavior (K(R)) of human enamel in relation to its microstructure. Human molar teeth were precision cut, polished and tested using Vickers micro-indentation at different loads ranging from 0.98 to 9.8 N. Five indentation load levels were considered, 20 indentation cracks for each load level were introduced on the surface of the test specimen (10 indentations per tooth) and their variability was evaluated using Weibull statistics and an empirical model. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the crack morphology and propagation mechanisms involved. The results showed that enamel exhibited increasing cracking resistance (K(R)) with increasing load. It was found that the crack propagation mainly depended on the location and the microstructure it encountered. SEM showed the formation of crack bridges and crack deflection near the indentation crack tip. The crack mode was of Palmqvist type even at larger loads of 9.8 N. This was mainly attributed to the large process zone created by the interwoven lamellar rod like microstructure exhibited by the enamel surface. This study shows that there are still considerable prospects for improving dental ceramics and for mimicking the enamel structure developed by nature.

  4. [Dental enamel prisms of Mesopithecus pentelicus Wagner, 1839, compared with recent cercopithecids (Primates: Cercopithecidae)].

    Science.gov (United States)

    Dostal, A; Zapfe, H

    1986-01-01

    The dental enamel prisms of Cercopithecidae were examined by scanning electron microscopy. The main task of this study was to show the prism morphology representatives of different genera as well as their comparison with the fossil Mesopithecus pentelicus Wagner, 1839. The method used to show the enamel prisms was to etch the tooth surface with hydrochloric acid. In this way the outlines of the prisms were better contrasted for the descriptive morphology of the prisms than in etching with phosphoric acid. Two types were determined, in accord with the systematic division into subfamilies. In the subfamily Cercopithecinae elongated slender prisms were dominating, some with pointed, others with truncated tops. Most characteristic of this type were Macaca and Cercopithecus. An exception was Papio hamadryas which had broader, rounded prisms. In this way it differed largely from P. anubis whose prisms were short and mostly triangular. A very interesting fact was that very different patterns were found in P. anubis and P. hamadryas, although these two species are regarded as only one species by many authors. The second subfamily, the Colobinae, was characterized by broader prisms with a rounded shape, nearly as long as wide. Exceptions of the 'Colobine type' were at first Colobus with prisms little longer than wide and secondly Nasalis, with mostly parallel sides and truncated tops of the prisms. The prism outlines of Mesopithecus showed the greatest similarity to those of Presbytis which represents the characteristic 'Colobine type'. This fact confirmed the actual systematic position of the fossil Mesopithecus within the subfamily Colobinae. In addition to previously known primitive features of Mesopithecus within the subfamily of Colobinae, we present here a further concrete, common feature with asiatic Colobines.

  5. Calcium release rates from tooth enamel treated with dentifrices containing whitening agents and abrasives.

    Science.gov (United States)

    Araujo, Danilo Barral; Silva, Luciana Rodrigues; de Araujo, Roberto Paulo Correia

    2010-01-01

    Tooth whitening agents containing hydrogen peroxide and carbamide peroxide are used frequently in esthetic dental procedures. However, lesions on the enamel surface have been attributed to the action of these products. Using conventional procedures for separating and isolating biological structures, powdered enamel was obtained and treated with hydrogen peroxide, carbamide peroxide, and sodium bicarbonate, ingredients typically found in dentifrices. The enamel was exposed to different pH levels, and atomic emission spectrometry was used to determine calcium release rates. As the pH level increased, the rate of calcium release from enamel treated with dentifrices containing whitening agents decreased. Carbamide peroxide produced the lowest amount of decalcification, while sodium bicarbonate produced the highest release rates at all pH levels.

  6. Bonding performance of self-adhesive flowable composites to enamel, dentin and a nano-hybrid composite.

    Science.gov (United States)

    Peterson, Jana; Rizk, Marta; Hoch, Monika; Wiegand, Annette

    2018-04-01

    This study aimed to analyze bond strengths of self-adhesive flowable composites on enamel, dentin and nano-hybrid composite. Enamel, dentin and nano-hybrid composite (Venus Diamond, Heraeus Kulzer, Germany) specimens were prepared. Three self-adhesive composites (Constic, DMG, Germany; Fusio Liquid Dentin, Pentron Clinical, USA; Vertise Flow, Kerr Dental, Italy) or a conventional flowable composite (Venus Diamond Flow, Heraeus Kulzer, Germany, etch&rinse technique) were applied to enamel and dentin. Nano-hybrid composite specimens were initially aged by thermal cycling (5000 cycles, 5-55 °C). Surfaces were left untreated or pretreated by mechanical roughening, Al 2 O 3 air abrasion or silica coating/silanization. In half of the composite specimens, an adhesive (Optibond FL, Kerr Dental, Italy) was used prior to the application of the flowable composites. Following thermal cycling (5000 cycles, 5-55 °C) of all specimens, shear bond strengths (SBS) and failure modes were analyzed (each subgroup n = 16). Statistical analysis was performed by ANOVAs/Bonferroni post hoc tests, Weibull statistics and χ 2 -tests (p composites on enamel and dentin were significantly lower (enamel: composite (enamel: 13.0 ± 5.1, dentin: 11.2 ± 6.3), and merely adhesive failures could be observed. On the nano-hybrid composite, SBS were significantly related to the pretreatment. Adhesive application improved SBS of the conventional, but not of the self-adhesive composites. The self-adhesive composite groups showed less cohesive failures than the reference group; the occurence of cohesive failures increased after surface pretreatment. Bonding of self-adhesive flowable composites to enamel and dentin is lower than bonding to a nano-hybrid composite.

  7. HIV and AIDS related knowledge, sources of information, and reported need for further education among dental students in Sudan- a cross sectional study

    Directory of Open Access Journals (Sweden)

    Åstrøm Anne

    2008-08-01

    Full Text Available Abstract Background Information on the HIV and AIDS-related knowledge among dental students provides a crucial foundation for efforts aimed at developing an appropriate dental curriculum on HIV and AIDS, and for attracting the attention of dental school educators towards the subject. Purposes Focusing on a census of dental students attending their 3rd, 4th and 5th study year at publicly – and privately funded dental faculties in Khartoum, this study aimed to assess the prevalence and socio-economic correlates of dental students' knowledge, sources of information and reported need for further education related to HIV and AIDS. Methods At the time of the survey (March–May 2007, the total number of dental students registered was 782 of which 642 (response rate 82%, mean age 21.7 year, 72% girls completed anonymous self-administered questionnaires in supervised class room settings. Results A total of 49% and 86% had correct sum scores with respect to knowledge of transmission through contamination and through shaking hands and eating, respectively. About half the dental students recognized a need for further education across HIV related issues, varying from 75% (basic HIV/AIDS related issues to 84% (patient management. Only 38% of the students had correct sum scores regarding various occupational groups at risk for contacting HIV and AIDS. Multiple logistic regression analysis revealed that compared to privately funded dental school students, publicly funded dental school students were less likely to have correct knowledge about modes of HIV transmission (OR = 0.6 and occupational risk groups (OR = 0.6 and to have received information from lectures/health care workers (OR = 0.5. Conclusion Students attending privately funded schools were more knowledgeable about various HIV related issues than students from publicly funded schools. About half of the students investigated had received HIV/AIDS information from various sources and reported need

  8. Dental Pulp Defence and Repair Mechanisms in Dental Caries.

    Science.gov (United States)

    Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J; Cooper, Paul R

    2015-01-01

    Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

  9. Dental Pulp Defence and Repair Mechanisms in Dental Caries

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Farges

    2015-01-01

    Full Text Available Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

  10. Molecular analysis of tooth enamel by Raman spectroscopy after treatment with bleaching agents at different concentrations; Analisis molecular del esmalte dental por medio de espectroscopia Raman despues del tratamiento con agentes blanqueadores a diferentes concentraciones

    Energy Technology Data Exchange (ETDEWEB)

    Duran Sedo, Randall; Obando Rosabal, Sofia; Saenz Bonilla, Paola; Soto Aguilar, Calendy; Vasquez Rodriguez, Amaya

    2014-07-01

    The changes in the concentration of the v1 phosphate molecule of the surface of dentin enamel are treated and researched with bleaching agents of chemical activation to basis of hydrogen peroxide than 9,5% and 14% and carbamide peroxide than 38%, for a period of 28 days. Raman spectroscopy was used and 30 dental pieces extracted, of which, were to be free of blemishes and pigmentations, without possessing fractures of the enamel, decay nor any other type of defect. The Raman spectrum was obtained of each dental piece prior to the application of bleaching agents. The specimens were separated into three experimental groups according to the concentration of whitening. The concentration of the v1 phosphate molecule was measured in the tooth enamel to the second and fourth week of treatment. In addition, ANOVA was performed for respective measurements (p≤0.05). A reduction of the v1 phosphate molecule were observed during and after the bleaching process in the experimental groups that have used of hydrogen peroxide to 14% and carbamide peroxide 38%. In the group of hydrogen peroxide to 9,5% has remained unproven a significant reduction. Within the limitations of this study is concluded that the bleaching agent causes a loss of v1 phosphate. This loss has been greater in the whitening of higher concentration. In spite, that the possible effect remineralizing of the saliva on a teeth whitening process has been unevaluated, it is recommended using during and after the treatment, toothpastes, mouthwashes, chewing gums, dental floss, among others, that contain ACP to help to cushion the potential loss of phosphate from tooth enamel. (author) [Spanish] Los cambios en la concentracion de la molecula de fosfato v1 de la superficie del esmalte dental son tratados e investigados con agentes blanqueadores de activacion quimica a base de peroxido de hidrogeno al 9,5% y 14% y peroxido de carbamida al 38%, por un periodo de 28 dias. Espectroscopia Raman fue utilizada y 30 piezas

  11. In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel.

    Science.gov (United States)

    Fatima, Nazish; Ali Abidi, Syed Yawar; Meo, Ashraf Ali

    2016-02-01

    To evaluate the effect of home-use bleaching agent containing 16% Carbamide Peroxide (CP) and in-office bleaching agent containing 38% Hydrogen Peroxide (HP) on enamel micro-hardness. An in vitroexperimental study. Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Atotal of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37°C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37°C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. In the control group, the baseline micro-hardness was 181.1 ±9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ±10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ±23 on day 1, 170 ±30 on day 7 and 173 ±23 on day 14 (p = 0.256). The statistically insignificant difference was found among micro-hardness values of different bleaching

  12. In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel

    International Nuclear Information System (INIS)

    Fatima, N.; Abidi, S. Y. A.; Meo, A. A.

    2016-01-01

    Objective: To evaluate the effect of home-use bleaching agent containing 16 percentage Carbamide Peroxide (CP) and in-office bleaching agent containing 38 percentage Hydrogen Peroxide (HP) on enamel micro-hardness. Study Design: An in vitro experimental study. Place and Duration of Study: Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Methodology: A total of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37 Degree C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37 Degree C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. Results: In the control group, the baseline micro-hardness was 181.1 ± 9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ± 10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ± 23 on day 1, 170 ±30 on day 7 and 173 ± 23 on day 14 (p = 0

  13. Microsecond enamel ablation with 10.6μm CO2 laser radiation

    Science.gov (United States)

    Góra, W. S.; McDonald, A.; Hand, D. P.; Shephard, J. D.

    2016-02-01

    Lasers have been previously been used for dental applications, however there remain issues with thermally-induced cracking. In this paper we investigate the impact of pulse length on CO2 laser ablation of human dental enamel. Experiments were carried in vitro on molar teeth without any modification to the enamel surface, such as grinding or polishing. In addition to varying the pulse length, we also varied pulse energy and focal position, to determine the most efficient ablation of dental hard tissue and more importantly to minimize or eradicate cracking. The maximum temperature rise during the multi pulse ablation process was monitored using a set of thermocouples embedded into the pulpal chamber. The application of a laser device in dental surgery allows removal of tissue with higher precision, which results in minimal loss of healthy dental tissue. In this study we use an RF discharge excited CO2 laser operating at 10.6μm. The wavelength of 10.6 μm overlaps with a phosphate band (PO3-4) absorption in dental hard tissue hence the CO2 laser radiation has been selected as a potential source for modification of the tissue. This research describes an in-depth analysis of single pulse laser ablation. To determine the parameters that are best suited for the ablation of hard dental tissue without thermal cracking, a range of pulse lengths (10-200 μs), and fluences (0-100 J/cm2) are tested. In addition, different laser focusing approaches are investigated to select the most beneficial way of delivering laser radiation to the surface (divergent/convergent beam). To ensure that these processes do not increase the temperature above the critical threshold and cause the necrosis of the tissue a set of thermocouples was placed into the pulpal chambers. Intermittent laser radiation was investigated with and without application of a water spray to cool down the ablation site and the adjacent area. Results show that the temperature can be kept below the critical threshold

  14. Innovative Approaches to Regenerate Enamel and Dentin

    Directory of Open Access Journals (Sweden)

    Xanthippi Chatzistavrou

    2012-01-01

    Full Text Available The process of tooth mineralization and the role of molecular control of cellular behavior during embryonic tooth development have attracted much attention the last few years. The knowledge gained from the research in these fields has improved the general understanding about the formation of dental tissues and the entire tooth and set the basis for teeth regeneration. Tissue engineering using scaffold and cell aggregate methods has been considered to produce bioengineered dental tissues, while dental stem/progenitor cells, which can differentiate into dental cell lineages, have been also introduced into the field of tooth mineralization and regeneration. Some of the main strategies for making enamel, dentin, and complex tooth-like structures are presented in this paper. However, there are still significant barriers that obstruct such strategies to move into the regular clinic practice, and these should be overcome in order to have the regenerative dentistry as the important mean that can treat the consequences of tooth-related diseases.

  15. Esthetic management of anterior dental anomalies: A clinical case.

    Science.gov (United States)

    Chafaie, Amir

    2016-09-01

    Many types of dental abnormality can be observed in the anterior sectors, where they can cause genuine esthetic problems for our patients. While conventional prosthetic treatments offer the best solutions in terms of esthetic result and durability, they involve the sacrifice of significant quantities of mineralized dental material and cannot be undertaken before the periodontal tissues are mature. Other less invasive alternatives should be envisaged as transitional, or sometimes even permanent, solutions for the management of these anomalies in children and adolescents. This article discusses these options and presents a clinical case where composite resin veneers and microabrasion of the enamel were used to treat dental agenesis and enamel dysplasia. Copyright © 2016 CEO. Published by Elsevier Masson SAS. All rights reserved.

  16. Dental enamel defects predict adolescent health indicators: A cohort study among the Tsimane' of Bolivia.

    Science.gov (United States)

    Masterson, Erin E; Fitzpatrick, Annette L; Enquobahrie, Daniel A; Mancl, Lloyd A; Eisenberg, Dan T A; Conde, Esther; Hujoel, Philippe P

    2018-05-01

    Bioarchaeological findings have linked defective enamel formation in preadulthood with adult mortality. We investigated how defective enamel formation in infancy and childhood is associated with risk factors for adult morbidity and mortality in adolescents. This cohort study of 349 Amerindian adolescents (10-17 years of age) related extent of enamel defects on the central maxillary incisors (none, less than 1/3, 1/3 to 2/3, more than 2/3) to adolescent anthropometrics (height, weight) and biomarkers (hemoglobin, glycated hemoglobin, white blood cell count, and blood pressure). Risk differences and 95% confidence intervals were estimated using multiple linear regression. Enamel defects and stunted growth were compared in their ability to predict adolescent health indicators using log-binomial regression and receiver operating characteristics (ROCs). Greater extent of defective enamel formation on the tooth surface was associated with shorter height (-1.35 cm, 95% CI: -2.17, -0.53), lower weight (-0.98 kg, 95% CI: -1.70, -0.26), lower hemoglobin (-0.36 g/dL, 95% CI: -0.59, -0.13), lower glycated hemoglobin (-0.04 %A 1c , 95% CI: -0.08, -0.00008), and higher white blood cell count (0.74 10 9 /L, 95% CI: 0.35, 1.14) in adolescence. Extent of enamel defects and stunted growth independently performed similarly as risk factors for adverse adolescent outcomes, including anemia, prediabetes/type II diabetes, elevated WBC count, prehypertension/hypertension, and metabolic health. Defective enamel formation in infancy and childhood predicted adolescent health outcomes and may be primarily associated with infection. Extent of enamel defects and stunted growth may be equally predictive of adverse adolescent health outcomes. © 2018 Wiley Periodicals, Inc.

  17. Study in vitro of dental enamel irradiated with a high power diode laser operating at 960 nm: morphological analysis of post-irradiation dental surface and thermal effect analysis in pulp chamber due to laser application; Estudo in vitro do esmalte dental irradiado com laser de diodo de alta potencia em 960 nm: analise morfologica da superficie dental pos-irradiada e analise do comportamento termico na camara pulpar devido a aplicacao laser

    Energy Technology Data Exchange (ETDEWEB)

    Quinto Junior, Jose

    2001-07-01

    Objectives: This study examines the structural and thermal modifications induced in dental enamel under dye assisted diode laser irradiation. The aim of this study is to verify if this laser-assisted treatment is capable to modify the enamel surface by causing fusion of the enamel surface layer. At the same time, the pulpal temperature rise must be kept low enough in order not to cause pulpar necrosis. To achieve this target, it is necessary to determine suitable laser parameters. As is known, fusion of the enamel surface followed by re-solidification produce a more acid resistant layer. This surface treatment is being researched as a new method for caries prevention. Method and Materials: A series of fourteen identically prepared enamel samples of human teeth were irradiated with a high power diode laser operating at 960 nm and using fiber delivery. Prior to irradiation, a fine layer of cromophorous ink was applied to the enamel surface. In the first part of the experiment the best parameter for pulse duration was determined. In the second part of the experimental phase the same energy density was used but with different repetition rates. During irradiation we monitored the temperature rise in the pulpal cavity. The morphology of the treated samples was analysed under SEM. Results: The morphology of the treated samples showed a homogeneously re-solidified enamel layer. The results of the temperature analysis showed a decrease of the pulpal temperature rise with decreasing repetition rate. Conclusion: With the diode laser it is possible to cause morphological alterations of the enamel surface, which is known to increase the enamel resistance against acid attack, and still maintain the temperature rise in the pulpar chamber below damage threshold. (author)

  18. Fiber optic-based optical coherence tomography (OCT) for dental applications

    Science.gov (United States)

    Everett, Matthew J.; Colston, Bill W., Jr.; Da Silva, Luiz B.; Otis, Linda L.

    1998-09-01

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity. We have produced, using this scanning device, in vivo cross-sectional images of hard and soft dental tissues in human volunteers. Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento- enamel junction, were visible in all the images. The cemento- enamel junction and the alveolar bone were identified in approximately two thirds of the images. These images represent, or our knowledge, the first in vivo OCT images of human dental tissue.

  19. Fiber optic based optical coherence tomography (OCT) for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Everett, M. J., LLNL

    1998-06-02

    We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity We have produced, using this scanning device, in viva cross-sectional images of hard and soft dental tissues in human volunteers Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento-enamel junction, were visible in all the images The dento-enamel junction and the alveolar bone were identifiable in approximately two thirds of the images These images represent, to our knowledge, the first in viva OCT images of human dental tissue.

  20. Application of the ultrashort pulses in bovine dental enamel; Aplicacao de pulsos ultracurtos em esmalte dental bovino

    Energy Technology Data Exchange (ETDEWEB)

    Todescan, Carla de Rago

    2003-07-01

    The interaction of lasers with the hard structures of the teeth, has found the excess of heat as a problem for its utilization. This study analyzes, in vitro, the interaction of the ultrashort pulse laser of Ti:safire (830 nm) with the bovine dental enamel. The system consisted in one main oscillator integrated with an amplifier (CPA). The pulses extracted before the temporal compression inside the amplifier had 30 ps, 1000 Hz and {approx}1 mJ. The pulses extracted after the compression had 60 fs, 1000 Hz and {approx}0,7 mJ. The M{sup 2} was 1,3, the focal lens 2,5 cm, the focal distance 29,7 and a computerized translation stage x,y,z. We evaluated the amount of tissue removed per pulse,the resulting cavities and the surrounding tissues not irradiated, under OM and SEM. The fluency was the major factor for differentiating the two regimens studied, therefore, the intensity was not so important as we expected in this process. We found: one ablation region in 'cat tongue', one ablation length, one fluency {approx}0,7 J/cm{sup 2} for 30 ps and {approx}0,5 J/cm{sup 2} for 60 fs (50% of high speed burr), smooth edge for 30 ps and high precision of the sharp edge cut of submicrometric order for 60 fs. (author)

  1. Application of the ultrashort pulses in bovine dental enamel; Aplicacao de pulsos ultracurtos em esmalte dental bovino

    Energy Technology Data Exchange (ETDEWEB)

    Todescan, Carla de Rago

    2003-07-01

    The interaction of lasers with the hard structures of the teeth, has found the excess of heat as a problem for its utilization. This study analyzes, in vitro, the interaction of the ultrashort pulse laser of Ti:safire (830 nm) with the bovine dental enamel. The system consisted in one main oscillator integrated with an amplifier (CPA). The pulses extracted before the temporal compression inside the amplifier had 30 ps, 1000 Hz and {approx}1 mJ. The pulses extracted after the compression had 60 fs, 1000 Hz and {approx}0,7 mJ. The M{sup 2} was 1,3, the focal lens 2,5 cm, the focal distance 29,7 and a computerized translation stage x,y,z. We evaluated the amount of tissue removed per pulse,the resulting cavities and the surrounding tissues not irradiated, under OM and SEM. The fluency was the major factor for differentiating the two regimens studied, therefore, the intensity was not so important as we expected in this process. We found: one ablation region in 'cat tongue', one ablation length, one fluency {approx}0,7 J/cm{sup 2} for 30 ps and {approx}0,5 J/cm{sup 2} for 60 fs (50% of high speed burr), smooth edge for 30 ps and high precision of the sharp edge cut of submicrometric order for 60 fs. (author)

  2. Implications of gluten exposure period, CD clinical forms, and HLA typing in the association between celiac disease and dental enamel defects in children. A case-control study.

    Science.gov (United States)

    Majorana, Alessandra; Bardellini, Elena; Ravelli, Alberto; Plebani, Alessandro; Polimeni, Antonella; Campus, Guglielmo

    2010-03-01

    The association between coeliac disease (CD) and dental enamel defects (DED) is well known. The aim of this study was to investigate the prevalence of DED in children with CD and to specifically find the association of DED and gluten exposure period, CD clinical forms, HLA class II haplotype. This study was designed as a matched case-control study: 250 children were enrolled (125 coeliac children - 79 female and 46 male, 7.2 +/- 2.8 years and 125 healthy children). Data about age at CD diagnosis, CD clinical form, and HLA haplotype were recorded. Dental enamel defects were detected in 58 coeliac subjects (46.4%) against seven (5.6%) controls (P < 0.005). We found an association between DED and gluten exposure period, as among CD subjects the mean age at CD diagnosis was significantly (P = 0.0004) higher in the group with DED (3.41 +/- 1.27) than without DED (1.26 +/- 0.7). DED resulted more frequent (100%) in atypical and silent CD forms than in the typical one (30.93%). The presence of HLA DR 52-53 and DQ7antigens significantly increased the risk of DED (P = 0.0017) in coeliac children. Our results confirmed a possible correlation between HLA antigens and DED.

