WorldWideScience

Sample records for based dental materials

  1. Nanotechnology-based restorative materials for dental caries management.

    Science.gov (United States)

    Melo, Mary A S; Guedes, Sarah F F; Xu, Hockin H K; Rodrigues, Lidiany K A

    2013-08-01

    Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhibit the demineralization process, to be used for remineralizing tooth structure, and to combat caries-related bacteria. These results are encouraging and open the doors to future clinical studies that will allow the therapeutic value of nanotechnology-based restorative materials to be established.

  2. Nanotechnology-based restorative materials for dental caries management

    OpenAIRE

    Melo, Mary A. S.; Guedes, Sarah F.F.; Xu, Hockin H. K.; Rodrigues, Lidiany K. A.

    2013-01-01

    Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhi...

  3. [Current status and further prospects of dental resin-based materials with antibacterial properties].

    Science.gov (United States)

    Shi, X; Lu, H B; Mao, J; Gong, S Q

    2016-09-01

    The mode of dental antibacterial resin-based materials can be divided into two types, namely, single and combined antibacterial mode. With regard to single antibacterial mode, only one kind of antibacterial agent is added into the resin, which can be released or act as contacting antibacterial agent. The single mode resin has limitation in sterilization methods and effect. As for combined antibacterial mode, it is a combination of different types of biocides and thus maximizes the sterilizing effect, including the releasing antibacterial agent incorporated with the contacting antibacterial agent or antibacterial agents combined with calcium compound possessing biological mineralization function. In this paper, current status and further prospects of dental resin-based materials with antibacterial properties are reviewed from the perspectives of single and combined antibacterial modes to provide guidance for dental antibacterial resin material research.

  4. [Biocompatibility of dental materials: Part 2. Materials with mucosal contact].

    Science.gov (United States)

    Klötzer, W T; Reuling, N

    1990-08-01

    Dental materials which are supposed to contact the oral, mucous membranes during their intended dental use may affect our patients health in different ways. Their local and systemic toxicity, and their allergenic and tumorigenic potential are reviewed and methods of biocompatibility testing discussed. Special emphasis is placed on impression materials, denture base resins and dental alloys. PMID:2269166

  5. A novel laser-based method for controlled crystallization in dental prosthesis materials

    Science.gov (United States)

    Cam, Peter; Neuenschwander, Beat; Schwaller, Patrick; Köhli, Benjamin; Lüscher, Beat; Senn, Florian; Kounga, Alain; Appert, Christoph

    2015-02-01

    Glass-ceramic materials are increasingly becoming the material of choice in the field of dental prosthetics, as they can feature both high strength and very good aesthetics. It is believed that their color, microstructure and mechanical properties can be tuned such as to achieve an optimal lifelike performance. In order to reach that ultimate perfection a controlled arrangement of amorphous and crystalline phases in the material is required. A phase transformation from amorphous to crystalline is achieved by a heat treatment at defined temperature levels. The traditional approach is to perform the heat treatment in a furnace. This, however, only allows a homogeneous degree of crystallization over the whole volume of the parent glass material. Here a novel approach using a local heat treatment by laser irradiation is presented. To investigate the potential of this approach the crystallization process of SiO2-Li2O-Al2O3-based glass has been studied with laser systems (pulsed and continuous wave) operating at different wavelengths. Our results show the feasibility of gradual and partial crystallization of the base material using continuous laser irradiation. A dental prosthesis machined from an amorphous glassy state can be effectively treated with laser irradiation and crystallized within a confined region of a few millimeters starting from the body surface. Very good aesthetics have been achieved. Preliminary investigation with pulsed nanosecond lasers of a few hundreds nanoseconds pulse width has enabled more refinement of crystallization and possibility to place start of phase change within the material bulk.

  6. Tribology of dental materials: a review

    International Nuclear Information System (INIS)

    The application of tribology in dentistry is a growing and rapidly expanding field. Intensive research has been conducted to develop an understanding of dental tribology for successful design and selection of artificial dental materials. In this paper, the anatomy and function of human teeth is presented in brief, three types of current artificial dental materials are summarized, and their advantages and disadvantages, as well as typical clinical applications, are compared based on the literature. Possible tribological damage of tooth structure, which is induced by complex interfacial motion, and friction-wear test methods are reported. According to results obtained by the authors and from the literature, the main progress in the area of dental tribology on both natural teeth and artificial dental materials is reviewed. Problems and challenges are discussed and future research directions for dental tribology are recommended. (topical review)

  7. Mechanical behaviour of dental composite filling materials using digital holography

    OpenAIRE

    Monteiro, J. M.; Lopes, H.; Vaz, M.A.P.; Campos, J.C. Reis

    2010-01-01

    One of the most common clinical problems in dentistry is tooth decay. Among the dental filling materials used to repair tooth structure that has been destroyed by decay are dental amalgam and composite materials based on acrylics. Dental amalgam has been used by dentists for the past 150 years as a dental restorative material due to its low cost, ease of application, strength, durability, and bacteriostatic effects. However its safety as a filling material has been questioned due to th...

  8. Cell death effects of resin-based dental material compounds and mercurials in human gingival fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Reichl, Franz-Xaver [Walther-Straub-Institute of Pharmacology and Toxicology, Munich (Germany); Ludwig-Maximilians-University, Department of Operative Dentistry and Periodontology, Munich (Germany); Esters, Magali; Simon, Sabine; Seiss, Mario [Walther-Straub-Institute of Pharmacology and Toxicology, Munich (Germany); Kehe, Kai [Bundeswehr Institute of Pharmacology and Toxicology, Munich (Germany); Kleinsasser, Norbert [University of Regensburg, Head and Neck Surgery, Department of Otolaryngology, Regensburg (Germany); Folwaczny, Matthias; Glas, Juergen; Hickel, Reinhard [Ludwig-Maximilians-University, Department of Operative Dentistry and Periodontology, Munich (Germany)

    2006-06-15

    In order to test the hypothesis that released dental restorative materials can reach toxic levels in human oral tissues, the cytotoxicities of the resin-based dental (co)monomers hydroxyethylmethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and bisglycidylmethacrylate (BisGMA) compared with methyl mercury chloride (MeHgCl) and the amalgam component mercuric chloride (HgCl{sub 2}) were investigated on human gingival fibroblasts (HGF) using two different test systems: (1) the modified XTT-test and (2) the modified H 33342 staining assay. The HGF were exposed to various concentrations of the test-substances in all test systems for 24 h. All tested (co)monomers and mercury compounds significantly (P<0.05) decreased the formazan formation in the XTT-test. EC{sub 50} values in the XTT assay were obtained as half-maximum-effect concentrations from fitted curves. Following EC{sub 50} values were found (mean [mmol/l]; s.e.m. in parentheses; n=12; * significantly different to HEMA): HEMA 11.530 (0.600); TEGDMA* 3.460 (0.200); UDMA* 0.106 (0.005); BisGMA* 0.087 (0.001); HgCl{sub 2}* 0.013 (0.001); MeHgCl* 0.005 (0.001). Following relative toxicities were found: HEMA 1; TEGDMA 3; UDMA 109; BisGMA 133; HgCl{sub 2} 887; MeHgCl 2306. A significant (P<0.05) increase of the toxicity of (co)monomers and mercurials was found in the XTT-test in the following order: HEMA < TEGDMA < UDMA < BisGMA < HgCl{sub 2} < MeHgCl. TEGDMA and MeHgCl induced mainly apoptotic cell death. HEMA, UDMA, BisGMA, and HgCl{sub 2} induced mainly necrotic cell death. The results of this study indicate that resin composite components have a lower toxicity than mercury from amalgam in HGF. HEMA, BisGMA, UDMA, and HgCl{sub 2} induced mainly necrosis, but it is rather unlikely that eluted substances (solely) can reach concentrations, which might induce necrotic cell death in the human physiological situation, indicating that other (additional) factors may be involved in

  9. Quantification of organic eluates from polymerized resin-based dental restorative materials by use of GC/MS.

    Science.gov (United States)

    Michelsen, Vibeke Barman; Moe, Grete; Skålevik, Rita; Jensen, Einar; Lygre, Henning

    2007-05-01

    Residual monomers, additives and degradation products from resin-based dental restorative materials eluted into the oral cavity may influence the biocompatibility of these materials. Emphasis has been placed on studies addressing cytotoxic, genotoxic and estrogenic potential of these substances. A prerequisite for analyzing the potential of exposure to eluted compounds from dental materials is reliable quantification methods, both real time and accelerated measurements. The purpose of the present study was to quantify nine eluates; 2-hydroxyethyl methacrylate (HEMA), hydroquinone monomethyl ether (MEHQ), camphorquinone (CQ), butylated hydroxytoluene (BHT), ethyl 4-(dimethylamino)benzoate (DMABEE), triethylene glycoldimethacrylate (TEGDMA), trimethylolpropane trimethacrylate (TMPTMA), oxybenzone (HMBP) and drometrizole (TIN P) leaching from specimens of four commonly used resin-based dental materials in ethanol and an aqueous solution. All analyses were performed by use of GC/MS, each component was quantified separately and the results presented in microg mm(-2). This study has shown that elution from various materials differs significantly, not only in the types of eluates, but also regarding amounts of total and of single components. A high amount of HMBP, a UV stabilizer with potential estrogenic activity, was detected from one material in both solutions. PMID:17127109

  10. Roughness Measurement of Dental Materials

    Directory of Open Access Journals (Sweden)

    Shulev Assen

    2016-06-01

    Full Text Available This paper presents a roughness measurement of zirconia ceramics, widely used for dental applications. Surface roughness variations caused by the most commonly used dental instruments for intraoral grinding and polishing are estimated. The applied technique is simple and utilizes the speckle properties of the scattered laser light. It could be easily implemented even in dental clinic environment. The main criteria for roughness estimation is the average speckle size, which varies with the roughness of zirconia. The algorithm used for the speckle size estimation is based on the normalized autocorrelation approach.

  11. Roughness Measurement of Dental Materials

    Science.gov (United States)

    Shulev, Assen; Roussev, Ilia; Karpuzov, Simeon; Stoilov, Georgi; Ignatova, Detelina; See, Constantin von; Mitov, Gergo

    2016-06-01

    This paper presents a roughness measurement of zirconia ceramics, widely used for dental applications. Surface roughness variations caused by the most commonly used dental instruments for intraoral grinding and polishing are estimated. The applied technique is simple and utilizes the speckle properties of the scattered laser light. It could be easily implemented even in dental clinic environment. The main criteria for roughness estimation is the average speckle size, which varies with the roughness of zirconia. The algorithm used for the speckle size estimation is based on the normalized autocorrelation approach.

  12. Degradation of dental ZrO2-based materials after hydrothermal fatigue. Part I: XRD, XRF, and FESEM analyses.

    Science.gov (United States)

    Perdigão, Jorge; Pinto, Ana M; Monteiro, Regina C C; Braz Fernandes, Francisco M; Laranjeira, Pedro; Veiga, João P

    2012-01-01

    The aim was to investigate the effect of simulated low-temperature degradation (s-LTD) and hydrothermal fatigue on the degradation of three ZrO(2)-based dental materials. Lava, IPS, and NanoZr discs were randomly assigned to (1) Control-Storage in distilled water at 37°C; (2) Aging at 134°C for 5 h (s-LTD); (3) Thermocycling in saliva for 30,000 cycles (TF). XRD revealed that ZrO(2) m phase was identified in all groups but TF increased the m phase only for Lava. Under the FESEM, Lava showed no alterations under s-LTD, but displayed corrosion areas up to 60 µm wide after TF. We conclude that TF accelerated the degradation of Lava through an increase in the m phase and grain pull-out from the material surface. PMID:22447060

  13. Tissue mimicking materials for dental ultrasound

    OpenAIRE

    Singh, Rahul S.; Culjat, Martin O.; Grundfest, Warren S.; Brown, Elliott R.; White, Shane N

    2008-01-01

    While acoustic tissue mimicking materials have been explored for a variety of soft and hard biological tissues, no dental hard tissue mimicking materials have been characterized. Tooth phantoms are necessary to better understand acoustic phenomenology within the tooth environment and to accelerate the advancement of dental ultrasound imaging systems. In this study, soda lime glass and dental composite were explored as surrogates for human enamel and dentin, respectively, in terms of compressi...

  14. Materials for endosseous dental implants.

    Science.gov (United States)

    Wataha, J C

    1996-02-01

    The goal of placement of endosseous dental implants is to achieve osseointegration or biointegration of the bone with the implant. A wide variety of materials has been used for these implants, but only a few promote osseointegration and biointegration. Titanium and titanium alloy (Ti6A14V) have been the most widely used of these materials. The surface oxide of titanium appears to be central to the ability of this material to osseointegrate. The oxide limits dissolution of elements and promotes the deposition of biological molecules which allow bone to exist as close as 30 A to the surface of the implant. The details of the ultrastructure of the gap between the implant and bone remain undefined, and the consequences of elements which are released on the interface over time are not known. These areas of investigation are particularly important in defining the differences between commercially pure titanium implants and those made of titanium, aluminium and vanadium. The epithelial interface between the gingiva and titanium appears to contain many of the structural characteristics of the native tooth-gingiva interface, but details are still vague. The connective tissue interface with the titanium appears to be one of tightly fitting tissues rather than adhesion. Ceramic coatings appear to improve the ingrowth of bone and promote chemical integration of the implant with the bone. The characteristics of these coatings are complex and affect the bony response, but the mechanisms remain obscure. The degradation of the coatings is an issue of particular controversy. Progress in dental implantology is likely to continue as the interface between the material and bone is more clearly understood, and biological molecules and artificial tissues are developed.

  15. Effects of dental materials on MR images

    International Nuclear Information System (INIS)

    As MR imaging of the head and neck area becomes increasingly important in evaluating pathologic conditions of the brain, mid-face, and pharynx, it is becoming apparent that artifacts due to certain dental materials can obscure the findings. Although this fact has been known for some time, a study to identify which materials produce artifacts has not been performed. The authors examined the degree of artifact production caused by various materials commonly used in dental restorations. Since not all dental materials produce artifacts during MR imaging, these materials are described also

  16. Ex vivo and in vitro synchrotron-based micro-imaging of biocompatible materials applied in dental surgery

    Science.gov (United States)

    Rack, A.; Stiller, M.; Nelson, K.; Knabe, C.; Rack, T.; Zabler, S.; Dalügge, O.; Riesemeier, H.; Cecilia, A.; Goebbels, J.

    2010-09-01

    Biocompatible materials such as porous bioactive calcium phosphate ceramics or titanium are regularly applied in dental surgery: ceramics are used to support the local bone regeneration in a given defect, afterwards titanium implants replace lost teeth. The current gold standard for bone reconstruction in implant dentistry is the use of autogenous bone grafts. But the concept of guided bone regeneration (GBR) has become a predictable and well documented surgical approach using biomaterials (bioactive calcium phosphate ceramics) which qualify as bone substitutes for this kind of application as well. We applied high resolution synchrotron microtomography and subsequent 3d image analysis in order to investigate bone formation and degradation of the bone substitute material in a three-dimensional manner, extending the knowledge beyond the limits of classical histology. Following the bone regeneration, titanium-based implants to replace lost teeth call for high mechanical precision, especially when two-piece concepts are used in order to guaranty leak tightness. Here, synchrotron-based radiography in comparison with classical laboratory radiography yields high spatial resolution in combination with high contrast even when exploiting micro-sized features in these kind of highly attenuating objects. Therefore, we could study micro-gap formation at interfaces in two-piece dental implants with the specimen under different mechanical load. We could prove the existence of micro-gaps for implants with conical connections as well as to study the micromechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential issue of failure, i. e. bacterial leakage which can induce an inflammatory process.

  17. A chemical activity evaluation of two dental calcium silicate-based materials

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2015-06-01

    Full Text Available Calcium silicate-based materials are interesting products widely used in dentistry. The study was designed to compare the chemical reaction between analyzed two preparates and dentin during cavity lining. In our work, dentinal discs were prepared from human extracted teeth filled with Biodentine and MTA+. The samples were then analyzed by way of SEM, EDS and Raman spectroscopy. The obtained results revealed differences in elemental composition between both materials. Biodentine showed higher activity in contact with dentine. Moreover, the interfacial layer in the tooth filled by Biodentine was wider than that in the tooth filled with MTA+. The applied methods of analysis confirmed that both materials have a bioactive potential which is a promising ability.

  18. International distribution of dental materials publications and patents.

    Science.gov (United States)

    Garrison, H H; Herman, S S; Lipton, J A

    1992-01-01

    International patterns of research and development in the field of restorative dental materials were examined with data on publications (1981-85) and patents (1979-88). It was found that United States-based authors produced approximately one-half of all dental materials journal articles published worldwide, while US inventors had nearly the same share of the US dental materials patents. During the periods studied, the share of US patents in dental materials awarded to US inventors declined, while the share of US patents awarded to Japanese inventors rose. The role of the United States in research (as measured by journal articles) remained stable. Nations differed in the degree to which their researchers specialized in particular research areas. US-based authors and inventors were relatively over-represented in prosthetic materials and under-represented in dental cements, an area in which the British and the Japanese concentrated more of their activity. There was some, but not complete, agreement in the patterns of national specialization as indexed by patent and publication data. When dental materials data were compared with data for broader fields of science and technology, important differences were found. For publications, US-based authors displayed greater dominance in dental materials than in the fields of dentistry, chemistry, and materials science. US-based inventors' share of US dental materials patents was smaller than their share of all US patents. These analyses demonstrated that it was possible to use indicators derived from publication and patent data files to conduct insightful studies of a discrete specialty of science and technology. PMID:1521683

  19. Side Effects and Complications of Dental Materials on Oral Cavity

    Directory of Open Access Journals (Sweden)

    Z. Atai

    2007-01-01

    Full Text Available Development of dental materials has had a great impact on the modern dentistry. The materials ranging from polymers to metals have different applications in dentistry. Besides their important role in healing or improving the function of oral tissues, the materials may show side effects which may, in some cases, lead to severe lesions. In this review the side effects have been summarized considering a new classification for dental materials according to the duration of their applications as temporary or permanent materials. The side effects of the materials are then discussed based on clinical and cellular views.

  20. Interactions of liposomes with dental restorative materials.

    Science.gov (United States)

    Nguyen, Sanko; Adamczak, Malgorzata; Hiorth, Marianne; Smistad, Gro; Kopperud, Hilde Molvig

    2015-12-01

    The in vitro adsorption and retention of liposomes onto four common types of dental restorative materials (conventional and silorane-based resin composites as well as conventional and resin-modified glass ionomer cements (GIC)) have been investigated due to their potential use in the oral cavity. Uncoated liposomes (positively and negatively charged) and pectin (low- and high-methoxylated) coated liposomes were prepared and characterized in terms of particle size and zeta potential. The adsorption of liposomes was performed by immersion, quantified by fluorescence detection, and visualized by fluorescence imaging and atomic force microscopy. Positive liposomes demonstrated the highest adsorption on all four types of materials likely due to their attractive surface charge. They also retained well (minimum 40% after 60 min) on both conventional resin composite and GIC even when exposed to simulated salivary flow. Although an intermediate initial level of adsorption was found for the pectin coated liposomes, at least 70% high methoxylated-pectin coated liposomes still remained on the conventional resin composite after 60 min flow exposure. This indicates significant contribution of hydrophobic interactions in the prolonged binding of liposomes to resin composites. Based on these results, the present paper suggests two new possible applications of liposomes in the preservation of dental restorations.

  1. Finite element calculation of residual stress in dental restorative material

    Science.gov (United States)

    Grassia, Luigi; D'Amore, Alberto

    2012-07-01

    A finite element methodology for residual stresses calculation in dental restorative materials is proposed. The material under concern is a multifunctional methacrylate-based composite for dental restorations, activated by visible light. Reaction kinetics, curing shrinkage, and viscoelastic relaxation functions were required as input data on a structural finite element solver. Post cure effects were considered in order to quantify the residual stresses coming out from natural contraction with respect to those debited to the chemical shrinkage. The analysis showed for a given test case that residual stresses frozen in the dental restoration at uniform temperature of 37°C are of the same order of magnitude of the strength of the dental composite material per se.