  3. Physical and adhesive properties of dental enamel after radiotherapy and bonding of metal and ceramic brackets.

    Science.gov (United States)

    Santin, Gabriela Cristina; Palma-Dibb, Regina Guenka; Romano, Fábio Lourenço; de Oliveira, Harley Francisco; Nelson Filho, Paulo; de Queiroz, Alexandra Mussolino

    2015-08-01

    The increasing success rates for cancer patients treated with radiotherapy and the frequent occurrence of tooth loss during treatment have led to an increased demand for orthodontic treatment after radiotherapy. The aim of this study was to evaluate tooth enamel of irradiated teeth after the bonding and debonding of metal and ceramic brackets. Ten permanent molars were cut into enamel fragments measuring 1 mm(2) and divided into an irradiated group (total dose of 60 Gy) and a nonirradiated group. The fragments were subjected to microshear testing to evaluate whether radiotherapy altered the strength of the enamel. Furthermore, 90 prepared premolars were divided into 6 groups and subgroups (n = 15): group 1, nonirradiated and nonaged; group 2, nonirradiated and aged (thermal cycled); group 3, irradiated and aged; each group was divided into 2 subgroups: metallic and ceramic brackets. After thermal cycling and radiotherapy, the brackets were bonded onto the specimens with Transbond XT (3M Unitek, Monrovia, Calif). After 24 hours, the specimens were subjected to the shear tests. Images of the enamel surfaces were classified using the adhesive remnant index. The composite resin-enamel interface was also evaluated. Enamel fragments subjected to radiation had lower strength than did the nonirradiated samples (P enamel interface, resin tags were more extensive on irradiated tooth enamel. Radiation decreased tooth enamel strength, and the specimens treated with radiotherapy had higher frequencies of adhesive failure between the bracket and the composite resin as well as more extensive tags. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  4. HeNe-laser light scattering by human dental enamel

    NARCIS (Netherlands)

    Zijp, [No Value; tenBosch, JJ; Groenhuis, RAJ

    1995-01-01

    Knowledge of the optical properties of tooth enamel and an understanding of the origin of these properties are necessary for the development of new optical methods for caries diagnosis and the measurement of tooth color. We measured the scattering intensity functions for HeNe-laser light of 80- to

  5. Influence of Etching Mode on Enamel Bond Durability of Universal Adhesive Systems.

    Science.gov (United States)

    Suzuki, T; Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Endo, H; Erickson, R L; Latta, M A; Miyazaki, M

    2016-01-01

    The purpose of this study was to determine the enamel bond durability of three universal adhesives in different etching modes through fatigue testing. The three universal adhesives used were Scotchbond Universal, Prime&Bond Elect universal dental adhesive, and All-Bond Universal light-cured dental adhesive. A single-step self-etch adhesive, Clearfil S 3 Bond Plus was used as a control. The shear bond strength (SBS) and shear fatigue strength (SFS) to human enamel were evaluated in total-etch mode and self-etch mode. A stainless steel metal ring with an internal diameter of 2.4 mm was used to bond the resin composite to the flat-ground (4000-grit) tooth surfaces for determination of both SBS and SFS. For each enamel surface treatment, 15 specimens were prepared for SBS and 30 specimens for SFS. The staircase method for fatigue testing was then used to determine the SFS of the resin composite bonded to the enamel using 10-Hz frequencies for 50,000 cycles or until failure occurred. Scanning electron microscopy was used to observe representative debonded specimen surfaces and the resin-enamel interfaces. A two-way analysis of variance and the Tukey post hoc test were used for analysis of the SBS data, whereas a modified t-test with Bonferroni correction was used for the SFS data. All adhesives in total-etch mode showed significantly higher SBS and SFS values than those in self-etch mode. Although All-Bond Universal in self-etch mode showed a significantly lower SBS value than the other adhesives, there was no significant difference in SFS values among the adhesives in this mode. All adhesives showed higher SFS:SBS ratios in total-etch mode than in self-etch mode. With regard to the adhesive systems used in this study, universal adhesives showed higher enamel bond strengths in total-etch mode. Although the influence of different etching modes on the enamel-bonding performance of universal adhesives was found to be dependent on the adhesive material, total-etch mode

  6. EMMPRIN/CD147 deficiency disturbs ameloblast-odontoblast cross-talk and delays enamel mineralization.

    Science.gov (United States)

    Khaddam, Mayssam; Huet, Eric; Vallée, Benoît; Bensidhoum, Morad; Le Denmat, Dominique; Filatova, Anna; Jimenez-Rojo, Lucia; Ribes, Sandy; Lorenz, Georg; Morawietz, Maria; Rochefort, Gael Y; Kiesow, Andreas; Mitsiadis, Thimios A; Poliard, Anne; Petzold, Matthias; Gabison, Eric E; Menashi, Suzanne; Chaussain, Catherine

    2014-09-01

    Tooth development is regulated by a series of reciprocal inductive signaling between the dental epithelium and mesenchyme, which culminates with the formation of dentin and enamel. EMMPRIN/CD147 is an Extracellular Matrix MetalloPRoteinase (MMP) INducer that mediates epithelial-mesenchymal interactions in cancer and other pathological processes and is expressed in developing teeth. Here we used EMMPRIN knockout (KO) mice to determine the functional role of EMMPRIN on dental tissue formation. We report a delay in enamel deposition and formation that is clearly distinguishable in the growing incisor and associated with a significant reduction of MMP-3 and MMP-20 expression in tooth germs of KO mice. Insufficient basement membrane degradation is evidenced by a persistent laminin immunostaining, resulting in a delay of both odontoblast and ameloblast differentiation. Consequently, enamel volume and thickness are decreased in adult mutant teeth but enamel maturation and tooth morphology are normal, as shown by micro-computed tomographic (micro-CT), nanoindentation, and scanning electron microscope analyses. In addition, the dentino-enamel junction appears as a rough calcified layer of approximately 10±5μm thick (mean±SD) in both molars and growing incisors of KO adult mice. These results indicate that EMMPRIN is involved in the epithelial-mesenchymal cross-talk during tooth development by regulating the expression of MMPs. The mild tooth phenotype observed in EMMPRIN KO mice suggests that the direct effect of EMMPRIN may be limited to a short time window, comprised between basement membrane degradation allowing direct cell contact and calcified matrix deposition. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. 21 CFR 101.80 - Health claims: dietary noncariogenic carbohydrate sweeteners and dental caries.

    Science.gov (United States)

    2010-04-01

    ... sweeteners and dental caries. 101.80 Section 101.80 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... caries. (a) Relationship between dietary carbohydrates and dental caries. (1) Dental caries, or tooth... development of dental caries. Risk factors include tooth enamel crystal structure and mineral content, plaque...

  8. Remineralization of initial enamel caries in vitro using a novel peptide based on amelogenin

    Science.gov (United States)

    Li, Danxue; Lv, Xueping; Tu, Huanxin; Zhou, Xuedong; Yu, Haiyang; Zhang, Linglin

    2015-09-01

    Dental caries is the most common oral disease with high incidence, widely spread and can seriously affect the health of oral cavity and the whole body. Current caries prevention measures such as fluoride treatment, antimicrobial agents, and traditional Chinese herbal, have limitations to some extent. Here we design and synthesize a novel peptide based on the amelogenin, and assess its ability to promote the remineralization of initial enamel caries lesions. We used enamel blocks to form initial lesions, and then subjected to 12-day pH cycling in the presence of peptide, NaF and HEPES buffer. Enamel treated with peptide or NaF had shallower, narrower lesions, thicker remineralized surfaces and less mineral loss than enamel treated with HEPES. This peptide can promote the remineralization of initial enamel caries and inhibit the progress of caries. It is a promising anti-caries agent with various research prospects and practical application value.

  9. The effects of three different food acids on the attrition-corrosion wear of human dental enamel

    Science.gov (United States)

    Zhang, Yichi; Arsecularatne, Joseph A.; Hoffman, Mark

    2015-07-01

    With increased consumption of acidic drinks and foods, the wear of human teeth due to attrition in acidic environments is an increasingly important issue. Accordingly, the present paper investigates in vitro the wear of human enamel in three different acidic environments. Reciprocating wear tests in which an enamel cusp slides on an enamel flat surface were carried out using acetic, citric and lactic acid lubricants (at pH 3-3.5). Distilled water was also included as a lubricant for comparison. Focused ion beam milling and scanning electron microscopy imaging were then used to investigate the enamel subsurfaces following wear tests. Nanoindentation was used to ascertain the changes in enamel mechanical properties. The study reveals crack generation along the rod boundaries due to the exposure of enamel to the acidic environments. The wear mechanism changes from brittle fracture in distilled water to ploughing or shaving of the softened layer in acidic environments, generating a smooth surface with the progression of wear. Moreover, nanoindentation results of enamel samples which were exposed to the above acids up to a duration of the wear tests show decreasing hardness and Young’s modulus with exposure time.

  10. A comparative evaluation of four restorative materials to support undermined occlusal enamel of permanent teeth

    Directory of Open Access Journals (Sweden)

    Prabhakar A

    2006-09-01

    Full Text Available The purpose of this study was to test the support to undermined occlusal enamel provided by posterior restorative composite (FiltekTM P60, 3M Dental products USA, polyacid modified resin composite (F2000 compomer, 3M Dental products, USA., radiopaque silver alloy-glass ionomer cement (Miracle Mix. GC Corp, Tokyo, Japan and Glass Ionomer cement (Fuji IX GP. To test each material, 20 human permanent mandibular third molars were selected. The lingual cusps were removed and the dentin supporting the facial cusps was cut away, leaving a shell of enamel. Each group of prepared teeth was restored using the materials according to the manufacturer′s instructions. All the specimens were thermocycled (250 cycles, 6°C- 60°C, dwell time 30 seconds and then mounted on an acrylic base. Specimens were loaded evenly across the cusp tips at a crosshead speed of 5 mm /minute in Hounsfield universal testing machine until fracture occurred. Data obtained was analyzed using analysis of variance and Studentized- Newman- Keul′s range test. No significant differences were detected in the support provided by P-60, F 2000, Miracle Mix or Fuji IX GP groups. The support provided to undermined occlusal enamel by these materials was intermediate between no support and that provided by sound dentin. Without further development in dental material technology and evidence of its efficacy, restorative materials should not be relied upon to support undermined occlusal enamel to a level comparable to that provided by sound dentin.

  11. Tooth enamel surface micro-hardness with dual species Streptococcus biofilm after exposure to Java turmeric (Curcuma xanthorrhiza Roxb.) extract

    Science.gov (United States)

    Isjwara, F. R. G.; Hasanah, S. N.; Utami, Sri; Suniarti, D. F.

    2017-08-01

    Streptococcus biofilm on tooth surfaces can decrease mouth environment pH, thus causing enamel demineralization that can lead to dental caries. Java Turmeric extract has excellent antibacterial effects and can maintain S. mutans biofilm pH at neutral levels for 4 hours. To analyze the effect of Java Turmeric extract on tooth enamel micro-hardness, the Java Turmeric extract was added on enamel tooth samples with Streptococcus dual species biofilm (S. sanguinis and S. mutans). The micro-hardness of enamel was measured by Knoop Hardness Tester. Results showed that Curcuma xanthorrhiza Roxb. could not maintain tooth enamel surface micro-hardness. It is concluded that Java Turmeric extract ethanol could not inhibit the hardness of enamel with Streptococcus dual species biofilm.

  12. Analysis of synchrotron X-ray diffraction patterns from fluorotic enamel samples

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ana P.G.; Braz, Delson, E-mail: anapaulagalmeida@gmail.co [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear; Colaco, Marcos V.; Barroso, Regina C., E-mail: cely@uerj.b [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Fisica; Porto, Isabel M., E-mail: belporto@ig.com.b [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Faculdade de Odontologia; Gerlach, Raquel F., E-mail: rfgerlach@forp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Odontologia; Droppa Junior, Roosevelt, E-mail: rdroppa@lnls.b [Associacao Brasileira de Tecnologia de Luz Sincrotron (ABTLuS), Campinas, SP (Brazil)

    2009-07-01

    With the introduction of fluoride as the main anticaries agent used in preventive dentistry, and perhaps an increase in fluoride in our food chain, dental fluorosis has become an increasing world-wide problem. Visible signs of fluorosis begin to become obvious on the enamel surface as opacities, implying some porosity in the tissue. The mechanisms that conduct the formation of fluorotic enamel are unknown, but should involve modifications in the basics physical-chemistry reactions of demineralisation and remineralisation of the enamel of the teeth, which is the same reaction of formation of the enamel's hydroxyapatite (HAp) in the maturation phase. The increase of the amount of fluoride inside of the apatite will result in gradual increase of the lattice parameters. The hexagonal symmetry seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. The aim of this work is to characterize the healthy and fluorotic enamel in human tooth using technique Synchrotron X-ray diffraction in order to determine the crystal structure and crystallinity of on fluoroapatite (FAp) crystal present in fluoritic enamel. All the scattering profile measurements was carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. (author)

  13. Analysis of synchrotron X-ray diffraction patterns from fluorotic enamel samples

    International Nuclear Information System (INIS)

    Almeida, Ana P.G.; Braz, Delson

    2009-01-01

    With the introduction of fluoride as the main anticaries agent used in preventive dentistry, and perhaps an increase in fluoride in our food chain, dental fluorosis has become an increasing world-wide problem. Visible signs of fluorosis begin to become obvious on the enamel surface as opacities, implying some porosity in the tissue. The mechanisms that conduct the formation of fluorotic enamel are unknown, but should involve modifications in the basics physical-chemistry reactions of demineralisation and remineralisation of the enamel of the teeth, which is the same reaction of formation of the enamel's hydroxyapatite (HAp) in the maturation phase. The increase of the amount of fluoride inside of the apatite will result in gradual increase of the lattice parameters. The hexagonal symmetry seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. The aim of this work is to characterize the healthy and fluorotic enamel in human tooth using technique Synchrotron X-ray diffraction in order to determine the crystal structure and crystallinity of on fluoroapatite (FAp) crystal present in fluoritic enamel. All the scattering profile measurements was carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. (author)

  14. EFFECT OF FREQUENT CONSUMPTION OF STARCHY FOOD ITEMS ON ENAMEL AND DENTIN DEMINERALIZATION AND ON PLAQUE PH IN-SITU

    NARCIS (Netherlands)

    LINGSTROM, P; BIRKHED, D; RUBEN, J; ARENDS, J

    The aim of this cross-over study was to determine the cariogenic potential of starchy food items as between-meal snacks. This was done by measuring demineralization of human enamel and dentin as well as the pH of dental plaque in situ. Eight volunteers with complete dentures carried two enamel and

  15. Dental abnormalities in long-term survivors child cancer patients

    International Nuclear Information System (INIS)

    Bajciova, V.

    2016-01-01

    Cancer therapy (chemotherapy and radiotherapy) is known to disturb tooth development in children. Children cancer survivors are at risk to develop dental late effects in form of arrested dental development, enamel development, xerostomy, root development and increased risk of dental caries. This review summarizes association between treatment and dental late effects and analysed vulnerable groups of patients with specific host and treatment characteristics. Also summary provides recommendations for early detection and prevention of dental late effects. (author)

  16. Dental bleaching on teeth submitted to enamel microabrasion 30 years ago-a case report of patients' compliance during bleaching treatment.

    Science.gov (United States)

    Sundfeld, Daniel; Pavani, Caio Cesar; Schott, Timm Cornelius; Machado, Lucas Silveira; Pini, Núbia Inocêncya Pavesi; Bertoz, André Pinheiro de Magalhães; Sundfeld, Renato Herman

    2018-04-20

    The present dental bleaching case report describes a new method that precisely quantifies the daily wearing-times of the bleaching product by inserting a microsensor in the acetate custom tray. The bleaching efficacy was also discussed since the patient was previously submitted to enamel microabrasion. The patient was submitted to enamel microabrasion in 1987, and bleaching treatment was performed in 2005. In 2017, re-bleaching was executed using 10% peroxide carbamide. The electronic microsensor, TheraMon (TheraMon® microelectronic system; Sales Agency Gschladt, Hargelsberg, Austria), was embedded in the labial region of the upper and lower acetate trays to evaluate the wearing-times of the acetate trays/bleaching product. The patient was instructed to wear the tray for 6 to 8 h/day while sleeping. After 24 days of bleaching treatment, the data obtained from the TheraMon electronic devices was collected and interpreted. The patient did not entirely follow the bleaching treatment as recommended, as there was no evidence of use of the upper and lower trays for some days; additionally, the bleaching product was used for shorter and longer periods than was instructed. The TheraMon microeletronic device precisely measured the wearing-times of the acetate tray/bleaching product during the bleaching treatment. Teeth submitted to enamel microabrasion presented with a healthy clinical appearance after 30 years. Measuring the length and frequency of use of an acetate tray/bleaching product can be important to clinicians and patients for obtaining a controlled and adequate bleaching treatment.

  17. The knowledge and attitude about HIV/AIDS among Jordanian dental students: (Clinical versus pre clinical students at the University of Jordan

    Directory of Open Access Journals (Sweden)

    Shayyab Mohammad H

    2011-06-01

    Full Text Available Abstract Background The present study aimed to address the suspected deficiency in the level of understanding of HIV/AIDS among clinical and pre clinical dental students at the University of Jordan. In this cross-sectional study, structured questionnaires were distributed to fifth year dental students (n = 121 and to third year dental students (n = 144 in the academic year 2008/2009. Findings Significantly higher percentage of fifth-year students compared to third-year students felt that the teaching they received on cross-infection precautions and barrier dentistry was adequate (P Significantly higher proportion of third-year students compared to fifth-year (39.2% vs. 26.3% thought that HIV patients should be referred to other centers or support groups for treatment (P = 0.04. Conclusions The level of knowledge of Jordanian dental students about HIV and AIDS was generally acceptable; there were inadequacies, however, in their understanding regarding some aspects of AIDS epidemic which demands that dental school curriculum needs some improvement.

  18. Dental Wear: A Scanning Electron Microscope Study

    Directory of Open Access Journals (Sweden)

    Luca Levrini

    2014-01-01

    Full Text Available Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction studied by scanning electron microscopy (SEM. The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp, to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders. It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction.

  19. Wear of human enamel: a quantitative in vitro assessment.

    Science.gov (United States)

    Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

    1998-12-01

    Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

  20. Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization

    International Nuclear Information System (INIS)

    Kato, Ilka Tiemy

    2004-01-01

    The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm 2 , 3.7 J/cm 2 , 5.6 J/cm 2 , 7.4 J/cm 2 and 9.3 J/cm 2 ) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

  1. Use of radioisotopes in the study of permeability of hard dental tissue

    Energy Technology Data Exchange (ETDEWEB)

    Tarjan, I [Semmelweis Orvostudomanyi Egyetem, Budapest (Hungary)

    1978-04-01

    A literature survey. According to in vivo experiments /sup 32/P, /sup 131/I and /sup 45/Ca penetrate dental enamel and dentine. In vitro studies revealed that the healthy enamel and that damaged by caries and dentine are penetrable by /sup 22/Na and /sup 24/Na both in centripetal and in centrifugal directions. /sup 32/P, /sup 18/F and urea, labelled with /sup 14/C penetrate healthy hard dental tissue. /sup 45/CaCl/sub 2/, /sup 110/AgNO/sub 3/, /sup 111/AgNO/sub 3/, /sup 103/PdCl/sub 2/, /sup 64/Cu(NO/sub 3/)/sub 2/, /sup 63/ZnCl/sub 2/, /sup 65/ZnCl/sub 2/ and glucose, labelled with /sup 14/C penetrate enamel defects, lamellas and caries areas. /sup 239/Pu citrate complex links to the surface of enamel and cement, but does not penetrate them.

  2. In vitro effect of energy drinks on human enamel surface

    Directory of Open Access Journals (Sweden)

    Marise Sano Suga MATUMOTO

    Full Text Available Abstract Introduction Energy drinks (ED possess low pH and citric acid in their composition, making them potentially erosive beverages that can contribute to the high dental erosion rates found currently in the general population and also in young people. Objective To evaluate the mean pH and titratable acidity of commercial ED and the influence of a brand of ED on the superficial microhardness of human enamel. Material and method Ten commercial ED were selected and the pH of two lots of each ED with and without gas was obtained. Acid titration was conducted with the addition of NaOH aliquots until the pH 7 was reached. Eighteen human enamel specimens were allocated in three groups (N=6, Red Bull (RB, Red Bull Light (RBL and distilled water (C, submitted to an acid challenge with the ED, six consecutive times, with 12 hours intervals, during three days. Knoop microhardness was measured before and after the acid challenge. Result All ED brands tested presented low pH levels ranging from 2.1 to 3.2. Regarding titratable acidity, it was found that the amount of base required promoting the neutralization of the solutions ranged from 1200μL to 3750μL. Samples of human enamel in the RB and RBL groups submitted to the acid challenge presented significantly decreased Knoop microhardness when compared with the group C. Conclusion All ED examined have potential to promote mineral loss due to the low pH and high titratable acidity. The ED analyzed promoted significant mineral losses on the dental enamel surface.

  3. Polarization sensitive camera for the in vitro diagnostic and monitoring of dental erosion

    Science.gov (United States)

    Bossen, Anke; Rakhmatullina, Ekaterina; Lussi, Adrian; Meier, Christoph

    Due to a frequent consumption of acidic food and beverages, the prevalence of dental erosion increases worldwide. In an initial erosion stage, the hard dental tissue is softened due to acidic demineralization. As erosion progresses, a gradual tissue wear occurs resulting in thinning of the enamel. Complete loss of the enamel tissue can be observed in severe clinical cases. Therefore, it is essential to provide a diagnosis tool for an accurate detection and monitoring of dental erosion already at early stages. In this manuscript, we present the development of a polarization sensitive imaging camera for the visualization and quantification of dental erosion. The system consists of two CMOS cameras mounted on two sides of a polarizing beamsplitter. A horizontal linearly polarized light source is positioned orthogonal to the camera to ensure an incidence illumination and detection angles of 45°. The specular reflected light from the enamel surface is collected with an objective lens mounted on the beam splitter and divided into horizontal (H) and vertical (V) components on each associate camera. Images of non-eroded and eroded enamel surfaces at different erosion degrees were recorded and assessed with diagnostic software. The software was designed to generate and display two types of images: distribution of the reflection intensity (V) and a polarization ratio (H-V)/(H+V) throughout the analyzed tissue area. The measurements and visualization of these two optical parameters, i.e. specular reflection intensity and the polarization ratio, allowed detection and quantification of enamel erosion at early stages in vitro.

  4. Ameloblasts require active RhoA to generate normal dental enamel.

    Science.gov (United States)

    Xue, Hui; Li, Yong; Everett, Eric T; Ryan, Kathleen; Peng, Li; Porecha, Rakhee; Yan, Yan; Lucchese, Anna M; Kuehl, Melissa A; Pugach, Megan K; Bouchard, Jessica; Gibson, Carolyn W

    2013-08-01

    RhoA plays a fundamental role in regulation of the actin cytoskeleton, intercellular attachment, and cell proliferation. During amelogenesis, ameloblasts (which produce the enamel proteins) undergo dramatic cytoskeletal changes and the RhoA protein level is up-regulated. Transgenic mice were generated that express a dominant-negative RhoA transgene in ameloblasts using amelogenin gene-regulatory sequences. Transgenic and wild-type (WT) molar tooth germs were incubated with sodium fluoride (NaF) or sodium chloride (NaCl) in organ culture. Filamentous actin (F-actin) stained with phalloidin was elevated significantly in WT ameloblasts treated with NaF compared with WT ameloblasts treated with NaCl or with transgenic ameloblasts treated with NaF, thereby confirming a block in the RhoA/Rho-associated protein kinase (ROCK) pathway in the transgenic mice. Little difference in quantitative fluorescence (an estimation of fluorosis) was observed between WT and transgenic incisors from mice provided with drinking water containing NaF. We subsequently found reduced transgene expression in incisors compared with molars. Transgenic molar teeth had reduced amelogenin, E-cadherin, and Ki67 compared with WT molar teeth. Hypoplastic enamel in transgenic mice correlates with reduced expression of the enamel protein, amelogenin, and E-cadherin and cell proliferation are regulated by RhoA in other tissues. Together these findings reveal deficits in molar ameloblast function when RhoA activity is inhibited. © 2013 Eur J Oral Sci.

  5. Erosive effects of acidic center-filled chewing gum on primary and permanent enamel

    Directory of Open Access Journals (Sweden)

    Bolan M

    2008-01-01

    Full Text Available Background: The higher incidence of dental erosion in children and teenagers possibly reflects a high intake of acidic food and beverages as well as a more frequent diagnosis on this condition. Aim: The aim of this study was to evaluate the erosive potential of acidic filling of chewing gum in primary and permanent enamel. Methods and Materials: Eighty enamel blocks (40 primary and 40 permanent teeth were used and randomly distributed into eight groups. Groups were divided according to types of dental substrates (permanent or primary, frequency of exposure to the acidic substance (2X or 4X/day, and concentration (pure or diluted. Exposure time to the acidic content of the chewing gum was five minutes under agitation, during five days. Results: All groups showed a significant decrease in surface microhardness (P < 0.001. There was neither any significant difference in the frequency of exposure to the acidic content nor to the types of dental substrates. There was a statistically significant difference between D1 (pure, 2X/day and D2 (diluted, 2X/day (P = 0.002, D3 (pure, 4X/day and D4 (diluted, 4X/day (P = 0.009 regarding the concentration, then the diluted acid content was associated with a greater decrease in microhardness. Conclusion: It is concluded that the acidic filling of a chewing gum reduced the microhardness of primary and permanent enamel.

  6. Enamel alteration following tooth bleaching and remineralization.

    Science.gov (United States)

    Coceska, Emilija; Gjorgievska, Elizabeta; Coleman, Nichola J; Gabric, Dragana; Slipper, Ian J; Stevanovic, Marija; Nicholson, John W

    2016-06-01

    The purpose of this study was to compare the effects of professional tooth whitening agents containing highly concentrated hydrogen peroxide (with and without laser activation), on the enamel surface; and the potential of four different toothpastes to remineralize any alterations. The study was performed on 50 human molars, divided in two groups: treated with Opalescence(®) Boost and Mirawhite(®) Laser Bleaching. Furthermore, each group was divided into five subgroups, a control one and 4 subgroups remineralized with: Mirasensitive(®) hap+, Mirawhite(®) Gelleѐ, GC Tooth Mousse™ and Mirafluor(®) C. The samples were analysed by SEM/3D-SEM-micrographs, SEM/EDX-qualitative analysis and SEM/EDX-semiquantitative analysis. The microphotographs show that both types of bleaching cause alterations: emphasized perikymata, erosions, loss of interprizmatic substance; the laser treatment is more aggressive and loss of integrity of the enamel is determined by shearing off the enamel rods. In all samples undergoing remineralization deposits were observed, those of toothpastes based on calcium phosphate technologies seem to merge with each other and cover almost the entire surface of the enamel. Loss of integrity and minerals were detected only in the line-scans of the sample remineralized with GC Tooth Mousse™. The semiquantitative EDX analysis of individual elements in the surface layer of the enamel indicates that during tooth-bleaching with HP statistically significant loss of Na and Mg occurs, whereas the bleaching in combination with a laser leads to statistically significant loss of Ca and P. The results undoubtedly confirm that teeth whitening procedures lead to enamel alterations. In this context, it must be noted that laser bleaching is more aggressive for dental substances. However, these changes are reversible and can be repaired by application of remineralization toothpastes. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  7. Enzyme replacement prevents enamel defects in hypophosphatasia mice

    Science.gov (United States)

    Yadav, Manisha C.; de Oliveira, Rodrigo Cardoso; Foster, Brian L.; Fong, Hanson; Cory, Esther; Narisawa, Sonoko; Sah, Robert L.; Somerman, Martha; Whyte, Michael P.; Millán, José Luis

    2012-01-01

    Hypophosphatasia (HPP) is the inborn error of metabolism characterized by deficiency of alkaline phosphatase activity leading to rickets or osteomalacia and to dental defects. HPP occurs from loss-of-function mutations within the gene that encodes the tissue-nonspecific isozyme of alkaline phosphatase (TNAP). TNAP knockout (Alpl−/−, a.k.a. Akp2−/−) mice closely phenocopy infantile HPP, including the rickets, vitamin B6-responsive seizures, improper dentin mineralization, and lack of acellular cementum. Here, we report that lack of TNAP in Alpl−/− mice also causes severe enamel defects, which are preventable by enzyme replacement with mineral-targeted TNAP (ENB-0040). Immunohistochemistry was used to map the spatiotemporal expression of TNAP in the tissues of the developing enamel organ of healthy mouse molars and incisors. We found strong, stage-specific expression of TNAP in ameloblasts. In the Alpl−/− mice, histological, μCT, and scanning electron microscopy analysis showed reduced mineralization and disrupted organization of the rods and inter-rod structures in enamel of both the molars and incisors. All of these abnormalities were prevented in mice receiving from birth daily subcutaneous injections of mineral-targeting, human TNAP (sALP-FcD10, a.k.a. ENB-0040) at 8.2 mg/kg/day for up to 44 days. These data reveal an important role for TNAP in enamel mineralization, and demonstrate the efficacy of mineral-targeted TNAP to prevent enamel defects in HPP. PMID:22461224

  8. Interaction of slow highly charged ions with hard dental tissue: studies of fluoride uptake and reminalization efficacy

    International Nuclear Information System (INIS)

    Daskalova, A; Kasperski, G; Rousseau, P; Domaracka, A; Lawicki, A

    2014-01-01

    TOF-SIMS mass spectroscopy data are presented on ion irradiation of hard dental tissue using a beam of 129 Xe 20+ (15 kV) ions delivered in the ARIBE facility by an ECR source. The investigation was focused on the mass distribution of the fragment ions. A comparison is made between the mass spectra from hard dental tissue treated by olaflur-(C 27 H 60 F 2 N 2 O 3 ) and untreated hard dental tissue obtained under irradiation by low-energy highly-charged ions (HCIs). We found significant differences between the mass spectra of enamel after introducing amine fluoride (olaflur) and the mass spectra of pure untreated enamel. Further, we separated out the effects caused by radiation induced in the tooth enamel from those induced in dentin, which has not been performed before. In order to conduct a further detailed analysis, it is necessary to extend the research scope to include the influence of fluorine compounds on enamel and dentin.

  9. Novel hydroxyapatite nanorods improve anti-caries efficacy of enamel infiltrants.

    Science.gov (United States)

    Andrade Neto, D M; Carvalho, E V; Rodrigues, E A; Feitosa, V P; Sauro, S; Mele, G; Carbone, L; Mazzetto, S E; Rodrigues, L K; Fechine, P B A

    2016-06-01

    Enamel resin infiltrants are biomaterials able to treat enamel caries at early stages. Nevertheless, they cannot prevent further demineralization of mineral-depleted enamel. Therefore, the aim of this work was to synthesize and incorporate specific hydroxyapatite nanoparticles (HAps) into the resin infiltrant to overcome this issue. HAps were prepared using a hydrothermal method (0h, 2h and 5h). The crystallinity, crystallite size and morphology of the nanoparticles were characterized through XRD, FT-IR and TEM. HAps were then incorporated (10wt%) into a light-curing co-monomer resin blend (control) to create different resin-based enamel infiltrants (HAp-0h, HAp-2h and HAp-5h), whose degree of conversion (DC) was assessed by FT-IR. Enamel caries lesions were first artificially created in extracted human molars and infiltrated using the tested resin infiltrants. Specimens were submitted to pH-cycling to simulate recurrent caries. Knoop microhardness of resin-infiltrated underlying and surrounding enamel was analyzed before and after pH challenge. Whilst HAp-0h resulted amorphous, HAp-2h and HAp-5h presented nanorod morphology and higher crystallinity. Resin infiltration doped with HAp-2h and HAp-5h caused higher enamel resistance against demineralization compared to control HAp-free and HAp-0h infiltration. The inclusion of more crystalline HAp nanorods (HAp-2h and HAp-5h) increased significantly (p<0.05) the DC. Incorporation of more crystalline HAp nanorods into enamel resin infiltrants may be a feasible method to improve the overall performance in the prevention of recurrent demineralization (e.g. caries lesion) in resin-infiltrated enamel. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Pleiotropic function of DLX3 in amelogenesis: from regulating pH and keratin expression to controlling enamel rod decussation.

    Science.gov (United States)

    Duverger, Olivier; Morasso, Maria I

    2018-12-01

    DLX3 is essential for tooth enamel development and is so far the only transcription factor known to be mutated in a syndromic form of amelogenesis imperfecta. Through conditional deletion of Dlx3 in the dental epithelium in mouse, we have previously established the involvement of DLX3 in enamel pH regulation, as well as in controlling the expression of sets of keratins that contribute to enamel rod sheath formation. Here, we show that the decussation pattern of enamel rods was lost in conditional knockout animals, suggesting that DLX3 controls the coordinated migration of ameloblasts during enamel secretion. We further demonstrate that DLX3 regulates the expression of some components of myosin II complexes potentially involved in driving the movement of ameloblasts that leads to enamel rod decussation.

  11. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning......: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  12. Effect of vegetable oils applied over acquired enamel pellicle on initial erosion

    Directory of Open Access Journals (Sweden)

    Franciny Querobim IONTA

    Full Text Available Abstract Objective The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. Material and Methods Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group: GP5 and GP100 – 5% and pure palm oil, respectively; GC5 and GC100 – 5% and pure coconut oil; GSa5 and GSa100 – 5% and pure safflower oil; GSu5 and GSu100 – 5% and pure sunflower oil; GO5 and GO100 – 5% and pure olive oil; CON− – Deionized Water (negative control and CON+ – Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control. Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf / SHf ×100]. Data were analyzed by one-way ANOVA and Tukey’s test (p0.05 and less than the other groups (p<0.05. There was no difference between GP5, GC5, GC100, GSa5, GSu100, GSa100, GSu5, GO5, GO100, CON− and CON+. Conclusion Palm oil seems to be a promising alternative for preventing enamel erosion. However, further studies are necessary to evaluate a long-term erosive cycling.

  13. Effect of vegetable oils applied over acquired enamel pellicle on initial erosion

    Science.gov (United States)

    IONTA, Franciny Querobim; de ALENCAR, Catarina Ribeiro Barros; VAL, Poliana Pacifico; BOTEON, Ana Paula; JORDÃO, Maisa Camillo; HONÓRIO, Heitor Marques; BUZALAF, Marília Afonso Rabelo; RIOS, Daniela

    2017-01-01

    Abstract Objective The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. Material and Methods Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group): GP5 and GP100 – 5% and pure palm oil, respectively; GC5 and GC100 – 5% and pure coconut oil; GSa5 and GSa100 – 5% and pure safflower oil; GSu5 and GSu100 – 5% and pure sunflower oil; GO5 and GO100 – 5% and pure olive oil; CON− – Deionized Water (negative control) and CON+ – Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control). Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf) / SHf )×100]. Data were analyzed by one-way ANOVA and Tukey’s test (p0.05) and less than the other groups (p<0.05). There was no difference between GP5, GC5, GC100, GSa5, GSu100, GSa100, GSu5, GO5, GO100, CON− and CON+. Conclusion Palm oil seems to be a promising alternative for preventing enamel erosion. However, further studies are necessary to evaluate a long-term erosive cycling. PMID:28877281

  14. Baring the teeth. [Dental caries and the analysis of trace elements in dental tissues

    Energy Technology Data Exchange (ETDEWEB)

    Cleaton-Jones, P [University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit; Retief, H [Alabama Univ., Birmingham (USA); Turkstra, J [Fort Hare Univ. (South Africa). Dept. of Chemistry

    1979-07-01

    To determine whether trace elements other than fluorine play a role in the varying prevalences of dental caries in different South African population groups, neutron activation techniques have been devised to establish the concentrations of trace elements in tooth enamel and dentine.

  15. Effect of Fluoride Mouthrinse and Toothpaste on Number of Streptococcal Colony Forming Units of Dental Plaque

    OpenAIRE

    SE Jabbarifar; SA Tabibian; F Poursina

    2005-01-01

    Background: Frequent topical fluoride therapy through toothpaste, mouthrinse, professional gels and solutions causes decrease in incidence, pause and repair of dental caries in the enamel. These mechanisms are done through penetration of fluoride ions (F-) and their replacement with hydroxyl ions (OH-) of hydroxyappatite of enamel, interfere with microbial metabolism of dental plaque and bacteriostatic effect on some cariogenic bacterial strains such as streptococci. The aim of this study was...

  16. Estimation of accumulated dose of radiation by the method of ESR-spectrometry of dental enamel of mammals

    International Nuclear Information System (INIS)

    Serezhenkov, V.A.; Moroz, I.A.; Vanin, A.F.; Klevezal, G.A.

    1997-01-01

    ESR-spectrometry was used to investigate radiation-induced paramagnetic centers in enamel of mammals: carnivores (polar bear and fox), ungulates (reindeer, European bison, moose), and man. Values at half the microwave power saturation of the radiation signal, P 1/2 , evaluated at room temperature, was found to range from 16 to 26 mW for animals and man. A new approach to discrimination of the radiation induced signal from the total ESR spectrum of reindeer enamel is proposed. ''Dose-response'' dependencies of enamel of different species mammals were measured within the dose range from 0.48 up to 10.08 Gy. Estimations of ''radiosensitivity'' enamel of carnivores and ungulates showed good agreement with radiosensitivity enamel of man by ESR method. (Author)

  17. Smile restoration through use of enamel microabrasion associated with tooth bleaching.

    Science.gov (United States)

    Sundfeld, Renato Herman; Rahal, Vanessa; de Alexandre, Rodrigo Sversut; Briso, André Luiz Fraga; Sundfeld Neto, Daniel

    2011-01-01

    in 1989, correction of the color pattern of teeth can be obtained through the use of whitening products containing carbamide peroxide in custom trays. A considerable margin of clinical success has been shown when diligence to at-home protocols is achieved by the patient and supervised by the professional. Considering these possibilities, this article presents the microabrasion technique for removal of stains on dental enamel, followed by tooth bleaching with carbamide peroxide and composite resin restoration, if required.

  18. Prevalence of traumadc dental Injuries among new orthodondc ...

    African Journals Online (AJOL)

    The prevalence of dental trauma was significantly higher in males (p<0.05) and most frequently observed In patients aged 6 to 10 years. Falls was the commonest cause of dental traumatic Injuries among the patients (37.5%). The most common type of trauma to the teeth was enamel fracture (46. 9%) followed by avulslon ...

  19. Interaction of ArF laser with dental hard tissue (AEM Study

    Directory of Open Access Journals (Sweden)

    Abbas Majdabadi

    2016-07-01

    Full Text Available Background and Aims: Nowadays lasers are used as alternatives to the tooth preparation because of reducing pain and bloodshed. The aim of this study was to observe the effect of ArF laser on the dental hard tissues. Materials and Methods: For this research human molar teeth with no caries or dental restoration and enamel cracks were used. Irradiation laser energies were taken 95, 70 and 50 mJ for enamel and 80, 70 and 50 mJ for dentine. Then, for each of energy values pulse numbers (repetition rate were adjusted at 200, 400, 600, 800, 1000 and 1500. Ablation was carried out without water spray on both enamel and dentine. Finally, the dimensions of ablated areas were measured by using a camera connected to the computer and results were applied in graphs. Results: For each energy value, the ablation dimension increased by increasing pulse numbers. Ablation depth in dentine was more than that of for enamel. Trends of graphs for dentine and enamel were the same. SEM images of ablations by 95 mJ energy on enamel and 80 mJ energy on dentine showed sharp edges. Conclusion: Ablation depths increased by increasing pulse numbers, for each energy level. However, this increase was not that as expected, because the lack of water spray while irradiating.

  20. Chronic Fluoride Toxicity: Dental Fluorosis

    OpenAIRE

    DenBesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2–3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enam...

  1. Molecular analysis of tooth enamel by Raman spectroscopy after treatment with bleaching agents at different concentrations

    International Nuclear Information System (INIS)

    Duran Sedo, Randall; Obando Rosabal, Sofia; Saenz Bonilla, Paola; Soto Aguilar, Calendy; Vasquez Rodriguez, Amaya

    2014-01-01

    The changes in the concentration of the v1 phosphate molecule of the surface of dentin enamel are treated and researched with bleaching agents of chemical activation to basis of hydrogen peroxide than 9,5% and 14% and carbamide peroxide than 38%, for a period of 28 days. Raman spectroscopy was used and 30 dental pieces extracted, of which, were to be free of blemishes and pigmentations, without possessing fractures of the enamel, decay nor any other type of defect. The Raman spectrum was obtained of each dental piece prior to the application of bleaching agents. The specimens were separated into three experimental groups according to the concentration of whitening. The concentration of the v1 phosphate molecule was measured in the tooth enamel to the second and fourth week of treatment. In addition, ANOVA was performed for respective measurements (p≤0.05). A reduction of the v1 phosphate molecule were observed during and after the bleaching process in the experimental groups that have used of hydrogen peroxide to 14% and carbamide peroxide 38%. In the group of hydrogen peroxide to 9,5% has remained unproven a significant reduction. Within the limitations of this study is concluded that the bleaching agent causes a loss of v1 phosphate. This loss has been greater in the whitening of higher concentration. In spite, that the possible effect remineralizing of the saliva on a teeth whitening process has been unevaluated, it is recommended using during and after the treatment, toothpastes, mouthwashes, chewing gums, dental floss, among others, that contain ACP to help to cushion the potential loss of phosphate from tooth enamel. (author) [es

  2. Radiation exposure during in-vivo analysis of human dental enamel by proton irradiation

    International Nuclear Information System (INIS)

    Baijot-Stroobants, J.; Bodart, F.; Deconninck, G.; Vreven, J.

    Fluorine can be analysed by proton activation, with detection of prompt γ-rays. Using external beams, it is possible to make in-vivo determinations and to follow the concentration in fluoridated enamel. Radiation damage and radiation hazards are investigated. It is found that the dose rate is very small and that the technique can be used without radiation problems. Local destruction on the enamel surface is investigated using a scanning microscope, no modification is observed in the cristallite structure after irradiation. (author)

  3. Nanostructured synthetic hydroxyapatite and dental enamel heated and irradiated by ER,CR:YSGG: characterized by FTIR and XRD; Hidroxiapatita sintetica nanoestruturada e esmalte dental aquecidos e irradiados por laser de Er,Cr:YSGG: caracterizacao por FTIR e por DRX

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo Neto, Jose da Silva

    2009-07-01

    The study evaluate the physical changes and/or chemical that occurs in synthetic hydroxyapatite (HAP) and in enamel under action of thermal heating in oven or laser irradiation of Er,Cr:YSGG that may cause changes in its structure to make them more resistant to demineralization aiming the formation of dental caries. The synthetic HAP was produced by reaction of solutions of Ca(NO{sub 3}) and (NH{sub 4}){sub 2}HPO{sub 4} with controlled temperature and pH. The enamel powder was collected from the bovine teeth. Samples of powder enamel and synthetic HAP were subjected to thermal heating in oven at temperatures of 200 deg C, 400 deg C, 600 deg C, 800 deg C and 1000 deg C. For the laser irradiation of materials, were made with 5,79 J/cm{sup 2} of irradiation, 7,65 J/cm{sup 2}, 10,55 J/cm{sup 2} and 13,84 J/cm{sup 2} for synthetic HAP and 7,53 J/cm{sup 2}, 10,95 J/cm{sup 2}, and 13,74 J/cm{sup 2} for the enamel. The samples were evaluated by X-ray diffraction (XRD) for analysis of crystallographic phases and analysis by the Rietveld method, to determine their respective proportions in the material, as well as results of changes of the lattice unit cell parameters (axis-a, axis-c and volume), crystallites sizes and the occupation rate of sites of Ca and P atoms. The samples were analyzed by Fourier transform infrared spectroscopy (FTIR), which should compositional changes due to treatment related to carbonate, phosphate, adsorbed water and hydroxyl radicals content. The infrared was used to measure the surface temperature generated by the laser beam in the solid samples of enamel. Besides the major hydroxyapatite crystallographic phases, there was formations of octa calcium phosphate (OCP) and phase {beta} of tricalcium phosphate ({beta}-TCP ) in enamel heated at 800 deg C. There was reduction of the axis-a, volume and size of crystallites to the temperatures between 400 degree C and 600 deg C and also on laser irradiated samples. Above the temperature of 600 degree C it

  4. Enamel Bond Strength of New Universal Adhesive Bonding Agents.

    Science.gov (United States)

    McLean, D E; Meyers, E J; Guillory, V L; Vandewalle, K S

    2015-01-01

    Universal bonding agents have been introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinician's preference. The purpose of this study was to evaluate the shear bond strength (SBS) of composite to enamel using universal adhesives compared to a self-etch adhesive when applied in self-etch and etch-and-rinse modes over time. Extracted human third molars were used to create 120 enamel specimens. The specimens were ground flat and randomly divided into three groups: two universal adhesives and one self-etch adhesive. Each group was then subdivided, with half the specimens bonded in self-etch mode and half in etch-and-rinse mode. The adhesives were applied as per manufacturers' instructions, and composite was bonded using a standardized mold and cured incrementally. The groups were further divided into two subgroups with 10 specimens each. One subgroup was stored for 24 hours and the second for six months in 37°C distilled water and tested in shear. Failure mode was also determined for each specimen. A three-way analysis of variance (ANOVA) found a significant difference between groups based on bonding agent (p0.05). Clearfil SE in etch-and-rinse and self-etch modes had more mixed fractures than either universal adhesive in either mode. Etching enamel significantly increased the SBS of composite to enamel. Clearfil SE had significantly greater bond strength to enamel than either universal adhesive, which were not significantly different from each other.

  5. Effect of bracket bonding with Er: YAG laser on nanomechanical properties of enamel.

    Science.gov (United States)

    Alavi, Shiva; Birang, Reza; Hajizadeh, Fatemeh; Banimostafaee, Hamed

    2014-01-01

    The aim of this study was to compare the effects of conventional acid etching and laser etching on the nano-mechanical properties of the dental enamel using nano-indentation test. In this experimental in vitro study, buccal surfaces of 10 premolars were divided into three regions. One of the regions was etched with 37% phosphoric acid and another etched with Er:YAG laser, the third region was not etched. The brackets were bonded to both of etched regions. After thermocycling for 500 cycles, the brackets were removed and the teeth were decoronated from the bracket bonding area. Seven nano-indentations were applied at 1-31 μm depth from the enamel surface in each region. Mean values of the hardness and elastic modulus were analyzed with repeated measures analysis of variance and Tukey HSD tests, using the SPSS software (SPSS Inc., version16.0, Chicago, Il, USA). P < 0.05 was considered as significant. The hardness up to 21 μm in depth and elastic modulus up to 6 μm in depth from the enamel surface for laser-etched enamel had significantly higher values than control enamel and the hardness up to 11 μm in depth and elastic modulus up to 6 μm in depth for acid-etched enamel had significantly lower values than the control enamel. The mechanical properties of the enamel were decreased after bracket bonding with conventional acid etching and increased after bonding with Er:YAG laser.

  6. Influence of Enamel Thickness on Bleaching Efficacy: An In-Depth Color Analysis.

    Science.gov (United States)

    Públio, Juliana do Carmo; D'Arce, Maria Beatriz Freitas; Catelan, Anderson; Ambrosano, Gláucia Maria Bovi; Aguiar, Flávio Henrique Baggio; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

    2016-01-01

    This study evaluated the influence of different enamel thicknesses and bleaching agents on treatment efficacy in-depth by spectrophotometry color analysis. Eighty bovine dental fragments were previously stained in black tea solution and randomly assigned into eight groups (n=10), 1.75mm dentin thickness and different enamel thicknesses as follows: 0.5mm, 1.0mm planned, 1.0mm unplanned (aprismatic enamel), and absence of enamel. The 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching gels were applied on the enamel surface following the manufacturer's recommendations. Color of underlying dentin was evaluated at four times: after staining with tea (baseline) and after each one of the three weeks of bleaching treatment, by CIE L*a*b* system using reflectance spectrophotometer (CM 700d, Konica Minolta). The ΔE, ΔL, Δa, and Δb values were recorded and subjected to repeated measures ANOVA and Tukey's test (α=0.05). The results showed an increase on lightness (L*), with decreased redness (a*) and yellowness (b*). At first and second week, bleaching with CP showed higher whitening effectiveness compared to bleaching with HP and the presence of aprismatic enamel significantly reduced ΔE for bleaching with CP. After three weeks of bleaching, few differences were observed between CP and HP groups, and outer enamel layer caused no influence on bleaching effectiveness. Overall, both at-home and in-office bleaching treatments were effective and the presence of aprismatic enamel did not interfere on the whitening efficacy.

  7. Using dental enamel wrinkling to define sauropod tooth morphotypes from the Cañadón Asfalto Formation, Patagonia, Argentina.

    Directory of Open Access Journals (Sweden)

    Femke M Holwerda

    Full Text Available The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic-early Middle Jurassic in Central Patagonia (Argentina, which may help to shed light on the early evolution of eusauropods. These eusauropod remains include teeth associated with cranial and mandibular material as well as isolated teeth found at different localities. In this study, an assemblage of sauropod teeth from the Cañadón Asfalto Formation found in four different localities in the area of Cerro Condor (Chubut, Argentina is used as a mean of assessing sauropod species diversity at these sites. By using dental enamel wrinkling, primarily based on the shape and orientation of grooves and crests of this wrinkling, we define and describe three different morphotypes. With the exception of one taxon, for which no cranial material is currently known, these morphotypes match the local eusauropod diversity as assessed based on postcranial material. Morphotype I is tentatively assigned to Patagosaurus, whereas morphotypes II and III correspond to new taxa, which are also distinguished by associated postcranial material. This study thus shows that enamel wrinkling can be used as a tool in assessing sauropod diversity.

  8. Using dental enamel wrinkling to define sauropod tooth morphotypes from the Cañadón Asfalto Formation, Patagonia, Argentina.

    Science.gov (United States)

    Holwerda, Femke M; Pol, Diego; Rauhut, Oliver W M

    2015-01-01

    The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic-early Middle Jurassic) in Central Patagonia (Argentina), which may help to shed light on the early evolution of eusauropods. These eusauropod remains include teeth associated with cranial and mandibular material as well as isolated teeth found at different localities. In this study, an assemblage of sauropod teeth from the Cañadón Asfalto Formation found in four different localities in the area of Cerro Condor (Chubut, Argentina) is used as a mean of assessing sauropod species diversity at these sites. By using dental enamel wrinkling, primarily based on the shape and orientation of grooves and crests of this wrinkling, we define and describe three different morphotypes. With the exception of one taxon, for which no cranial material is currently known, these morphotypes match the local eusauropod diversity as assessed based on postcranial material. Morphotype I is tentatively assigned to Patagosaurus, whereas morphotypes II and III correspond to new taxa, which are also distinguished by associated postcranial material. This study thus shows that enamel wrinkling can be used as a tool in assessing sauropod diversity.

  9. SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance.

    Science.gov (United States)

    Souza-Gabriel, A E; Chinelatti, M A; Borsatto, M C; Pécora, J D; Palma-Dibb, R G; Corona, S A M

    2008-07-01

    Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

  10. [Effects of tooth whitening agents and acidic drinks on the surface properties of dental enamel].

    Science.gov (United States)

    Chen, Xiaoling; Chen, Zhiqun; Lin, Yao; Shao, Jinquan; Yin, Lu

    2013-10-01

    Using tooth whitening agents (bleaching clip) in vitro and acidic drinks, we conducted a comparative study of the changes in enamel surface morphology, Ca/P content, and hardness. Tooth whitening glue pieces, cola, and orange juice were used to soak teeth in artificial saliva in vitro. Physiological saline was used as a control treatment. The morphology of the four groups was observed under a scanning electron microscope (SEM) immediately after the teeth were soaked for 7 and 14 d. The changes in Ca/P content and microhardness were analyzed. The enamel surfaces of the teeth in the three test groups were demineralized. The Ca/P ratio and the average microhardness were significantly lower than those of the control group immediately after the teeth were soaked (P 0.05). Bleaching agents caused transient demineralization of human enamel, but these agents could induce re-mineralization and repair of enamel over time. Demineralization caused by bleaching covered a relatively normal range compared with acidic drinks and daily drinking.

  11. Adhesive Bonding to Computer-aided Design/ Computer-aided Manufacturing Esthetic Dental Materials: An Overview.

    Science.gov (United States)

    Awad, Mohamed Moustafa; Alqahtani, H; Al-Mudahi, A; Murayshed, M S; Alrahlah, A; Bhandi, Shilpa H

    2017-07-01

    To review the adhesive bonding to different computer-aided design/computer-aided manufacturing (CAD/CAM) esthetic restorative materials. The use of CAD/CAM esthetic restorative materials has gained popularity in recent years. Several CAD/ CAM esthetic restorative materials are commercially available. Adhesive bonding is a major determinant of success of CAD/ CAM restorations. Review result: An account of the currently available bonding strategies are discussed with their rationale in various CAD/ CAM materials. Different surface treatment methods as well as adhesion promoters can be used to achieve reliable bonding of CAD/CAM restorative materials. Selection of bonding strategy to such material is determined based on its composition. Further evidence is required to evaluate the effect of new surface treatment methods, such as nonthermal atmospheric plasma and self-etching ceramic primer on bonding to different dental ceramics. An understanding of the currently available bonding strategies to CA/CAM materials can help the clinician to select the most indicated system for each category of materials.