  2. Dental materials for cleft palate repair.

    Science.gov (United States)

    Sharif, Faiza; Ur Rehman, Ihtesham; Muhammad, Nawshad; MacNeil, Sheila

    2016-04-01

    Numerous bone and soft tissue grafting techniques are followed to repair cleft of lip and palate (CLP) defects. In addition to the gold standard surgical interventions involving the use of autogenous grafts, various allogenic and xenogenic graft materials are available for bone regeneration. In an attempt to discover minimally invasive and cost effective treatments for cleft repair, an exceptional growth in synthetic biomedical graft materials have occurred. This study gives an overview of the use of dental materials to repair cleft of lip and palate (CLP). The eligibility criteria for this review were case studies, clinical trials and retrospective studies on the use of various types of dental materials in surgical repair of cleft palate defects. Any data available on the surgical interventions to repair alveolar or palatal cleft, with natural or synthetic graft materials was included in this review. Those datasets with long term clinical follow-up results were referred to as particularly relevant. The results provide encouraging evidence in favor of dental and other related biomedical materials to fill the gaps in clefts of lip and palate. The review presents the various bones and soft tissue replacement strategies currently used, tested or explored for the repair of cleft defects. There was little available data on the use of synthetic materials in cleft repair which was a limitation of this study. In conclusion although clinical trials on the use of synthetic materials are currently underway the uses of autologous implants are the preferred treatment methods to date.

  3. Dental material artifacts on MR images.

    Science.gov (United States)

    Hinshaw, D B; Holshouser, B A; Engstrom, H I; Tjan, A H; Christiansen, E L; Catelli, W F

    1988-03-01

    Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.

  4. Insights on Ceramics as Dental Materials. Part I: Ceramic Material Types in Dentistry

    OpenAIRE

    Ho, GW; Matinlinna, JP

    2011-01-01

    Ceramics are widely used biomaterials in prosthetic dentistry due to their attractive clinical properties. They are aesthetically pleasing with their color, shade and luster, and they are chemically stable. The main constituents of dental ceramic are Si-based inorganic materials, such as feldspar, quartz, and silica. Traditional feldspar-based ceramics are also referred to as "Porcelain". The crucial difference between a regular ceramic and a dental ceramic is the proportion of feldspar, quar...

  5. Fifty years of Brazilian Dental Materials Group: scientific contributions of dental materials field evaluated by systematic review

    Science.gov (United States)

    ROSA, Wellington Luiz de Oliveira; SILVA, Tiago Machado; LIMA, Giana da Silveira; SILVA, Adriana Fernandes; PIVA, Evandro

    2016-01-01

    ABSTRACT Objective A systematic review was conducted to analyze Brazilian scientific and technological production related to the dental materials field over the past 50 years. Material and Methods This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (Prisma) statement. Searches were performed until December 2014 in six databases: MedLine (PubMed), Scopus, LILACS, IBECS, BBO, and the Cochrane Library. Additionally, the Brazilian patent database (INPI - Instituto Nacional de Propriedade Industrial) was screened in order to get an overview of Brazilian technological development in the dental materials field. Two reviewers independently analyzed the documents. Only studies and patents related to dental materials were included in this review. Data regarding the material category, dental specialty, number of documents and patents, filiation countries, and the number of citations were tabulated and analyzed in Microsoft Office Excel (Microsoft Corporation, Redmond, Washington, United States). Results A total of 115,806 studies and 53 patents were related to dental materials and were included in this review. Brazil had 8% affiliation in studies related to dental materials, and the majority of the papers published were related to dental implants (1,137 papers), synthetic resins (681 papers), dental cements (440 papers), dental alloys (392 papers) and dental adhesives (361 papers). The Brazilian technological development with patented dental materials was smaller than the scientific production. The most patented type of material was dental alloys (11 patents), followed by dental implants (8 patents) and composite resins (7 patents). Conclusions Dental materials science has had a substantial number of records, demonstrating an important presence in scientific and technological development of dentistry. In addition, it is important to approximate the relationship between academia and industry to expand the technological development in

  6. Protection and Reinforcement of Tooth Structures by Dental Coating Materials

    Directory of Open Access Journals (Sweden)

    Toru Nikaido

    2012-10-01

    Full Text Available It has been proposed that a resin coating can serve as a means to protect dental structure after preparation of the tooth for indirect restorations, sealing the exposed dentin. The resin coating is applied on the cut surfaces immediately after tooth preparation and before making an impression by assembling a dentin bonding system and a flowable composite. Resin coatings minimize pulp irritation and improve the bond strength between a resin cement and tooth when bonding the restoration to tooth. Recently, thin-film coating dental materials based on all-in-one adhesive technology were introduced for resin coating of indirect restorations. The thin coating materials are applied in a single clinical step and create a barrier-like film layer on the prepared dentin. The thin coatings play an important role in protecting the dentin from physical, chemical, and biological irritation. In addition, these thin-film coating materials reportedly prevent marginal leakage beneath inlays or crown restorations. In light of the many benefits provided by such a protective layer, these all-in-one adhesive materials may therefore also have the potential to cover exposed root dentin surfaces and prevent caries formation. In this paper, recent progress of the dental coating materials and their clinical applications are reviewed.

  7. Modeling the Residual Stresses in Reactive Resins-Based Materials: a Case Study of Photo-Sensitive Composites for Dental Applications

    Science.gov (United States)

    Grassia, Luigi; D'Amore, Alberto

    2010-06-01

    Residual stresses in reactive resins-based composites are associated to the net volumetric contraction (shrinkage) arising during the cross-linking reactions. Depending on the restoration geometry (the ratio of the free surface area to the volume of the cavity) the frozen-in stresses can be as high as the strength of the dental composites. This is the main reason why the effectiveness and then the durability of restorations with composites remains quite lower than those realized with metal alloys based materials. In this paper we first explore the possibility to circumvent the mathematical complexity arising from the determination of residual stresses in reactive systems three-dimensionally constrained. Then, the results of our modeling approach are applied to a series of commercially available composites showing that almost all samples develop residual stresses such that the restoration undergoes failure as soon as it is realized.

  8. Determination of dose rates from natural radionuclides in dental materials

    International Nuclear Information System (INIS)

    Different types of materials used for dental prosthetics restoration, including feldspathic ceramics, glass ceramics, zirconia-based ceramics, alumina-based ceramics, and resin-based materials, were investigated with regard to content of natural radionuclides by means of thermoluminescence beta dosimetry and gamma spectrometry. The gross beta dose rate from feldspathic and glass ceramics was about ten times higher than the background measurement, whereas resin-based materials generated negligible beta dose rate, similarly to natural tooth samples. The specific activity of uranium and thorium was significantly below the levels found in the period when addition of uranium to dental porcelain materials was still permitted. The high-beta dose levels observed in feldspathic porcelains and glass ceramics are thus mainly ascribable to 4K, naturally present in these specimens. Although the measured values are below the recommended limits, results indicate that patients with prostheses are subject to higher dose levels than other members of the population. Alumina- and zirconia-based ceramics might be a promising alternative, as they have generally lower beta dose rates than the conventional porcelain materials. However, the dosimetry results, which imply the presence of inhomogeneously distributed clusters of radionuclides in the sample matrix, and the still unsuitable structural properties call for further optimization of these materials

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

    International Nuclear Information System (INIS)

    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 1012n 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)

  10. Dental Assisting Course. Bilingual Vocational Instructional Materials.

    Science.gov (United States)

    Lopez-Cox, Guadalupe

    This course in dental assisting, one of a series of bilingual English-Spanish vocational education courses, is designed to prepare the student to assist the dentist at the chairside in the dental operatory, to perform reception and clerical functions, and to carry out selected dental laboratory work. The course covers an introduction to the…

  11. Multi-material laser densification (MMLD) of dental restorations: Process optimization and properties evaluation

    Science.gov (United States)

    Li, Xiaoxuan

    This Ph.D. thesis proposes to investigate the feasibility of laser-assisted dental restoration and to develop a fundamental understanding of the interaction between laser beam and dental materials. Traditional dental restorations are produced by the porcelain-fused-to-metal (PFM) process, in which a dental restoration is cast from a metallic alloy and then coated with dental porcelains by multiple furnace-firing processes. PFM method is labor-intensive and hence very expensive. In order to fabricate dental restoration units faster and more cost-effectively, the Solid Freeform Fabrication (SFF) technique has been employed in this study. In particular, a Multi-Material Laser Densification (MMLD) process has been investigated for its potential to fabricate artificial teeth automatically from 3-D computer dental tooth files. Based on the principle of SFF, the MMLD process utilizes a micro-extruder system to deliver commercial dental alloy and porcelain slurry in a computer-controlled pattern line by line and layer by layer. Instead of firing the artificial tooth/teeth in a furnace, the extruded dental materials are laser scanned to convert the loose powder to a fully dense body. Different laser densification parameters including the densification temperature, laser output power, laser beam size, line dimension, ratio of the beam size to line width, beam scanning rate, processing atmosphere and pressure, dental powder state (powder bed or slurry), powder particle size, etc. have been used to evaluate their effects on the microstructures and properties of the laser densified dental body, and hence to optimize MMLD conditions. Furthermore, laser-scanning induced phase transformations in dental porcelains have been studied because the transformations have great impact on coefficient of thermal expansion (CTE) of dental porcelains, which should match that of dental alloy substrate. Since a single dental material line delivered by the MMLD system functions as a "construction

  12. Educational material of dental anatomy applied to study the morphology of permanent teeth.

    Science.gov (United States)

    Siéssere, Selma; Vitti, Mathias; de Sousa, Luiz Gustavo; Semprini, Marisa; Regalo, Simone Cecílio Hallak

    2004-01-01

    The purpose of this report is to present educational material that would allow the dental student to learn to easily identify the morphologic characteristics of permanent teeth, and how they fit together (occlusion). In order to do this, macro models of permanent teeth with no attrition were carved in wax and later molded with alginate. These molds were filled with plaster, dental stone and/or cold-cured acrylic resin. The large individual dental stone tooth models were mounted on a wax base, thus obtaining maxillary and mandibular arches which were occluded. These dental arches were molded with plaster or dental stone. The authors suggest that these types of macro models allow an excellent visualization of the morphologic characteristics of permanent teeth and occlusion. Dental students are able to carve the permanent dentition in wax with great facility when they can observe macro models.

  13. Effects of Different pH-Values on the Nanomechanical Surface Properties of PEEK and CFR-PEEK Compared to Dental Resin-Based Materials

    Directory of Open Access Journals (Sweden)

    Shuai Gao

    2015-07-01

    Full Text Available The study determines the stability and durability of polyetheretherketone (PEEK and a carbon fiber-reinforced PEEK (CFR-PEEK with 30% short carbon fibers, a dental composite based on Bis-GMA and polymethylmethacrylate (PMMA under the influence of different pH-values of the oral environment in vitro. Nanomechanical properties were investigated by nanoindentation and nanoscratch tests before and after incubation of the specimens at 37 °C for 30 days in artificial saliva with pH-values of 3, 7 and 10, respectively. Nanoindentation and nanoscratching tests were performed using the Hysitron TI950 TriboIndenter to evaluate the reduced elastic moduli, nanohardness, viscoelasticity, friction coefficient and residual scratch profiles. After treatment, the nanomechanical properties of unfilled PEEK did not change. The reduced elastic moduli and nanohardness of the carbon fiber-reinforced PEEK increased significantly. The reduced elastic moduli and nanohardness of CHARISMA decreased. The plasticity of all materials except that of the unfilled PEEK increased. This indicates that different pH-values of the artificial saliva solutions had no obvious influences on the nanomechanical properties of the PEEK matrix. Therefore, the aging resistance of the unfilled PEEK was higher than those of other materials. It can be deduced that the PEEK matrix without filler was more stable than with filler in the nanoscale.

  14. Creating a Successful School-Based Mobile Dental Program

    Science.gov (United States)

    Jackson, David M.; Jahnke, Lauren R.; Kerber, Lisa; Nyer, Genie; Siemens, Kammi; Clark, Carol

    2007-01-01

    Background: Dental disease is one of the leading causes of school absenteeism for children. This article describes the creation and evolution of the St. David's Dental Program, a mobile school-based dental program for children. Methods: The dental program is a collaboration of community partners in Central Texas that provides free dental care to…

  15. Role of dental restoration materials in oral mucosal lichenoid lesions

    Directory of Open Access Journals (Sweden)

    Rajneesh Sharma

    2015-01-01

    Full Text Available Background: Dental restorative materials containing silver-mercury compounds have been known to induce oral lichenoid lesions. Objectives: To determine the frequency of contact allergy to dental restoration materials in patients with oral lichenoid lesions and to study the effect of removal of the materials on the lesions. Results: Forty-five patients were recruited in three groups of 15 each: Group A (lesions in close contact with dental materials, Group B (lesions extending 1 cm beyond the area of contact and Group C (no topographic relationship. Thirty controls were recruited in two groups of 15 individuals each: Group D (oral lichenoid lesions but no dental material and Group E (dental material but no oral lichenoid lesions. Patch tests were positive in 20 (44.5% patients. Mercury was the most common allergen to elicit a positive reaction in eight patients, followed by nickel (7, palladium (5, potassium dichromate (3, balsam of Peru, gold sodium thiosulphate 2 and tinuvin (2 and eugenol (1, cobalt chloride (1 and carvone (1. Seven patients elicited positive response to more than one allergen. In 13 of 20 patients who consented to removal of the dental material, complete healing was observed in 6 (30%, marked improvement in 7 (35% and no improvement in 7 (35% patients. Relief of symptoms was usually observed 3 months after removal. Limitations: Limited number of study subjects and short follow up after removal/replacement of dental restoration materials are the main limitations of this study. Conclusion: Contact allergy to amalgam is an important etiologic factor in oral lichenoid lesions and removal of restorative material should be offered to patients who have lesions in close proximity to the dental material.

  16. Readability of pediatric health materials for preventive dental care

    Directory of Open Access Journals (Sweden)

    Riedy Christine A

    2006-11-01

    Full Text Available Abstract Background This study examined the content and general readability of pediatric oral health education materials for parents of young children. Methods Twenty-seven pediatric oral health pamphlets or brochures from commercial, government, industry, and private nonprofit sources were analyzed for general readability ("usability" according to several parameters: readability, (Flesch-Kincaid grade level, Flesch Reading Ease, and SMOG grade level; thoroughness, (inclusion of topics important to young childrens' oral health; textual framework (frequency of complex phrases, use of pictures, diagrams, and bulleted text within materials; and terminology (frequency of difficult words and dental jargon. Results Readability of the written texts ranged from 2nd to 9th grade. The average Flesch-Kincaid grade level for government publications was equivalent to a grade 4 reading level (4.73, range, 2.4 – 6.6; F-K grade levels for commercial publications averaged 8.1 (range, 6.9 – 8.9; and industry published materials read at an average Flesch-Kincaid grade level of 7.4 (range, 4.7 – 9.3. SMOG readability analysis, based on a count of polysyllabic words, consistently rated materials 2 to 3 grade levels higher than did the Flesch-Kincaid analysis. Government sources were significantly lower compared to commercial and industry sources for Flesch-Kincaid grade level and SMOG readability analysis. Content analysis found materials from commercial and industry sources more complex than government-sponsored publications, whereas commercial sources were more thorough in coverage of pediatric oral health topics. Different materials frequently contained conflicting information. Conclusion Pediatric oral health care materials are readily available, yet their quality and readability vary widely. In general, government publications are more readable than their commercial and industry counterparts. The criteria for usability and results of the analyses

  17. Artifacts in magnetic resonance imaging and computed tomography caused by dental materials.

    Directory of Open Access Journals (Sweden)

    Thomas Klinke

    Full Text Available BACKGROUND: Artifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images. METHODS: Test samples of 44 materials (Metal and Non-Metal commonly used in dental restorations were fabricated and embedded with reference specimens in gelatin moulds. MRI imaging of 1.5T and CT scan were performed on the samples and evaluated in two dimensions. Artifact size and distortions were measured using a digital image analysis software. RESULTS: In MRI, 13 out of 44 materials produced artifacts, while in CT 41 out of 44 materials showed artifacts. Artifacts produced in both MRI and CT images were categorized according to the size of the artifact. SIGNIFICANCE: Metal based restoration materials had strong influence on CT and less artifacts in MRI images. Rare earth elements such as Ytterbium trifluoride found in composites caused artifacts in both MRI and CT. Recognizing these findings would help dental materials manufacturers and developers to produce materials which can cause less artifacts in MRI and CT images.

  18. Ablation by-products of dental materials from the Er:YAG laser and the dental handpiece

    Science.gov (United States)

    Wigdor, Harvey A.; Visuri, Steven R.; Walsh, Joseph T., Jr.

    1995-05-01

    Recently there has been much interest in lasers and their potential use to replace the dental drill. The research has been directed towards vital dental tissues. It must be understood that any laser to be used in dentistry which will replace the dental drill must also ablate and remove existing dental materials. Some concern exists about the ablation products when the Er:YAG laser is used to ablate dental materials. It is incumbent on the professionals using these lasers to understand the materials being produced by these lasers and protect themselves and their patients from possible toxic products. It is the intent of this paper to evaluate the products produced by the ablation of both dental amalgam and composite dental restorative materials and compare them with those produced by the traditional dental handpiece (drill).

  19. A rare allergy to a polyether dental impression material.

    Science.gov (United States)

    Mittermüller, Pauline; Szeimies, Rolf-Markus; Landthaler, Michael; Schmalz, Gottfried

    2012-08-01

    Polyether impression materials have been used in dentistry for more than 40 years. Allergic reactions to these materials such as reported in the 1970s ceased after replacement of a catalyst. Very recently, however, patients have started to report symptoms that suggest a new allergic reaction from polyether impression materials. Here, we report on the results of allergy testing with polyether impression materials as well as with its components. Eight patients with clinical symptoms of a contact allergy (swelling, redness or blisters) after exposure to a polyether impression material were subjected to patch tests, two of them additionally to a prick test. A further patient with atypical symptoms of an allergy (nausea and vomiting after contact with a polyether impression material in the oral cavity) but with a history of other allergic reaction was also patch tested. The prick tests showed no immediate reactions in the two patients tested. In the patch tests, all eight patients with typical clinical symptoms showed positive reactions to the mixed polyether impression materials, to the base paste or to a base paste component. The patient with the atypical clinical symptoms did not show any positive patch test reactions. Polyether impression materials may evoke type IV allergic reactions. The causative agent was a component of the base paste. In consideration of the widespread use of this impression material (millions of applications per year) and in comparison to the number of adverse reactions from other dental materials, the number of such allergic reactions is very low. In very scarce cases, positive allergic reactions to polyether impression materials are possible.

  20. Reasons for placement of restorations on previously unrestored tooth surfaces by dentists in The Dental Practice-Based Research Network

    DEFF Research Database (Denmark)

    Nascimento, Marcelle M; Gordan, Valeria V; Qvist, Vibeke;

    2010-01-01

    The authors conducted a study to identify and quantify the reasons used by dentists in The Dental Practice-Based Research Network (DPBRN) for placing restorations on unrestored permanent tooth surfaces and the dental materials they used in doing so.......The authors conducted a study to identify and quantify the reasons used by dentists in The Dental Practice-Based Research Network (DPBRN) for placing restorations on unrestored permanent tooth surfaces and the dental materials they used in doing so....

  1. Application of reference point indentation for micro-mechanical surface characterization of calcium silicate based dental materials.