  12. Enamel apatite crystallinity significantly contributes to mammalian dental adaptations

    Czech Academy of Sciences Publication Activity Database

    Kallistová, Anna; Skála, Roman; Šlouf, Miroslav; Čejchan, Petr; Matulková, I.; Horáček, I.

    2018-01-01

    Roč. 8, APR 3 2018 (2018), č. článku 5544. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:67985831 ; RVO:61389013 Keywords : tooth enamel * mechanical -properties * electron-microscopy * diffraction * teeth * size * morphology * behavior * minipig * pattern Subject RIV: EA - Cell Biology; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Other biological topics; Polymer science (UMCH-V) Impact factor: 4.259, year: 2016

  13. Erosion of enamel by non-carbonated soft drinks with and without toothbrushing abrasion.

    Science.gov (United States)

    Hemingway, C A; Parker, D M; Addy, M; Barbour, M E

    2006-10-07

    To investigate how enamel loss due to erosion, and due to cycling of erosion and abrasion, depends on compositional parameters of soft drinks, and particularly whether the thickness of the erosive softened layer is a function of drink composition. University dental hospital research laboratory in the UK, 2004. Six drinks were chosen based on their popularity and composition: apple juice, orange juice, apple drink, orange drink, cranberry drink and 'ToothKind' blackcurrant drink. Group A samples (n = 36) were exposed to soft drinks at 36 degrees C for six consecutive 10 minute periods. Group B samples (n = 36) were subjected to alternating erosion and toothbrushing, repeated six times. Enamel loss was measured using optical profilometry. Group A: significant enamel loss was seen for all drinks (p composition of the erosive medium.

  14. Self-induced vomiting and dental erosion--a clinical study.

    Science.gov (United States)

    Uhlen, Marte-Mari; Tveit, Anne Bjørg; Stenhagen, Kjersti Refsholt; Mulic, Aida

    2014-07-29

    In individuals suffering from eating disorders (ED) characterized by vomiting (e.g. bulimia nervosa), the gastric juice regularly reaches the oral cavity, causing a possible risk of dental erosion. This study aimed to assess the occurrence, distribution and severity of dental erosions in a group of Norwegian patients experiencing self-induced vomiting (SIV). The individuals included in the study were all undergoing treatment at clinics for eating disorders and were referred to a university dental clinic for examinations. One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system. Of 72 referred patients, 66 (63 females and three males, mean age 27.7 years) were or had been experiencing SIV (mean duration 10.6 years; range: 3 - 32 years), and were therefore included in the study. Dental erosions were found in 46 individuals (69.7%), 19 had enamel lesions only, while 27 had both enamel and dentine lesions. Ten or more teeth were affected in 26.1% of those with erosions, and 9% had ≥10 teeth with dentine lesions. Of the erosions, 41.6% were found on palatal/lingual surfaces, 36.6% on occlusal surfaces and 21.8% on buccal surfaces. Dentine lesions were most often found on lower first molars, while upper central incisors showed enamel lesions most frequently. The majority of the erosive lesions (48.6%) were found in those with the longest illness period, and 71.7% of the lesions extending into dentine were also found in this group. However, despite suffering from SIV for up to 32 years, 30.3% of the individuals showed no lesions. Dental erosion commonly affects individuals with ED experiencing SIV, and is more often found on the palatal/lingual surfaces than on the buccal in these individuals, confirming a common clinical assumption.

  15. β-pyrophosphate: A potential biomaterial for dental applications

    OpenAIRE

    Anastasiou, AD; Strafford, S; Posada-Estefan, O; Thomson, CL; Hussaein, SA; Edwards, TJ; Malinowski, M; Hondow, N; Metzger, NK; Brown, CTA; Routledge, MN; Brown, AP; Duggal, MS; Jha, A

    2017-01-01

    Tooth hypersensitivity is a growing problem affecting both the young and ageing population worldwide. Since an effective and permanent solution is not yet available, we propose a new methodology for the restoration of dental enamel using femtosecond lasers and novel calcium phosphate biomaterials. During this procedure the irradiated mineral transforms into a densified layer of acid resistant iron doped β-pyrophosphate, bonded with the surface of eroded enamel. Our aim therefore is to evaluat...

  16. Development of a computer-aided design software for dental splint in orthognathic surgery

    Science.gov (United States)

    Chen, Xiaojun; Li, Xing; Xu, Lu; Sun, Yi; Politis, Constantinus; Egger, Jan

    2016-12-01

    In the orthognathic surgery, dental splints are important and necessary to help the surgeon reposition the maxilla or mandible. However, the traditional methods of manual design of dental splints are difficult and time-consuming. The research on computer-aided design software for dental splints is rarely reported. Our purpose is to develop a novel special software named EasySplint to design the dental splints conveniently and efficiently. The design can be divided into two steps, which are the generation of initial splint base and the Boolean operation between it and the maxilla-mandibular model. The initial splint base is formed by ruled surfaces reconstructed using the manually picked points. Then, a method to accomplish Boolean operation based on the distance filed of two meshes is proposed. The interference elimination can be conducted on the basis of marching cubes algorithm and Boolean operation. The accuracy of the dental splint can be guaranteed since the original mesh is utilized to form the result surface. Using EasySplint, the dental splints can be designed in about 10 minutes and saved as a stereo lithography (STL) file for 3D printing in clinical applications. Three phantom experiments were conducted and the efficiency of our method was demonstrated.

  17. Raman spectroscopy analysis of dental enamel treated with whitening product - Influence of saliva in the remineralization

    Science.gov (United States)

    Silveira, J.; Coutinho, S.; Marques, D.; Castro, J.; Mata, A.; Carvalho, M. L.; Pessanha, S.

    2018-06-01

    In this work we present the analysis of dental enamel treated with an over-the-counter whitening product, bought in e-commerce at a very low cost, used without medical supervision in an abusive manner, in order to evaluate its demineralization action. Moreover, we studied the influence of renewal or non-renewal of saliva solution in which the specimens were stored throughout the study. The Degree of Demineralization was determined through the evaluation of the PO43- symmetric stretching band ( 959 cm-1) in Raman spectra of the specimens in different days during the course of the study. Results showed that a maximum of demineralization occurred between days 27 and 34 of application. Titration of the whitening product revealed a content of hydrogen peroxide 170-fold higher than what is allowed in Europe, according with legislation. Despite this extreme concentration of hydrogen peroxide, the demineralization was not as great as could be expected suggesting an important role of the pH of the solution in this demineralization mechanism.

  18. New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration.

    Science.gov (United States)

    Lee, M-Y; Chang, C-C; Ku, Y C

    2008-01-01

    Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.

  19. Mapping residual organics and carbonate at grain boundaries and in the amorphous interphase in mouse incisor enamel

    Directory of Open Access Journals (Sweden)

    Lyle M Gordon

    2015-03-01

    Full Text Available Dental enamel has evolved to resist the most grueling conditions of mechanical stress, fatigue, and wear. Adding insult to injury, it is exposed to the frequently corrosive environment of the oral cavity. While its hierarchical structure is unrivaled in its mechanical resilience, heterogeneity in the distribution of magnesium ions and the presence of Mg-substituted amorphous calcium phosphate (Mg-ACP as an intergranular phase have recently been shown to increase the susceptibility of mouse enamel to acid attack. Herein we investigate the distribution of two important constituents of enamel, residual organic matter and inorganic carbonate. We find that organics, carbonate, and possibly water show distinct distribution patterns in the mouse enamel crystallites, at simple grain boundaries, and in the amorphous interphase at multiple grain boundaries. This has implications for the resistance to acid corrosion, mechanical properties, and the mechanism by which enamel crystals grow during amelogenesis.

  20. Automated classification and visualization of healthy and pathological dental tissues based on near-infrared hyper-spectral imaging

    Science.gov (United States)

    Usenik, Peter; Bürmen, Miran; Vrtovec, Tomaž; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2011-03-01

    Despite major improvements in dental healthcare and technology, dental caries remains one of the most prevalent chronic diseases of modern society. The initial stages of dental caries are characterized by demineralization of enamel crystals, commonly known as white spots which are difficult to diagnose. If detected early enough, such demineralization can be arrested and reversed by non-surgical means through well established dental treatments (fluoride therapy, anti-bacterial therapy, low intensity laser irradiation). Near-infrared (NIR) hyper-spectral imaging is a new promising technique for early detection of demineralization based on distinct spectral features of healthy and pathological dental tissues. In this study, we apply NIR hyper-spectral imaging to classify and visualize healthy and pathological dental tissues including enamel, dentin, calculus, dentin caries, enamel caries and demineralized areas. For this purpose, a standardized teeth database was constructed consisting of 12 extracted human teeth with different degrees of natural dental lesions imaged by NIR hyper-spectral system, X-ray and digital color camera. The color and X-ray images of teeth were presented to a clinical expert for localization and classification of the dental tissues, thereby obtaining the gold standard. Principal component analysis was used for multivariate local modeling of healthy and pathological dental tissues. Finally, the dental tissues were classified by employing multiple discriminant analysis. High agreement was observed between the resulting classification and the gold standard with the classification sensitivity and specificity exceeding 85 % and 97 %, respectively. This study demonstrates that NIR hyper-spectral imaging has considerable diagnostic potential for imaging hard dental tissues.

  1. In situ effect of CPP-ACP chewing gum upon erosive enamel loss

    Directory of Open Access Journals (Sweden)

    Catarina Ribeiro Barros de ALENCAR

    Full Text Available Abstract Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP is able to increase salivary calcium and phosphate levels at an acidic pH. Previous studies demonstrated that a CPP-ACP chewing gum was able to enhance the re-hardening of erosion lesions, but could not diminish enamel hardness loss. Therefore, there is no consensus regarding the effectiveness of CPP-ACP on dental erosion. Objective This in situ study investigated the ability of a CPP-ACP chewing gum in preventing erosive enamel loss. Material and Methods: During three experimental crossover phases (one phase per group of seven days each, eight volunteers wore palatal devices with human enamel blocks. The groups were: GI – Sugar free chewing gum with CPP-ACP; GII – Conventional sugar free chewing gum; and GIII – No chewing gum (control. Erosive challenge was extraorally performed by immersion of the enamel blocks in cola drink (5 min, 4x/day. After each challenge, in groups CPP and No CPP, volunteers chewed one unit of the corresponding chewing gum for 30 minutes. Quantitative analysis of enamel loss was performed by profilometry (µm. Data were analyzed by Repeated-Measures ANOVA and Tukey’s test (p0.05. Conclusion The CPP-ACP chewing gum was not able to enhance the anti-erosive effect of conventional chewing gum against enamel loss.

  2. Effects of a Novel Whitening Formulation on Dental Enamel.

    Science.gov (United States)

    Takesh, Thair; Sargsyan, Anik; Anbarani, Afarin; Ho, Jessica; Wilder-Smith, Petra

    2017-04-01

    The goal of this study was to evaluate the enamel whitening effects of 2 new test formulations, one of which was a rinse, and the other a whitening strip. Forty enamel chips were prepared from 20 healthy extracted teeth (2 from each tooth). After pre-staining and colorimetry to measure L* and b* values, 20 matched samples were immersed in either test or control rinses, and then colorimetry was performed again after 1 hr, 2 hr, 3 hr, 6 hr, 12 hr, 24 hr and 48 hrs (Each hour equates to one month of clinical use at the recommended dosage of 1 minute exposure 2 times a day). The remaining 20 matched samples were exposed to the test or control whitening strips and colorimetry was performed every 30 minutes for a total of 10 treatments. Overall, the whitening performance of test and control strips was similar. The test and control rinses had a similar lightening effect over the first 3 hours (equivalent to 3 months of clinical use). Subsequently, the control rinse continued to lighten samples, whereas the test rinse had little further effect. Test and control-whitening strips showed similar effects; over time whitening strips showed a greater lightening effect than whitening rinses.

  3. Assessing the Penetrating Abilities of Experimental Preparation with Dental Infiltrant Features Using Optical Microscope: Preliminary Study.

    Science.gov (United States)

    Skucha-Nowak, Małgorzata; Machorowska-Pieniążek, Agnieszka; Tanasiewicz, Marta

    2016-01-01

    The aim of the infiltration technique is to penetrate demineralized enamel with a low viscosity resin. Icon® (DMG) is the first ever and so far the only dental infiltrant. Bacteriostaticity is one of the properties that should be inherent in dental infiltrants, but Icon lacks this feature. The aim of the preliminary study was to properly choose a dye which would allow us to assess the penetrating abilities of our own, experimental preparation with features of a dental infiltrant with bacteriostatic properties and to compare using an optical microscope the depth of infiltration of the designed experimental preparation with the infiltrant available on the market. The preparation is supposed to infiltrate decalcified human enamel and be assessed with an optical microscope. Eosin, neutral fuchsine and methylene blue were added to experimental preparation with dental infiltrant features and to Icon® (DMG) in order to assess the depth of penetration of the experimental solution into the decalcified layers of enamel. The experimental solution mixes well with eosin, neutral fuchsine, and methylene blue. During the preliminary study, the authors concluded that the experimental solution mixes well with methylene blue, neutral fuchsine, and eosin. An addition of eosin to a preparation which infiltrates inner, demineralized enamel layers, facilitates the assessment of such a preparation with an optical microscope. A designed experimental solution with the main ingredients, i.e., 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethacrylate (TEGDMA) with a ratio of 75% to 25% penetrates the demineralized (decalcified) inner parts of the enamel and polymerizes when exposed to light. In order to assess the infiltration of the experimental solution into the demineralized enamel layers, it is required to improve the measurement techniques that utilize optical microscopy.

  4. In vitro study of 960 nm high power diode laser applications in dental enamel, aided by the presence of a photoinitiator dye: scanning electron microscopy analysis; Estudo in vitro das aplicacoes do laser de diodo de alta potencia 960 nm em esmalte dentario, assistido por um fotoiniciador: analise de microscopia eletronica de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcelo Vinicius de

    2002-06-15

    The objective of this study is to verify if a high power diode laser can effectively modify the morphology of an enamel surface, and if this can be done in a controlled fashion by changing the lasers parameters. Previous studies using SEM demonstrated that through irradiation with Nd:YAG laser (1064 nm) it is possible to modify the morphology of the dental surface in such way as to increase its resistance against caries decays. The desired procedures that should achieve a decrease of the index of caries decays and of its sequels are on a primary level, which means that action is necessary before the disease installs itself. In this study it was used for the first time a prototype of a high power diode laser operating at 960 nm, produced by the Laboratory of Development of Lasers of the Center for Lasers and Applications of the IPEN. This equipment can present several advantages as reliability, reduced size and low cost. The aim was establish parameters of laser irradiation that produce the desired effects wanted in the enamel and protocols that guarantee its safety during application in dental hard tissues, protecting it of heating effects such as fissures and carbonization. (author)

  5. Comparison Of Bond Strength Of Orthodontic Molar Tubes Using Different Enamel Etching Techniques And Their Effect On Enamel

    International Nuclear Information System (INIS)

    Abd el Rahman, H.Y.

    2013-01-01

    In fixed orthodontic treatment, brackets and tubes are used for transferring orthodontic forces to the teeth. Those attachments were welded to cemented bands. Fifty years ago, direct bonding of brackets and other attachments has become a common technique in fixed orthodontic treatment. Orthodontists used to band teeth, especially molars and second premolars, to avoid the need for re bonding accessories in these regions of heavy masticatory forces. However, it is a known fact that direct bonding saves chair time as it does not require prior band selection and fitting, has the ability to maintain good oral hygiene, improve esthetics and make easier attachment to crowded and partially erupted teeth. Moreover, when the banding procedure is not performed with utmost care it can damage periodontal and/or dental tissues. Molar tubes bonding decreases the chance of decalcification caused by leakage beneath the bands. Since molar teeth are subjected to higher masticatory impact, especially lower molars, it would be convenient to devise methods capable of increasing the efficiency of their traditional bonding. These methods may include variation in bond able molar tube material, design, bonding materials and etching techniques. For achieving successful bonding, the bonding agent must penetrate the enamel surface; have easy clinical use, dimensional stability and enough bond strength. Different etching techniques were introduced in literature to increase the bond strength which includes: conventional acid etching, sandblasting and laser etching techniques. The process of conventional acid etching technique was invented In (1955) as the surface of enamel has great potential for bonding by micromechanical retention, to form ‘the mechanical lock‘. The primary effect of enamel etching is to increase the surface area. However, this roughens the enamel microscopically and results in a greater surface area on which to bond. By dissolving minerals in enamel, etchants remove the

  6. The Prevalence of Enamel Defects in Students 7-12 Years of Age in Isfahan

    Directory of Open Access Journals (Sweden)

    Mahmodian J

    2000-05-01

    Full Text Available Dental enamel is the end product of amelogenesis, which can be considered to take place in"nthree interrelated phases. When this complex sequence of cytological and physicochemica! events"ndisrupted by genetic or environmental factors, the function of the ameloblasts may be disrupted"npermanently or temporarily. The result shows qualitative and quantitative defects that may range from a"ncomplete absence of enamel or a slight discoloration. The aim of this study was to determine the"nprevalence of enamel defects by DDE index in a randomly selection group of 1637 students age 7-12"nyears old in Isfahan (0.2-0.3 PPMF". Enamel defects were present on one or more teeth in 27% of the"ncases. The most common affected tooth was the central maxillary and then first molar of maxilla. The"nmost common affected surfaces were buccal. Hypoplastic defects were found in first molar; however"npremolar and canine were affected by diffuse white lines opacity.

  7. Relationship between free radical content in human tooth enamel and radiation dose

    International Nuclear Information System (INIS)

    Zhou Yongzeng; Wang Jiadong; Jia Xiaomei; Wu Ke; Cong Jianbo; Sun Cunpu

    2000-01-01

    Application of ESR technique of tooth enamel have become more and more wide-spread in accidental and retrospective dosimetry. The purpose of this paper is to study relationship between free radical content in tooth enamel and radiation dose. Method Samples of 25 Chinese adult teeth, 25 child permanent teeth and 35 milk teeth were used in the study. All teeth were obtained from patients in the course of dental practice. Tooth enamel was separated from dentine using dental drill and then crushed manually into grains of about 0.5-1.5 mm in diameter. The mass of each sample is 100 mg. Signal intensity of enamel samples was measured by ESR technique (Bruker-ESP300). Parameters used were modulation frequency 50 KHz, modulation amplitude 0.2 mT, time constant 41 ms, scan width 15 mT, microwave power 5 mw, room temperature. Samples of 25 adult teeth, 25 child permanent teeth and 35 milk teeth were divided into 5 dose groups, respectively, and irradiated with 60 Co γ-ray at dose rate of 0.48 Gy/min. Radiation doses of the 5 groups were 0.30, 0.50, 1.00, 3.00 and 5.00 Gy, respectively. After irradiation, each sample was subjected to ESR measurements. There is no significant difference in background signal intensity between male and female samples for both child permanent teeth and milk teeth. And also no significant difference in background signal intensity between child permanent teeth and milk teeth was observed. Results of study on adult teeth indicated that radiation sensitivity of different teeth is fairly uniform. Free radical content in enamel of child permanent teeth and milk teeth increases linearly with increasing of radiation dose, and similar results were obtained for adult teeth. Slope of the dose-response curve for adult teeth is somewhat steeper than that for milk teeth. There exists a linear relation between ESR signals intensity and radiation doses for adult teeth, child permanent and milk teeth. In the case of radiation accident, the dose-response curves

  8. Effects of sintering temperature on electrical properties of sheep enamel hydroxyapatite

    Science.gov (United States)

    Dumludag, F.; Gunduz, O.; Kılıc, O.; Kılıc, B.; Ekren, N.; Kalkandelen, C.; Oktar, F. N.

    2017-12-01

    Bioceramics, especially calcium phosphate based bioceramics, whose examples are hydroxyapatite, and calcium phosphate powders have been widely used in the biomedical engineering applications. Hydroxyapatite (HA) is one of the most promising biomaterials, which are derived from natural sources, chemical method, animal like dental enamel and corals. The influence of sintering temperature on the electrical properties (i.e. DC conductivity, AC conductivity) of samples of sintered sheep enamel (SSSE) was studied in air and in vacuum ambient at room temperature. The sheep enamel were sintered at varying temperatures between 1000°C and 1300°C. DC conductivity results revealed that while dc conductivity of the SSSE decreases with increasing the sintering temperature in air ambient the values increased with increasing the sintering temperature in vacuum ambient. AC conductivity measurements were performed in the frequency range of 40 Hz - 105 Hz. The results showed that ac conductivity values decrease with increasing the sintering temperature.

  9. Bioinspired design of dental multilayers.

    Science.gov (United States)

    Huang, M; Wang, R; Thompson, V; Rekow, D; Soboyejo, W O

    2007-01-01

    This paper considers the use of bioinspired functionally graded structures in the design of dental multi-layers that are more resistant to sub-surface crack nucleation. Unlike existing dental crown restorations that give rise to high stress concentration, the functionally graded layers (between crown materials and the joins that attach them to dentin) are shown to promote significant reductions in stress and improvements in the critical crack size. Special inspiration is drawn from the low stress concentrations associated with the graded distributions in the dentin-enamel-junction (DEJ). The implications of such functionally graded structures are also discussed for the design of dental restorations.

  10. Effect of bracket bonding with Er: YAG laser on nanomechanical properties of enamel

    Directory of Open Access Journals (Sweden)

    Shiva Alavi

    2014-01-01

    Full Text Available Background: The aim of this study was to compare the effects of conventional acid etching and laser etching on the nano-mechanical properties of the dental enamel using nano-indentation test. Materials and Methods: In this experimental in vitro study, buccal surfaces of 10 premolars were divided into three regions. One of the regions was etched with 37% phosphoric acid and another etched with Er:YAG laser, the third region was not etched. The brackets were bonded to both of etched regions. After thermocycling for 500 cycles, the brackets were removed and the teeth were decoronated from the bracket bonding area. Seven nano-indentations were applied at 1-31 μm depth from the enamel surface in each region. Mean values of the hardness and elastic modulus were analyzed with repeated measures analysis of variance and Tukey HSD tests, using the SPSS software (SPSS Inc., version16.0, Chicago, Il, USA. P < 0.05 was considered as significant. Results: The hardness up to 21 μm in depth and elastic modulus up to 6 μm in depth from the enamel surface for laser-etched enamel had significantly higher values than control enamel and the hardness up to 11 μm in depth and elastic modulus up to 6 μm in depth for acid-etched enamel had significantly lower values than the control enamel. Conclusion: The mechanical properties of the enamel were decreased after bracket bonding with conventional acid etching and increased after bonding with Er:YAG laser.

  11. Porcine Dental Epithelial Cells Differentiated in a Cell Sheet Constructed by Magnetic Nanotechnology

    Directory of Open Access Journals (Sweden)

    Wataru Koto

    2017-10-01

    Full Text Available Magnetic nanoparticles (MNPs are widely used in medical examinations, treatments, and basic research, including magnetic resonance imaging, drug delivery systems, and tissue engineering. In this study, MNPs with magnetic force were applied to tissue engineering for dental enamel regeneration. The internalization of MNPs into the odontogenic cells was observed by transmission electron microscopy. A combined cell sheet consisting of dental epithelial cells (DECs and dental mesenchymal cells (DMCs (CC sheet was constructed using magnetic force-based tissue engineering technology. The result of the iron staining indicated that MNPs were distributed ubiquitously over the CC sheet. mRNA expression of enamel differentiation and basement membrane markers was examined in the CC sheet. Immunostaining showed Collagen IV expression at the border region between DEC and DMC layers in the CC sheet. These results revealed that epithelial–mesenchymal interactions between DEC and DMC layers were caused by bringing DECs close to DMCs mechanically by magnetic force. Our study suggests that the microenvironment in the CC sheet might be similar to that during the developmental stage of a tooth bud. In conclusion, a CC sheet employing MNPs could be developed as a novel and unique graft for artificially regenerating dental enamel.

  12. Effect of three nanobiomaterials on the surface roughness of bleached enamel

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2015-01-01

    Full Text Available Background: The ever-increasing demand for enhanced esthetic appearance has resulted in significant developments in bleaching products. However, the enamel surface roughness (SR might be negatively affected by bleaching agents. This in vitro study was undertaken to compare the effects of three nanobiomaterials on the enamel SR subsequent to bleaching. Materials and Methods: The crowns of six extracted intact nonerupted human third molars were sectioned. Five dental blocks measuring 2 mm × 3 mm × 4 mm were prepared from each tooth and placed in colorless translucent acrylic resin. The enamel areas from all the specimens were divided into five groups (n = 6: Group 1 did not undergo any bleaching procedures; Group 2 was bleached with a 40% hydrogen peroxide (HP gel; Groups 3, 4, and 5 were bleached with a 40% HP gel modified by bioactive glass (BAG, amorphous calcium phosphate, and hydroxyapatite, respectively. The enamel SR was evaluated before and after treatment by atomic force microscopy. The data were analyzed by Kruskal–Wallis and Mann–Whitney tests. Results: SR increased significantly in the HP group. SR decreased significantly in the HP gel modified by BAG group as compared to other groups. Conclusions: Within the limitations of this study, incorporation of each one of the three test biomaterials proved effective in decreasing enamel SR subsequent to in-office bleaching technique.

  13. Effects of bleaching agents on human enamel light reflectance.

    Science.gov (United States)

    Markovic, Ljubisa; Fotouhi, Kasra; Lorenz, Heribert; Jordan, Rainer A; Gaengler, Peter; Zimmer, Stefan

    2010-01-01

    Tooth whitening has been associated with splitting-up chromogenic molecules by hydrogen peroxides. Though micromorphological alterations are well documented, little is known about optical changes as a function of shifting in wavelengths. Therefore, the aim of the current study was to measure reflectance changes after bleaching in vitro by using a spectrometer. Forty-eight enamel slabs (diameter = 5 mm) were prepared from the sound enamel of extracted human teeth that were: 1) fully impacted, 2) from juveniles ages 10 to 16 years, 3) from adults 35 to 45 years of age and 4) from seniors older than age 65. In all specimens, the baseline total reflectance measurement was performed with a computer-assisted spectrometer (Ocean Optics, Dunedin, FL, USA) within wavelengths (wl) from 430 nm to 800 nm. Four enamel samples of each age group were exposed to either 10% or 15% carbamide peroxide (Illuminé Home, Dentsply, Konstanz, Germany) or 35% hydrogen peroxide (Pola Office, SDI Limited, Victoria, Australia). After surface treatment, all slabs underwent total reflectance measurement again. Statistical analysis was calculated at wl 450, 500 and 750 nm using the Student's paired t-test and one-way variance analysis. Total reflectance significantly increased after bleaching at all enamel maturation stages, irrespective of the bleaching agent concentration, for wl 450 nm (blue) and 500 nm (green) with penamel from adults and seniors (pwhitening of the dental enamel works at different maturation stages, even in impacted teeth. This effect is irrespective of the bleaching protocol used and the bleaching agent concentration.

  14. The remineralisation of enamel: a review of the literature.

    Science.gov (United States)

    Li, Xiaoke; Wang, Jinfang; Joiner, Andrew; Chang, Jiang

    2014-06-01

    The purpose of this paper is to review current knowledge and technologies for tooth remineralisation. The literature was searched using the "Scopus" and "Web of Knowledge" database from the year 1971, with principal key words of *miner*, teeth and enamel. Language was restricted to English. Original studies and reviews were included. Conference papers and posters were excluded. The importance of oral health for patients and consumers has seen a steady increase in the number of tooth remineralisation agents, products and procedures over recent years. Concomitantly, there has been continued publication of both in vivo and in vitro tooth remineralisation and demineralisation studies. It is clear that fluoride treatments are generally effective in helping to protect the dental enamel from demineralisation and enhancing remineralisation. Continued efforts to increase the efficacy of fluoride have been made, in particular, by the addition of calcium salts or calcium containing materials to oral care products which may enhance the delivery and retention of fluoride into the oral cavity. In addition, the calcium salts or materials may act as additional sources of calcium to promote enamel remineralisation or reduce demineralisation processes. Inspired by the concept of bioactive materials for bone repair and regeneration, bioglass and in particular calcium silicate type materials show potential for enamel health benefits and is a growing area of research. © 2014 Elsevier Ltd. All rights reserved.

  15. Recent advances in engineering of tooth and tooth structures using postnatal dental cells

    Directory of Open Access Journals (Sweden)

    Masaki J. Honda

    2010-02-01

    This review focuses on the performance of postnatal and adult dental cells that have been used for generating teeth. Their ability to contribute to tooth development was assessed in the omentum or in the tooth socket. Adult dental cells were limited in their potential owing to various parameters. From these results described, new approaches for regenerated teeth are proposed in this review. One strategy to replace teeth is tooth root engineering using tissue from postnatal teeth. Since the enamel organ epithelium disappears after tooth maturation, the epithelial rest cells of Malassez were evaluated to determine their capacity to generate enamel. From these results, it is suggested that erupted mature teeth have cell sources with the capacity to produce tooth root. The development of biological approaches for tooth root regeneration using postnatal dental cells is promising and remains one of the greatest challenges in the dental field in the years to come.

  16. Enamel ultrastructure in fossil cetaceans (Cetacea: Archaeoceti and Odontoceti.

    Directory of Open Access Journals (Sweden)

    Carolina Loch

    Full Text Available The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand to Pliocene (Caldera, Chile. Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth, the inner enamel was organized in Hunter-Schreger bands (HSB with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward

  17. Enamel ultrastructure in fossil cetaceans (Cetacea: Archaeoceti and Odontoceti).

    Science.gov (United States)

    Loch, Carolina; Kieser, Jules A; Fordyce, R Ewan

    2015-01-01

    The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti) underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand) to Pliocene (Caldera, Chile). Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM) observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth), the inner enamel was organized in Hunter-Schreger bands (HSB) with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward odontocetes, with

  18. Effect of ultrasonic, sonic and rotating-oscillating powered toothbrushing systems on surface roughness and wear of white spot lesions and sound enamel: An in vitro study.

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    Hernandé-Gatón, Patrícia; Palma-Dibb, Regina Guenka; Silva, Léa Assed Bezerra da; Faraoni, Juliana Jendiroba; de Queiroz, Alexandra Mussolino; Lucisano, Marília Pacífico; Silva, Raquel Assed Bezerra da; Nelson Filho, Paulo

    2018-04-01

    To evaluate the effect of ultrasonic, sonic and rotating-oscillating powered toothbrushing systems on surface roughness and wear of white spot lesions and sound enamel. 40 tooth segments obtained from third molar crowns had the enamel surface divided into thirds, one of which was not subjected to toothbrushing. In the other two thirds, sound enamel and enamel with artificially induced white spot lesions were randomly assigned to four groups (n=10) : UT: ultrasonic toothbrush (Emmi-dental); ST1: sonic toothbrush (Colgate ProClinical Omron); ST2: sonic toothbrush (Sonicare Philips); and ROT: rotating-oscillating toothbrush (control) (Oral-B Professional Care Triumph 5000 with SmartGuide). The specimens were analyzed by confocal laser microscopy for surface roughness and wear. Data were analyzed statistically by paired t-tests, Kruskal-Wallis, two-way ANOVA and Tukey's post-test (α= 0.05). The different powered toothbrushing systems did not cause a significant increase in the surface roughness of sound enamel (P> 0.05). In the ROT group, the roughness of white spot lesion surface increased significantly after toothbrushing and differed from the UT group (Pspot lesion compared with sound enamel, and this group differed significantly from the ST1 group (Pspot lesion increased surface roughness and wear. None of the powered toothbrushing systems (ultrasonic, sonic and rotating-oscillating) tested caused significant alterations on sound dental enamel. However, conventional rotating-oscillating toothbrushing on enamel with white spot lesion increased surface roughness and wear. Copyright©American Journal of Dentistry.

  19. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

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    Espigares, Jorge; Sadr, Alireza; Hamba, Hidenori; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Sumi, Yasunori

    2015-01-01

    Abstract. A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography (μCT) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μCT, the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer–Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to 606  μm in SS-OCT. A correlation between μCT and SS-OCT was found regarding lesion depth (R=0.81, p<0.001) and also surface layer thickness (R=0.76, p<0.005). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution μCT without the use of x-ray. PMID:26158079

  20. Dynamic measurement of the optical properties of bovine enamel demineralization models using four-dimensional optical coherence tomography

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    Aden, Abdirahman; Anthony, Arthi; Brigi, Carel; Merchant, Muhammad Sabih; Siraj, Huda; Tomlins, Peter H.

    2017-07-01

    Dental enamel mineral loss is multifactorial and is consequently explored using a variety of in vitro models. Important factors include the presence of acidic pH and its specific ionic composition, which can both influence lesion characteristics. Optical coherence tomography (OCT) has been demonstrated as a promising tool for studying dental enamel demineralization. However, OCT-based characterization and comparison of demineralization model dynamics are challenging without a consistent experimental environment. Therefore, an automated four-dimensional OCT system was integrated with a multispecimen flow cell to measure and compare the optical properties of subsurface enamel demineralization in different models. This configuration was entirely automated, thus mitigating any need to disturb the specimens and ensuring spatial registration of OCT image volumes at multiple time points. Twelve bovine enamel disks were divided equally among three model groups. The model demineralization solutions were citric acid (pH 3.8), acetic acid (pH 4.0), and acetic acid with added calcium and phosphate (pH 4.4). Bovine specimens were exposed to the solution continuously for 48 h. Three-dimensional OCT data were obtained automatically from each specimen at a minimum of 1-h intervals from the same location within each specimen. Lesion dynamics were measured in terms of the depth below the surface to which the lesion extended and the attenuation coefficient. The net loss of surface enamel was also measured for comparison. Similarities between the dynamics of each model were observed, although there were also distinct characteristic differences. Notably, the attenuation coefficients showed a systematic offset and temporal shift with respect to the different models. Furthermore, the lesion depth curves displayed a discontinuous increase several hours after the initial acid challenge. This work demonstrated the capability of OCT to distinguish between different enamel demineralization

  1. Influence of a pulsed CO2 laser operating at 9.4 μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting

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    Kim, Jin Wan; Lee, Raymond; Chan, Kenneth H.; Jew, Jamison M.; Fried, Daniel

    2017-02-01

    Below the threshold for laser ablation, the mineral phase of enamel is converted into a purer phase hydroxyapatite with increased acid resistance. Studies suggest the possibility of achieving the conversion without visible surface alteration. In this study, changes in the surface morphology, reflectivity, and acid resistance were monitored with varying irradiation intensity. Bovine enamel specimens were irradiated using a CO2 laser operating at 9.4 μm with a Gaussian spatial beam profile-1.6 to 3.1 mm in diameter. After laser treatment, samples were subjected to demineralization to simulate the acidic intraoral conditions of dental decay. The resulting demineralization and erosion were assessed using polarization-sensitive optical coherence tomography, three-dimensional digital microscopy, and polarized light microscopy. Distinct changes in the surface morphology and the degree of inhibition were found within the laser-treated area in accordance with the laser intensity profile. Subtle visual changes were noted below the melting point for enamel that appear to correspond to thresholds for denaturation of the organic phase and thermal decomposition of the mineral phase. There was significant protection from laser irradiation in areas in which the reflectivity was not increased significantly, suggesting that aesthetically sensitive areas of the tooth can be treated for caries prevention.

  2. Prevention of enamel demineralization during orthodontic treatment: an in vitro comparative study.

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    Bichu, Yashodhan M; Kamat, Nandini; Chandra, Pavan Kumar; Kapoor, Aditi; Razmus, Thomas; Aravind, N K S

    2013-01-01

    Enamel demineralization is considered to be the most prevalent and significant iatrogenic effect associated with fixed orthodontic treatment and can seriously jeopardize both tooth longevity and dental esthetics. This in vitro study was undertaken to compare the effectiveness of four different commercially available surface treatment medicaments for the inhibition of enamel demineralization. Seventy-five intact maxillary premolars extracted from patients undergoing orthodontic treatment were divided into five equal groups and were subjected to one of the following protocols: no treatment (control group) or treatment with one of the following four medicaments: fluoride varnish (Fluor Protector [FP]), casein phosphopeptide-amorphous calcium phosphate (GC Tooth Mousse [TM]), calcium sodium phosphosilicate (SHY-NM), and casein phosphopeptide-amorphous calcium phosphate with fluoride (GC Tooth Mousse Plus [TMP]). All the teeth were subjected to ten Cate demineralization solution?for 96 hours and subsequently evaluated under polarized light microscopy to obtain the mean depths of enamel demineralization. One-way analysis of variance and Bonferroni comparison tests were used to obtain statistically significant differences between the five different groups at P < .05. All four surface treatment medicaments provided statistically significant reduction in the depths of enamel demineralization as compared with the control group. FP provided the greatest protection of enamel surface in terms of reduction of lesion depth, followed by TMP, SHY-NM, and TM. The use of these commercially available medicaments could prove to be beneficial for patients undergoing orthodontic treatment and who are at a risk for developing enamel decalcification.

  3. Scanning electron microscopy analysis of marginal adaptation of composite resines to enamel after using of standard and gradual photopolimerization

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    Dačić Stefan

    2014-01-01

    Full Text Available Introduction. Bonding between composite and hard dental tissue is most commonly assessed by measuring bonding strength or absence of marginal gap along the restoration interface. Marginal index (MI is a significant indicator of the efficiency of the bond between material and dental tissue because it also shows the values of width and length of marginal gap. Objective. The aim of this investigation was to estimate quantitative and qualitative features of the bond between composite resin and enamel and to determine the values of MI in enamel after application of two techniques of photopolymerization with two composite systems. Methods. Forty Class V cavities on extracted teeth were prepared and restored for scanning electron microscope (SEM analysis of composite bonding to enamel. Adhesion to enamel was achieved by Adper Single Bond 2 - ASB (3M ESPE, or by Adper Easy One - AEO (3M ESPE. Photopolymerization of Filtek Ultimate - FU (3M ESPE was performed using constant halogen light (HIP or soft start program (SOF. Results. Quantitative and qualitative analysis, showed better mikromorphological bonding with SOF photopolymerization and ASB/FU composite system. Differences in MI between different photopolymerization techniques (HIP: 0.6707; SOF: 0.2395 were statistically significant (p<0.001, as well as differences between the composite systems (ASB/FU: 0.0470; AEO/ FU: 0.8651 (p<0.001 by two-way ANOVA test. Conclusion. Better marginal adaptation of composite to enamel was obtained with SOF photopolymerization in both composite systems.

  4. A review of the effect of vital teeth bleaching on the mechanical properties of tooth enamel.

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    Elfallah, Hunida M; Swain, Michael V

    2013-09-01

    Tooth whitening is considered the easiest and most cost-effective procedure for treating tooth discoloration. Contemporary bleaching agents contain hydrogen peroxide as the active ingredient. It is either applied directly or produced from its precursor, carbamide peroxide. A review of the published literature was undertaken to investigate the potential adverse effects of whitening products on dental enamel, with a focus on its mechanical properties and the influence of various parameters on study outcomes. There appear to be considerable differences in opinion as to whether changes in mechanical properties occur as a result of tooth whitening. However, the mechanical property findings of those studies appear to be related to the load applied during the indentation tests. Most studies which used loads higher than 500mN to determine enamel hardness showed no effect of bleaching, whereas those using lower loads were able to detect hardness reduction in the surface layer of enamel. In conclusion, bleaching reduces the hardness of the enamel surface of enamel, and that is more readily detected with instrumented low load testing systems. This hardness reduction may arise due to degradation or denaturation of enamel matrix proteins by the peroxide oxidation.

  5. Analysis of dental abfractions by optical coherence tomography

    Science.gov (United States)

    Demjan, Enikö; Mărcăuţeanu, Corina; Bratu, Dorin; Sinescu, Cosmin; Negruţiu, Meda; Ionita, Ciprian; Topală, Florin; Hughes, Michael; Bradu, Adrian; Dobre, George; Podoleanu, Adrian Gh.

    2010-02-01

    Aim and objectives. Abfraction is the pathological loss of cervical hard tooth substance caused by biomechanical overload. High horizontal occlusal forces result in large stress concentrations in the cervical region of the teeth. These stresses may be high enough to cause microfractures in the dental hard tissues, eventually resulting in the loss of cervical enamel and dentin. The present study proposes the microstructural characterization of these cervical lesions by en face optical coherence tomography (eFOCT). Material and methods: 31 extracted bicuspids were investigated using eFOCT. 24 teeth derived from patients with active bruxism and occlusal interferences; they presented deep buccal abfractions and variable degrees of occlusal pathological attrition. The other 7 bicuspids were not exposed to occlusal overload and had a normal morphology of the dental crowns. The dental samples were investigated using an eFOCT system operating at 1300 nm (B-scan at 1 Hz and C-scan mode at 2 Hz). The system has a lateral resolution better than 5 μm and a depth resolution of 9 μm in tissue. OCT images were further compared with micro - computer tomography images. Results. The eFOCT investigation of bicuspids with a normal morphology revealed a homogeneous structure of the buccal cervical enamel. The C-scan and B-scan images obtained from the occlusal overloaded bicuspids visualized the wedge-shaped loss of cervical enamel and damage in the microstructure of the underlaying dentin. The high occlusal forces produced a characteristic pattern of large cracks, which reached the tooth surface. Conclusions: eFOCT is a promising imaging method for dental abfractions and it may offer some insight on the etiological mechanism of these noncarious cervical lesions.

  6. Incremental growth of therizinosaurian dental tissues: implications for dietary transitions in Theropoda

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    Khai Button

    2017-12-01

    Full Text Available Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum. Here we examine dental histology of Therizinosauria, a clade of large-bodied theropods bearing significant morphological evidence for herbivory, by examining the teeth of the early-diverging therizinosaurian Falcarius utahensis, and an isolated tooth referred to Suzhousaurus megatherioides, a highly specialized large-bodied representative. Despite attaining some of the largest body masses among maniraptoran theropod dinosaurs, therizinosaurian teeth are diminutive, measuring no more than 0.90 cm in crown height (CH and 0.38 cm in crown base length (CBL. Comparisons with other theropods and non-theropodan herbivorous dinosaurs reveals that when controlling for estimated body mass, crown volume in therizinosaurians plots most closely with dinosaurs of similar dietary strategy as opposed to phylogenetic heritage. Analysis of incremental growth lines in dentin, observed in thin sections of therizinosaurian teeth, demonstrates that tooth growth rates fall within the range of other archosaurs, conforming to hypothesized physiological limitations on the production of dental tissues. Despite dietary differences between therizinosaurians and hypercarnivorous theropods, the types of enamel crystallites present and their spatial distribution—i.e., the schmelzmuster of both taxa—is limited to parallel enamel crystallites, the simplest form of enamel and the plesiomorphic condition for Theropoda. This finding supports previous hypotheses that dental microstructure is strongly influenced by phylogeny, yet equally supports suggestions of reduced reliance on oral processing in omnivorous

  7. A comparison of sports and energy drinks--Physiochemical properties and enamel dissolution.

    Science.gov (United States)

    Jain, Poonam; Hall-May, Emily; Golabek, Kristi; Agustin, Ma Zenia

    2012-01-01

    The consumption of sports and energy drinks by children and adolescents has increased at an alarming rate in recent years. It is essential for dental professionals to be informed about the physiochemical properties of these drinks and their effects on enamel. The present study measured the fluoride levels, pH, and titratable acidity of multiple popular, commercially available brands of sports and energy drinks. Enamel dissolution was measured as weight loss using an in vitro multiple exposure model consisting of repeated short exposures to these drinks, alternating with exposure to artificial saliva. The relationship between enamel dissolution and fluoride levels, pH, and titratable acidity was also examined. There was a statistically significant difference between the fluoride levels (p = 0.034) and pH (p = 0.04) of the sports and energy drinks studied. The titratable acidity of energy drinks (11.78) was found to be significantly higher than that of sports drinks (3.58) (p energy drinks (Red Bull Sugar Free, Monster Assault, Von Dutch, Rockstar, and 5-Hour Energy) were found to have the highest titratable acidity values among the brands studied. Enamel weight loss after exposure to energy drinks was significantly higher than it was after exposure to sports drinks. The effect of titratable acidity on enamel weight loss was found to vary inversely with the pH of the drinks. The findings indicated that energy drinks have significantly higher titratable acidity and enamel dissolution associated with them than sports drinks. Enamel weight loss after exposure to energy drinks was more than two times higher than it was after exposure to sports drinks. Titratable acidity is a significant predictor of enamel dissolution, and its effect on enamel weight loss varies inversely with the pH of the drink. The data from the current study can be used to educate patients about the differences between sports and energy drinks and the effects of these drinks on tooth enamel.

  8. Microbiologic aspects of dental plaque and dental caries.

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    Marsh, P D

    1999-10-01

    Dental plaque is an example of a microbial biofilm with a diverse microbial composition; it is found naturally on teeth and confers advantages to the host, for example, by preventing colonization by exogenous, and often pathogenic, micro-organisms. In individuals with a high frequency sugar diet, or with a severely compromised saliva flow, the levels of potentially cariogenic bacteria (acid-producing and acid-tolerating species) can increase beyond those compatible with enamel health. This article discusses antimicrobial strategies to control dental caries, including; reducing plaque levels, in general or specific cariogenic bacteria in particular, by antiplaque or antimicrobial agents; reducing bacterial acid production by replacing fermentable carbohydrates in the diet with sugar substitutes, or by interfering with bacterial metabolism with fluoride or antimicrobial agents.

  9. Testing the Effect of Aggressive Beverage on the Damage of Enamel Structure

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    Mitar Lutovac

    2017-12-01

    Full Text Available BACKGROUND: Dental erosion is a common problem in modern societies, owing to the increased consumption of acid drinks such as soft drinks, sports drinks, fruit juice. Examining the enamel surface with the Atomic Force Microscopy (AFM enables more precise registering and defining the changes of enamel surface structure and microhardness. This method can be used to compare the efficiency of application of different preventive and therapy materials and medicaments in dentistry. The chronic regular consumption of low pH cola drinks encouraged the erosion of the teeth. The loss of anatomy and sensitivity are direct results of acid cola dissolving coronal tooth material. Under the influence of coca cola, a change of crystal structure and nanomorphology on enamel surface occurs. AIM: This paper reflects dental damage from abusive cola drinking, and the clinical presentation can be explained from data presented in this thesis. MATERIAL AND METHODS: The trial was conducted on a total of 40 extracted teeth which were divided into two groups treated with the solution of coca cola during 5 minutes, and then prepared and tested with a standard AFM procedure, type SPM-5200. Quantitative analysis was performed by comparing the roughness parameters (Ra of the treated and non-treated sample. RESULTS: Based on the test of a hypothesis of the existence of differences between the treated and untreated sample, with an application of a t-test, it is shown that there are statistically highly significant differences between Ra of the treated sample with a 5-minute treatment of coca cola and Ra of the same sample without the treatment. CONCLUSION: Use of AFM enables successful monitoring of changes on enamel surface as well as the interpretation of the ultrastructural configuration of the crystal stage and the damage created under the influence of different external factors.

  10. Testing the Effect of Aggressive Beverage on the Damage of Enamel Structure

    Science.gov (United States)

    Lutovac, Mitar; Popova, Olga V.; Macanovic, Gordana; Kristina, Radoman; Lutovac, Bojana; Ketin, Sonja; Biocanin, Rade

    2017-01-01

    BACKGROUND: Dental erosion is a common problem in modern societies, owing to the increased consumption of acid drinks such as soft drinks, sports drinks, fruit juice. Examining the enamel surface with the Atomic Force Microscopy (AFM) enables more precise registering and defining the changes of enamel surface structure and microhardness. This method can be used to compare the efficiency of application of different preventive and therapy materials and medicaments in dentistry. The chronic regular consumption of low pH cola drinks encouraged the erosion of the teeth. The loss of anatomy and sensitivity are direct results of acid cola dissolving coronal tooth material. Under the influence of coca cola, a change of crystal structure and nanomorphology on enamel surface occurs. AIM: This paper reflects dental damage from abusive cola drinking, and the clinical presentation can be explained from data presented in this thesis. MATERIAL AND METHODS: The trial was conducted on a total of 40 extracted teeth which were divided into two groups treated with the solution of coca cola during 5 minutes, and then prepared and tested with a standard AFM procedure, type SPM-5200. Quantitative analysis was performed by comparing the roughness parameters (Ra) of the treated and non-treated sample. RESULTS: Based on the test of a hypothesis of the existence of differences between the treated and untreated sample, with an application of a t-test, it is shown that there are statistically highly significant differences between Ra of the treated sample with a 5-minute treatment of coca cola and Ra of the same sample without the treatment. CONCLUSION: Use of AFM enables successful monitoring of changes on enamel surface as well as the interpretation of the ultrastructural configuration of the crystal stage and the damage created under the influence of different external factors. PMID:29362633

  11. Testing the Effect of Aggressive Beverage on the Damage of Enamel Structure.

    Science.gov (United States)

    Lutovac, Mitar; Popova, Olga V; Macanovic, Gordana; Kristina, Radoman; Lutovac, Bojana; Ketin, Sonja; Biocanin, Rade

    2017-12-15

    Dental erosion is a common problem in modern societies, owing to the increased consumption of acid drinks such as soft drinks, sports drinks, fruit juice. Examining the enamel surface with the Atomic Force Microscopy (AFM) enables more precise registering and defining the changes of enamel surface structure and microhardness. This method can be used to compare the efficiency of application of different preventive and therapy materials and medicaments in dentistry. The chronic regular consumption of low pH cola drinks encouraged the erosion of the teeth. The loss of anatomy and sensitivity are direct results of acid cola dissolving coronal tooth material. Under the influence of coca cola, a change of crystal structure and nanomorphology on enamel surface occurs. This paper reflects dental damage from abusive cola drinking, and the clinical presentation can be explained from data presented in this thesis. The trial was conducted on a total of 40 extracted teeth which were divided into two groups treated with the solution of coca cola during 5 minutes, and then prepared and tested with a standard AFM procedure, type SPM-5200. Quantitative analysis was performed by comparing the roughness parameters (Ra) of the treated and non-treated sample. Based on the test of a hypothesis of the existence of differences between the treated and untreated sample, with an application of a t-test, it is shown that there are statistically highly significant differences between Ra of the treated sample with a 5-minute treatment of coca cola and Ra of the same sample without the treatment. Use of AFM enables successful monitoring of changes on enamel surface as well as the interpretation of the ultrastructural configuration of the crystal stage and the damage created under the influence of different external factors.

  12. Dental erosion: Prevalence and severity among 16-year-old adolescents in Troms, Norway.

    Science.gov (United States)

    Mulic, A; Fredriksen, Ø; Jacobsen, I D; Tveit, A B; Espelid, I; Crossner, C G

    2016-09-01

    To study the prevalence, distribution and severity of dental erosion among 16-year-old adolescents in the Troms region of Norway. Study design: The participants were recruited through the Tromsø-study ("Fit Futures"), and 392 16-year-olds were examined for dental erosion using clinical intraoral photographs. Three calibrated clinicians used the Visual Erosion Dental Examination (VEDE) system to register and grade the dental erosive wear. More than one third (38%) of the participants showed dental erosion on at least one tooth surface, 18% were limited to the enamel, while 20% of the adolescents showed erosive wear extending into the dentine. The occlusal surfaces of the lower first molars, and the palatal surfaces of the maxillary incisors were the most often and most severely affected. Of the participants showing dental erosion, 93% exhibited "cuppings" on the molars, with 48% limited to the enamel and 52% extending into the dentine. The highest prevalence of "cuppings" (73%) was found on the first lower molars, especially the mesiobuccal cusp of the teeth. The prevalence and severity of dental erosion was found to be higher in male than in female participants (p dental erosion among adolescents in Troms and stress the importance of information, early and effective diagnostics and implementation of prevention strategies.