    Science.gov (United States)

    Antonijević, Djordje; Milovanović, Petar; Riedel, Christoph; Hahn, Michael; Amling, Michael; Busse, Björn; Djurić, Marija

    2016-04-01

    The objective of this study was to elucidate micromechanical properties of Biodentine and two experimental calcium silicate cements (CSCs) using Reference Point Indentation (RPI). Biomechanical characteristics of the cement type and the effects of a radiopacifier, liquid components, acid etching treatment and bioactivation in simulated body fluid (SBF) were investigated by measuring the microhardness, average unloading slope (Avg US) and indentation distance increase (IDI). Biodentine had a greater microhardness than the experimental CSCs, while the Avg US and IDI values were not significantly different among investigated materials. There was a statistically significant difference in microhardness and IDI values between pure CSCs and radiopacified cements (p < 0.05). Micromechanical properties were not affected by different liquid components used. Acid-etching treatment reduced Biodentine's microhardness while cements' immersion in SBF resulted in greater microhardness and higher IDI values compared to the control group. Clearly, the physiological environment and the cements' composition affect their surface micromechanical properties. The addition of calcium chloride and CSCs' immersion in SBF are beneficial for CSCs' micromechanical performance, while the addition of radiopacifiers and acid etching treatment weaken the CSCs' surface. Application of RPI aids with the characterization of micromechanical properties of synthetic materials' surfaces. PMID:26888441

  2. Use of Case-Based Learning in Dental Hygiene Curricula.

    Science.gov (United States)

    Vaughan, Dina Agnone; DeBiase, Christina B.; Gibson-Howell, Joan C.

    1998-01-01

    A survey investigated the extent of use of case-based learning in 141 dental hygiene programs. A majority of responding schools use the approach, most frequently in clinical dental hygiene, community dental health, and dental science courses. Proportion of instructional time was greatest in the content areas of special needs, ethics, medical…

  3. The difference of dental anxiety in children based on frequency of dental appointment

    OpenAIRE

    Mia Giri Astri; Eka Chemiawan; Eriska Rriyanti

    2011-01-01

    Background: Problem of children’s anxiety during dental procedures is a common phenomenon. This is called dental anxiety. The anxiety children patien need to be paid a special attention, because it will affect the success of dental treatment. Purpose: The purpose of this research was to find out the difference of dental anxiety degree in children aged 8 to 12 years old based on the frequency of dental visits in dental community health centre Bandung. Methods: The method of this research was a...

  4. Designing Multiagent Dental Materials for Enhanced Resistance to Biofilm Damage at the Bonded Interface.

    Science.gov (United States)

    Melo, Mary Anne; Orrego, Santiago; Weir, Michael D; Xu, Huakun H K; Arola, Dwayne D

    2016-05-11

    The oral environment is considered to be an asperous environment for restored tooth structure. Recurrent dental caries is a common cause of failure of tooth-colored restorations. Bacterial acids, microleakage, and cyclic stresses can lead to deterioration of the polymeric resin-tooth bonded interface. Research on the incorporation of cutting-edge anticaries agents for the design of new, long-lasting, bioactive resin-based dental materials is demanding and provoking work. Released antibacterial agents such as silver nanoparticles (NAg), nonreleased antibacterial macromolecules (DMAHDM, dimethylaminohexadecyl methacrylate), and released acid neutralizer amorphous calcium phosphate nanoparticles (NACP) have shown potential as individual and dual anticaries approaches. In this study, these agents were synthesized, and a prospective combination was incorporated into all the dental materials required to perform a composite restoration: dental primer, adhesive, and composite. We focused on combining different dental materials loaded with multiagents to improve the durability of the complex dental bonding interface. A combined effect of bacterial acid attack and fatigue on the bonding interface simulated the harsh oral environment. Human saliva-derived oral biofilm was grown on each sample prior to the cyclic loading. The oral biofilm viability during the fatigue performance was monitored by the live-dead assay. Damage of the samples that developed during the test was quantified from the fatigue life distributions. Results indicate that the resultant multiagent dental composite materials were able to reduce the acidic impact of the oral biofilm, thereby improving the strength and resistance to fatigue failure of the dentin-resin bonded interface. In summary, this study shows that dental restorative materials containing multiple therapeutic agents of different chemical characteristics can be beneficial toward improving resistance to mechanical and acidic challenges in oral

  5. Various Effects of Sandblasting of Dental Restorative Materials

    OpenAIRE

    Goro Nishigawa; Yukinori Maruo; Masao Irie; Naoto Maeda; Kumiko Yoshihara; Noriyuki Nagaoka; Takuya Matsumoto; Shogo Minagi

    2016-01-01

    Background Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical ...

  6. Theoretical and practical aspects regarding the development and control of microbial biofilms attached to the surface of dental materials and dental prostheses in particular

    OpenAIRE

    Zisi, Sonila; Bortollini, Sergio; Muntianu, Ligia; Papakoca, Kiro; Burlibasa, Mihai

    2012-01-01

    Microbial biofilms play an essential role in oral pathology, in the etiology of dental caries, periodontopathy, but also in surface contamination of dental materials (and here we refer to prosthetic material such as acrylic materials usedfor dentures, occlusal rims, try-in dentures, dental alloys used in fixed dental restorations, impression materials, etc.)

  7. Various Effects of Sandblasting of Dental Restorative Materials

    Science.gov (United States)

    Nishigawa, Goro; Maruo, Yukinori; Irie, Masao; Maeda, Naoto; Yoshihara, Kumiko; Nagaoka, Noriyuki; Matsumoto, Takuya; Minagi, Shogo

    2016-01-01

    Background Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials. Methods We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC) group and non-ultrasonic cleaning (NUSC) group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength. Results For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group. Conclusions Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials. PMID:26764913

  8. Various Effects of Sandblasting of Dental Restorative Materials.

    Directory of Open Access Journals (Sweden)

    Goro Nishigawa

    Full Text Available Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials.We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC group and non-ultrasonic cleaning (NUSC group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength.For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group.Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials.

  9. In situ reaction kinetic analysis of dental restorative materials

    Science.gov (United States)

    Younas, Basma; Samad Khan, Abdul; Muzaffar, Danish; Hussain, Ijaz; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur

    2013-12-01

    The objective of this study was to evaluate in situ structural and thermal changes of dental restorative materials at periodical time intervals. The commercial materials included zinc oxide eugenol (ZOE), zinc phosphate type I (ZnPO4), glass ionomer cement type II (GIC) and resin-based nano-omposite (Filtek Z350 XT). These materials were processed according to manufacturer's instructions. For the structural analysis Fourier transform infrared spectroscopy (FTIR) was used at high resolution. TGA was used to evaluate thermal weight-loss. The FTIR spectra were collected at periodic time intervals. FTIR spectra showed that with time passing all materials exhibited an increase in peak intensities and a new appearance of shoulders and shifting of peaks for example, ZnPO4 (P-O), ZOE (C═O, C═N, C-O-C), GIC (COO-, C-H, Si-OH), composites (C═O, C═C, C═N, C-N-H). The peaks were replaced by bands and these bands became broader with time interval. Composites showed a degree of conversion and new peaks corresponded to the cross-linking of polymer composites. TGA analysis showed that significant changes in weight loss of set materials were observed after 24 h, where ZOE showed continuous changes in thermal degradation. The spectral changes and thermal degradation with time interval elucidated in situ setting behaviour and understanding of their bonding compatibility with tooth structure and change in relation to time.

  10. Pressure behavior of different PEEK materials for dental implants.

    Science.gov (United States)

    Schwitalla, Andreas Dominik; Spintig, Tobias; Kallage, Ilona; Müller, Wolf-Dieter

    2016-02-01

    Due to its mechanical properties, the biocompatible high-performance material PEEK (polyetheretherketone) and PEEK-based compounds may represent viable alternatives to titanium in the field of dental implantology. Therefore we performed static pressure tests with 11 PEEK materials (two unfilled grades, two grades filled with titanium-dioxide-powder, two grades filled with barium-sulfate-powder, two grades reinforced with short carbon fibers, one grade reinforced with glass fibers and two grades reinforced with continuous carbon fibers) in the form of cylindrical specimens with a diameter of 4, 5 and 6mm. The specimens had a height to diameter ratio of 2:1 and were therefore 8, 10 and 12mm high. The parameters elastic modulus, elastic limit and pressure strength were evaluated. The elastic moduli ranged between 2.65±0.03GPa for specimens of a titanium-dioxide-filled grade and 106.71±14.83GPa for specimens reinforced with continuous carbon fibers. The elastic limits ranged between 808.1±42.44N for specimens of a barium-sulfate-filled grade and 7256.4±519.86N for specimens reinforced with continuous carbon fibers. The lowest pressure strength of 122.77MPa was observed for specimens of an unfilled grade, whereas the highest pressure strength of 712.67±66.02MPa could be evaluated for specimens containing continuous carbon fibers. Regarding the maximum bite force of a first molar, all tested materials seem to be suitable for the use as dental implants. PMID:26492595

  11. Advances in Dental Materials through Nanotechnology: Facts, Perspectives and Toxicological Aspects.

    Science.gov (United States)

    Padovani, Gislaine C; Feitosa, Victor P; Sauro, Salvatore; Tay, Franklin R; Durán, Gabriela; Paula, Amauri J; Durán, Nelson

    2015-11-01

    Nanotechnology is currently driving the dental materials industry to substantial growth, thus reflecting on improvements in materials available for oral prevention and treatment. The present review discusses new developments in nanotechnology applied to dentistry, focusing on the use of nanomaterials for improving the quality of oral care, the perspectives of research in this arena, and discussions on safety concerns regarding the use of dental nanomaterials. Details are provided on the cutting-edge properties (morphological, antibacterial, mechanical, fluorescence, antitumoral, and remineralization and regeneration potential) of polymeric, metallic and inorganic nano-based materials, as well as their use as nanocluster fillers, in nanocomposites, mouthwashes, medicines, and biomimetic dental materials. Nanotoxicological aspects, clinical applications, and perspectives for these nanomaterials are also discussed.

  12. [Comparative analysis of conventional dental floss and alternative materials].

    Science.gov (United States)

    Campos Júnior, A; Passanezi, E; Serizawa, T C; Barros, A S; Navarro, M F; Lopes, E S

    1990-01-01

    The interproximal plaque-removing effect of three different materials (classic dental floss, rafia floss and indian floss) was tested in a group of 80 males (18 years-old). After two weeks all the materials had the same efficacy in removing the bacterial plaque, with significant reduction in interproximal plaque index. According to an opinion inquiry the rafia floss was the most comfortable material to use and has the lowest cost as well. PMID:2135334

  13. Recent Advances and Developments in Composite Dental Restorative Materials

    OpenAIRE

    Cramer, N.B.; Stansbury, J.W.; Bowman, C.N.

    2011-01-01

    Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with t...

  14. Longevity of dental amalgam in comparison to composite materials

    Directory of Open Access Journals (Sweden)

    Windisch, Friederike

    2008-11-01

    fillings in posterior teeth is difficult. Apart from the difficulties in conducting a randomized, controlled long-term study comparing the longevity of direct fillings, the fact that composites and adhesives used in a study have often already been replaced by the next generation of the product at the time of study publication presents an additional problem. Not only the filling material, but also patient parameters and local, intraoral factors (e. g. localisation of the filling as well as the treating dentist have an impact on the longevity of dental fillings. In evaluating economic studies, one has to refer to the heterogeneity of data on longevity in the medical evaluation. The only effect parameter used in the studies is longevity, other aspects (e. g. long-term functionality are only referred to in discussions. Extensive counselling of patients regarding the selection of the appropriate filling material is important. Conclusions: Amalgam fillings show a longer longevity than composite fillings. Two out of six systematic reviews conclude that the expected survival time of composite fillings can be comparable to amalgam fillings. However, these conclusions are based on the results of short-term studies which usually overestimate the longevity of filling materials. From an economic standpoint, amalgam is the more economic filling material compared to direct composite fillings in posterior teeth when considering longevity as the only result parameter. Other aspects than longevity need to be considered in individually choosing the appropriate dental filling material. For future studies aiming to compare the longevity of amalgam and composite fillings, a sufficient sample size and study period, preferably in the setting of a private dental practice, should be aimed for. An evaluation of the cost-effectiveness of amalgam and composite fillings should take the functionality of teeth over a longer time period into account, as well as patients’ preferences. The rapid

  15. Influence of metal dental materials on MR imaging

    International Nuclear Information System (INIS)

    Differences in magnetic susceptibility produce artifacts and signal loss in magnetic resonance imaging (MRI). This study was undertaken to compare the degree of artifacts on MRI caused by metallic dental materials. The influence on MRI of six types of dental alloys, a dental implant, orthodontic appliance, and magnetic attachment was investigated. Among the dental metals, nickel-chromium alloy and cobalt-chromium alloy, which have ferromagnetism, caused significant metal artifacts. Gold-platinum alloy, gold-silver-palladium alloy, silver alloy, and amalgam alloy produced slight metal artifacts. The orthodontic appliance mainly consisted of iron, and the keeper for its magnetic attachment was made of stainless steel. For these reasons, marked metal artifacts and signal loss could be seen in both of them owing to their ferromagnetism. These results suggest that orthodontic appliances and magnetic attachments impair evaluation of the GRE and EPI techniques. It is therefore preferable to use predominantly diamagnetic or paramagnetic dental materials for MRI of the head and neck. Removable keepers should be used more widely to prevent metal artifacts and enhance safety on MRI. (author)

  16. Influence of metal dental materials on MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchihashi, Toshio; Chiba, Michiko; Yoshizawa, Satoshi; Sasaki, Sadayuki; Maki, Toshio; Kitagawa, Matsuo; Suzuki, Takeshi [Nippon Medical School, Tokyo (Japan). Main Hospital; Nakata, Minoru; Fujita, Isao

    1998-11-01

    Differences in magnetic susceptibility produce artifacts and signal loss in magnetic resonance imaging (MRI). This study was undertaken to compare the degree of artifacts on MRI caused by metallic dental materials. The influence on MRI of six types of dental alloys, a dental implant, orthodontic appliance, and magnetic attachment was investigated. Among the dental metals, nickel-chromium alloy and cobalt-chromium alloy, which have ferromagnetism, caused significant metal artifacts. Gold-platinum alloy, gold-silver-palladium alloy, silver alloy, and amalgam alloy produced slight metal artifacts. The orthodontic appliance mainly consisted of iron, and the keeper for its magnetic attachment was made of stainless steel. For these reasons, marked metal artifacts and signal loss could be seen in both of them owing to their ferromagnetism. These results suggest that orthodontic appliances and magnetic attachments impair evaluation of the GRE and EPI techniques. It is therefore preferable to use predominantly diamagnetic or paramagnetic dental materials for MRI of the head and neck. Removable keepers should be used more widely to prevent metal artifacts and enhance safety on MRI. (author)

  17. COMPARATIVE CHARACTERISTICS OF MATERIALS USED IN DENTAL IMPLANTATION

    Directory of Open Access Journals (Sweden)

    A. A. Yegorov

    2014-01-01

    Full Text Available The objective of the research is a review of some characteristics of dental implants’ products and an analysis of prospects of using them in modern medicine.Dental implantation as a high-technology method of restoring the natural anatomical structure has no competitors at present. The advantages of dental implants consist in their high operational dependability, a longer life time, a higher functionality and a lesser rate of complications as compared to the use of complete or bridge prostheses.The materials used in dental implantation for this purpose are rather diverse. Doctors using them rely on extensive clinical experience, a developed industry of accessory materials, instruments, that is everything that ensures comfortable work and conveniences for the patient.At the same time, the data mentioned in the article testify to the effect that ceramic implants as compared to titanium alloy implants have comparable or better indices. This is guaranteed, for example, by the requirements of the new international standard ISO6474-2:2012: first-rate strength and wear resistance; thermal stability and corrosion resistance; ceramics’ four point bending strength over 750 MPa.The result of the conducted analysis is a review of using various materials in dental implantation. The author compares the aesthetic indices and durability of titanium or metal alloy implants to those of ceramic ones. The comparison shows that, under the current level of ceramic materials’ structural property, it is actual for dentistry to develop its own methodological approaches in relation to a wide use of ceramic implants and creation of various ceramic mono-implants with the purpose of improving the results of treatment of patients, suffering from secondary partial or complete adentia accompanied by bone tissue deficiency, by applying the methods of dental implantation.

  18. Backscattering from dental restorations and splint materials during therapeutic radiation

    International Nuclear Information System (INIS)

    Models were constructed to simulate as closely as possible the human oral cavity. Radiation absorbed doses were determined for controls and various test situations involving the presence of dental restorative and splint materials during cobalt-60 irradiation of the models. Adjacent gold full crowns and adjacent solid dental silver amalgam cores both increased the dose to the interproximal gingivae by 20%. Use of orthodontic full bands for splinting the jaws increased the dose to the buccal tissues by an average of 10%. Augmentation of dose through backscatter radiation was determined to be only slight for intracoronal amalgam fillings and stainless steel or plastic bracket splints

  19. Degree of conversion and microhardness of dental composite resin materials

    Science.gov (United States)

    Marovic, D.; Panduric, V.; Tarle, Z.; Ristic, M.; Sariri, K.; Demoli, N.; Klaric, E.; Jankovic, B.; Prskalo, K.

    2013-07-01

    Dental composite resins (CRs) are commonly used materials for the replacement of hard dental tissues. Degree of conversion (DC) of CR measures the amount of the un-polymerized monomers in CR, which can cause adverse biological reactions and weakening of the mechanical properties. In the past, studies have determined the positive correlation of DC values determined by Fourier transform infrared spectroscopy (FT-IR) and microhardness (MH) values. The aim of this study was to establish whether MH can replace FTIR for the determination of DC of contemporary CR.

  20. Endocrine disruptors and dental materials: health implications associated with their use in Brazil

    Directory of Open Access Journals (Sweden)

    Coelho Antonio Jorge Molinário

    2002-01-01

    Full Text Available This study analyzes international historical trends in the use of different types of materials in dental practice. The author describes the chemical properties of their ingredients and the potential and observed adverse effects in patients and dental technicians resulting from clinical or occupational exposure to various metals like beryllium, used to produce metal alloys. The growing use of various products (resin cements, ionomer cements, aesthetic restorative materials, resins, endodontal cements, and others based on the compound bisphenol-A, whose chemical structure is similar to that of estrogen. Considering the demographic and contemporary work force characteristics of those involved in dental practice in the Brazil, the study highlights the possible effect of the use of these materials in both male and female patients and all age strata, as well as in health professionals with occupational exposure to products containing bisphenol-A.

  1. Chipping fracture resistance of dental CAD/CAM restorative materials: Part 2. Phenomenological model and the effect of indenter type

    OpenAIRE

    Quinn, G. D.; Giuseppetti, A. A.; Hoffman, K. H.

    2014-01-01

    The edge chipping resistances of six CAD/CAM dental restoration materials are analyzed and correlated to other mechanical properties. A new quadratic relationship that is based on a phenomenological model is presented.

  2. Determination of setting expansion of dental materials using fibre optical sensing

    Science.gov (United States)

    Milczewski, M. S.; da Silva, J. C. C.; Abe, I.; Carvalho, L.; Nogueira, R. N.; Paterno, A. S.; Kalinowski, H. J.; Pinto, J. L.

    2006-05-01

    The use of fibre Bragg grating sensors to study dental materials like resin-based composite and gypsum products is reported. Two commercially available composite resins and three types of gypsum products were tested in order to determine polymerization contraction and setting expansion. Temperature and strain evolution during the hardening phase of the material were also obtained. The presented technique can be a good tool for dentists in order to better manipulate a material and predict how it will behave in vivo.

  3. Niobium based coatings for dental implants

    International Nuclear Information System (INIS)

    Niobium based thin films were deposited on stainless steel (SS) substrates to evaluate them as possible biocompatible surfaces that might improve the biocompatibility and extend the life time of stainless steel dental implants. Niobium nitride and niobium oxide thin films were deposited by reactive unbalanced magnetron sputtering under standard deposition conditions without substrate bias or heating. The biocompatibility of the surfaces was evaluated by testing the cellular adhesion and viability/proliferation of human cementoblasts during different culture times, up to 7 days. The response of the films was compared to the bare substrate and pieces of Ti6Al4V; the most commonly used implant material for orthopedics and osteo-synthesis applications. The physicochemical properties of the films were evaluated by different means; X-ray diffraction, Rutherford backscattering spectroscopy and contact angle measurements. The results suggested that the niobium oxide films were amorphous and of stoichiometric Nb2O5 (a-Nb2O5), while the niobium nitride films were crystalline in the FCC phase (c-NbN) and were also stoichiometric with an Nb to N ratio of one. The biological evaluation showed that the biocompatibility of the SS could be improved by any of the two films, but neither was better than the Ti6Al4V alloy. On the other hand, comparing the two films, the c-NbN seemed to be a better surface than the oxide in terms of the adhesion and proliferation of human cemetoblasts.