  13. Histo-anatomic 3D printing of dental structures.

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    Schweiger, J; Beuer, F; Stimmelmayr, M; Edelhoff, D; Magne, P; Güth, J F

    2016-11-04

    The creation of dental restorations with natural appearance and biomechanics represents a major challenge for the restorative team. The manufacturing-process of high-aesthetic restorations from tooth-coloured restorative materials is currently dominated by manual manufacturing procedures and the outcome is highly dependent on the knowledge and skills of the performing dental technician. On the other hand, due to the simplicity of the manufacturing process, CAD/CAM restorations from different material classes gain more and more acceptance in the daily routine. Multi-layered restorations show significant aesthetic advantages versus monolithic ones, but are difficult to fabricate using digital technologies. The key element for the successful automated digital fabrication of aesthetic anterior restorations seems to be the form of the individual dentine core as defined by dentine enamel junction (DEJ) covered by a more transparent layer of material imitating the enamel layer to create the outer enamel surface (OES). This article describes the possibilities and technologies available for so-called '4D-printing'. It introduces the digital manufacturing process of multilayered anterior teeth using 3D multipart printing, taking the example of manufacturing replicas of extracted intact natural teeth.

  14. Er:YAG Laser Dental Treatment of Patients Affected by Epidermolysis Bullosa

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    Angela Galeotti

    2014-01-01

    Full Text Available Aim. The purpose of this study was to evaluate the efficacy of Er:YAG laser used for treating hard dental tissue in patients with epidermolysis bullosa (EB. Methods. We report two cases of EB in which an Er:YAG laser was used for conservative treatments. In the first case, the Er:YAG laser (2,940 μm, 265 mJ, 25 Hz was used to treat caries on a deciduous maxillary canine in an 8-year-old male patient affected by dystrophic EB. In the second case, we treated a 26-year-old female patient, affected by junctional EB, with generalized enamel hypoplasia, and an Er:YAG laser (2,940 μm, 265 mJ, 25 Hz was used to remove the damaged enamel on maxillary incisors. Results. The use of the Er:YAG laser, with the appropriate energy, was effective in the selective removal of carious tissue and enamel hypoplasia. During dental treatment with the Er:YAG laser, patients required only a few interruptions due to the absence of pain, vibration, and noise. Conclusions. Laser treatment of hard dental tissues is a valuable choice for patients affected by EB since it is less invasive compared to conventional treatment, resulting in improved patient compliance.

  15. Morphology of enamel in primary teeth from children in Thailand exposed to environmental lead

    International Nuclear Information System (INIS)

    Youravong, Nattaporn; Chongsuvivatwong, Virasakdi; Teanpaisan, Rawee; Geater, Alan F.; Dietz, Wolfram; Dahlen, Gunnar; Noren, Joergen G.

    2005-01-01

    Lead is one of the major environmental pollutants and a health risk. Dental hard tissues have a capacity to accumulate lead from the environment. Eighty exfoliated primary teeth were collected from children residing around a shipyard area in southern Thailand, known for its lead contamination. The morphology of the enamel was examined by polarized light microscopy (PLM), microradiography (MRG), and scanning electron microscopy (SEM). The specimens derived from two groups of children, one group with high blood levels of lead (57 teeth) and one group having low blood levels of lead (23 teeth). The enamel irrespective of group appeared normal. However, in a majority of the specimens the enamel surface appeared hypomineralized, which was confirmed in SEM. No morphological changes connected to lead in blood could be found. The hypomineralized surface zone could possibly be attributed to an acid oral environment

  16. Morphology of enamel in primary teeth from children in Thailand exposed to environmental lead

    Energy Technology Data Exchange (ETDEWEB)

    Youravong, Nattaporn [Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla (Thailand); Chongsuvivatwong, Virasakdi [Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla (Thailand); Teanpaisan, Rawee [Department of Stomatology, Faculty of Dentistry, Prince of Songkla University, Songkhla (Thailand); Geater, Alan F. [Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla (Thailand); Dietz, Wolfram [Centre of Electron Microscopy, Friedrich-Schiller-University Jena (Germany); Dahlen, Gunnar [Department of Oral Microbiology, Faculty of Odontology, Goeteborg University (Sweden); Noren, Joergen G. [Department of Pedodontics, Faculty of Odontology, Goeteborg University, Box 450 SE-405 30 Goeteborg (Sweden)]. E-mail: Jorgen.noren@odontologi.gu.se

    2005-09-15

    Lead is one of the major environmental pollutants and a health risk. Dental hard tissues have a capacity to accumulate lead from the environment. Eighty exfoliated primary teeth were collected from children residing around a shipyard area in southern Thailand, known for its lead contamination. The morphology of the enamel was examined by polarized light microscopy (PLM), microradiography (MRG), and scanning electron microscopy (SEM). The specimens derived from two groups of children, one group with high blood levels of lead (57 teeth) and one group having low blood levels of lead (23 teeth). The enamel irrespective of group appeared normal. However, in a majority of the specimens the enamel surface appeared hypomineralized, which was confirmed in SEM. No morphological changes connected to lead in blood could be found. The hypomineralized surface zone could possibly be attributed to an acid oral environment.

  17. Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography.

    Science.gov (United States)

    Segarra, M S; Shimada, Y; Sadr, A; Sumi, Y; Tagami, J

    2017-03-01

    The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch ( n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I - superficial horizontal cracks; Type II - vertically (occluso-gingival) oriented cracks; and Type III - hybrid or complicated cracks, a combination of a Type I and Type III cracks, which may or may not be confluent with each other. Type II cracks were predominant on noncontacting surfaces of incisors and canines and nonfunctional cusps of posterior teeth. Type I and III cracks were predominant on the contacting surfaces of incisors, cusps of canines, and functional cusps of posterior teeth. Cracks originating from the dental-enamel junction and enamel tufts, crack deflections, and the initiation of new cracks within the enamel (internal cracks) were observed as bright areas. CLSM observations corroborated the SS-OCT findings. We found that crack pattern, tooth type, and the location of the crack on the tooth exhibited a strong correlation. We show that the use of 3D SS-OCT permits for the nondestructive 3D imaging and analysis of enamel crack behavior in whole human teeth in vitro. 3D SS-OCT possesses potential for use in clinical studies for the analysis of enamel crack behavior.

  18. Correlation between enamel morphological and dental pulp physiological outcomes as a function of lasing parameters

    Science.gov (United States)

    Arcoria, Charles J.; Wagner, Martin J.; Vitasek, Bunny A.

    1992-06-01

    Previous oral medicine research has insufficiently quantified and correlated laser effects on calcified/soft-tissue combinations. The purpose of this study was to explain lasing effects on outcome variables (pulp response and enamel condition). Vital animal molars were irradiated using several mediums, with predetermined energy densities serving as independent variables. Predetermined safe-tissue thresholds, including pulp/enamel conditions, can be demonstrated to display linear relationships using several laser systems.

  19. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser; Estudo in vitro das alteracoes morfologicas e quimicas do esmalte dental bovino irradiado pelo laser de holmio

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo, Patricia Lerro de Paula

    2001-07-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm{sup 2} and 450 J/cm{sup 2} were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous

  20. Mechanism of Action of TiF4 on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis.

    Science.gov (United States)

    Comar, Lívia P; Souza, Beatriz M; Al-Ahj, Luana P; Martins, Jessica; Grizzo, Larissa T; Piasentim, Isabelle S; Rios, Daniela; Buzalaf, Marília Afonso Rabelo; Magalhães, Ana Carolina

    2017-10-12

    This in vitro study aimed to evaluate the action of TiF4 on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF4 (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF4 varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF4 (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF4 induced the formation of new compounds such as CaF2, TiO2, and Ti(HPO4)2·H2O. In conclusion, TiF4 (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF4 provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF4 application, while Ti uptake was dependent on the enamel condition and origin. © 2017 S. Karger AG, Basel.

  1. Distribution and structure of dental enamel in incisors of Tabby mice

    Czech Academy of Sciences Publication Activity Database

    Risnes, S.; Peterková, Renata; Lesot, H.

    2005-01-01

    Roč. 50, - (2005), s. 181-184 ISSN 0003-9969 R&D Projects: GA MŠk(CZ) OC B23.002; GA ČR GA304/02/0448 Institutional research plan: CEZ:AV0Z5039906 Keywords : enamel * incisor * mouse Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.288, year: 2005

  2. Carabelli's trait revisited: an examination of mesiolingual features at the enamel-dentine junction and enamel surface of Pan and Homo sapiens upper molars.

    Science.gov (United States)

    Ortiz, Alejandra; Skinner, Matthew M; Bailey, Shara E; Hublin, Jean-Jacques

    2012-10-01

    Carabelli's trait is a morphological feature that frequently occurs on the mesiolingual aspect of Homo sapiens upper molars. Similar structures also referred to as Carabelli's trait have been reported in apes and fossil hominins. However, the morphological development and homology of these mesiolingual structures among hominoids are poorly understood. In this study, we employ micro-computed tomography to image the enamel-dentine junction (EDJ) and outer enamel surface (OES) of Pan (n = 48) and H. sapiens (n = 52) upper molars. We investigate the developmental origin of mesiolingual features in these taxa and establish the relative contribution of the EDJ and enamel cap to feature expression. Results demonstrate that mesiolingual features of H. sapiens molars develop at the EDJ and are similarly expressed at the OES. Morphological variation at both surfaces in this taxon can satisfactorily be assessed using standards for Carabelli's trait developed by the Arizona State University Dental Anthropology System (ASUDAS). Relative to H. sapiens, Pan has an even greater degree of correspondence in feature expression between the EDJ and OES. Morphological manifestations in Pan molars are not necessarily limited to the protocone and are best characterized by a lingual cingulum that cannot be captured by the ASUDAS. Cusp-like structures, similar to those seen in marked Carabelli's trait expressions in H. sapiens, were not found in Pan. This study provides a foundation for further analyses on the evolutionary history of mesiolingual dental traits within the hominoid lineage. It also highlights the wealth of morphological data that can be obtained at the EDJ for understanding tooth development and for characterizing tooth crown variation in worn fossil teeth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Effect of titanium dioxide nanoparticle addition into orthodontic adhesive resin on enamel microhardness

    Science.gov (United States)

    Andriani, A.; Krisnawati; Purwanegara, M. K.

    2017-08-01

    White spots are an early sign of enamel demineralization, which may lead to development of dental caries. Enamel demineralization can be determined by examining the microhardness number of the enamel. Addition of antibacterial agents such as TiO2 nanoparticles into the orthodontic adhesive (TiO2 nanocomposite) is expected to prevent enamel demineralization. The objective of this study is to evaluate the effect of TiO2 nanocomposites in maintaining enamel microhardness around orthodontic brackets. The bracket was bonded to the premolar using Transbond XT (group 1), 1% TiO2 nanocomposites (group 2), and 2% TiO2 nanocomposites (group 3). Group 4 was the control group, and it was not given any treatment prior to the microhardness test. The samples of groups 1, 2, and 3 were soaked in BHI solution containing Streptococcus mutans, and then stored in an incubator at 37°C for 30 days. Demineralizations were determined on cross-sectioned tooth 100μm and 200μm cervical to the bracket by the Vickers microhardness test. The microhardness values were significantly different between every group, with the highest value obtained for control group, followed by the 2% TiO2 nanocomposite group, 1% TiO2 nanocomposite group, and then the Transbond XT group. The results of this study reveal that 2% TiO2 nanocomposites have the ability to maintain enamel microhardness around the orthodontic bracket.

  4. Energy dispersive X-ray spectrometry study of the protective effects of fluoride varnish and gel on enamel erosion.

    Science.gov (United States)

    De Carvalho Filho, Antonio Carlos Belfort; Sanches, Roberto Pizarro; Martin, Airton Abrahão; Do Espírito Santo, Ana Maria; Soares, Luís Eduardo Silva

    2011-09-01

    Dental erosion is a risk factor for dental health, introduced by today's lifestyle. Topical fluoride applications in the form of varnishes and gel may lead to deposition of fluoride on enamel. This in vitro study aimed to evaluate the effect of two fluoride varnishes and one fluoride gel on the dissolution of bovine enamel by acids. Enamel samples (72) were divided (n = 8): artificial saliva (control-G1), Pepsi Twist® (G2), orange juice (G3), Duraphat® + Pepsi Twist® (G4), Duraphat® + orange juice (G5), Duofluorid® + Pepsi Twist® (G6), Duofluorid® + orange juice (G7), fluoride gel + Pepsi Twist® (G8), and fluoride gel + orange juice (G9). Fluoride gel was applied for 4 min and the varnishes were applied and removed after 6 h. The samples were submitted to six cycles (demineralization: Pepsi Twist® or orange juice, 10 min; remineralization: saliva, 1 h). Samples were analyzed by energy-dispersive X-ray fluorescence (144 line-scanning). The amount of Ca and P decreased significantly in the samples of G2 and G3, and the Ca/P ratio decreased in G3. Mineral gain (Ca) was greater in G9 samples than in G4 > G3 > G5 > G1, and (P) greater in G7 samples than in G9 > G4-6 > G2-3. The protective effect of Duofluorid® was significantly lower than fluoride gel against orange juice. The fluoride varnishes can interfere positively with the dissolution of dental enamel in the presence of acidic beverages. Fluoride gel showed the best protection level to extrinsic erosion with low costs. Copyright © 2010 Wiley-Liss, Inc.

  5. Functional resistance of enamel and the phenomenon of transtegumental fluid transport

    Directory of Open Access Journals (Sweden)

    Okushko V.R. Okushko R.V. Ursan R.V.

    2011-03-01

    Full Text Available Current data related to transport of fluid through the covering tissue formations (skin, nail plate, dental enamel, gum valley are being analyzed. A supposition is made of transtegumental fluid transport (TFT as a general biological regularity which is specifically manifested in tissues of different functional purposes. Depending on the peculiarity of the organ, the tooth performs the TFT providing functional resistance of the enamel, whose level is clinically detected in the «test of enamel resistance» (TER used in modern research. The article draws attention to the reasonability of an in-depth study of the tooth physiology, where the central element is TFT. This phenomenon is of interest both from fundamental and highly practical standpoints. Identification of seasonal periods in the functional resistance decline makes it possible to get a distinct effect by means of concentrating prevention efforts on this. The TER sample, as well as other transtegumental fluid transport patterns, is to find place in the system of personalized predictive approach to caries diseases

  6. Effect of Enamel and Dentin Irradiation by Gamma Rays on the Bond Strength of Two Adhesive Restorations

    International Nuclear Information System (INIS)

    Zein, N.S.A.

    2014-01-01

    There have been many reports related to the high incidence of the head and neck cancers including those of the oral cavity. Ablative surgery, radiotherapy, chemotherapy and reconstructive surgery are components of the curative or palliative treatment of head and neck cancers which are intended to improve survival time and quality of life. In addition to the desirable anticancer effects, ionizing radiation causes damage to normal tissues located within the irradiation fields (1). The early responses of teeth to irradiation include dental hypersensitivity and spontaneous pain (2). Several types of desensitizers may be applied to the tooth after cavity preparation in an attempt to manage dental hypersensitivity. The most common form of management is the placement of a topically applied agent either by a dental professional or by the patient at home. These agents stimulate mineral deposition or occlude dental tubules to reduce hypersensitivity (3,4). Radiation caries is another irradiation-related damage to dental structures. It remains the most threatening complication of radiotherapy for the dentition. It is a highly destructive form of dental caries with a rapid onset and progression. Radiation caries may become evident as early as three months following the initiation of head and neck radiotherapy. In severe cases, a previously healthy dentition can be completely lost within a year (5). Radiation caries involves both enamel and dentin; it tends to first affect the cervical and incisal edges of the teeth. Beside the irradiation-induced xerostomia, the effect of irradiation on dental hard tissues may be an important factor in radiation caries. Studies have reported the physical and chemical changes in enamel after radiotherapy, which are a direct consequence of the irradiation treatment. For dentin, a significant reduction in microhardness is observed after irradiation accompanied by reduced stability of the dentino-enamel junction (DEJ) The oral environment of head

  7. Effectiveness of anchovy substrate application on decreasing acid solubility of Sprague Dawley rats’ tooth enamel (in vivo)

    Science.gov (United States)

    Triputra, F.; Puspitawati, R.; Gunawan, H. A.

    2017-08-01

    Anchovies (Stolephorus insularis), a natural resource of Indonesia, contain fluoride in the form of CaF2 and can function as a fluoridation material to prevent dental caries. The aim of this study is to study the effectiveness of anchovy substrate, through food or topical application, in decreasing the acid solubility of tooth enamel. This research used 14 Sprague Dawley rats as subjects divided into the following 5 groups: baseline, experimental feeding, experimental smearing, and their negative controls. After 15 days of anchovy substrate application, lower incisors were extracted and the acid solubility of enamel was analyzed qualitatively and quantitatively using a stereo microscope and a Micro-Vickers Hardness Tester. Analysis of enamel surface destruction and enamel surface microscopic hardness shifting after a 60 sec application of H2PO4 (50% concentration) resulted in a decrease in acid solubility of enamel treated with anchovy substrate. This result can be seen with both the chewing and smearing method. S. insularis can be used as an alternative material for fluoridation.

  8. Two-body wear rate of CAD/CAM resin blocks and their enamel antagonists.

    Science.gov (United States)

    Stawarczyk, Bogna; Özcan, Mutlu; Trottmann, Albert; Schmutz, Felix; Roos, Malgorzata; Hämmerle, Christoph

    2013-05-01

    Computer-aided design and computer-aided manufacturing (CAD/CAM) resins exhibit good mechanical properties and can be used as long-term restorations. The wear rate of such resins and their enamel antagonists is unknown. The purpose of this study was to test and compare the 2-body wear rate of CAD/CAM resin blocks. Wear specimens (N=42, n=6) were made from 5 CAD/CAM resins: ZENO PMMA (ZP), artBloc Temp (AT), Telio CAD (TC), Blanc High-class (HC), CAD-Temp (CT); 1 manually polymerized resin: Integral esthetic press (negative control group, IEP); and 1 glass-ceramic: VITA Mark II (positive control group, VM2). The specimens for the wear resistance were aged in a thermomechanical loading machine (49 N, 1.67 Hz, 5/50°C) with human enamel antagonists. The material loss of all specimens before, during, and after aging was evaluated with a 3DS profilometer. The measured material loss data of all tested groups were statistically evaluated with linear mixed model analysis (a=.05). Manually polymerized resin showed significantly higher material wear (P<.001) than all other tested groups. Glass-ceramic showed significantly lower wear values (P<.001) than CAD/CAM resins ZP, AT, HC, CT, and IES. CAD/CAM resin TC was not significantly different from the positive control group. Glass-ceramic showed the highest enamel wear values (P<.001) of all tested resins. No differences were found in the enamel wear among all resins. The glass-ceramic group showed damage in the form of cracks on the worn enamel surface in 50% of specimens. CAD/CAM resins showed lower wear rates than those conventionally polymerized. Only one CAD/CAM resin, TC, presented material wear values comparable with glass-ceramic. The tested glass-ceramic developed cracks in the enamel antagonist and showed the highest enamel wear values of all other tested groups. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  9. Ultrastructure of the surface of dental enamel with molar incisor hypomineralization (MIH) with and without acid etching.

    Science.gov (United States)

    Bozal, Carola B; Kaplan, Andrea; Ortolani, Andrea; Cortese, Silvina G; Biondi, Ana M

    2015-01-01

    The aim of the present work was to analyze the ultrastructure and mineral composition of the surface of the enamel on a molar with MIH, with and without acid etching. A permanent tooth without clinical MIH lesions (control) and a tooth with clinical diagnosis of mild and moderate MIH, with indication for extraction, were processed with and without acid etching (H3PO4 37%, 20") for observation with scanning electron microscope (SEM) ZEISS (Supra 40) and mineral composition analysis with an EDS detector (Oxford Instruments). The control enamel showed normal prismatic surface and etching pattern. The clinically healthy enamel on the tooth with MIH revealed partial loss of prismatic pattern. The mild lesion was porous with occasional cracks. The moderate lesion was more porous, with larger cracks and many scales. The mineral composition of the affected surfaces had lower Ca and P content and higher O and C. On the tooth with MIH, even on normal looking enamel, the demineralization does not correspond to an etching pattern, and exhibits exposure of crystals with rods with rounded ends and less demineralization in the inter-prismatic spaces. Acid etching increased the presence of cracks and deep pores in the adamantine structure of the enamel with lesion. In moderate lesions, the mineral composition had higher content of Ca, P and Cl. Enamel with MIH, even on clinically intact adamantine surfaces, shows severe alterations in the ultrastructure and changes in ionic composition, which affect the acid etching pattern and may interfere with adhesion.

  10. Enamel erosion caused by the effervescent acid powder in Tiritón ice cream: An in vitro study.

    Directory of Open Access Journals (Sweden)

    Katherine Beltrán

    2014-12-01

    Full Text Available The aim of this study was to visualize the erosive effect on human dental enamel of effervescent acid powder in the Tiritón ice cream (Savory, Nestle, Vevey, Switzerland. The erosive potential of Tiritón ice cream was determined in in vitro conditions by submitting 5 enamel pieces from 3 healthy first molars. The samples were submitted to the mixture of saliva from a girl without cavity incidence and the effervescent powder in the Tiritón ice cream, at 10, 20, 30, 40 and 50 seconds, then the results were measured by scanning electron microscopy (SEM and measurement of pH. All specimens showed pH 3.0. SEM showed increasing degrees of erosion with longer periods of exposure. The Tiritón ice cream generates a much larger acid solution than necessary for the onset of the dissolution of enamel which subsequently causes susceptibility to dental cavities and erosion, higher than reported for other candies. The images obtained by SEM made possible to visualize clearly the erosive effect produced by the effervescent acid powder in periods of exposure of less than a minute.

  11. Surface morphological changes on the human dental enamel and cement after the Er:YAG laser irradiation at different incidence angles

    International Nuclear Information System (INIS)

    Tannous, Jose Trancoso

    2001-01-01

    This is a morphological analysis study through SEM of the differences of the laser tissue interaction as a function of the laser beam irradiation angle, under different parameters of energy. Fourteen freshly extracted molars stored in a 0,9% sodium chloride solution were divided in seven pairs and were irradiated with 100, 200, 300, 400, 500, 600 and 700 mJ per pulse, respectively. Each sample received three enamel irradiations and three cement irradiations, either in the punctual or in the contact mode, one near to the other, with respectively 30, 45 and 90 inclinations degrees of dental surface-laser-beam incidence. Four Er:YAG pulses (2,94 μm, 7-20 Hz, 0,1-1 J energy/pulse - Opus 20 - Opus Dent) with water cooling system (0,4 ml/s) were applied. After the laser irradiation the specimens were analysed through scanning electron microscope (SEM). The results were analysed by SEM micrographs showing a great difference on the laser tissue interaction characteristics as a function of the irradiation angle of the laser beam. All the observations led to conclude that, considering the laser parameters used, the incidence angle variation is a very important parameter regarding the desired morphological effects. This represents an extremely relevant detail on the technical description of the Er:YAG laser irradiation protocols on dental tissues. (author)

  12. Dental Caries Experience in Texan Children with Cleft Lip and Palate.

    Science.gov (United States)

    Sunderji, Sabrina; Acharya, Bhavini; Flaitz, Catherine; Chiquet, Brett

    2017-09-15

    The purpose of this study was to assess the caries experience in the primary dentition of children born with cleft lip and palate (CLP). A retrospective chart review was conducted on subjects between two and six years old recruited from a university-based pediatric dentistry residency clinic. The number of dental visits and professional fluoride applications, the plaque index and treatment modality, and the presence/location of caries, white spot lesions, and enamel hypoplastic lesions were compared between CLP patients and healthy age- and gender-matched controls. Descriptive statistics, Student's t test, Mann-Whitney U test, and regression analysis were completed. A total of 183 charts were reviewed. Compared to healthy children, CLP children had increases in number of dental visits (P0.05). Children with cleft lip and palate are at a greater risk of enamel hypoplasia and dental caries. No significant caries experience difference was found between unilateral or bilateral CLP cases.

  13. Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

    International Nuclear Information System (INIS)

    Gomez, Jorge A.; Kinoshita, Angela; Leonor, Sergio J.; Belmonte, Gustavo C.; Baffa, Oswaldo

    2011-01-01

    In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

  14. Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Jorge A. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Kinoshita, Angela [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Leonor, Sergio J. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Belmonte, Gustavo C. [Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Baffa, Oswaldo, E-mail: baffa@usp.br [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2011-09-15

    In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

  15. Dental Defects as a Potential Indicator of Chronic Malnutrition in a Population of Fallow Deer (Dama dama) from Northwestern Germany.