  4. Niobium based coatings for dental implants

    Science.gov (United States)

    Ramírez, G.; Rodil, S. E.; Arzate, H.; Muhl, S.; Olaya, J. J.

    2011-01-01

    Niobium based thin films were deposited on stainless steel (SS) substrates to evaluate them as possible biocompatible surfaces that might improve the biocompatibility and extend the life time of stainless steel dental implants. Niobium nitride and niobium oxide thin films were deposited by reactive unbalanced magnetron sputtering under standard deposition conditions without substrate bias or heating. The biocompatibility of the surfaces was evaluated by testing the cellular adhesion and viability/proliferation of human cementoblasts during different culture times, up to 7 days. The response of the films was compared to the bare substrate and pieces of Ti6Al4V; the most commonly used implant material for orthopedics and osteo-synthesis applications. The physicochemical properties of the films were evaluated by different means; X-ray diffraction, Rutherford backscattering spectroscopy and contact angle measurements. The results suggested that the niobium oxide films were amorphous and of stoichiometric Nb2O5 (a-Nb2O5), while the niobium nitride films were crystalline in the FCC phase (c-NbN) and were also stoichiometric with an Nb to N ratio of one. The biological evaluation showed that the biocompatibility of the SS could be improved by any of the two films, but neither was better than the Ti6Al4V alloy. On the other hand, comparing the two films, the c-NbN seemed to be a better surface than the oxide in terms of the adhesion and proliferation of human cemetoblasts.

  5. 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)

  6. [Fluorescence of dental porcelain: material and methods].

    Science.gov (United States)

    Monsénégo, G; Burdairon, G; Porte, C; Naud, C

    1990-06-01

    Dental porcelain emits some fluorescence under the action of ultra-violet rays. This emission may be at the origin of errors in the choice of the colour of a crown. In order to study this fluorescence phenomenon, the following experimental protocol has been developed: 363.8 nm exciting radiation isolated from the emission by an Argon laser; Fluorescence emitted by the sample and dispersed via a spectrometer, protected by a stop-U.V. filter; Influx collected by a photomultiplier, then directed, after passage in a picoamperemeter, toward a mini-computer programmed to print the spectra; Correction of the spectra by a tungsten lamp used at the 2,600 K colour temperature; Use of reference spectra. On the same graph, the sample spectra are represented in solid lines, while the spectrum of the enamel used as a reference is shown as a dotted line. The results show that: Enamel has a fluorescence spectrum which has the shape of a wide band, with a maximum of 450 nm (characteristic of a blue-green shade) and a slow decrease up to 680 nm. The enamel fluorescence does not depend on the colour of the tooth; Dentine has a distribution spectrum which is similar to that of enamel but is three times fuller; The spectra of the ceramic samples reveal: a wide band due to transition metals, fine lines due to rare earth (terbium and europium). When the saturation degree of the ceramic increases, its fluorescence colour varies due to the relative increase in the amplitude of the lines in relation to the bands. Thus, when the sample colour progresses from B1 to B4, its fluorescence colour becomes greener.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2207845

  7. Compressive fatigue limit of four types of dental restorative materials.

    Science.gov (United States)

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

  8. Compressive fatigue limit of four types of dental restorative materials.

    Science.gov (United States)

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC. PMID:27085845

  9. Degradation, fatigue, and failure of resin dental composite materials.

    Science.gov (United States)

    Drummond, J L

    2008-08-01

    The intent of this article is to review the numerous factors that affect the mechanical properties of particle- or fiber-filler-containing indirect dental resin composite materials. The focus will be on the effects of degradation due to aging in different media, mainly water and water and ethanol, cyclic loading, and mixed-mode loading on flexure strength and fracture toughness. Several selected papers will be examined in detail with respect to mixed and cyclic loading, and 3D tomography with multi-axial compression specimens. The main cause of failure, for most dental resin composites, is the breakdown of the resin matrix and/or the interface between the filler and the resin matrix. In clinical studies, it appears that failure in the first 5 years is a restoration issue (technique or material selection); after that time period, failure most often results from secondary decay.

  10. Degradation, Fatigue, and Failure of Resin Dental Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.L. (UIC)

    2008-11-03

    The intent of this article is to review the numerous factors that affect the mechanical properties of particle- or fiber-filler-containing indirect dental resin composite materials. The focus will be on the effects of degradation due to aging in different media, mainly water and water and ethanol, cyclic loading, and mixed-mode loading on flexure strength and fracture toughness. Several selected papers will be examined in detail with respect to mixed and cyclic loading, and 3D tomography with multi-axial compression specimens. The main cause of failure, for most dental resin composites, is the breakdown of the resin matrix and/or the interface between the filler and the resin matrix. In clinical studies, it appears that failure in the first 5 years is a restoration issue (technique or material selection); after that time period, failure most often results from secondary decay.

  11. Novel surface coating materials for endodontic dental implant

    International Nuclear Information System (INIS)

    The aim of this study was to design and produce novel coating materials in order to obtain two goals including; improvement of the corrosion behavior of metallic dental endodontic implant and the bone osteointegration simultaneously. Stainless steel 316L (SS) was used as a metallic substrate and a novel Hydroxyapatite/Titanium (HA/Ti) composite coating was prepared on it. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure and morphology of the coating. Electrochemical tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. Two types of endodontic implants including; SS with and without (HA/Ti) composite coating were prepared and subsequently implanted in the mandibular canine of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, osteointegration evaluation and histopathological interpretation was carried out using SEM and optical microscopy. Results indicate that the novel HA/Ti composite coating improves the corrosion behavior and biocompatibility of SS endodontic dental implant. The clinical evaluation (in vivo test) results showed that there was significant difference in osteointegration between coated and uncoated endodontic dental implants and average bone osteointegration of coated implants were more than uncoated implants. The histopathological results and bone tissue response to the coated implants was acceptable and it was concluded that HA/Ti composite coated SS could be used as well as an endodontic dental implant. (author)

  12. Obtaining New Dental Materials Reinforced with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    I.V. Zaporotskova

    2014-07-01

    Full Text Available The article seeks to explore the change of strength properties of composite polymer material on the basis of fast-hardening dental plastic "Carbogen", when reinforcing its coal-native nanotubes. Were discussed peculiarities of composition of Carboante, ways of creation of polymeric composition deposits by doping their carbon nanotubes, the results of measuring the strength characteristic characteristics obtained new polymer materials. On the basis of the analysis of the practical and the theoretical-sky research, conclusions were drawn on the feasibility of a new filling material with the use of carbon nanotubes with unique strength characteristics and use of their in dentistry.

  13. [Dental restoration materials in pediatric dentistry].

    Science.gov (United States)

    Davidson, C L

    1997-02-01

    Restorative materials in pediatric dentistry have to fulfill special requirements. They should be easy to handle and applicable in a not always dry mouth. They should potentially be adhesive in order to avoid too much mechanical preparation. They do not have to be extremely wear resistant as the dwell time of the restorations is relatively short. Glass-ionomer cements and in particular the resin modified types possess properties which make them almost ideal for the required purpose.

  14. Titanium Nitride and Nitrogen Ion Implanted Coated Dental Materials

    Directory of Open Access Journals (Sweden)

    David W. Berzins

    2012-07-01

    Full Text Available Titanium nitride and/or nitrogen ion implanted coated dental materials have been investigated since the mid-1980s and considered in various applications in dentistry such as implants, abutments, orthodontic wires, endodontic files, periodontal/oral hygiene instruments, and casting alloys for fixed restorations. Multiple methodologies have been employed to create the coatings, but detailed structural analysis of the coatings is generally lacking in the dental literature. Depending on application, the purpose of the coating is to provide increased surface hardness, abrasion/wear resistance, esthetics, and corrosion resistance, lower friction, as well as greater beneficial interaction with adjacent biological and material substrates. While many studies have reported on the achievement of these properties, a consensus is not always clear. Additionally, few studies have been conducted to assess the efficacy of the coatings in a clinical setting. Overall, titanium nitride and/or nitrogen ion implanted coated dental materials potentially offer advantages over uncoated counterparts, but more investigation is needed to document the structure of the coatings and their clinical effectiveness.

  15. Artifacts by dental materials on magnetic resonance imaging

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study

  16. Artifacts by dental materials on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hyun Sook; Choi, Deuk Lin; Kim, Ki Jung [Soonchunhyang University Hospital, Asan (Korea, Republic of); Suh, Won Hyuck [Korea University Hospital, Seoul (Korea, Republic of)

    1992-05-15

    Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study.

  17. Pattern of dental diseases among patients attending outpatient department of dental: a hospital based cross-sectional study

    Directory of Open Access Journals (Sweden)

    Pitamber Datt Garkoti

    2015-06-01

    Full Text Available Introduction: The public health problems associated with oral disease are a serious burden in India and other countries of the world. The causes of oral diseases are primarily rooted in poor socioeconomic and physical environment; unhealthy lifestyles and oral health related behaviour accordingly the action towards improvement of oral health should be directed towards modification of unhealthy environment and behaviours. Objective: To know the pattern of dental diseases among the patients attending Dental OPD. Materials and Methods: A hospital based cross sectional study among patients attending dental OPD in a tertiary care centre of Kumaun region during a period of one year i.e. from 1st January 2012 to 31st December 2012. Results: A total of 8928 patients attended dental OPD. Majority of the patients (25.3% were in the age group 30-39 years. Mostly were males (51.54%. Most common disease was dental caries (54.54%, followed by gingivitis (37.62%, abrasion (3.82%, malocclusion (3.05%, pericoronitis (0.53% and jaw fracture (0.44%. Conclusion: Dental Caries was the most common disease. Majority of the patients were in 30-39 years of age group. Health education and awareness at school level and in the community might prevent tooth loss in later life. [Natl J Med Res 2015; 5(2.000: 112-115

  18. Niobium based coatings for dental implants

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, G., E-mail: enggiova@hotmail.com [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, CU, Mexico D.F. 04510 (Mexico); Facultad de Quimica, Departamento de Ingenieria Quimica, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Rodil, S.E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, CU, Mexico D.F. 04510 (Mexico); Arzate, H. [Laboratorio de Biologia Celular y Molecular, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, CU, Mexico D.F. 04510 (Mexico); Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, CU, Mexico D.F. 04510 (Mexico); Olaya, J.J. [Unidad de Materiales, Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de Colombia, Cra. 30 45-03 Bogota (Colombia)

    2011-01-15

    Niobium based thin films were deposited on stainless steel (SS) substrates to evaluate them as possible biocompatible surfaces that might improve the biocompatibility and extend the life time of stainless steel dental implants. Niobium nitride and niobium oxide thin films were deposited by reactive unbalanced magnetron sputtering under standard deposition conditions without substrate bias or heating. The biocompatibility of the surfaces was evaluated by testing the cellular adhesion and viability/proliferation of human cementoblasts during different culture times, up to 7 days. The response of the films was compared to the bare substrate and pieces of Ti6Al4V; the most commonly used implant material for orthopedics and osteo-synthesis applications. The physicochemical properties of the films were evaluated by different means; X-ray diffraction, Rutherford backscattering spectroscopy and contact angle measurements. The results suggested that the niobium oxide films were amorphous and of stoichiometric Nb{sub 2}O{sub 5} (a-Nb{sub 2}O{sub 5}), while the niobium nitride films were crystalline in the FCC phase (c-NbN) and were also stoichiometric with an Nb to N ratio of one. The biological evaluation showed that the biocompatibility of the SS could be improved by any of the two films, but neither was better than the Ti6Al4V alloy. On the other hand, comparing the two films, the c-NbN seemed to be a better surface than the oxide in terms of the adhesion and proliferation of human cemetoblasts.

  19. 75 FR 16511 - Pentron Clinical Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental...

    Science.gov (United States)

    2010-04-01

    ... such as dental prosthetics, dental composites, dental impressions, dental adhesives, and other dental... prosthetics, dental composites, dental impressions, dental adhesives, and other dental materials to Mexicali... Dental/Sybron Dental Specialities, Formally Known as Customedix Corporation, Including......

  20. Embryotoxicity assays for leached components from dental restorative materials

    Directory of Open Access Journals (Sweden)

    Mummolo Stefano

    2011-10-01

    Full Text Available Abstract Background Currently, there are no suitable assays available to evaluate the embryotoxicity of leached components from restorative dental materials. Methods The effect of the medium conditioned by composites and amalgam on mouse blastocysts in vitro was tested. The materials were also subcutaneously implanted, and the effect of the medium supplemented with serum from the host blood was evaluated in the embryotoxicity assay. The embryo implantation rate in the material-transplanted mothers was also evaluated. Results The results show that while the culture in media conditioned by amalgams did not affect blastocyst development, the medium conditioned by composites caused blastocyst degeneration and apoptosis. The development of blastocysts in a medium containing serum obtained from animals after transplantation was, however, without effect. Finally, inconsistent reduction in the implantation rate in transplanted mothers was observed. Conclusions In this study, we provide examples of in vitro and in vivo tests that may be used to evaluate embryotoxicity for dental materials. Our results show that leached components from our composite-material induced embryotoxicity in vitro, however, no toxicity was observed when subcutaneously implanted in vivo. This highlights the necessity of integrated in vitro and in vivo tests for valuable predictive estimation of embryotoxicity for complex materials.

  1. Advances in dental veneers: materials, applications, and techniques

    Directory of Open Access Journals (Sweden)

    Pini NP

    2012-02-01

    Full Text Available Núbia Pavesi Pini1, Flávio Henrique Baggio Aguiar1, Débora Alves Nunes Leite Lima1, José Roberto Lovadino1, Raquel Sano Suga Terada2, Renata Corrêa Pascotto21Area of Restorative Dentistry, Piracicaba Dental School, State University of Campinas – FOP/Unicamp – Piracicaba, São Paulo, 2Area of Restorative Dentistry, State University of Maringá – UEM – Maringá, Paraná, BrazilAbstract: Laminate veneers are a conservative treatment of unaesthetic anterior teeth. The continued development of dental ceramics offers clinicians many options for creating highly aesthetic and functional porcelain veneers. This evolution of materials, ceramics, and adhesive systems permits improvement of the aesthetic of the smile and the self-esteem of the patient. Clinicians should understand the latest ceramic materials in order to be able to recommend them and their applications and techniques, and to ensure the success of the clinical case. The current literature was reviewed to search for the most important parameters determining the long-term success, correct application, and clinical limitations of porcelain veneers.Keywords: dental ceramic, porcelain veneers, aesthetic treatment

  2. Special cluster issue on tribocorrosion of dental materials

    Science.gov (United States)

    Mathew, Mathew T.; Stack, Margaret M.

    2013-10-01

    Tribocorrosion affects all walks of life from oil and gas conversion to biomedical materials. Wear can interact with corrosion to enhance it or impede it; conversely, corrosion can enhance or impede wear. The understanding of the interactions between physical and chemical phenomena has been greatly assisted by electrochemical and microscopic techniques. In dentistry, it is well recognized that erosion due to dissolution (a term physicists use to denote wear) of enamel can result in tooth decay; however, the effects of the oral environment, i.e. pH levels, electrochemical potential and any interactions due to the forces involved in chewing are not well understood. This special cluster issue includes investigations on the fundamentals of wear-corrosion interactions involved in simulated oral environments, including candidate dental implant and veneer materials. The issue commences with a fundamental study of titanium implants and this is followed by an analysis of the behaviour of commonly used temporomandibular devices in a synovial fluid-like environment. The analysis of tribocorrosion mechanisms of Ti6Al4V biomedical alloys in artificial saliva with different pHs is addressed and is followed by a paper on fretting wear, on hydroxyapatite-titanium composites in simulated body fluid, supplemented with protein (bovine serum albumin). The effects of acid treatments on tooth enamel, and as a surface engineering technique for dental implants, are investigated in two further contributions. An analysis of the physiological parameters of intraoral wear is addressed; this is followed by a study of candidate dental materials in common beverages such as tea and coffee with varying acidity and viscosity and the use of wear maps to identify the safety zones for prediction of material degradation in such conditions. Hence, the special cluster issue consists of a range of tribocorrosion contributions involving many aspects of dental tribocorrosion, from analysis of physiological

  3. DEVELOPMENT AND VERIFICATION OF NEW SOLID DENTAL FILLING TEMPORARY MATERIALS CONTAINING ZINC. FORMULA DEVELOPMENT STAGE.

    Science.gov (United States)

    Pytko-Polończyk, Jolanta; Antosik, Agata; Zajac, Magdalena; Szlósarczyk, Marek; Krywult, Agnieszka; Jachowicz, Renata; Opoka, Włodzimierz

    2016-01-01

    Caries is the most popular problem affecting teeth and this is the reason why so many temporary dental filling materials are being developed. An example of such filling is zinc oxide paste mixed with eugenol, Thymodentin and Coltosol F®. Zinc-oxide eugenol is used in dentistry because of its multiplied values: it improves heeling of the pulp by dentine bridge formation; has antiseptic properties; is hygroscopic. Because of these advantages compouds of zinc oxide are used as temporary fillings, especially in deep caries lesions when treatment is oriented on support of vital pulp. Temporary dental fillings based on zinc oxide are prepared ex tempone by simple mixing powder (Thymodentin) and eugenol liqiud together or a ready to use paste Coltosol F®. Quantitative composition depends mainly on experience of person who is preparing it, therefore, exact qualitative composition of dental fillings is not replicable. The main goal of the study was to develop appropriate dental fillings in solid form containing set amount of zinc oxide. Within the study, the influence of preparation method on solid dental fillings properties like mechanical properties and zinc ions release were examined. PMID:27476293

  4. Mechanical characterization of materials for dental applications; Caracterizacion mecanica de materiales para aplicaciones dentales

    Energy Technology Data Exchange (ETDEWEB)

    Pajares, A.; Miranda, P.; Guiberteau, F.; Cumbrera, F. I.

    2001-07-01

    An study of the damage induced in dental materials and model multilayer systems by masticatory contact stresses, simulated by hertz ian indentation test, have been performed. In particular, the nature of induced damage has been identified, and quantified from stress-strain curves and critical loads for yielding or crack initiation. For multilayer systems, test have been numerically simulated using finite element techniques (FEM). FEM simulations complement indentation test, allowing to justify the observed fracture modes from calculated stress fields. Practical implications can be derived from our results, relevant to the design of multilayer structures tolerant to contact damage. (Author) 34 refs.

  5. Determination of residual monomers resulting from the chemical polymerization process of dental materials

    Energy Technology Data Exchange (ETDEWEB)

    Boboia, S. [Babes Bolyai University, Raluca Ripan Chemistry Research Institute, Department of Polymer Composites, 400294 Cluj-Napoca, Romania and Technical University of Cluj-Napoca, Physics and Chemistry Department, 400114 Cluj-Napoca (Romania); Moldovan, M. [Babes Bolyai University, Raluca Ripan Chemistry Research Institute, Department of Polymer Composites, 400294 Cluj-Napoca (Romania); Ardelean, I. [Technical University of Cluj-Napoca, Physics and Chemistry Department, 400114 Cluj-Napoca (Romania)

    2013-11-13

    The residual monomer present in post-polymerized dental materials encourages premature degradation of the reconstructed tooth. That is why the residual monomer should be quantified in a simple, fast, accurate and reproducible manner. In our work we propose such an approach for accurate determination of the residual monomer in dental materials which is based on low-field nuclear magnetic resonance (NMR) relaxometry. The results of the NMR approach are compared with those of the high performance liquid chromatography (HPLC) technique. The samples under study contain the main monomers (2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane and triethylene glycol dimethacrylate) constituting the liquid phase of most dental materials and an initiator. Two samples were analyzed with different ratios of chemical initiation systems: N,N-dimethyl-p-toluide: benzoyl peroxide (1:2 and 0.7:1.2). The results obtained by both techniques highlight that by reducing the initiator the polymerization process slows down and the amount of residual monomer reduces. This prevents the premature degradation of the dental fillings and consequently the reduction of the biomaterial resistance.

  6. Calculation of the shrinkage-induced residual stress in a viscoelastic dental restorative material

    Science.gov (United States)

    Grassia, Luigi; D'Amore, Alberto

    2013-02-01

    A procedure able to describe the curing process of a particulate composite material used in a dental restoration is developed in the ANSYS environment. The material under concern is a multifunctional methacrylate-based composite for dental restoration, activated by visible light. The model accounts for the dependence of the viscoelastic functions on temperature and degree of cure. Three geometries have been considered in the analysis that are representative of three different classes of dental restoration and mainly differ by the C (constrained)-factor, (i.e. the bounded to unbounded surface ratio). It was found that the temperature could give a necrosis in the vicinity of the tooth nerve and that the average stress at the interface between the composite and the tooth scales exponentially with the C-factor. The residual stress at the dental restoration interface is also compared with the uniaxial tensile strength of twelve commercially available composite materials: it clearly appears that the level of residual stress may overcome the strength of the composite, especially at high C-factors.

  7. Tribological behaviour of unveneered and veneered lithium disilicate dental material.

    Science.gov (United States)

    Figueiredo-Pina, C G; Patas, N; Canhoto, J; Cláudio, R; Olhero, S M; Serro, A P; Ferro, A C; Guedes, M

    2016-01-01

    The friction and wear behaviour of a lithium disilicate dental ceramic against natural dental enamel is studied, including the effect of the presence of a fluorapatite veneering upon the tribological properties of the material. The tribological behaviour was assessed using reciprocating pin-on-plate test configuration, at pH 3 and pH 7. The surface energy of the plates was determined, as well as the zeta potential of fluorapatite, lithium disilicate and enamel particles in artificial saliva. It was found that the friction and wear behaviour of the tested enamel/plate material tribocouples is less severe in unveneered plates. Initial surface roughness of the plate does not affect wear results. However the topography of the resulting wear track affects the corresponding wear loss: a smoother final wear track is associated with lower wear. The surface topography of the wear track, and thus the tribological performance of the tested materials, is very sensitive to the pH of the sliding solution. This is because the dissolution trend, wettability and surface charge of the used materials are pH dependent. Overall friction and wear are higher under basic pH conditions, especially when plates are veneered. A wear model is proposed that correlates the effect of the described parameters with the observed tribological behaviour at pH 7. Attained results show that fluorapatite coating of lithium disilicate dental crowns affects tooth/crown wear behaviour, resulting in increased wear of both the artificial crown and the opposing natural teeth. Coating should therefore be avoided in occlusal crown surfaces. PMID:26342288

  8. Color measurement of teeth and dental materials using a fiberoptic probe

    Science.gov (United States)

    Melnik, Ivan S.; Rawicz, Andrew H.; Dets, Sergiy M.

    1998-04-01

    Assessment of tooth color by visual evaluation is a complex task. A number of attempts to build a reliable instrument that can measure the color of teeth have been undertaken in the last 15 years. These attempts were aimed at using conventional colorimeters designed for color measurement of oblique objects. However, the translucency of teeth strongly affected the colorimeters' readout because of the size of the measuring aperture and the geometry of the spectroscope. Here we present the results of our spectroscopic study of dental materials and human teeth that show a characteristic behavior of optical spectra collected with a fiberoptic probe. The probe consisted of 300 micrometer irradiating and 1 mm detecting fibers that were coupled to a white light source (color temperature 6500 K) and to a spectroscope. The conventional shades from Vita and Chromascop shade guides were measured with different location of the fibers. The color of the dental shades was measured by a standard spectrophotometer with two different apertures. We found that registered spectra depended on fiber position and color coordinates changed with aperture size. The influence of the fiber positioning was approved with color measurement of vital teeth. A simplified colorimetric system based on two color coordinates, lightness L*, and the difference, (a* - b*), has been proposed. Finally, we describe a novel dental color matching device based on a fiberoptic probe. The device is able to classify all dental shades from Vita, Chromascop, and Bioform shade guides and is aimed at better color matching of restorative materials to native teeth.

  9. Study of the luminescence properties of dental materials for their use in accidental dosimetry

    International Nuclear Information System (INIS)

    Full text: The current social and political situation in many world areas and the increasing hostilities between countries and cultures have accentuated the risk of a malicious use of ionising radiations. Terrorist attacks with the intentional disseminations of radioactive materials in urban settlements may involve a large number of persons, and a rapid estimation of the severity of the exposure is required for undertaking suitable protective actions and supporting decision making. Promising methodologies for a prompt dose evaluation, are those exploiting the luminescence and dosimetric properties of objects and materials which can be easily found in the contaminated area. Among these objects, dental materials have the advantage to be on contact with human body and they could therefore represent individual dosimeters in case of accidental exposure to ionising radiation. The interest in the use of dental ceramics for dosimetric purposes dates back to late 1970, however, it is only through the use of high-sensitive experimental techniques and instrumentation today available, that the potentiality of such materials as accidental dosimeters can be exploited. Moreover, innovative materials are being continuously introduced into the market, containing new additives and pigments with peculiar optical properties. In this study, Thermally Stimulated Luminescence (TSL) and Optically Stimulated Luminescence (OSL) techniques are applied to investigate the luminescence and dosimetric properties of several dental materials, including resins, glass and feldspatic ceramics, and also zirconia and alumina based ceramics, being their use widely increased in the recent years in substitution of metal cores. (author)

  10. Recent advances and developments in composite dental restorative materials.

    Science.gov (United States)

    Cramer, N B; Stansbury, J W; Bowman, C N

    2011-04-01

    Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance. PMID:20924063

  11. Evaluation of dental material series from patients with dental prostheses and suspicion of delayed hypersensitivity*

    OpenAIRE

    Yoshimura, Fernanda Cortinhas; Cunha, Victor do Espirito Santo; Hahnstadt, Ruppert Ludwig; Pires, Mário Cezar

    2016-01-01

    BACKGROUND Patients with oral sensitivity are common in our practice. Allergic contact dermatitis is one of the most frequent etiologies. OBJECTIVES Evaluate oral contact dermatitis using the Brazilian standard series and complementary dental series in patients using dental prostheses, with or without oral complaints. Determine specific dental Brazilian series. METHODS Patients using dental prostheses with or without oral complaints realized patch tests. Brazilian standard series and compleme...

  12. Biological evaluation of dental materials, in vitro and in vivo

    International Nuclear Information System (INIS)

    In this paper, the correlation between the user of tissue culture for in vitro tests and the tissue irritability and pupal response observed in in vitro tests, will be discussed. It would produce confusion if dental materials were standardised with the unreliable parameter of the living system in dynamic balance. Biological tests, both in vitro and in vivo, should be used for pre-standards testing, without any political control to establish physicochemical standards. As a first step, corrosion tests and the dissolution dosje of toxic components from the material in the tissue culture medium and/or artificial salvia should be standardised under conditions simulating the oral environment. The CNC method and photo-pattern analysis are used for the interpretation of cytotoxicity. The need for biological testing, both in vitro and in vivo, definitely exists in order to obtain physicochemical standards, with a biological simulation depending upon the feedback obtained from the results of in vitro and in vivo tests

  13. In vivo characterization of polymer based dental cements

    Directory of Open Access Journals (Sweden)

    Widiyanti P

    2011-12-01

    Full Text Available Background: In vivo studies investigating the characterization of dental cements have been demonstrated. As few in vitro studies on this cement system have been performed. Previous researches in dental material has been standardized dental cement which fulfilled the physical and mechanical characteristic such as shear strength but were on in vitro condition, the animal model and clinical study of dental cement from laboratory has not been done yet. This research examined physical and mechanical characteristic in vivo using rabbit by making the caries (class III in anterior teeth especially in mesial or distal incisive, fulfilled the cavity by dental cement and analyzed the compressive strength, tensile strength, and microstructure using scanning electron microscope (SEM. Purpose: This study is aimed to describe the in vivo characterization of dental cements based on polymer (zinc phosphate cement, polycarboxylate, glass ionomer cement and zinc oxide eugenol. Methods: First, preparation was done on animal model’s teeth (6 rabbits, male, 5 months old. The cavity was made which involved the dentin. Then the cavity was filled with dental cement. After the filling procedure, the animal model should be kept until 21 days and than the compressive test, tensile test and microstructure was characterized. Compressive test and tensile test was analyzed using samples from extracted tooth and was measured with autograph. The microstructure test was measured using SEM. Results: The best compressive strength value was belongs to zinc phosphate cement which was 101.888 Mpa and the best tensile strength value was belongs to glass ionomer cement which was 6.555 Mpa. Conclusion: In conclusion, comparing with 3 others type of dental cements which are zinc phosphate, polycarboxylate and glass ionomer cement, zinc oxide eugenol cement has the worst for both physical and mechanical properties.Latar belakang: Studi in vivo meneliti karakterisasi secara in vivo dari

  14. Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials

    Directory of Open Access Journals (Sweden)

    Adamczyk Jakub

    2015-07-01

    Full Text Available Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz electron paramagnetic resonance (EPR spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very first and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g and synthetic (~1019 spin/g dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp: 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.

  15. Optimization of compressive strength of zirconia based dental composites

    Indian Academy of Sciences (India)

    U V Hambire; V K Tripathi

    2014-10-01

    Dental composites are tooth-coloured restorative material used by dentists for various applications. Restoration of a lost tooth structure requires a material having mechanical as well as aesthetic properties similar to that of tooth. This poses challenges to engineers and the dentist alike. Dental composites consist of a matrix and a dispersed phase called filler, which are mainly responsible for its mechanical properties. Most commonly used matrix is bisphenol glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGMA). Silica and glass are conventional fillers used in the past. Recently, zirconia is being used due to its improved mechanical properties. A study was conducted to evaluate the contribution of zirconia to the mechanical properties in general and compressive strength in particular. We have attempted to make an experimental dental composite with a conglomerate of nanofillers, namely, zirconia, glass and silica, and optimize this filler volume percentage and obtain an optimum compressive strength for the experimental dental composite.

  16. Natural radioactivity in zirconia-based dental ceramics

    International Nuclear Information System (INIS)

    Zirconia-based ceramics are being increasingly used in dental prosthetics in substitution of metal cores, which are known to induce local toxic reactions and delayed allergic responses in the oral tissues. Some concerns have been however raised about the use of zirconia, since it is known that unpurified zirconia materials may contain non negligible levels of natural radionuclides of the U/Th series. Combined measurements of alpha and gamma spectrometry as well as beta dosimetry were conducted on zirconia samples used for dental applications. Samples were available in form of powder and/or solid blocks. The results showed that the beta dose rate in zirconia ceramics was on average only slightly higher than the levels measured in natural teeth, and generally lower than the values measured in feldspatic and glass ceramics. These materials are indeed known to deliver a beta dose significantly higher than that measured from natural teeth, due to the relatively high levels of 40K (between 2 and 3 kBq·kg-1). The content of radionuclides of the U/Th series in the zirconia sample was estimated to be lower than 15 Bq·kg-1, i.e. doubtlessly below the exclusion level of 1 kBq·kg-1 recommended by IAEA in the Safety Standard Series. Beta dosimetry measurements, however, gave indications of possible inhomogeneous clusters of radioactivity, which might give rise to local doses above the background. (author)

  17. Determination of dose rate from natural radionuclide in porcelain dental materials

    International Nuclear Information System (INIS)

    There are three main aims that make this study particularly important and interesting to radiometric studies. Firstly, it will provides information on the concentration composition of natural and the associated man-made radioactivity of imported dental porcelain materials to be used by most dental laboratories in Great Jamahiriya. Since these materials do not pass radiation inspection tests before their entry or use and there is a large variety of supply source of these dental materials to be used for all dental works on Libyan patients, anomalies can be identified easily. Secondly, the analysis of selective elemental abundance (U, Th, and K ) and dose rate calculations may be used to calculate effective dose rates to dental laboratory technicians and also to the patient who will be using these specific materials. This research project will provide the first results of such measurements and the corresponding average annual effective dose rates equivalent to the patients using these materials and also to the dental technician and doctors work in the various dental laboratories that make use of these materials in their daily work. A total number of 30 dental powder samples were collected from a number of dental laboratories around Tripoli area will be analyzed. In this research project, the results from this preliminary survey regarding Th, U and K elemental concentrations in a wide variety of dental materials by means of high-resolution X-ray spectrometry will be presented. Further results from these investigations concerning activity concentrations and the associated dose rates, effective dose and the committed dose due to the use of these materials are going to be calculated and compared with other published data elsewhere and recommendation of their use will be derived accordingly. (author)

  18. Surface detail reproduction of Type IV dental stones with selected polyvinyl siloxane impression materials.

    Science.gov (United States)

    Schelb, E; Cavazos, E; Troendle, K B; Prihoda, T J

    1991-01-01

    Four polyvinyl siloxane impression materials and 14 modified Type IV dental stones were evaluated for their abilities to reproduce surface detail. Each combination of impression material and dental stone was used to duplicate a 20-microns-wide line. Surface detail reproduction was observed by two paired-rater groups. The line was reproduced in all impression material specimens, but in only 32% of the stone cast specimens. Some combinations of impression material/dental stone reproduced the line all or most of the time, but 12 combinations did not reproduce the line at all.

  19. Influence of the casting material on the dimensional accuracy of dental dies

    Directory of Open Access Journals (Sweden)

    Daher Antonio Queiroz

    2011-08-01

    Full Text Available The purpose of this study was to evaluate the dimensional accuracy of different materials used in the confection of dies. Two stainless steel standard models were confected. One of the models, which was 2 mm larger than the other model, was used to provide a uniform relief for the two-step putty-wash impression technique. Thirty impressions were obtained using a polyvinyl siloxane impression material and randomly divided into three groups (n = 10 according to the type of casting material: type IV dental stone, commercially available epoxy resin (Tri-Epoxy, and industrial epoxy resin (Sikadur. After the setting/polymerization of the casting material, the dimensional stability was measured in terms of the height, diameter of the base and diameter of the top from the obtained dies and from the standard metal model using a profile projector. Results were analyzed by ANOVA and Dunnet test (α = 0.05. In the height values, no significant difference was observed between the groups, except for Sikadur casts, which showed lower mean values. The Tri-Epoxi group showed statistically lower mean base diameter values, compared with the other groups, and both epoxy resin groups showed statistically lower mean top diameter values, compared with that for the type IV dental stone group. We concluded that type IV gypsum and the commercially available epoxy resin showed similar behavior in most areas. The industrial epoxy resin did not show the same characteristics, although the diameter of the base obtained with it was similar to that obtained with type IV dental stone.

  20. An overview of case-based and problem-based learning methodologies for dental education.

    Science.gov (United States)

    Nadershahi, Nader A; Bender, Daniel J; Beck, Lynn; Lyon, Cindy; Blaseio, Alexander

    2013-10-01

    Dental education has undergone significant curriculum reform in response to the 1995 Institute of Medicine report Dental Education at the Crossroads and the series of white papers from the American Dental Education Association Commission on Change and Innovation in Dental Education (ADEA CCI) first published in the Journal of Dental Education and subsequently collected in a volume titled Beyond the Crossroads: Change and Innovation in Dental Education. An important element of this reform has been the introduction into academic dentistry of active learning strategies such as problem-based and case-based learning. As an aide to broadening understanding of these approaches in order to support their expansion in dental education, this article reviews the major characteristics of each approach, situates each in adult learning theory, and discusses the advantages of case-based learning in the development of a multidisciplinary, integrated predoctoral dental curriculum. PMID:24098033

  1. Evaluation of dental material series from patients with dental prostheses and suspicion of delayed hypersensitivity*

    Science.gov (United States)

    Yoshimura, Fernanda Cortinhas; Cunha, Victor do Espirito Santo; Hahnstadt, Ruppert Ludwig; Pires, Mário Cezar

    2016-01-01

    BACKGROUND Patients with oral sensitivity are common in our practice. Allergic contact dermatitis is one of the most frequent etiologies. OBJECTIVES Evaluate oral contact dermatitis using the Brazilian standard series and complementary dental series in patients using dental prostheses, with or without oral complaints. Determine specific dental Brazilian series. METHODS Patients using dental prostheses with or without oral complaints realized patch tests. Brazilian standard series and complementary dental series were used according to ICDRG recommendations. The results were analysed according to age, sex, race, atopic conditions and symptoms associated. RESULTS From 54 patients tested, 34 (63%) were positive at least to one substance. Nineteen had oral complaints, such as burning mouth, itch or oral erythema. There was no association between atopic condition and tests results. Without the oral series, just 23(42,6%) patients had a positive result. Using the Brazilian standard series with the complementary dental series we improved the positivity of the patch test to 47%. CONCLUSION In patients using prostheses and with oral complaints, patch tests with Brazilian standard series with complementary dental series improve the tests positivity. PMID:27192511

  2. Effect of curing with a plasma light on the properties of polymerizable dental restorative materials.

    Science.gov (United States)

    Millar, B J; Nicholson, J W

    2001-06-01

    Specimens of light-curable dental restoratives have been prepared using either a conventional dental curing lamp (for 20 or 30 s) or a plasma light (for 1 or 2 s). The specimens were then stored in water until their mass equilibrated, then dried to constant mass. Most specimens lost material in this process but the losses in all specimens cured with the plasma light were significantly greater than those cured with the conventional lights (P cure times gave slightly reduced losses in water in most cases. The specimens were then returned to water and allowed to re-equilibrate and their equilibrium water uptake determined. There was no simple trend in this latter property because elution of loosely bound hydrophilic species may have resulted in a less hydrophilic specimen, whose equilibrium water content was therefore correspondingly lower. Overall, the losses through dissolution in water suggest that plasma curing is less effective for these materials than conventional light curing, as it probably results in material with lower molar mass. The losses for the resin-modified glass-ionomer were much greater than for other materials, and it was concluded that the more rapid polymerization with plasma light caused a significant inhibitation of the acid-base part of the setting process. These findings suggest that long-term durability of materials may be compromised by employing plasma light cure rather than a conventional cure system and further studies of this point are recommended.

  3. Discrimination of tooth layers and dental restorative materials using cutting sounds.

    Science.gov (United States)

    Zakeri, Vahid; Arzanpour, Siamak; Chehroudi, Babak

    2015-03-01

    Dental restoration begins with removing carries and affected tissues with air-turbine rotary cutting handpieces, and later restoring the lost tissues with appropriate restorative materials to retain the functionality. Most restoration materials eventually fail as they age and need to be replaced. One of the difficulties in replacing failing restorations is discerning the boundary of restorative materials, which causes inadvertent removal of healthy tooth layers. Developing an objective and sensor-based method is a promising approach to monitor dental restorative operations and to prevent excessive tooth losses. This paper has analyzed cutting sounds of an air-turbine handpiece to discriminate between tooth layers and two commonly used restorative materials, amalgam and composite. Support vector machines were employed for classification, and the averaged short-time Fourier transform coefficients were selected as the features. The classifier performance was evaluated from different aspects such as the number of features, feature scaling methods, classification schemes, and utilized kernels. The total classification accuracies were 89% and 92% for cases included composite and amalgam materials, respectively. The obtained results indicated the feasibility and effectiveness of the proposed method.

  4. Translucency of human teeth and dental restorative materials and its clinical relevance

    Science.gov (United States)

    Lee, Yong-Keun

    2015-04-01

    The purpose was to review the translucency of human teeth and related dental materials that should be considered for the development of esthetic restorative materials. Translucency is the relative amount of light transmission or diffuse reflection from a substrate surface through a turbid medium. Translucency influences the masking ability, color blending effect, and the degree of light curing through these materials. Regarding the translucency indices, transmission coefficient, translucency parameter, and contrast ratio have been used, and correlations among these indices were confirmed. Translucency of human enamel and dentine increases in direct proportion to the wavelength of incident light in the visible light range. As for the translucency changes by aging, limited differences were reported in human dentine, while those for enamel proved to increase. There have been studies for the adjustment of translucency in dental esthetic restorative materials; the size and amount of filler and the kind of resin matrix were modified in resin composites, and the kind of ingredient and the degree of crystallization were modified in ceramics. Based on the translucency properties of human enamel and dentine, those of replacing restorative materials should be optimized for successful esthetic rehabilitation. Biomimetic simulation of the natural tooth microstructure might be a promising method.