    Science.gov (United States)

    Kierdorf, Horst; Filevych, Olexander; Lutz, Walburga; Kierdorf, Uwe

    2016-10-01

    We studied enamel defects in mandibular cheek teeth of fallow deer from an enclosed population that had grown far beyond the carrying capacity of its habitat. Macroscopic inspection revealed a high frequency of pathological enamel alterations in the permanent premolars and the third molar, which form late during dental development, while earlier forming teeth (deciduous premolars and first molar) were generally not affected. Macroscopic enamel alterations comprised opacity and posteruptive discoloration, loss of occlusal enamel ridges, and presence of enamel surface lesions. Backscattered electron imaging in the SEM revealed a marked hypomineralization and related increased porosity of the outer compared to the central and inner enamel portions in the affected teeth. In contrast, the enamel of the unaffected first molars showed a homogeneous high degree of mineralization. Microindentation hardness testing demonstrated a significantly reduced and highly variable hardness of the outer enamel of the affected teeth. The recorded enamel alterations are indicative of a disturbance of enamel maturation. Based on findings of experimental studies by other authors that explored the effects of dietary deficiencies on the mineralization of dental hard tissues in different mammal species, we suggest a dietary calcium deficiency as the cause of the observed pathological enamel changes in the fallow deer. The supposed calcium deficiency only affected teeth whose crown mineralization takes place after weaning, while the deciduous premolars and the first molar, whose crown formation occurs prenatally or during the early postnatal period of intense milk feeding, were unaffected. Anat Rec, 299:1409-1423, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Study of two new methods of geochronometry: dating method of carbonaceous formations by U-series disequilibrium gamma spectrometry; ESR dating method of rich U-content fossil dental enamel

    International Nuclear Information System (INIS)

    Ma, Jean-Luc

    1984-01-01

    First, the U-series disequilibrium dating method was re-examined using non-destructive γ-spectrometry. A new low-background (≤ 10 ppb U- equivalent) Ge-HP γ-spectrometer has been used to date travertine with small U-content (∼ 0.1 ppm) and low (≤ 5%) Th/U , content, by comparison with old-limestone γ-spectra. Second, a new ESR dating method has been developed using fossil dental enamel which is rich in U-content (10 - 100 ppm). Both methods were applied to Arago Cave (Tautavel, France): - with an ionium-age of 120 ka (10%), the upper travertine seems to have been set up during the Riss-deglaciation period. - the high (∼ 50%) Th/U-content samples of the intermediate travertine are un-datable. - the ESR-age of EQUUS mosbachensis enamel is 400 ka (10%) for the G-soil of Arago. XXI H. erectus, and 600 ka (10%) for the Q-soil above (- 1 m) of the lower travertine of which Io-age is older than 350 ka. (author)

  17. Treatment of enamel hypoplasia in a patient with Usher syndrome.

    Science.gov (United States)

    de la Peña, Victor Alonso; Valea, Martín Caserío

    2011-08-01

    Usher syndrome (USH) is a group of autosomal recessive diseases characterized by the association of retinitis pigmentosa with sensorineural hearing loss. There are three types of USH. In addition, in people with USH and hypoplasia, the thickness of the enamel is reduced. The authors describe a case of a patient with USH type II associated with severe enamel hypoplasia and multiple unerupted teeth. The authors placed direct composite crowns and extracted severely affected and impacted molars. There is little information available on the oral pathologies of USH. Because the authors did not know how the patient's condition would progress and the patient still was growing, the authors treated the patient conservatively by placing direct composite crowns. The treatment has met both esthetic and functional expectations for 10 years. Copyright © 2011 American Dental Association. All rights reserved.

  18. Improved classification and visualization of healthy and pathological hard dental tissues by modeling specular reflections in NIR hyperspectral images

    Science.gov (United States)

    Usenik, Peter; Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2012-03-01

    Despite major improvements in dental healthcare and technology, dental caries remains one of the most prevalent chronic diseases of modern society. The initial stages of dental caries are characterized by demineralization of enamel crystals, commonly known as white spots, which are difficult to diagnose. Near-infrared (NIR) hyperspectral imaging is a new promising technique for early detection of demineralization which can classify healthy and pathological dental tissues. However, due to non-ideal illumination of the tooth surface the hyperspectral images can exhibit specular reflections, in particular around the edges and the ridges of the teeth. These reflections significantly affect the performance of automated classification and visualization methods. Cross polarized imaging setup can effectively remove the specular reflections, however is due to the complexity and other imaging setup limitations not always possible. In this paper, we propose an alternative approach based on modeling the specular reflections of hard dental tissues, which significantly improves the classification accuracy in the presence of specular reflections. The method was evaluated on five extracted human teeth with corresponding gold standard for 6 different healthy and pathological hard dental tissues including enamel, dentin, calculus, dentin caries, enamel caries and demineralized regions. Principal component analysis (PCA) was used for multivariate local modeling of healthy and pathological dental tissues. The classification was performed by employing multiple discriminant analysis. Based on the obtained results we believe the proposed method can be considered as an effective alternative to the complex cross polarized imaging setups.

  19. High resolution ultrastructure imaging of fractures in human dental tissues

    Directory of Open Access Journals (Sweden)

    Tan Sui

    2014-01-01

    Full Text Available Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of dentine and enamel was imaged by transmission electron microscopy (TEM of samples prepared by focused ion beam (FIB milling. High resolution TEM was carried out in the vicinity of a crack tip in dentine. An intricate “random weave” pattern of hydroxyapatile crystallites was observed and this provided a possible explanation for toughening of the mineralized dentine tissue at the nano-scale. The results reported here provide the basis for improved understanding of the relationship between the multi-scale nature and the mechanical properties of hierarchically structured biomaterials, and will also be useful for the development of better prosthetic and dental restorative materials.

  20. Prevalence of developmental dental hard-tissue anomalies and association with caries and oral hygiene status of children in Southwestern, Nigeria.

    Science.gov (United States)

    Popoola, Bamidele O; Onyejaka, Nneka; Folayan, Morenike O

    2016-07-07

    Developmental dental hard tissue anomalies are often associated with oral health problems. This study determined the clinical prevalence of developmental dental hard tissue anomalies in the permanent dentition of children resident in southwestern Nigeria and its association with dental caries and poor oral hygiene status. This was a cross-sectional study recruiting 1565 school children, 12 to 15 year old attending schools in Ibadan, Oyo State and Ile-Ife, Osun State. All eligible study participants had oral examinations conducted to determine presence of developmental hard dental tissue anomalies, caries and oral hygiene status. The prevalence of developmental dental hard tissue anomalies was determined. Logistic Poisson regression was used to determine the association of between developmental dental hard tissue anomalies, caries and oral hygiene status. Only 65 (4.2 %) children had clinically diagnosed developmental dental hard tissue anomalies. The most prevalent anomaly was enamel hypoplasia (2.2 %). More females (p = 0.003) and more children with middle socioeconomic class (p = 0.001) had enamel hypoplasia. The probability of having poor oral hygiene was significantly increased for children with developmental dental anomalies (APR: 0.07; 95 % CI: 0.03 - 0.12; p = 0.002). The probability of having caries was insignificantly increased for children with developmental dental hard tissue anomalies (APR: 0.005; 95 % CI: -0.03 - 0.04; p = 0.08). The most prevalence clinically detectable developmental dental hard tissue anomalies for the study population was enamel hypoplasia. The presence of developmental dental hard tissue anomalies significantly increased the chances of having poor oral hygiene but not caries. Further studies are required to understand if poor oral hygiene is associated with dental caries in children with developmental dental hard tissue anomalies.

  1. Caries prevalence and enamel defects in 5- and 10-year-old children with cleft lip and/or palate

    DEFF Research Database (Denmark)

    Sundell, Anna Lena; Nilsson, Anna-Karin; Ullbro, Christer

    2016-01-01

    OBJECTIVE: To determine the prevalence of dental caries and enamel defects in 5- and 10-year-old Swedish children with cleft lip and/or palate (CL(P)) in comparison to non-cleft controls. MATERIALS AND METHODS: The study group consisted of 139 children with CL(P) (80 subjects aged 5 years and 59...... aged 10 years) and 313 age-matched non-cleft controls. All children were examined by one of two calibrated examiners. Caries was scored according to the International Caries Detection and Assessment System (ICDAS-II) and enamel defects as presence and frequency of hypoplasia and hypomineralization...... prevalence of enamel defects was found in CL(P) children of both age groups and anterior permanent teeth were most commonly affected. CONCLUSIONS: Preschool children with cleft lip and/or palate seem to have more caries in the primary dentition than age-matched non-cleft controls. Enamel defects were more...

  2. Spectrally enhanced imaging of occlusal surfaces and artificial shallow enamel erosions with a scanning fiber endoscope

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Seibel, Eric J.

    2012-07-01

    An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used to image dental occlusal surfaces as well as shallow artificially induced enamel erosions from human extracted teeth (n=40). Enhanced image resolution of occlusal surfaces was obtained using a short-wavelength 405-nm illumination laser. In addition, artificial erosions of varying depths were also imaged with 405-, 404-, 532-, and 635-nm illumination lasers. Laser-induced autofluorescence images of the teeth using 405-nm illumination were also obtained. Contrast between sound and eroded enamel was quantitatively computed for each imaging modality. For shallow erosions, the image contrast with respect to sound enamel was greatest for the 405-nm reflected image. It was also determined that the increased contrast was in large part due to volume scattering with a smaller component from surface scattering. Furthermore, images obtained with a shallow penetration depth illumination laser (405 nm) provided the greatest detail of surface enamel topography since the reflected light does not contain contributions from light reflected from greater depths within the enamel tissue. Multilayered Monte Carlo simulations were also performed to confirm the experimental results.

  3. Hyperspectral laser-induced autofluorescence imaging of dental caries

    Science.gov (United States)

    Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2012-01-01

    Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentine and pulp. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Laser induced autofluorescence was shown to be a useful method for early detection of demineralization. The existing studies involved either a single point spectroscopic measurements or imaging at a single spectral band. In the case of spectroscopic measurements, very little or no spatial information is acquired and the measured autofluorescence signal strongly depends on the position and orientation of the probe. On the other hand, single-band spectral imaging can be substantially affected by local spectral artefacts. Such effects can significantly interfere with automated methods for detection of early caries lesions. In contrast, hyperspectral imaging effectively combines the spatial information of imaging methods with the spectral information of spectroscopic methods providing excellent basis for development of robust and reliable algorithms for automated classification and analysis of hard dental tissues. In this paper, we employ 405 nm laser excitation of natural caries lesions. The fluorescence signal is acquired by a state-of-the-art hyperspectral imaging system consisting of a high-resolution acousto-optic tunable filter (AOTF) and a highly sensitive Scientific CMOS camera in the spectral range from 550 nm to 800 nm. The results are compared to the contrast obtained by near-infrared hyperspectral imaging technique employed in the existing studies on early detection of dental caries.

  4. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2016-12-01

    Full Text Available Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group; Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm–1 exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm-1 area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention.

  5. THE EFFECT OF IRRADIATION ON ENAMEL MICRO-STRUCTURE CHANGES

    Directory of Open Access Journals (Sweden)

    Harun Gunawan

    2015-06-01

    Full Text Available Radiotherapy plays an important role in the management of head and neck carcinoma therapy. The radiation dose ranges from 40 – 70 Gy, depends on the severity and location of the malignancy. Many patients experience an increased dental caries or sensitivity occurrence following radiotherapy. The objective of this study is to analyze the enamel micro-structure changes after irradiation. Nine polished enamel slabs were prepared from impacted 3rd molars. The slabs were flushed in non-ionic distilled water and dried by using air spray and divided into 3 groups, the control, 20 Gy and 40 Gy irradiation group. Irradiations were performed from Co60 using Gammacell-220E, with duration variables to produce the irradiation doses of 20 and 40 Gy. Philips pW370-XRD was used to examine specimen microstructure changes after irradiation. 1-way ANOVA was used for statistics analysis. It was revealed that grain size after 40 Gy irradiation was 66.29±2.7 nm, and after 20 Gy was 51.64±15.8 whilst 43.95±11.1 nm for the control group. The micro-stain deviation of the 40 Gy group was 0.594±0.15 N/m, and 0.45±2.6 N/m for the 20 Gy group, and 0.378±0.27 N/m for control group. Statistic analysis showed significant grain size differences between 40 Gy compared to both 20 Gy and control groups, but not between 20 Gy compared to the control group. Similarly, there were micro-stain differences between 40 Gy compared to 20 Gy and control groups, but not between 20 Gy compared to control group. It was concluded that irradiation with 40 Gy caused elevation of the enamel microstrain and apaite grainsize. Elevation of the enamel microstrain could lead to enamel crack and gave hypersensitive sensation.

  6. Sub ablative Er: YAG laser irradiation on surface roughness of eroded dental enamel.

    Science.gov (United States)

    Curylofo-Zotti, Fabiana Almeida; Lepri, Taísa Penazzo; Colucci, Vivian; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

    2015-11-01

    This study evaluated the effects of Er:YAG laser irradiation applied at varying pulse repetition rate on the surface roughness of eroded enamel. Bovine enamel slabs (n = 10) were embedded in polyester resin, ground, and polished. To erosive challenges, specimens were immersed two times per day in 20mL of concentrated orange juice (pH = 3.84) under agitation, during a two-day period. Specimens were randomly assigned to irradiation with the Er:YAG laser (focused mode, pulse energy of 60 mJ and energy density of 3.79 J/cm(2) ) operating at 1, 2, 3, or 4 Hz. The control group was left nonirradiated. Surface roughness measurements were recorded post erosion-like formation and further erosive episodes by a profilometer and observed through atomic force microscopy (AFM). Analysis of variance revealed that the control group showed the lowest surface roughness, while laser-irradiated substrates did not differ from each other following post erosion-like lesion formation. According to analysis of covariance, at further erosive episodes, the control group demonstrated lower surface roughness (P > 0.05), than any of the irradiated groups (P enamel eroded. The AFM images showed that the specimens irradiated by the Er:YAG laser at 1 Hz presented a less rough surface than those irradiated at 2, 3, and 4 Hz. © 2015 Wiley Periodicals, Inc.

  7. Effect of One-Step and Multi-Steps Polishing System on Enamel Roughness

    Directory of Open Access Journals (Sweden)

    Cynthia Sumali

    2013-07-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 The final procedures of orthodontic treatment are bracket debonding and cleaning the remaining adhesive. Multi-step polishing system is the most common method used. The disadvantage of that system is long working time, because of the stages that should be done. Therefore, dental material manufacturer make an improvement to the system, to reduce several stages into one stage only. This new system is known as one-step polishing system. Objective: To compare the effect of one-step and multi-step polishing system on enamel roughness after orthodontic bracket debonding. Methods: Randomized control trial was conducted included twenty-eight maxillary premolar randomized into two polishing system; one-step OptraPol (Ivoclar, Vivadent and multi-step AstroPol (Ivoclar, Vivadent. After bracket debonding, the remaining adhesive on each group was cleaned by subjective polishing system for ninety seconds using low speed handpiece. The enamel roughness was subjected to profilometer, registering two roughness parameters (Ra, Rz. Independent t-test was used to analyze the mean score of enamel roughness in each group. Results: There was no significant difference of enamel roughness between one-step and multi-step polishing system (p>0.005. Conclusion: One-step polishing system can produce a similar enamel roughness to multi-step polishing system after bracket debonding and adhesive cleaning.DOI: 10.14693/jdi.v19i3.136

  8. An investigation using atomic force microscopy nanoindentation of dental enamel demineralization as a function of undissociated acid concentration and differential buffer capacity

    International Nuclear Information System (INIS)

    Barbour, Michele E; Shellis, R Peter

    2007-01-01

    Acidic drinks and foodstuffs can demineralize dental hard tissues, leading to a pathological condition known as dental erosion, which is of increasing clinical concern. The first step in enamel dissolution is a demineralization of the outer few micrometres of tissue, which results in a softening of the structure. The primary determinant of dissolution rate is pH, but the concentration of undissociated acid, which is related to buffer capacity, also appears to be important. In this study, atomic force microscopy nanoindentation was used to measure the first initial demineralization (softening) induced within 1 min by exposure to solutions with a range of undissociated acid concentration and natural pH of 3.3 or with an undissociated acid concentration of 10 mmol l -1 and pH adjusted to 3.3. The results indicate that differential buffering capacity is a better determinant of softening than undissociated acid concentration. Under the conditions of these experiments, a buffer capacity of >3 mmol l -1 pH -1 does not have any further effect on dissolution rate. These results imply that differential buffering capacity should be used for preference over undissociated acid concentration or titratable acidity, which are more commonly employed in the literature

  9. An investigation using atomic force microscopy nanoindentation of dental enamel demineralization as a function of undissociated acid concentration and differential buffer capacity

    Science.gov (United States)

    Barbour, Michele E.; Shellis, R. Peter

    2007-02-01

    Acidic drinks and foodstuffs can demineralize dental hard tissues, leading to a pathological condition known as dental erosion, which is of increasing clinical concern. The first step in enamel dissolution is a demineralization of the outer few micrometres of tissue, which results in a softening of the structure. The primary determinant of dissolution rate is pH, but the concentration of undissociated acid, which is related to buffer capacity, also appears to be important. In this study, atomic force microscopy nanoindentation was used to measure the first initial demineralization (softening) induced within 1 min by exposure to solutions with a range of undissociated acid concentration and natural pH of 3.3 or with an undissociated acid concentration of 10 mmol l-1 and pH adjusted to 3.3. The results indicate that differential buffering capacity is a better determinant of softening than undissociated acid concentration. Under the conditions of these experiments, a buffer capacity of >3 mmol l-1 pH-1 does not have any further effect on dissolution rate. These results imply that differential buffering capacity should be used for preference over undissociated acid concentration or titratable acidity, which are more commonly employed in the literature.

  10. Development, characterization and comparison of two strontium doped nano hydroxyapatite molecules for enamel repair/regeneration.

    Science.gov (United States)

    Krishnan, Vinod; Bhatia, Ankit; Varma, Harikrishna

    2016-05-01

    Enamel damage resulting or arising from/associated with orthodontic treatment such as white spot lesions and surface deterioration after debonding brackets along with incipient carious lesions are considered problems not amenable for routine restorations due to its invasive nature. The present study was aimed at synthesizing and characterizing nHAp and 25 and 50 mol% strontium nHAp as a surface application modality for dental enamel remineralization/repair. 25 and 50 mol% Sr nHAp was synthesized and characterized in comparison with custom made pure nHAp initially with the help of transmission and scanning electron microscopy as well as toxicological assessment. Further, comparative evaluation of these novel synthesized strontium substituted particles was assessed for its efficacy in repairing damaged enamel with the help of atomic force microscopy, scanning electron microscopy and micro indentation testing. There is increase in crystallinity and reduced particle size favoring dissolution and re-precipitation through small incipient carious lesions and soft white spot areas with 25% Sr-nHAp. Sr doped specimens showed more cell viability in comparison with pure nHAP make it less cytotoxic and hence a biologically friendly material which can be safely applied in patient's mouth. AFM images obtained from 25% and 50% Sr nHAp treated specimens clearly indicated increased roughness in surface topography and performed well with micro indentation test. The novel synthesized Sr doped nHAp forms an improved treatment modality to tackle the long standing quest for solving the problem of enamel loss with incipient carious lesions and WSL from orthodontic procedures. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation.

    Science.gov (United States)

    Weng, Z Y; Liu, Z Q; Ritchie, R O; Jiao, D; Li, D S; Wu, H L; Deng, L H; Zhang, Z F

    2016-12-01

    The giant panda׳s teeth possess remarkable load-bearing capacity and damage resistance for masticating bamboos. In this study, the hierarchical structure and mechanical behavior of the giant panda׳s tooth enamel were investigated under indentation. The effects of loading orientation and location on mechanical properties of the enamel were clarified and the evolution of damage in the enamel under increasing load evaluated. The nature of the damage, both at and beneath the indentation surfaces, and the underlying toughening mechanisms were explored. Indentation cracks invariably were seen to propagate along the internal interfaces, specifically the sheaths between enamel rods, and multiple extrinsic toughening mechanisms, e.g., crack deflection/twisting and uncracked-ligament bridging, were active to shield the tips of cracks from the applied stress. The giant panda׳s tooth enamel is analogous to human enamel in its mechanical properties, yet it has superior hardness and Young׳s modulus but inferior toughness as compared to the bamboo that pandas primarily feed on, highlighting the critical roles of the integration of underlying tissues in the entire tooth and the highly hydrated state of bamboo foods. Our objective is that this study can aid the understanding of the structure-mechanical property relations in the tooth enamel of mammals and further provide some insight on the food habits of the giant pandas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Effect of different concentrations of fluoride varnish on enamel surface microhardness: An in vitro randomized controlled study

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2016-01-01

    Full Text Available Introduction: Dental caries occurs as a result of demineralization-remineralization phases occurring alternately at the tooth surface. Fluoride varnishes have a caries-inhibiting effect on teeth through remineralization. The resulting enamel is resistant to acid dissolution. Aim: The aim of this study is to assess enamel surface microhardness (SMH following varnish application with different fluoride concentrations. Materials and Methods: Ninety freshly extracted, caries-free premolar teeth were used. Teeth were sectioned to obtain enamel blocks from the buccal surface of crown. The blocks were serially polished and flattened, embedded in acrylic blocks and smoothened to achieve a flat surface. The samples were divided into three groups, namely, A, B, and C consisting of 30 enamel blocks each. In Group A, Fluor Protector® varnish and in Group B, Bi-Fluorid 10® varnish was applied. Group C served as controls. All samples were subjected to a demineralization-remineralization cycle for 7 days. The SMH of enamel was measured. Data obtained was subjected to statistical analysis using the Student's t-test and one-way ANOVA. Results: The mean values of enamel SMH of Groups A and B were 496.99 ± 4.81 and 449.47 ± 7.37 Vickers Hardness Number, respectively. Conclusion: Fluor Protector varnish showed significantly higher enamel SMH than that of the other two groups (P < 0.05.

  13. Direct spectrometry: a new alternative for measuring the fluorescence of composite resins and dental tissues.

    Science.gov (United States)

    da Silva, Tm; de Oliveira, Hpm; Severino, D; Balducci, I; Huhtala, Mfrl; Gonçalves, Sep

    2014-01-01

    The aim of this study was to evaluate the fluorescence intensity of different composite resins and compare those values with the fluorescence intensity of dental tissues. Different composite resins were used to make 10 discs (2 mm in depth and 4 mm in diameter) of each brand, divided into groups: 1) Z (Filtek Z350, 3M ESPE), 2) ES (Esthet-X, Dentsply), 3) A (Amelogen Plus, Ultradent), 4) DVS (Durafill-VS, Heraeus Kulzer) with 2 mm composite resin for enamel (A2), 5) OES ([Esthet-X] opaque-OA [1 mm] + enamel-A2 [1 mm]); 6) ODVSI ([Charisma-Opal/Durafill-VSI], opaque-OM (1 mm) + translucent [1mm]), and 7) DVSI ([Durafill- VSI] translucent [2 mm]). Dental tissue specimens were obtained from human anterior teeth cut in a mesiodistal direction to obtain enamel, dentin, and enamel/dentin samples (2 mm). The fluorescence intensity of specimens was directly measured using an optic fiber associated with a spectrometer (Ocean Optics USB 4000) and recorded in graphic form (Origin 8.0 program). Data were submitted to statistical analysis using Dunnet, Tukey, and Kruskall-Wallis tests. Light absorption of the composite resins was obtained in a spectral range from 250 to 450 nm, and that of dental tissues was between 250 and 300 nm. All composite resins were excited at 398 nm and exhibited maximum emissions of around 485 nm. Fluorescence intensity values for all of the resins showed statistically significant differences (measured in arbitrary units [AUs]), with the exception of groups Z and DVS. Group DVSI had the highest fluorescence intensity values (13539 AU), followed by ODVS (10440 AU), DVS (10146 AU), ES (3946 AU), OES (3841 AU), A (3540 AU), and Z (1146 AU). The fluorescence intensity values for the composite resins differed statistically from those of dental tissues (E=1380 AU; D=6262 AU; E/D=3251 AU). The opacity interfered with fluorescence intensity, and group Z demonstrated fluorescence intensity values closest to that of tooth enamel. It is concluded that the

  14. Dental erosion--an overview with emphasis on chemical and histopathological aspects.

    Science.gov (United States)

    Lussi, A; Schlueter, N; Rakhmatullina, E; Ganss, C

    2011-01-01

    The quality of dental care and modern achievements in dental science depend strongly on understanding the properties of teeth and the basic principles and mechanisms involved in their interaction with surrounding media. Erosion is a disorder to which such properties as structural features of tooth, physiological properties of saliva, and extrinsic and intrinsic acidic sources and habits contribute, and all must be carefully considered. The degree of saturation in the surrounding solution, which is determined by pH and calcium and phosphate concentrations, is the driving force for dissolution of dental hard tissue. In relation to caries, with the calcium and phosphate concentrations in plaque fluid, the 'critical pH' below which enamel dissolves is about 5.5. For erosion, the critical pH is lower in products (e.g. yoghurt) containing more calcium and phosphate than plaque fluid and higher when the concentrations are lower. Dental erosion starts by initial softening of the enamel surface followed by loss of volume with a softened layer persisting at the surface of the remaining tissue. Dentine erosion is not clearly understood, so further in vivo studies, including histopathological aspects, are needed. Clinical reports show that exposure to acids combined with an insufficient salivary flow rate results in enhanced dissolution. The effects of these and other interactions result in a permanent ion/substance exchange and reorganisation within the tooth material or at its interface, thus altering its strength and structure. The rate and severity of erosion are determined by the susceptibility of the dental tissues towards dissolution. Because enamel contains less soluble mineral than dentine, it tends to erode more slowly. The chemical mechanisms of erosion are also summarised in this review. Special attention is given to the microscopic and macroscopic histopathology of erosion. Copyright © 2011 S. Karger AG, Basel.

  15. Androgen Receptor Involvement in Rat Amelogenesis: An Additional Way for Endocrine-Disrupting Chemicals to Affect Enamel Synthesis.