  5. Surface characterization of titanium based dental implants

    International Nuclear Information System (INIS)

    Dental implantology uses metallic devices made of commercially pure titanium in order to replace lost teeth. Titanium presents favorable characteristics as bio material and modern implants are capable of integrate, witch is the union between bone and implant without fibrous tissue development. Three of the major Brazilian implant manufacturers were chosen to join the study. A foreign manufacturer participated as standard. The manufacturers had three specimens of each implant with two different surface finishing, as machined and porous, submitted to analysis. Surface chemical composition and implant morphology were analyzed by X-ray photoelectron spectroscopy (XP S), scanning electron microscopy (SEM) and microprobe. Implant surface is mainly composed of titanium, oxygen and carbon. Few contaminants commonly present on implant surface were found on samples. Superficial oxide layer is basically composed of titanium dioxide (TiO2), another oxides as Ti O and Ti2O3 were also found in small amount. Carbon on implant surface was attributed to manufacturing process. Nitrogen, Phosphorous and Silicon appeared in smaller concentration on surface. There was no surface discrepancy among foreign and Brazilian made implants. SEM images were made on different magnification, 35 X to 3500 X, and showed similarity among as machined implants. Porous surface finishing implants presented distinct morphology. This result was attributed to differences on manufacturing process. Implant bioactivity was accessed through immersion on simulated body solution (SBF) in order to verify formation of an hydroxyapatite (HA) layer on surface. Samples were divided on three groups according to immersion time: G1 (7 days), G2 (14 days), G3 (21 days), and deep in SBF solution at 37 deg C. After being removed from solution, XPS analyses were made and then implants have been submitted to microprobe analysis. XPS showed some components of SBF solution on sample surface but microprobe examinations did not

  6. A useful and non-invasive microanalysis method for dental restoration materials

    Energy Technology Data Exchange (ETDEWEB)

    Hosoki, M., E-mail: hosoki@tokushima-u.ac.jp [Department of Fixed Prosthodontics, Institute of Health Biosciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan); Satsuma, T.; Nishigawa, K.; Takeuchi, H. [General Dentistry, Tokushima University Hospital, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan); Asaoka, K. [Department of Biomaterials and Bioengineering, Institute of Health Biosciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer This method for the microanalysis of dental alloys is beneficial for patients with allergies to dental materials. Black-Right-Pointing-Pointer This metal sample is easy to mail it for inspection at specialist institutes. Black-Right-Pointing-Pointer This method can be also be used in general dental clinics. - Abstract: The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 {mu}g. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

  7. A useful and non-invasive microanalysis method for dental restoration materials

    International Nuclear Information System (INIS)

    Highlights: ► This method for the microanalysis of dental alloys is beneficial for patients with allergies to dental materials. ► This metal sample is easy to mail it for inspection at specialist institutes. ► This method can be also be used in general dental clinics. - Abstract: The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 μg. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

  8. Effects of radio-opacifier addition in dental impression material

    Directory of Open Access Journals (Sweden)

    Mota Eduardo

    2010-01-01

    Full Text Available Objective: The aim of this in vitro study was to determine the effects of barium sulfate addition in two dental impression materials previously proved as radiolucent. Materials and Methods: An irreversible hydrocolloid (IH and polyether (PE were tested for optical density, linear dimension stability and detail reproduction. Statistical Analysis Used: The optical density data were submitted to Kolmogorov-Smirnov normality test and compared with two-way ANOVA and Tukey (alpha=0.05. Results: The results of optical density (pixel were: IH control 45.24 f (±7.6, PE control 54.93 e (±4.45, PE 5Wt% 60.43 d (±6.27, IH 1Wt% 61.54 cd (±5.3, PE 1Wt% 66.9 bc (±5.05, IH 5Wt% 67.17 b (±6.01, PE 10Wt% 84.55 a (±5.14, IH 10Wt% 85.33 a (±5.53. On detail reproduction, polyether control was able to copy the 6 μm line. Adding 1 or 5Wt% of barium sulfate have not change this characteristic. For the irreversible hydrocolloid, the control group was able to copy a line with 14 μm, however, adding 1Wt% barium sulfate, the capability decreased to 22 μm. Adding barium sulfate in the polyether promoted an increase in between the copied lines, for the control, the average distance was 931.6 μm, 936 μm to 1Wt% and 954.5 μm to 5 Wt%. For the IH, the control presented 975 μm in comparison to 987.25 μm for 1 Wt% samples. Conclusion: The addition of barium sulfate was capable of increasing significantly the optical density of tested material, have changed the linear dimension stability, however, have not interfered in detail reproduction only for PE.

  9. The role of school-based dental programme on dental caries experience in Yogyakarta Province, Indonesia

    NARCIS (Netherlands)

    Amalia, Rosa; Schaub, Rob M. H.; Widyanti, Niken; Stewart, Roy; Groothoff, Johan W.

    2012-01-01

    Objectives. To assess the effectiveness of a school-based dental programme (SBDP) in controlling caries by measuring the relationship between the SBDP performance and caries experience in children aged 12 in Yogyakarta Province, Indonesia, by taking into account influencing factors. Methods. A cross

  10. A useful and non-invasive microanalysis method for dental restoration materials

    Science.gov (United States)

    Hosoki, M.; Satsuma, T.; Nishigawa, K.; Takeuchi, H.; Asaoka, K.

    2012-12-01

    The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 μg. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

  11. Preparing dental students for careers as independent dental professionals: clinical audit and community-based clinical teaching.

    Science.gov (United States)

    Lynch, C D; Llewelyn, J; Ash, P J; Chadwick, B L

    2011-05-28

    Community-based clinical teaching programmes are now an established feature of most UK dental school training programmes. Appropriately implemented, they enhance the educational achievements and competences achieved by dental students within the earlier part of their developing careers, while helping students to traverse the often-difficult transition between dental school and vocational/foundation training and independent practice. Dental school programmes have often been criticised for 'lagging behind' developments in general dental practice - an important example being the so-called 'business of dentistry', including clinical audit. As readers will be aware, clinical audit is an essential component of UK dental practice, with the aims of improving the quality of clinical care and optimising patient safety. The aim of this paper is to highlight how training in clinical audit has been successfully embedded in the community-based clinical teaching programme at Cardiff.

  12. IN VITRO TESTING – AN ESENTIAL METHOD FOR EVALUATING THE PERFORMANCE OF DENTAL MATERIALS AND DEVICES

    Directory of Open Access Journals (Sweden)

    Anca VIŢALARIU

    2015-06-01

    Full Text Available Dentistry is unique among biomaterials specialties as to the large variety of materials used, and nature of the challenges they must resist. Intra-oral service demands materials adapted to a warm and moist environment, resisting the attack of digestive acids and enzymes. The materials subjected to mechanical forces should preserve their strength, fatigue and wear characteristics, for accomplishing their function. The wide range of materials available for restorative dentistry demands knowledge of their relative strengths and trade-offs, and offers the opportunity for many interesting lines of research. The spectrum extensively ranges from elastic impression materials to extremely stiff metal and ceramic appliances, so that familiarity with a variety of mechanical testing situations is required from a well-rounded dental materials laboratory. Evaluating the mechanical and wear characteristics of dental restorative materials and analyzing the durability of adhesives is critical to the development of improved dental devices

  13. Potentiometric stripping analysis of lead and cadmium leaching from dental prosthetic materials and teeth

    Directory of Open Access Journals (Sweden)

    GORAN M. NIKOLIC

    2004-07-01

    Full Text Available Potentiometric stipping analysis (PSA was applied for the determination of lead and cadmium leaching from dental prosthetic materials and teeth. The soluble lead content in finished dental implants was found to be much lower than that of the individual components used for their preparation. Cadmium was not detected in dental implants and materials under the defined conditions. The soluble lead and cadmium content of teeth was slightly lower than the lead and cadmium content in whole teeth (w/w reported by other researchers, except in the case of a tooth with removed amalgam filling. The results of this work suggest that PSA may be a good method for lead and cadmium leaching studies for investigation of the biocompatibility of dental prosthetic materials.

  14. Restored viability and function of dental pulp cells on poly-methylmethacrylate (PMMA)-based dental resin supplemented with N-acetyl cysteine (NAC).

    Science.gov (United States)

    Kojima, N; Yamada, M; Paranjpe, A; Tsukimura, N; Kubo, K; Jewett, A; Ogawa, T

    2008-12-01

    This study examines cytotoxicity of poly-methylmethacrylate (PMMA)-based dental temporary filling resin to dental pulp cells, and the potential amelioration of the toxicity with an anti-oxidant amino-acid, N-acetyl cysteine (NAC). Dental pulp cells extracted from rat maxillary incisors were cultured on the resin material with or without NAC incorporation, or on the polystyrene. The cultures were supplied with osteoblastic media, containing dexamethasone. Forty five percent of cells on the PMMA dental resin were necrotic at 24h after seeding. However, this percentage was reduced to 27% by incorporating NAC in the resin, which was the level equivalent to that in the culture on polystyrene. The culture on the untreated resin was found to be negative for alkaline phosphate (ALP) activity at days 5 and 10 or von Kossa mineralized nodule formation at day 20. In contrast, some areas of the cultures on NAC-incorporated resin substrates were ALP and von Kossa positive. Collagen I and dentin sialoprotein genes were barely expressed in day 7 culture on the untreated resin. However, those genes were expressed in the culture on the resin with NAC. These results suggest that the decreased cell viability and the nearly completely suppressed odontoblast-like cell phenotype of dental pulp cells cultured on PMMA dental resin can be salvaged to a biologically significant degree by the incorporation of NAC in the resin.

  15. An evidence-based review of dental matrix systems.

    Science.gov (United States)

    Owens, Barry M; Phebus, Jeffrey G

    2016-01-01

    The restoration of proximal surface cavities, originating from Class II carious lesions, to "normal" anatomical specifications is a fundamental objective for the dental practitioner. Cognitive interpretation of tooth morphology attained from evidence-based resources, together with the necessary psychomotor skills for correct design and completion, are considered essential strategies for restoration success. Also, the visualization of the original tooth structure, if present, should substantially benefit the dentist in the creation of a clinically satisfactory restoration. The purpose of this evidence-based review is to define the cause and effect of decisions based on optimum treatment standards of care for the patient. The concepts of form and function, as related to the oral environment, and the consequences of unsatisfactory dental restorative care will be scrutinized. This article will identify and explain the different challenges and solutions for restoration of dental proximal lesions and provide an overview of past, present, and future procedures. PMID:27599285

  16. Experiments of Applying the Rare-Earth Modifying Agents in New Dental Materials Preparation

    Institute of Scientific and Technical Information of China (English)

    Chen Xiaohu; Wang Hua; Wang Qin; Li Xiaodi; Ma Rui

    2007-01-01

    Harmless rare-earth modifying agents were prepared by orthogonal experiments. A new resin material was synthesized with the qualities such as rigidity, rubbing abrasion, aging, luster and plasticity better than the dental resin materials in common used. It could be used as the substitutes for the applied resin teeth materials.

  17. Evidence-based prevention, management, and monitoring of dental caries.

    Science.gov (United States)

    Barber, Lois Rigmont; Wilkins, Esther M

    2002-01-01

    Dental caries, not unlike periodontal diseases, is now recognized as an infectious, transmissible, multifactorial disease of bacterial origin. Current evidence-based emphasis is on the need to recognize a carious lesion in its earliest stage before demineralization has produced a cavitated lesion that requires restoration by a dentist. As a result of current understanding of caries control, the dental hygienist's role as a prevention specialist is to determine the dental caries risk factors for patients of all ages and to introduce remineralization strategies into the patient's dental hygiene care plan. Conservative strategies of a concentrated program include initial infection control with a chlorhexidine rinse; extra daily fluoride exposures; placement of pit and fissure sealants where indicated; control of sucrose exposures; use of sugar substitutes, particularly xylitol-containing sugar-free chewing gum; and an emphasis on a daily bacterial plaque removal routine. Evidence supports the management and monitoring of dental caries. Caries risk level must be reevaluated at each maintenance appointment. Appropriate in-office strategies to preserve tooth structure should be carried out and followed by applicable home regimens that are based on need, not age.

  18. Comparative Analysis of Two Methods of Assessment Wear of Dental Materials

    OpenAIRE

    Wojda Sylwia M.

    2015-01-01

    Wear of dental materials used for permanent dental fillings has a significant impact on their lifetime. Wear products generated during chewing process involving direct tribological contact between a composite and tooth enamel can cause damage not only to enamel itself but also to the entire tooth structure thus affecting the patient’s the health. It is essential therefore to assess the process of wear rates as well as the usefulness and effectiveness of the method used to measure these values...

  19. Effect of dental materials on gluconeogenesis in rat kidney tubules

    NARCIS (Netherlands)

    Reichl, F.X.; Durner, J.; Mückter, H.; Elsenhans, B.; Forth, W.; Kunzelmann, K.H.; Hickel, R.; Spahl, W.; Hume, W.R.; Moes, G.W.

    1999-01-01

    The effect of dental composite components triethyleneglycoldimethacrylate (TEGDMA) and hydroxyethylmethacrylate (HEMA) as well as mercuric chloride (HgCl2) and methylmercury chloride (MeHgCl) on gluconeogenesis was investigated in isolated rat kidney tubules. From starved rats kidney tubules were pr

  20. FDI report on adverse reactions to resin-based materials.

    Science.gov (United States)

    Fan, P L; Meyer, D M

    2007-02-01

    Resin-based restorative materials are considered safe for the vast majority of dental patients. Although constituent chemicals such as monomers, accelerators and initiators can potentially leach out of cured resin-based materials after placement, adverse reactions to these chemicals are rare and reaction symptoms commonly subside after removal of the materials. Dentists should be aware of the rare possibility that patients could have adverse reactions to constituents of resin-based materials and be vigilant in observing any adverse reactions after restoration placement. Dentists should also be cognisant of patient complaints about adverse reactions that may result from components of resin-based materials. To minimise monomer leaching and any potential risk of dermatological reactions, resin-based materials should be adequately cured. Dental health care workers should avoid direct skin contact with uncured resin-based materials. Latex and vinyl gloves do not provide adequate barrier protection to the monomers in resin-based materials.

  1. 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.

  2. Effect of surfactant on surface hardness of dental stone and investment casts produced from polyvinyl siloxane duplicating materials.

    Science.gov (United States)

    Al-Johani, Attalah; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

    2008-06-01

    Polyvinylsiloxane duplicating materials are typically treated with a topical surfactant before pouring dental models, but the use of topical surfactants in the dental laboratory may affect the surface hardness of the resultant models. The effect of two different topical surfactants on surface hardness of two dental stones (FujiRock and Dentstone) and one phosphate bonded investment material (Croform WB) produced from polyvinyl siloxane (PVS) dental laboratory duplicating moulds was investigated. Topical surfactants affected the surface hardness of FujiRock, Dentstone and Croform WB investment material. Surface hardness of FujiRock increased with Wax-Mate surfactant. However, surface hardness of Croform WB investment material decreased with both topical surfactants.

  3. Advances in dental veneers: materials, applications, and techniques

    OpenAIRE

    Pini NP; Aguiar FHB; Lima DAN; Lovadino JR; Terada RS; Pascotto RC

    2012-01-01

    Núbia Pavesi Pini1, Flávio Henrique Baggio Aguiar1, Débora Alves Nunes Leite Lima1, José Roberto Lovadino1, Raquel Sano Suga Terada2, Renata Corrêa Pascotto21Area of Restorative Dentistry, Piracicaba Dental School, State University of Campinas – FOP/Unicamp – Piracicaba, São Paulo, 2Area of Restorative Dentistry, State University of Maringá – UEM – Maringá, Paran&...

  4. A critical review of dental implant materials with an emphasis on titanium versus zirconia

    NARCIS (Netherlands)

    R.B. Osman; M.V. Swain

    2015-01-01

    The goal of the current publication is to provide a comprehensive literature review on the topic of dental implant materials. The following paper focuses on conventional titanium implants and more recently introduced and increasingly popular zirconia implants. Major subtopics include the material sc

  5. The teaching of all-ceramic restorations in North American dental schools: materials and techniques employed.

    Science.gov (United States)

    Frazier, K B; Mjör, I A

    1997-01-01

    North American dental schools were surveyed to determine the types of clinical experiences and the extent of material use that predoctoral students encounter with restorative procedures that employ all-ceramic materials. The results were based on an overall response rate of 80% from the 64 surveyed schools. The majority (96%) of the 51 schools responding to the survey did offer an opportunity to become experienced with all-ceramic restorations. The selection of bases and liners for all-ceramic restorations included dentin adhesive agents, glass ionomer materials, and calcium hydroxide products, by a ratio of 5:4:1, respectively. The most commonly used impression material types were addition silicone and polyether. One or both of these materials were used by every school. Dicor glass ceramic and alumina core ceramic were the most commonly used materials by the responding schools for veneers, onlays, and crowns. Dicor glass ceramic and CAD/CAM ceramic were most commonly used for inlays. Crowns were made of more different all-ceramic material types than the other restoration classes. Fabrication of all-ceramic restorations was primarily by commercial laboratories and school technicians. Students have hands-on experience in the fabrication of all-ceramic restorations in 6% of the responding schools. Luting agents for all-ceramic restorations include dual-cured resin, in 96% of the responding schools, light-cured resin, 43%, and glass ionomer cement, 33%. Zinc phosphate, chemical-cured composite, and polycarboxylate were used by less than one fourth of the respondents. Only resin-based composite materials were used to lute ceramic veneers. Rubber dam was applied primarily during luting procedures involving all-ceramic inlays and onlays. Crowns and veneers were isolated by this method in less than 30% of the responding schools. Finishing procedures with all-ceramic restorations were accomplished with three or more instruments by 89% of the schools.

  6. Fluoride uptake from restorative dental materials by human enamel

    International Nuclear Information System (INIS)

    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 19F (p, αγ) 16O 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 106. 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)

  7. Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

    Science.gov (United States)

    Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

    2016-05-01

    Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

  8. A new method for training of ear framework creation by silicon dental impression material.

    Science.gov (United States)

    Thadani, Sandeep M; Ladani, Parit S

    2012-01-01

    This article presents the novel method of training of creating cartilage framework for total ear reconstruction in microtia. Replica of costal cartilage harvested for real surgery was simulated by silicon dental impression material. Carving of framework was done with wood carving instruments. Silicon dental impression material gives the consistency and texture almost comparable to real costal cartilage. Sequential steps similar to actual surgery were simulated to create the three-dimensional framework.By using this novel technique, novice surgeons can practice creating ear framework and improvise their results in the actual surgery.

  9. Ensuring the global availability of high-quality dental restorative materials.

    Science.gov (United States)

    Ferracane, J; Fisher, J; Eiselé, J L; Fox, C H

    2013-11-01

    The Minamata Convention, a global legally binding instrument (treaty) on mercury, has been the catalyst for the emerging agenda on global dental materials research. If the current and future challenges of oral health maintenance and healing on a global scale are to be met, a logical and effective research agenda for the discovery and introduction of new, environmentally sustainable, dental materials must be developed through a coordinated effort involving materials scientists, dental clinicians, representatives of industry, members of regional and national regulatory bodies, and advocacy from research organizations. For universal impact, this agenda should be created with awareness of several important ongoing initiatives, such as the WHO non-communicable diseases action plan, the UN sustainable development agenda, and the IADR Global Oral Health In Inequalities Research Agenda (GOHIRA). A significant contributor to this cause is the FDI and its membership, who, through their Vision 2020 initiative, acknowledge their role and responsibility in globally preventing and managing dental disease and providing leadership to the profession in terms of information dissemination and affecting change. Dental researchers also have an obligation to advocate for appropriate funding to match the identified research needs, thus enhancing the possibility that key decision-makers will provide the needed support to achieve the research agenda agreed upon by this diverse group of stakeholders.

  10. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  11. Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

    OpenAIRE

    Leticia Boldrin MESTIERI; GOMES-CORNÉLIO, Ana Lívia; RODRIGUES, Elisandra Márcia; SALLES, Loise Pedrosa; BOSSO-MARTELO, Roberta; Juliane Maria GUERREIRO-TANOMARU; TANOMARU-FILHO, Mário

    2015-01-01

    Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus. Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs). Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3...

  12. IDIOS: An innovative index for evaluating dental imaging-based osteoporosis screening indices

    Science.gov (United States)

    Halboub, Esam; Almashraqi, Abeer Abdulkareem; Khattab, Razan; Al Haffar, Iyad

    2016-01-01

    Purpose The goal of this study was to develop a new index as an objective reference for evaluating current and newly developed indices used for osteoporosis screening based on dental images. Its name; IDIOS, stands for Index of Dental-imaging Indices of Osteoporosis Screening. Materials and Methods A comprehensive PubMed search was conducted to retrieve studies on dental imaging-based indices for osteoporosis screening. The results of the eligible studies, along with other relevant criteria, were used to develop IDIOS, which has scores ranging from 0 (0%) to 15 (100%). The indices presented in the studies we included were then evaluated using IDIOS. Results The 104 studies that were included utilized 24, 4, and 9 indices derived from panoramic, periapical, and computed tomographic/cone-beam computed tomographic techniques, respectively. The IDIOS scores for these indices ranged from 0 (0%) to 11.75 (78.32%). Conclusion IDIOS is a valuable reference index that facilitates the evaluation of other dental imaging-based osteoporosis screening indices. Furthermore, IDIOS can be utilized to evaluate the accuracy of newly developed indices.

  13. [Adhesion of dental silicone rubber material to thermoplastic material for mouthguards].

    Science.gov (United States)

    Yokota, Kayoko

    2010-03-01

    A preliminary study revealed that an autopolymerization addition silicone resilient denture relining material (SI) had excellent shock absorption properties similar to those of thermoplastic materials commonly used for mouthguards (ethylene-vinyl acetate: EVA). The aim of the present study was to examine the bonding strength of SI and EVA using a newly-developed adhesive prototype. Delamination tests and tensile strength tests were performed to compare the bonding strengths of SI on EVA prepared under the following four conditions: 1) Control condition (no preparation; C), 2) Sandblasting (S), 3) Bonding with the adhesive prototype (M), and 4) Combination of sandblasting preparation and bonding with the adhesive prototype (SM). The mean bonding strength (S. D.) of the delamination tests under the C, S, M and SM conditions were 0.167 (0.003) N/mm, 0.273 (0.034) N/mm, 0.242 (0.027) N/mm and 0.506 (0.113) N/mm, respectively. The mean bonding strength (S. D.) of the tensile strength tests under the C, S, M and SM conditions were 0.006 (0.011) MPa, 0.081 (0.105) MPa, 0.231 (0.069) MPa and 0.590 (0.041) MPa, respectively. Two-way analysis of variances and Tukey's HSD test detected that the combination of sandblasting preparation and bonding with the adhesive prototype significantly improved the bonding strength between SI and EVA. The results indicate that the self-curing addition silicone resilient denture relining material may adhere to the thermoplastic material prepared by combined application of sandblasting and the adhesive prototype, suggesting the potential of the dental silicone rubber material as a material for repairing mouthguards in clinical practice. PMID:20415249

  14. Alternative materials study for dental magnetics attachments applications

    International Nuclear Information System (INIS)

    Ferromagnetic alloys have been investigated as potential candidates for dental prosthesis applications in replacement for magnetic attachments made of noble and expensive alloys. Three stainless steels were investigated: 17-4 PH produced by powder injection (PIM), PM2000 obtained by mechanical alloying and oxide dispersion strengthened, and nickel free stainless steel 1802. In the in vitro cytotoxicity analysis, none of the three steels tested showed cytotoxic effects. The corrosion resistance of stainless steels was evaluated by electrochemical impedance spectroscopy (EIS) and anodic potentiodynamic polarization, in sodium phosphate buffer solutions (PBS) at 25 degree C. The AISI 316L stainless steel was also tested under the same conditions for comparison reasons. All the stainless steel samples were passive in the electrolyte used and presented susceptibility to pitting. The steel that showed the highest pitting resistance was the PM2000, whereas the 1802 had the lowest resistance to pitting among the tested ones. The Mott-Schottky diagrams suggested that the passive film over the surface of PM2000 steel is at least one decade less doped compared to 316L stainless steel, so less defective in its structure. The results pointed out to the PM2000 as a potential candidate for substitution of high cost magnetic alloys used in dental prosthesis. (author)

  15. Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

    Science.gov (United States)

    Seki, Naoko; Moross, Janelle; Sunaga, Masayo; Hobo, Koki; Miyoshi, Tomoe; Nitta, Hiroshi; Kinoshita, Atsuhiro; Morio, Ikuko

    2016-01-01

    Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision.

  16. Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

    Science.gov (United States)

    Seki, Naoko; Moross, Janelle; Sunaga, Masayo; Hobo, Koki; Miyoshi, Tomoe; Nitta, Hiroshi; Kinoshita, Atsuhiro; Morio, Ikuko

    2016-01-01

    Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision. PMID:27181485

  17. Dental Implant Systems

    Directory of Open Access Journals (Sweden)

    Yoshiki Oshida

    2010-04-01

    Full Text Available Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities.

  18. Insights on Metal Based Dental Implants and their Interaction with the Surrounding Tissues.

    Science.gov (United States)

    Popa, Marcela; Hussien, Mohamed D; Cirstea, Alexandra; Grigore, Raluca; Lazar, Veronica; Bezirtzoglou, Eugenia; Chifiriuc, Mariana Carmen; Sakizlian, Monica; Stavropoulou, Elisavet; Bertesteanu, Serban

    2015-01-01

    At present, the use of dental implants is a very common practice as tooth loss is a frequent problem and can occur as a result of disease or trauma. An implant is usually made of biocompatible materials that do not cause rejection reactions and allow the implant union with the respective bone. To achieve this goal, the implant surface may have different structures and coatings, generally used to increase the adherence of the implant to the bone and to decrease the risk of the periimplantar inflammatory reactions. This review gives some insights of the metal based materials used for dental implants, their limits, improvement strategies as well as the pathophysiology, diagnosis, treatment and prevention of periimplantary diseases.

  19. The study of dental material artifact on magnetic resonance imaging

    International Nuclear Information System (INIS)

    To analyze possible metal-induced artifacts developed in dental MR images, quantitative analyses were done in a basic experiment using a medium intensity magnetic field. To simplify the relationship between the skull and dental restorations, we prepared metal (Nickel-chromium alloys, Cobalt-chromium alloys, Titanium alloys, Au alloys, Ag-Pd-Cu-Au alloys, silver) as well as acrylic resin specimens as 5 mm cubes and as a phantom. Imaging conditions were fast spin echo T2 weight, spin echo T2 weight, spin echo proton density weight, spin echo T1 weight and gradient echo T2*, and imaging directions were transverse, sagittal and coronal. Therefore, 645 different combinations were possible. Nickel-chromium alloys, Cobalt-chromium alloys and Titanium alloys showed artifacts when compared with the acrylic resin control. Au alloys, Ag-Pd-Cu-Au alloys and silver did not show a consistent tendency, and images obtained tended to differ from those of the acrylic resin control depending on imaging conditions and direction. The order of artifact development range was Nickel-chromium alloys, Cobalt-chromium alloys, Titanium alloys, Ag-Pd-Cu-Au alloys, Au alloys and silver. The strongest and weakest artifacts were observed under the condition of spin echo T2 weight and spin echo T1 weight, respectively. There was no consistent tendency observed among imaging directions; in Nickel-chromium alloys, Cobalt-chromium alloys and Titanium alloys, the artifact area increased in proportion to the increase in the number of specimens. In silver, Au alloys and Ag-Pd-Cu-Au alloys, the artifact area increased in proportion to the increase in the number of specimens, but only when specimens were arranged parallel to the imaging direction. In Nickel-chromium alloys, Cobalt-chromium alloys and Titanium alloys, artifacts were larger in the horizontal imaging direction than in the vertical direction. (K.H.)

  20. Resistance to Fracture of Dental Roots Obturated with Different Materials

    Directory of Open Access Journals (Sweden)

    Berkan Celikten

    2015-01-01

    Full Text Available The aim of this study was to compare the vertical fracture resistance of roots obturated with different root canal filling materials and sealers. Crowns of 55 extracted mandibular premolar teeth were removed to provide root lengths of 13 mm. Five roots were saved as negative control group (canals unprepared and unfilled. Fifty root canals were instrumented and then five roots were saved as positive control group (canals prepared but unfilled. The remaining 45 roots were randomly divided into three experimental groups (n=15 root/group and obturated with the following procedures: in group 1, glass ionomer-based sealer and cone (ActiV GP obturation system; in group 2, bioceramic sealer and cone (EndoSequence BC obturation system; and in group 3, roots were filled with bioceramic sealer and cone (Smartpaste bio obturation system. All specimens were tested in a universal testing machine for measuring fracture resistance. For each root, the force at the time of fracture was recorded in Newtons. The statistical analysis was performed by using Kruskal-Wallis and post hoc test. There were no significant differences between the three experimental groups. The fracture values of three experimental and negative control groups were significantly higher than the positive control group. Within the limitations of this study, all materials increased the fracture resistance of instrumented roots.

  1. Cytogenetic genotoxic investigation in peripheral blood lymphocytes of subjects with dental composite restorative filling materials.

    Science.gov (United States)

    Pettini, F; Savino, M; Corsalini, M; Cantore, S; Ballini, A

    2015-01-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. The objective of this study was to evaluate the genotoxicity of a common dental composite material (Enamel Plus-HFO), in subjects with average 13 filled teeth with the same material, compared to a control group (subjects having neither amalgam nor composite resin fillings). Genotoxicity assessment of composite materials was carried out in vitro in human peripheral blood leukocytes using sister-chromatid exchange (SCE) and chromosomal aberrations (CA) cytogenetic tests. The results of correlation and multiple regression analyses confirmed the absence of a relationship between SCE/cell, high frequency of SCE(HFC) or CA frequencies and exposure to dental composite materials. These results indicate that composite resins used for dental restorations differ extensively in vivo in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair.

  2. Characterization of the surface of protein-adsorbed dental materials by wetting and streaming potential measurements

    NARCIS (Netherlands)

    Matsumura, H; Kawasaki, K; Okumura, N; Kambara, M; Norde, W

    2003-01-01

    In this study we have elucidated the water-wettability and the electrokinetic surface potential of protein-covered dental materials. The proteins used here as typical proteins were human serum albumin and lysozyme from hen's egg. The wettability (hydrophobicity/hydrophilicity) and the surface potent

  3. Characterization of the surface of protein-adsorbed dental materials by wetting and streaming potential measurements

    NARCIS (Netherlands)

    Matsumura, H.; Kawasaki, K.; Okumura, N.; Kambara, M.; Norde, W.

    2003-01-01

    In this study we have elucidated the water-wettability and the electrokinetic surface potential of protein-covered dental materials. The proteins used here as typical proteins were human serum albumin and lysozyme from hen*s egg. The wettability (hydrophobicity/hydrophilicity) and the surface potent

  4. Three-dimensional assessment of dental casts' occlusal surfaces using two impression materials.

    Science.gov (United States)

    Tarawneh, F M; Panos, P G; Athanasiou, A E

    2008-11-01

    The aim of this study was to assess by means of a three-dimensional computed tomography scanning system the occlusal surface characteristics of dental casts made using two different impression materials. Alginate and polyvinyl siloxane impressions were taken of 20 dental students resulting in 40 dental casts. The casts were paired for each student separately so that each pair consisted of an alginate poured cast and a polyvinyl siloxane poured out cast. The casts were scanned using FlashCT scanner and for each cast, a three-dimensional digital image was obtained. The digitized casts were processed using the three-dimensional imaging software Geomagic Studio 9. A total of 464 paired teeth were digitally separated and superimposed. For each tooth, two measurements were obtained corresponding to the two different impression materials used. The two sets of volumes for all digitally separated teeth were compared and analysed using the Wilcoxon signed test. Larger volume measurements were obtained for teeth separated from alginate poured out casts than from their corresponding ones from polyvinyl siloxane casts (P = 0.005). When the teeth were divided into the groups of incisors, canines and premolars/molars, only the last one exhibited significant difference (P = 0.00). The mean difference between the volumes measured for all 464 teeth separated was 0.041 mm(3) (+/-0.33). The occlusal surfaces of teeth appear differently in dental casts depending on the impression materials used. Impressions of dental casts should be utilized with caution in relation to their research application and in reference with dental wear studies.

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

    International Nuclear Information System (INIS)

    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 32P 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)

  6. In vitro comparison of the radiopacity of cavity lining materials with human dental structures

    Directory of Open Access Journals (Sweden)

    Pires de Souza Fernanda

    2010-01-01

    Full Text Available Aim: To compare the optical densities (OD of calcium hydroxide (CH and glass ionomer cement with the same thicknesses of the dental structures. Materials and Methods: Eighteen specimens of each material, with thicknesses of 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm were made in a Teflon matrix. To compare the radiopacity of the materials with the dental structures, dental cuts of the first molars, increasing in thickness from 0.5 to 3.0 mm, were obtained. To standardize the radiographs, a transparent acrylic matrix (Standardizing Device was developed and used. Thirty radiographs were taken, five for each tested material. Results: Statistical analysis (Two-way ANOVA - Bonferroni, P < 0.05 demonstrated that when the materials were compared, there was statistically significant difference between the ODs, only for the thickness of 1.0 mm (P < 0.05. Conclusion: The thickness of the material contributed to its radiopacity, and these materials had to be used in a thickness between 1.5 and 2.0 mm.

  7. Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2016-11-01

    Full Text Available A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1 develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2 investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC; the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI. 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. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1, and much greater than RMGI (p < 0.05. Composite with 3% MPC had protein adsorption that was only 1/10 that of control composites (p < 0.05. Composite with 3% MPC had biofilm CFU and lactic acid much lower than control composites (p < 0.05. Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI (p > 0.1. In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

  8. Gold and palladium burden from dental restoration materials.

    Science.gov (United States)

    Drasch, G; Muss, C; Roider, G

    2000-06-01

    From 81 volunteers (16 without dental restorations, 65 with gold crowns or inlays) samples of saliva before and after chewing gum, blood, serum, urine and faeces were taken and analysed for gold (Au) and palladium (Pd). The Au concentration in all analysed biomonitors correlates significantly to the number of teeth with gold restorations. For Pd the correlations were still significant, but weaker than for Au. Persons with gold restorations show maximal Au and Pd concentrations, 10(2)-10(3) higher than the background burden. The calculated maximal daily Au load in saliva (1.38 mg Au per day) reaches the range of an oral Au therapy for rheumatoid arthritis with 6 mg Auranofin (= 1.74 mg Au per day). During this therapy severe and frequent side effects are reported. In contrast, the Au concentration in serum maximally reached from Au restorations, amounts to only approximately 1/20 of the Au level during arthritis therapy. But even under subtherapeutic doses of 1 mg Auranofin/day severe side effects have been reported (4 out of 56 cases). The mean Au blood concentration from 1 mg Auranofin daily was only 3 times higher than our maximum value. A toxicological classification of the Pd values is difficult, because no toxicological threshold limit has been established, especially for the low-level long-term burden with Pd.

  9. Biofilm formation on dental restorative and implant materials.

    Science.gov (United States)

    Busscher, H J; Rinastiti, M; Siswomihardjo, W; van der Mei, H C

    2010-07-01

    Biomaterials for the restoration of oral function are prone to biofilm formation, affecting oral health. Oral bacteria adhere to hydrophobic and hydrophilic surfaces, but due to fluctuating shear, little biofilm accumulates on hydrophobic surfaces in vivo. More biofilm accumulates on rough than on smooth surfaces. Oral biofilms mostly consist of multiple bacterial strains, but Candida species are found on acrylic dentures. Biofilms on gold and amalgam in vivo are thick and fully covering, but barely viable. Biofilms on ceramics are thin and highly viable. Biofilms on composites and glass-ionomer cements cause surface deterioration, which enhances biofilm formation again. Residual monomer release from composites influences biofilm growth in vitro, but effects in vivo are less pronounced, probably due to the large volume of saliva into which compounds are released and its continuous refreshment. Similarly, conflicting results have been reported on effects of fluoride release from glass-ionomer cements. Finally, biomaterial-associated infection of implants and devices elsewhere in the body is compared with oral biofilm formation. Biomaterial modifications to discourage biofilm formation on implants and devices are critically discussed for possible applications in dentistry. It is concluded that, for dental applications, antimicrobial coatings killing bacteria upon contact are more promising than antimicrobial-releasing coatings.

  10. Improved performance of diatomite-based dental nanocomposite ceramics using layer-by-layer assembly

    Directory of Open Access Journals (Sweden)

    Lu X

    2012-04-01

    Full Text Available Xiaoli Lu1,2, Yang Xia1, Mei Liu1, Yunzhu Qian3, Xuefeng Zhou4, Ning Gu4, Feimin Zhang1,41Institute of Stomatology, Nanjing Medical University, Nanjing, 2Nantong Stomatological Hospital, Nantong, 3Center of Stomatology, The Second Affiliated Hospital of Suzhou University, Suzhou, 4Suzhou Institute, Southeast University, Suzhou, People's Republic of ChinaAbstract: To fabricate high-strength diatomite-based ceramics for dental applications, the layer-by-layer technique was used to coat diatomite particles with cationic [poly(allylamine hydrochloride] and anionic [poly(sodium 4-styrenesulfonate] polymers to improve the dispersion and adsorption of positively charged nano-ZrO2 (zirconia as a reinforcing agent. The modified diatomite particles had reduced particle size, narrower size distribution, and were well dispersed, with good adsorption of nano-ZrO2. To determine the optimum addition levels for nano-ZrO2, ceramics containing 0, 20, 25, 30, and 35 wt% nano-ZrO2 were sintered and characterized by the three-point bending test and microhardness test. In addition to scanning electron microscopy, propagation phase-contrast synchrotron X-ray microtomography was used to examine the internal structure of the ceramics. The addition of 30 wt% nano-ZrO2 resulted in the highest flexural strength and fracture toughness with reduced porosity. Shear bond strength between the core and veneer of our diatomite ceramics and the most widely used dental ceramics were compared; the shear bond strength value for the diatomite-based ceramics was found to be significantly higher than for other groups (P < 0.05. Our results show that diatomite-based nanocomposite ceramics are good potential candidates for ceramic-based dental materials.Keywords: layer-by-layer, diatomite, nanoceramics, zirconia (ZrO2, dental materials

  11. LDEF materials data bases

    Science.gov (United States)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base.

  12. Cellulose Nanofibre Mesh for Use in Dental Materials

    Directory of Open Access Journals (Sweden)

    Anthony J. Ireland

    2012-07-01

    Full Text Available The aim of this study was to produce a 3D mesh of defect free electrospun cellulose acetate nanofibres and to use this to produce a prototype composite resin containing nanofibre fillers. This might find use as an aesthetic orthodontic bracket material or composite veneer for restorative dentistry. In this laboratory based study cellulose acetate was dissolved in an acetone and dimethylacetamide solvent solution and electrospun. The spinning parameters were optimised and lithium chloride added to the solution to produce a self supporting nanofibre mesh. This mesh was then silane coated and infiltrated with either epoxy resin or an unfilled Bis-GMA resin. The flexural strength of the produced samples was measured and compared to that of unfilled resin samples. Using this method cellulose acetate nanofibres were successfully electrospun in the 286 nm range. However, resin infiltration of this mesh resulted in samples with a flexural strength less than that of the unfilled control samples. Air inclusion during preparation and incomplete wetting of the nanofibre mesh was thought to cause this reduction in flexural strength. Further work is required to reduce the air inclusions before the true effect of resin reinforcement with a 3D mesh of cellulose acetate nanofibres can be determined.