    Science.gov (United States)

    Jedeon, Katia; Loiodice, Sophia; Salhi, Khaled; Le Normand, Manon; Houari, Sophia; Chaloyard, Jessica; Berdal, Ariane; Babajko, Sylvie

    2016-11-01

    Endocrine-disrupting chemicals (EDCs) that interfere with the steroid axis can affect amelogenesis, leading to enamel hypomineralization similar to that of molar incisor hypomineralization, a recently described enamel disease. We investigated the sex steroid receptors that may mediate the effects of EDCs during rat amelogenesis. The expression of androgen receptor (AR), estrogen receptor (ER)-α, and progesterone receptor was dependent on the stage of ameloblast differentiation, whereas ERβ remained undetectable. AR was the only receptor selectively expressed in ameloblasts involved in final enamel mineralization. AR nuclear translocation and induction of androgen-responsive element-containing promoter activity upon T treatment, demonstrated ameloblast responsiveness to androgens. T regulated the expression of genes involved in enamel mineralization such as KLK4, amelotin, SLC26A4, and SLC5A8 but not the expression of genes encoding matrix proteins, which determine enamel thickness. Vinclozolin and to a lesser extent bisphenol A, two antiandrogenic EDCs that cause enamel defects, counteracted the actions of T. In conclusion, we show, for the first time, the following: 1) ameloblasts express AR; 2) the androgen signaling pathway is involved in the enamel mineralization process; and 3) EDCs with antiandrogenic effects inhibit AR activity and preferentially affect amelogenesis in male rats. Their action, through the AR pathway, may specifically and irreversibly affect enamel, potentially leading to the use of dental defects as a biomarker of exposure to environmental pollutants. These results are consistent with the steroid hormones affecting ameloblasts, raising the issue of the hormonal influence on amelogenesis and possible sexual dimorphism in enamel quality.

  16. Beneficial effects of hydroxyapatite on enamel subjected to 30% hydrogen peroxide.

    Science.gov (United States)

    Jiang, Tao; Ma, Xiao; Wang, Zhejun; Tong, Hua; Hu, Jiming; Wang, Yining

    2008-11-01

    To evaluate the effect of combination of hydroxyapatite (HA) and hydrogen peroxide (HP) on color, microhardness and morphology of human tooth enamel. Forty-eight human dental blocks were obtained from 12 pairs of premolars and were randomly divided into four groups. Group DW was treated with distilled water, group HP with 30% HP, group HA+DW with HA mixed with distilled water and group HA+HP with HA mixed with 30% HP. Baseline and final color measurements and microhardness test were carried out before and after bleaching experiments. Two specimens from each group were selected for morphological investigation after final tests. The DeltaE of group HP and HA+HP were significantly higher than those of group DW (p=0.000 and p=0.000) and group HA+DW (p=0.000 and p=0.000). The percentage microhardness loss of group HA+HP was significantly lower than that of group HP (p=0.047), but significantly higher than those of group DW (p=0.000) and group HA+DW (p=0.000). The obvious variation of morphology was only observed on enamel surfaces in group HP. This study suggested that combination of HA and HP was effective in tooth whitening. HA could significantly reduce the microhardness loss of enamel caused by 30% HP and keep enamel surface morphology almost unchanged.

  17. Evaluation of microtensile bond strength of different fissure sealants to bovine enamel.

    Science.gov (United States)

    Sen Tunc, E; Bayrak, S; Tuloglu, N; Ertas, E

    2012-03-01

    The aim of this study was to evaluate the microtensile bond strength (μTBS) of a new fissure sealant and compare it with conventional sealants which are applied to enamel alone, and also with self-etch and etch-and-rinse adhesives. Enamel specimens were prepared and randomly distributed into three groups according to fissure sealant (Aegis, Helioseal F, Helioseal Clear). Each group was then subdivided according to adhesive system (Clearfil S3, Single Bond, no adhesive). A universal testing machine was used to measure μTBS, and data were analysed using one-way ANOVA and Tukey's tests. μTBS values for all Aegis subgroups were significantly lower than for comparable Helioseal F and Helioseal Clear subgroups (p 0.05). In the Helioseal Clear group, μTBS values for Single Bond were significantly higher than for Clearfil S3 (p adhesive subgroups in the Aegis or Helioseal F groups (p > 0.05). Sealant μTBS values may be affected by material content. The addition of an adhesive may improve μTBS values of sealant to enamel. © 2012 Australian Dental Association.

  18. Diet, nutrition and the prevention of dental diseases

    DEFF Research Database (Denmark)

    Moynihan, Paula; Petersen, Poul Erik

    2004-01-01

    on teeth is the local action of diet in the mouth on the development of dental caries and enamel erosion. Dental erosion is increasing and is associated with dietary acids, a major source of which is soft drinks. Despite improved trends in levels of dental caries in developed countries, dental caries......Oral health is related to diet in many ways, for example, nutritional influences on craniofacial development, oral cancer and oral infectious diseases. Dental diseases impact considerably on self-esteem and quality of life and are expensive to treat. The objective of this paper is to review...... the evidence for an association between nutrition, diet and dental diseases and to present dietary recommendations for their prevention. Nutrition affects the teeth during development and malnutrition may exacerbate periodontal and oral infectious diseases. However, the most significant effect of nutrition...

  19. DENTAL MATERIAL BIOCOMPATIBILITY: A CROSS-SECTIONAL STUDY

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    Carmen SAVIN

    2017-06-01

    Full Text Available The aim of this study is to assess the knowledge of the students in the Faculty of Dental Medicine of Iasi on the biocompatibility of the dental materials used in current practice. To this end, we elaborated our own questionnaire, including 10 questions to which 92 students from the last 2 years of study answered. The questionnaire cotains assertions on the potential toxic reactions of the most frequently used dental materials. The students answered correctly to the questions related to the biocompatibility of certain dental materials, such as glass-ionomer cement and calcium hydroxide, and they recognized that allergic reactions determined by acrylic resins may occur. We also noticed the lack of knowledge referring to the irreversible modifications produced by the tooth whitening substances on the enamel and dentin, as well as to the side effects produced by dental amalgam.

  20. PIXE analysis of caries related trace elements in tooth enamel

    International Nuclear Information System (INIS)

    Annegarn, H.J.; Jodaikin, A.; Cleaton-Jones, P.E.; Sellschop, J.P.F.; Madiba, C.C.P.; Bibby, D.; University of the Witwatersrand, Johannesburg

    1981-01-01

    PIXE analysis has been applied to a set of twenty human teeth to determine trace element concentration in enamel from areas suceptible to dental caries (mesial and distal contact points) and in areas less susceptible to the disease (buccal surface), with the aim of determining the possible roles of trace elements in the carious process. The samples were caries-free anterior incisors extracted for periodontal reasons from subjects 10-30 years of age. Prior to extraction of the sample teeth, a detailed dental history and examination was carried out in each individual. PIXE analysis, using a 3 MeV proton beam of 1 mm diameter, allowed the determination of Ca, Mn, Fe, Cu, Zn, Sr and Pb above detection limits. As demonstrated in this work, the enhanced sensitivity of PIXE analysis over electron microprobe analysis, and capability of localised surface analysis compared with the pooled samples require for neutron activation analysis, makes it a powerful and useful technique in dental analysis. (orig.)

  1. PIXE analysis of caries related trace elements in tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Annegarn, H J; Jodaikin, A; Cleaton-Jones, P E; Sellschop, J P.F.; Madiba, C C.P.; Bibby, D [University of the Witwatersrand, Johannesburg (South Africa). Nuclear Physics Research Unit; University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit)

    1981-03-01

    PIXE analysis has been applied to a set of twenty human teeth to determine trace element concentration in enamel from areas suceptible to dental caries (mesial and distal contact points) and in areas less susceptible to the disease (buccal surface), with the aim of determining the possible roles of trace elements in the carious process. The samples were caries-free anterior incisors extracted for periodontal reasons from subjects 10-30 years of age. Prior to extraction of the sample teeth, a detailed dental history and examination was carried out in each individual. PIXE analysis, using a 3 MeV proton beam of 1 mm diameter, allowed the determination of Ca, Mn, Fe, Cu, Zn, Sr and Pb above detection limits. As demonstrated in this work, the enhanced sensitivity of PIXE analysis over electron microprobe analysis, and capability of localised surface analysis compared with the pooled samples require for neutron activation analysis, makes it a powerful and useful technique in dental analysis.

  2. In Situ analysis of CO2 laser irradiation on controlling progression of erosive lesions on dental enamel.

    Science.gov (United States)

    Lepri, Taísa Penazzo; Scatolin, Renata Siqueira; Colucci, Vivian; De Alexandria, Adílis Kalina; Maia, Lucianne Cople; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

    2014-08-01

    The present study aimed to evaluate in situ the effect of CO2 laser irradiation to control the progression of enamel erosive lesions. Fifty-six slabs of bovine incisors enamel (5 × 3 × 2.5 mm(3) ) were divided in four distinct areas: (1) sound (reference area), (2) initial erosion, (3) treatment (irradiated or nonirradiated with CO2 laser), (4) final erosion (after in situ phase). The initial erosive challenge was performed with 1% citric acid (pH = 2.3), for 5 min, 2×/day, for 2 days. The slabs were divided in two groups according to surface treatment: irradiated with CO2 laser (λ = 10.6 µm; 0.5 W) and nonirradiate. After a 2-day lead-in period, 14 volunteers wore an intraoral palatal appliance containing two slabs (irradiated and nonirradiated), in two intraoral phases of 5 days each. Following a cross-over design during the first intraoral phase, half of the volunteers immersed the appliance in 100 mL of citric acid for 5 min, 3×/day, while other half of the volunteers used deionized water (control). The volunteers were crossed over in the second phase. Enamel wear was determined by an optical 3D profilometer. Three-way ANOVA for repeated measures revealed that there was no significant interaction between erosive challenge and CO2 laser irradiation (P = 0.419). Erosive challenge significantly increased enamel wear (P = 0.001), regardless whether or not CO2 laser irradiation was performed. There was no difference in enamel wear between specimens CO2 -laser irradiated and non-irradiated (P = 0.513). Under intraoral conditions, CO2 laser irradiation did not control the progression of erosive lesions in enamel caused by citric acid. © 2014 Wiley Periodicals, Inc.

  3. An unusual case of non-syndromic occurrence of multiple dental anomalies

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    Suprabha B

    2009-01-01

    Full Text Available Dental anomalies have been known to occur in humans due to a variety of genetic and environmental factors. Combinations of dental anomalies are known to be associated with specific syndromes. A few cases of multiple dental anomalies have been reported in patients with no generalized abnormalities. This case report describes an unusual occurrence of a combination of dental anomalies in an apparently normal healthy 12-year-old female patient. The dental anomalies in this patient were multiple dens invaginatus, generalized enamel hypoplasia, generalized microdontia, root resorption and multiple periapical lesions, shovel shaped incisors, cup shaped premolars, taurodontism, hypodontia and supernumerary teeth.

  4. Extra-high doses detected in the enamel of human teeth in the Techa riverside region

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A., E-mail: ElenaA.Shishkina@gmail.com [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Degteva, M.O.; Tolstykh, E.I.; Volchkova, A. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Ivanov, D.V. [Institute of Metal Physics, Russian Academy of Sciences, 18 S. Kovalevsky Str, 620041 Yekaterinburg (Russian Federation); Wieser, A. [Helmholtz Zentrum Muenchen, German Research Centre for Environmental Health, D-85764 Neuherberg (Germany); Della Monaca, S. [Istituto Superiore di Sanita, 00161 Rome (Italy); Istituto Regina Elena, 00144 Rome (Italy); Fattibene, P. [Istituto Superiore di Sanita, 00161 Rome (Italy); Istituto Nazionale di Fisica Nucleare, 00161 Rome (Italy)

    2011-09-15

    During the long-term study of tooth enamel by EPR dosimetry for population exposed to radiation due to contamination of the Techa River, it was found out that for some of the tooth donors the dose accumulated in tooth enamel could be as high as several tens of Gy. Such doses were absorbed only in tooth enamel and they should not be associated with exposures to other organs or the whole body. The nature of such doses was discussed in a number of previous papers where it was shown that the source of such doses is {sup 90}Sr incorporated in the calcified dental tissues. However, among specialists in radiation dosimetry who were not involved in the biokinetic studies, the nature and dosimetric significance of extra-high doses in tooth enamel are still raising questions. The aim of the current paper is to summarize the accumulated information on extra-high doses in the teeth of the Techa riverside residents, describe the dose levels observed, explain the nature of extra-high doses in the enamel and discuss their informative value. The paper includes an overview of already published findings and an analysis of information collected in the data bank of the Urals Research Center for Radiation Medicine (URCRM), Chelyabinsk, Russia, which has not been published before.

  5. Determination of atomic number and composition of human enamel

    International Nuclear Information System (INIS)

    Nogueira, M.S.; Rodas Duran, J.E.

    2001-01-01

    The teeth are organs of complicated structure that consist, partly, of hard tissue containing in its interior the dental pulp, rich in vases and nerves. The main mass of the tooth is constituted by the dentine, which is covered with hard tissues and of epithelial origin called enamel. The dentine of the human teeth used in this work were completely removed and the teeth were cut with a device with a diamond disc. In this work the chemical composition of the human enamel was determined, which showed a high percentage of Ca and P, in agreement with the results found in the literature. The effective atomic number of the material and the half-value layer in the energy range of diagnostic X-ray beams were determined. Teeth could be used to evaluated the public's individual doses as well as for retrospective dosimetry what confirms the importance of their effective atomic number and composition determination. (author)

  6. Endocytosis and Enamel Formation

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    Cong-Dat Pham

    2017-07-01

    Full Text Available Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build the enamel layer (secretory stage and to reach final mineralization (maturation stage. Each stage has specific functional requirements for the ameloblasts. Ameloblasts adopt different cell morphologies during each stage. Protein trafficking including the secretion and endocytosis of enamel proteins is a fundamental task in ameloblasts. The sites of internalization of enamel proteins on the ameloblast membrane are specific for every stage. In this review, an overview of endocytosis and trafficking of vesicles in ameloblasts is presented. The pathways for internalization and routing of vesicles are described. Endocytosis is proposed as a mechanism to remove debris of degraded enamel protein and to obtain feedback from the matrix on the status of the maturing enamel.

  7. Current dental adhesives systems. A narrative review.

    Science.gov (United States)

    Milia, Egle; Cumbo, Enzo; Cardoso, Rielson Jose A; Gallina, Giuseppe

    2012-01-01

    Adhesive dentistry is based on the development of materials which establish an effective bond with the tooth tissues. In this context, adhesive systems have attracted considerable research interest in recent years. Successful adhesive bonding depends on the chemistry of the adhesive, on appropriate clinical handling of the material as well as on the knowledge of the morphological changes caused on dental tissue by different bonding procedures. This paper outlines the status of contemporary adhesive systems, with particular emphasis on chemical characteristics and mode of interaction of the adhesives with enamel and dentinal tissues. Dental adhesives are used for several clinical applications and they can be classified based on the clinical regimen in "etch-and-rinse adhesives" and "self-etch adhesives". Other important considerations concern the different anatomical characteristics of enamel and dentine which are involved in the bonding procedures that have also implications for the technique used as well as for the quality of the bond. Etch-and-rinse adhesive systems generally perform better on enamel than self-etching systems which may be more suitable for bonding to dentine. In order to avoid a possible loss of the restoration, secondary caries or pulp damage due to bacteria penetration or due to cytotoxicity effects of eluted adhesive components, careful consideration of several factors is essential in selecting the suitable bonding procedure and adhesive system for the individual patient situation.

  8. Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization

    Science.gov (United States)

    Gaines, Carmen Veronica

    The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types

  9. Real-time near IR (1310 nm) imaging of CO2 laser ablation of enamel.

    Science.gov (United States)

    Darling, Cynthia L; Fried, Daniel

    2008-02-18

    The high-transparency of dental enamel in the near-IR (NIR) can be exploited for real-time imaging of ablation crater formation during drilling with lasers. NIR images were acquired with an InGaAs focal plane array and a NIR zoom microscope during drilling incisions in human enamel samples with a lambda=9.3-microm CO(2) laser operating at repetition rates of 50-300-Hz with and without a water spray. Crack formation, dehydration and thermal changes were observed during ablation. These initial images demonstrate the potential of NIR imaging to monitor laser-ablation events in real-time to provide information about the mechanism of ablation and to evaluate the potential for peripheral thermal and mechanical damage.

  10. Effects of in-office bleaching on human enamel and dentin. Morphological and mineral changes.

    Science.gov (United States)

    Llena, Carmen; Esteve, Irene; Forner, Leopoldo

    2018-05-01

    The effects of HP-based products upon dental enamel and dentin are inconclusive. To evaluate changes in micromorphology and composition of calcium (Ca) and phosphate (P) in enamel and dentin after the application of 37.5% hydrogen peroxide (HP) and 35% carbamide peroxide (CP) METHODS: Crowns of 20 human teeth were divided in two halves. One half was used as control specimen and the other as experimental specimen. The control specimens were kept in artificial saliva, and the experimental specimens were divided into four groups (n=5 each): group 1 (enamel HP for 45min); group 2 (dentin HP for 45min); group 3 (enamel CP for 90min); and group 4 (dentin CP for 90min). The morphological changes were evaluated using confocal laser scanning microscopy (CLSM), while the changes in the composition of Ca and P were assessed using environmental scanning electron microscopy combined with a microanalysis system (ESEM+EDX). The results within each group and between groups were compared using the Wilcoxon test and Mann-Whitney U-test, respectively (p0.05). When bleaching products with a neutral pH are used in clinical practice, both, the concentration and the application time should be taken into account in order to avoid possible structural and mineral changes in enamel and dentin. Copyright © 2018 Elsevier GmbH. All rights reserved.

  11. Influence of Conditioning Time of Universal Adhesives on Adhesive Properties and Enamel-Etching Pattern.

    Science.gov (United States)

    Cardenas, A M; Siqueira, F; Rocha, J; Szesz, A L; Anwar, M; El-Askary, F; Reis, A; Loguercio, A

    2016-01-01

    To evaluate the effect of application protocol in resin-enamel microshear bond strength (μSBS), in situ degree of conversion, and etching pattern of three universal adhesive systems. Sixty-three extracted third molars were sectioned in four parts (buccal, lingual, and proximals) and divided into nine groups, according to the combination of the main factors-Adhesive (Clearfil Universal, Kuraray Noritake Dental Inc, Tokyo, Japan; Futurabond U, VOCO, Cuxhaven, Germany; and Scotchbond Universal Adhesive, 3M ESPE, St Paul, MN, USA)-and enamel treatment/application time (etch-and-rinse mode [ER], self-etch [SE] application for 20 seconds [SE20], and SE application for 40 seconds [SE40]). Specimens were stored in water (37°C/24 h) and tested at 1.0 mm/min (μSBS). The degree of conversion of the adhesives at the resin-enamel interfaces was evaluated using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a scanning electron microscope. Data were analyzed with two-way analysis of variance and Tukey test (α=0.05). In general, the application of the universal adhesives in the SE40 produced μSBS and degree of conversion that were higher than in the SE20 (puniversal adhesives in the SE mode may be a viable alternative to increase the degree of conversion, etching pattern, and resin-enamel bond strength.

  12. Detection and Analysis of Enamel Cracks by Quantitative Light-induced Fluorescence Technology.

    Science.gov (United States)

    Jun, Mi-Kyoung; Ku, Hye-Min; Kim, Euiseong; Kim, Hee-Eun; Kwon, Ho-Keun; Kim, Baek-Il

    2016-03-01

    The ability to accurately detect tooth cracks and quantify their depth would allow the prediction of crack progression and treatment success. The aim of this in vitro study was to determine the capabilities of quantitative light-induced fluorescence (QLF) technology in the detection of enamel cracks. Ninety-six extracted human teeth were selected for examining naturally existing or suspected cracked teeth surfaces using a photocuring unit. QLF performed with a digital camera (QLF-D) images were used to assess the ability to detect enamel cracks based on the maximum fluorescence loss value (ΔFmax, %), which was then analyzed using the QLF-D software. A histologic evaluation was then performed in which the samples were sectioned and observed with the aid of a polarized light microscope. The relationship between ΔFmax and the histology findings was assessed based on the Spearman rank correlation. The sensitivity and specificity were calculated to evaluate the validity of using QLF-D to analyze enamel inner-half cracks and cracks extending to the dentin-enamel junction. There was a strong correlation between the results of histologic evaluations of enamel cracks and the ΔFmax value, with a correlation coefficient of 0.84. The diagnostic accuracy of QLF-D had a sensitivity of 0.87 and a specificity of 0.98 for enamel inner-half cracks and a sensitivity of 0.90 and a specificity of 1.0 for cracks extending to the dentin-enamel junction. These results indicate that QLF technology would be a useful clinical tool for diagnosing enamel cracks, especially given that this is a nondestructive method. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Numerical Analysis of Masticatory Forces on a Lower First Molar considering the Contact between Dental Tissues

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    Rosa Alicia Hernández-Vázquez

    2018-01-01

    Full Text Available The aim of the present work is to identify the reactions of the dental organs to the different forces that occur during chewing and the transcendence of the union and contact maintained by the dental tissues. The study used a lower first molar biomodel with a real morphology and morphometry and consisting of the three dental tissues (enamel, dentin, and pulp each with its mechanical properties. In it, two simulations were carried out, as would the process of chewing a food. One of the simulations considers the contact between the enamel and the dentin, and the other does not take it into account. The results obtained differ significantly between the simulations that consider contact and those that do not, establishing the importance of taking this contact into account. In this way, the theories that establish horizontal and lateral occlusion forces are present during the functional chewing process which are viable to be correct. The case studies carried out present not only the reasons for the failure of enamel but also the failure of the restoration materials used. This reflection will allow the development of more adequate materials, mechanical design of prostheses, implants, and treatment.

  14. Demineralization of Enamel in Primary Second Molars Related to Properties of the Enamel

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    N. Sabel

    2012-01-01

    Full Text Available Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher.

  15. Prosthetic rehabilitation with an implant-supported fixed prosthesis using computer-aided design and computer-aided manufacturing dental technology for a patient with a mandibulectomy: A clinical report.

    Science.gov (United States)

    Yoon, Hyung-In; Han, Jung-Suk

    2016-02-01

    The fabrication of dental prostheses with computer-aided design and computer-aided manufacturing shows acceptable marginal fits and favorable treatment outcomes. This clinical report describes the management of a patient who had undergone a mandibulectomy and received an implant-supported fixed prosthesis by using additive manufacturing for the framework and subtractive manufacturing for the monolithic zirconia restorations. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  16. All-optical photoacoustic imaging and detection of early-stage dental caries

    Science.gov (United States)

    Sampathkumar, Ashwin; Hughes, David A.; Longbottom, Chris; Kirk, Katherine J.

    2015-02-01

    Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (tooth decay. This AOPAI system provides a non-contact, non-invasive and non-ionizing means of detecting early-stage dental caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.

  17. Erosion and abrasion on dental structures undergoing at-home bleaching

    Directory of Open Access Journals (Sweden)

    Tarquinio SBC

    2011-07-01

    Full Text Available Flávio Fernando Demarco1, Sônia Saeger Meireles2, Hugo Ramalho Sarmento1, Raquel Venâncio Fernandes Dantas1, Tatiana Botero3, Sandra Beatriz Chaves Tarquinio11Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Brazil; 2Department of Operative Dentistry, Federal University of Paraíba, Brazil; 3Cariology, Restorative Science, and Endodontics Department, School of Dentistry, University of Michigan, MI, USAAbstract: This review investigates erosion and abrasion in dental structures undergoing at-home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled.Keywords: peroxide, tooth bleaching, enamel, dentin, erosion, abrasion

  18. In vitro wear of four ceramic materials and human enamel on enamel antagonist.

    Science.gov (United States)

    Nakashima, Jun; Taira, Yohsuke; Sawase, Takashi

    2016-06-01

    The purpose of the present study was to evaluate the wear of four different ceramics and human enamel. The ceramics used were lithium disilicate glass (e.max Press), leucite-reinforced glass (GN-Ceram), yttria-stabilized zirconia (Aadva Zr), and feldspathic porcelain (Porcelain AAA). Hemispherical styli were fabricated with these ceramics and with tooth enamel. Flattened enamel was used for antagonistic specimens. After 100,000 wear cycles of a two-body wear test, the height and volume losses of the styli and enamel antagonists were determined. The mean and standard deviation for eight specimens were calculated and statistically analyzed using a non-parametric (Steel-Dwass) test (α = 0.05). GN-Ceram exhibited greater stylus height and volume losses than did Porcelain AAA. E.max Press, Porcelain AAA, and enamel styli showed no significant differences, and Aadva Zr exhibited the smallest stylus height and volume losses. The wear of the enamel antagonist was not significantly different among GN-Ceram, e.max Press, Porcelain AAA, and enamel styli. Aadva Zr resulted in significantly lower wear values of the enamel antagonist than did GN-Ceram, Porcelain AAA, and enamel styli. In conclusion, leucite-reinforced glass, lithium disilicate glass, and feldspathic porcelain showed wear values closer to those for human enamel than did yttria-stabilized zirconia. © 2016 Eur J Oral Sci.

  19. Effects of 45S5 bioglass on surface properties of dental enamel subjected to 35% hydrogen peroxide.

    Science.gov (United States)

    Deng, Meng; Wen, Hai-Lin; Dong, Xiao-Li; Li, Feng; Xu, Xin; Li, Hong; Li, Ji-Yao; Zhou, Xue-Dong

    2013-06-01

    Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.

  20. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    International Nuclear Information System (INIS)

    Buckova, M; Kasparova, M; Dostalova, T; Jelinkova, H; Sulc, J; Nemec, M; Fibrich, M; Bradna, P; Miyagi, M

    2013-01-01

    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel. (paper)