  13. Forensic Identification Based on Tooth Material

    Directory of Open Access Journals (Sweden)

    Elza Ibrahim Auerkari

    2015-10-01

    Full Text Available Human teeth are the most robust and stable parts of the body, providing biological clue material for forensic purposes even when most of the oter means of identifcation have been seriously affected by adverse environmental conditions. In particular blood grouping, isozymes, serum proteins and DNA polymorhphisms can be detected from teeth that protect these identification markers in addition to the traditional dental records. While in general the value of traditional dental records in the forensic work is decreasing eg due to mproved dental care, the newer means of identification from tooth material provide considerable promise for effective identification in difficult cases.The DNA analysis from tooth material has been shown to ba a viable route in forensic analysis, when other material for such an analysis is unusable. However in most cases useful biologic material other than teeth is abailable, and then DNA analysis can be made from other tissue with less effort than by using teeth. Also, in cases with lacking other tissue, blood grouping, isozymes and serum proteins may provide cheaper inherited combinations of blood grouping, isozymes and serum proteins can be treated similary to polymorphic DNA loci as independent markers, their identification can be managed if the false positives and negatives in analysis can be minimmised, and the corresponding frequencies of occurrence are known.It was the purpose of the present work to review the methods of forensic identification from tooth material, based on analysis of blood grouping, isozymes and serum proteins. It appears that such a combined analysis provides a robust method for forensic purposes. Nevertheless, for efficient identification it is recommended that as many (multiple forensic methods as possible are combined, so that faster and cheaper methods such as imminent medical forensics are used first, and more thorough analysis is used to support and complement these methods.

  14. Students' perceptions of materials and techniques used at European dental schools in the education of fixed prosthodontics

    NARCIS (Netherlands)

    H.S. Brand; H. Kamell; A. Kharbanda; A. Dozic

    2013-01-01

    The aim of this study was to explore the materials and procedures used by students in dental schools across Europe for teaching fixed prosthodontics. An online questionnaire, containing twenty-eight dichotomous, multiple-choice, and Likert scale rating questions, was sent to students in forty dental

  15. Cytotoxicity assessment of graphene-based nanomaterials on human dental follicle stem cells.

    Science.gov (United States)

    Olteanu, Diana; Filip, Adriana; Socaci, Crina; Biris, Alexandru Radu; Filip, Xenia; Coros, Maria; Rosu, Marcela Corina; Pogacean, Florina; Alb, Camelia; Baldea, Ioana; Bolfa, Pompei; Pruneanu, Stela

    2015-12-01

    Graphene-oxide (GO) and its most encountered derivatives, thermally reduced graphene oxide (TRGO) and nitrogen-doped graphene (N-Gr), were synthesized and structurally characterized by spectroscopic techniques, like Raman and (13)C MAS solid state NMR. Several biological effects (cytotoxicity, oxidative stress induction, and cellular and mithocondrial membrane alterations) induced by such graphene-based materials on human dental follicle stem cells were investigated. Graphene oxide shows the lowest cytotoxic effect, followed by the nitrogen-doped graphene, while thermally reduced graphene oxide exhibits high cytotoxic effects. Graphene oxide induces oxidative stress without causing cell membrane damage. Nitrogen-doped graphene shows a slight antioxidant activity; however, at high doses (20 and 40 μg/ml) it causes membrane damage. Both graphene oxide and nitrogen-doped graphene seem to be valuable candidates for usage in dental nanocomposites.

  16. Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

    Science.gov (United States)

    Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

    2016-03-01

    This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

  17. An Exploration of Dental Students' Assumptions About Community-Based Clinical Experiences.

    Science.gov (United States)

    Major, Nicole; McQuistan, Michelle R

    2016-03-01

    The aim of this study was to ascertain which assumptions dental students recalled feeling prior to beginning community-based clinical experiences and whether those assumptions were fulfilled or challenged. All fourth-year students at the University of Iowa College of Dentistry & Dental Clinics participate in community-based clinical experiences. At the completion of their rotations, they write a guided reflection paper detailing the assumptions they had prior to beginning their rotations and assessing the accuracy of their assumptions. For this qualitative descriptive study, the 218 papers from three classes (2011-13) were analyzed for common themes. The results showed that the students had a variety of assumptions about their rotations. They were apprehensive about working with challenging patients, performing procedures for which they had minimal experience, and working too slowly. In contrast, they looked forward to improving their clinical and patient management skills and knowledge. Other assumptions involved the site (e.g., the equipment/facility would be outdated; protocols/procedures would be similar to the dental school's). Upon reflection, students reported experiences that both fulfilled and challenged their assumptions. Some continued to feel apprehensive about treating certain patient populations, while others found it easier than anticipated. Students were able to treat multiple patients per day, which led to increased speed and patient management skills. However, some reported challenges with time management. Similarly, students were surprised to discover some clinics were new/updated although some had limited instruments and materials. Based on this study's findings about students' recalled assumptions and reflective experiences, educators should consider assessing and addressing their students' assumptions prior to beginning community-based dental education experiences. PMID:26933101

  18. Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

    Science.gov (United States)

    Merghni, Abderrahmen; Kammoun, Dorra; Hentati, Hajer; Janel, Sébastien; Popoff, Michka; Lafont, Frank; Aouni, Mahjoub; Mastouri, Maha

    2016-08-01

    In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

  19. Palladium-based dental alloys are associated with oral disease and palladium-induced immune responses

    NARCIS (Netherlands)

    J. Muris; R.J. Scheper; C.J. Kleverlaan; T. Rustemeyer; I.M.W. van Hoogstraten; M.E. von Blomberg; A.J. Feilzer

    2014-01-01

    Background Palladium (Pd) and gold (Au) based dental alloys have been associated with oral disease. Objectives This study was designed to explore possible associations between the presence of Au-based and Pd-based dental alloys, and oral lesions, systemic complaints, and specific in vivo and in vitr

  20. Synthesis, characterization and antibacterial activity of copper, nickel and bimetallic Cu-Ni nanoparticles for potential use in dental materials

    Institute of Scientific and Technical Information of China (English)

    Liliana Argueta-Figueroa; Raúl A. Morales-Luckie; Rogelio J. Scougall-Vilchis; Oscar F. Olea-Mejía

    2014-01-01

    The antibacterial effect is a desirable property in dental materials. Development of simple methods for the preparation of nanosized metal particles has attracted significant attention because of their future applications due to unusual size-dependent antibacterial properties. Copper (Cu), Nickel (Ni) and bimetallic Cu-Ni nanoparticles were prepared by a simple chemical method and their antibacterial activity was tested against the widely used standard human pathogens Staphylococcus aureus (gram-negative) and Escherichia coli (gram-positive). Additionally, these nanoparticles were tested against the dental pathogen Streptococcus mutans. Our results are promising for potential use in dental materials science.

  1. Synthesis, characterization and antibacterial activity of copper, nickel and bimetallic Cu–Ni nanoparticles for potential use in dental materials

    Directory of Open Access Journals (Sweden)

    Liliana Argueta-Figueroa

    2014-08-01

    Full Text Available The antibacterial effect is a desirable property in dental materials. Development of simple methods for the preparation of nanosized metal particles has attracted significant attention because of their future applications due to unusual size-dependent antibacterial properties. Copper (Cu, Nickel (Ni and bimetallic Cu–Ni nanoparticles were prepared by a simple chemical method and their antibacterial activity was tested against the widely used standard human pathogens Staphylococcus aureus (gram-negative and Escherichia coli (gram-positive. Additionally, these nanoparticles were tested against the dental pathogen Streptococcus mutans. Our results are promising for potential use in dental materials science.

  2. Titanium: the mystery metal of implant dentistry. Dental materials aspects.

    Science.gov (United States)

    Parr, G R; Gardner, L K; Toth, R W

    1985-09-01

    A number of important points concerning titanium and its alloys have been discussed. They are summarized as follows. Ti and its alloys, particularly the alpha-beta alloys, possess mechanical properties that make them ideal implant materials. Ti and its alloys oxidize readily in air. This surface oxide is extremely stable in the physiologic environment of the body. The stability and inertness of this surface oxide layer acts to protect Ti from corrosive breakdown when used in the body. The elimination of surface irregularities and contaminants is important when preparing a metal for implantation. Titanium can be coupled with equally passive metals in the body without causing galvanic corrosion.

  3. Longer-Term Postcure Measurement of Cuspal Deformation Induced by Dimensional Changes in Dental Materials

    Directory of Open Access Journals (Sweden)

    A. Falsafi

    2015-01-01

    Full Text Available Aim. This paper presents a simple, versatile in vitro methodology that enables indirect quantification of shrinkage and expansion stresses under clinically relevant conditions without the need for a dedicated instrument. Methods. For shrinkage effects, resulting cusp deformation of aluminum blocks with MOD type cavity, filled with novel filling compositions and commercial cements, has been measured using a bench-top micrometer and a Linear Variable Differential Transformer (LVDT, a displacement transducer based instrument. Results. The results demonstrated the validity of the proposed simple methodology. The technique was successfully used in longer-term measurements of shrinkage and expansion stress for several dental compositions. Conclusions. In contrast to in situ techniques where a measuring instrument is dedicated to the sample and its data collection, the proposed simple methodology allows for transfer of the samples to the environment of choice for storage and conditioning. The presented technique can be reliably used to quantify stress development of curing materials under clinically relevant (oral conditions. This enables direct examination and comparison of structural properties corresponding to the final stage of formed networks. The proposed methodology is directly applicable to the study of self-curing systems as they require mouth-type conditions (temperature and humidity to achieve their designed kinetics and reactions.

  4. Development of highly porous scaffolds based on bioactive silicates for dental tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Goudouri, O.M., E-mail: menti.goudouri@ww.uni-erlangen.de [Institute for Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Theodosoglou, E. [School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kontonasaki, E. [Department of Fixed Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Will, J. [Institute for Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Chrissafis, K. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koidis, P. [Department of Fixed Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Paraskevopoulos, K.M. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Boccaccini, A.R. [Institute for Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen (Germany)

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis of an Mg-based glass-ceramic via the sol–gel technique. • The heat treatment of the glass-ceramic promoted the crystallization of akermanite. • Akermanite scaffolds coated with gelatin were successfully fabricated. • An HCAp layer was developed on the surface of all scaffolds after 9 days in SBF. - Abstract: Various scaffolding materials, ceramics and especially Mg-based ceramic materials, including akermanite (Ca{sub 2}MgSi{sub 2}O{sub 7}) and diopside (CaMgSi{sub 2}O{sub 6}), have attracted interest for dental tissue regeneration because of their improved mechanical properties and controllable biodegradation. The aim of the present work was the synthesis of an Mg-based glass-ceramic, which would be used for the construction of workable akermanite scaffolds. The characterization of the synthesized material was performed by Fourier Transform Infrared Spectroscopy (FTIR) X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). Finally, the apatite forming ability of the scaffolds was assessed by immersion in simulated body fluid. The scaffolds were fabricated by the foam replica technique and were subsequently coated with gelatin to provide a functional surface for increased cell attachment. Finally, SEM microphotographs and FTIR spectra of the scaffolds after immersion in SBF solution indicated the inorganic bioactive character of the scaffolds suitable for the intended applications in dental tissue engineering.

  5. Dental pulp vitality measurement based on multiwavelength photoplethysmography

    Science.gov (United States)

    Sarkela, Ville; Kopola, Harri K.; Oikarinen, Kyosti; Herrala, Esko

    1995-01-01

    Observation of the intradental blood supply is important in cases of dental trauma, but difficult. As the methods used by dentists to measure pulp vitality are not very reliable, a dental pulp vitalometer based on fiberoptic reflectance measurement and measurement of the absorption of blood has been designed and built. In addition to the fiber optic probe and reflectance sensor electronics, the vitalometer includes a data acquisition card, a PC and data processing programs. The thick dentin and enamel layers and the small amount of blood in a tooth are major problems for optical measurement of its vitality, and scattered light from the enamel and the dentin surrounding the pulpa also causes a problem in measurements based on reflectance. These problems are assessed here by means of theoretical models and calculations. The advantage of reflectance measurement is that only one probe is used, which is easy to put against the tooth. Thus measurements are simple to make. Three wavelengths (560 nm, 650 nm, 850 nm) are used to measure photoplethysmographic signals, and these should allow the oxygen saturation of the blood in a tooth to be measured as well in the future. Series of measurements have been performed on vital and non-vital teeth by recording photoplethysmographic signals, using the vitalometer and using a commercial laser-Doppler instrument. Verifications of the laser-Doppler and vitalometer results are presented and deduced here.

  6. Physicochemical characterization of three fiber-reinforced epoxide-based composites for dental applications.

    Science.gov (United States)

    Bonon, Anderson J; Weck, Marcus; Bonfante, Estevam A; Coelho, Paulo G

    2016-12-01

    Fiber-reinforced composite (FRC) biomedical materials are in contact with living tissues arising biocompatibility questions regarding their chemical composition. The hazards of materials such as Bisphenol A (BPA), phthalate and other monomers and composites present in FRC have been rationalized due to its potential toxicity since its detection in food, blood, and saliva. This study characterized the physicochemical properties and degradation profiles of three different epoxide-based materials intended for restorative dental applications. Characterization was accomplished by several methods including FTIR, Raman, Brunauer-Emmett-Teller (BET) Analysis, X-ray fluorescence spectroscopy, and degradation experiments. Physicochemical characterization revealed that although materials presented similar chemical composition, variations between them were more largely accounted by the different phase distribution than chemical composition. PMID:27612785

  7. Physicochemical characterization of three fiber-reinforced epoxide-based composites for dental applications.

    Science.gov (United States)

    Bonon, Anderson J; Weck, Marcus; Bonfante, Estevam A; Coelho, Paulo G

    2016-12-01

    Fiber-reinforced composite (FRC) biomedical materials are in contact with living tissues arising biocompatibility questions regarding their chemical composition. The hazards of materials such as Bisphenol A (BPA), phthalate and other monomers and composites present in FRC have been rationalized due to its potential toxicity since its detection in food, blood, and saliva. This study characterized the physicochemical properties and degradation profiles of three different epoxide-based materials intended for restorative dental applications. Characterization was accomplished by several methods including FTIR, Raman, Brunauer-Emmett-Teller (BET) Analysis, X-ray fluorescence spectroscopy, and degradation experiments. Physicochemical characterization revealed that although materials presented similar chemical composition, variations between them were more largely accounted by the different phase distribution than chemical composition.

  8. [A rapid prototype fabrication method of dental splint based on 3D simulation and technology].

    Science.gov (United States)

    Lin, Yanping; Chen, Xiaojun; Zhang, Shilei; Wang, Chengtao

    2006-04-01

    The conventional design and fabrication of the dental splint (in orthognathic surgery) is based on the preoperative planning and model surgery so this process is of low precision and efficiency. In order to solve the problems and be up to the trend of computer-assisted surgery, we have developed a novel method to design and fabricate the dental splint--computer-generated dental splint, which is based on three-dimensional model simulation and rapid prototype technology. After the surgical planning and simulation of 3D model, we can modify the model to be superior in chewing action (functional) and overall facial appearance (aesthetic). Then, through the Boolean operation of the dental splint blank and the maxillofacial bone model the model of dental splint is formed. At last, the dental splint model is fabricated through rapid prototype machine and applied in clinic. The result indicates that, with the use of this method, the surgical precision and efficiency are improved.

  9. Analysis of the probability of multiple taxa in a combined sample of Swartkrans and Kromdraai dental material.

    Science.gov (United States)

    Fuller, K

    1996-11-01

    It has been argued (Grine, [1988] Evolutionary History of the "Robust" Australopithecines [New York. Aldine de Gruyter], pp. 223-243) that the australopithecine material from Swartkrans and Kromdraai represents distinct species. In an attempt to test the validity of separate taxa at Swartkrans and Kromdraai, Cope's (Cope [1989] Systematic Variation in Cercopithecus Dental Samples [Austin: University of Texas]) method of analysis was adapted and utilized. This procedure includes an analysis of the coefficients of variation (CVs) of the individual posterior teeth (buccal-lingual breadth) of a combined fossil sample compared with the CVs of several known single taxon reference groups. The Cope and Lacy (Cope and Lacy [1992] Am. J. Phys. Anthropol. 89:359-378) stimulation technique was also employed in the analysis. Based on these analyses, there is no justification for a taxonomic separation between the australopithecine material from Swartkrans and Kromdraai. Therefore, the assertion that the Swartkrans and Kromdraai material represent two distinct species is not indicated by the available dental metric evidence. PMID:8922186

  10. Dynamic measurement of local displacements within curing resin-based dental composite using optical coherence elastography

    Science.gov (United States)

    Tomlins, Peter H.; Rahman, Mohammed Wahidur; Donnan, Robert S.

    2016-04-01

    This study aimed to determine the feasibility of using optical coherence elastography to measure internal displacements during the curing phase of a light-activated, resin-based composite material. Displacement vectors were spatially mapped over time within a commercial dental composite. Measurements revealed that the orientation of cure-induced displacement vectors varied spatially in a complex manner; however, each vector showed a systematic evolution with time. Precision of individual displacements was estimated to be ˜1 to 2 μm, enabling submicrometer time-varying displacements to be detected.

  11. Dental Training Films.

    Science.gov (United States)

    Veterans Administration Medical Center, Washington, DC.

    This dental training films catalog is organized into two sections. Section I is a category listing of the films by number and title, indexed according to generalized headings; categories are as follow: anatomy, articulator systems, complete dentures, dental assisting, dental laboratory technology, dental materials, dental office emergencies,…

  12. Influence of dental restorative material properties on bond interface reliability: a finite element analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-tao; ZHANG Yu-mei; HOU Shu-xun; KONG Liang; LIN Jun; ZHAO Yi-min; HUO Na

    2013-01-01

    Background Varieties of restorative materials are widely used in dentistry.The aim of this study is to explore the influence of different dental restorative materials on bond interface reliability.Methods A two-dimensional finite element analysis method was adopted to simulate the shear-bond efficacy test.The influence of elastic modulus and Poisson's ratio were investigated separately.Several dental restorative materials including resins,metals,and ceramics were analyzed in this study.Results The deformation and peak equivalent stress level of the dentin-adhesive interface rose sharply following a decrease in the elasticity of restorative materials,especially those with a low elastic modulus range.The influence of the Poisson's coefficient was not significant.Ceramics and gold alloy were preferred to resin composite in restorations bearing extensive shear load during service.Conclusions Restorative materials with an elastic modulus similar to that of teeth are not always the best clinical choice.This research provides a helpful guide for the application of different restorative materials in clinical practice.

  13. A Hyaluronan-Based Scaffold for the in Vitro Construction of Dental Pulp-Like Tissue

    OpenAIRE

    Letizia Ferroni; Chiara Gardin; Stefano Sivolella; Giulia Brunello; Mario Berengo; Adriano Piattelli; Eriberto Bressan; Barbara Zavan

    2015-01-01

    Dental pulp tissue supports the vitality of the tooth, but it is particularly vulnerable to external insults, such as mechanical trauma, chemical irritation or microbial invasion, which can lead to tissue necrosis. In the present work, we present an endodontic regeneration method based on the use of a tridimensional (3D) hyaluronan scaffold and human dental pulp stem cells (DPSCs) to produce a functional dental pulp-like tissue in vitro. An enriched population of DPSCs was seeded onto hyalur...

  14. A Comparison of Urban School- and Community-Based Dental Clinics

    Science.gov (United States)

    Larsen, Charles D.; Larsen, Michael D.; Handwerker, Lisa B.; Kim, Maile S.; Rosenthal, Murray

    2009-01-01

    Background: The objective of the study was to quantitatively compare school- and community-based dental clinics in New York City that provide dental services to children in need. It was hypothesized that the school-based clinics would perform better in terms of several measures. Methods: We reviewed billing and visit data derived from encounter…

  15. Analysis of dental materials as an aid to identification in aircraft accidents

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, G.S.; Cruickshanks-Boyd, D.W.

    1982-04-01

    The failure to achieve positive identification of aircrew following an aircraft accident need not prevent a full autopsy and toxicological examination to ascertain possible medical factors involved in the accident. Energy-dispersive electron microprobe analysis provides morphological, qualitative, and accurate quantitative analysis of the composition of dental amalgam. Wet chemical analysis can be used to determine the elemental composition of crowns, bridges and partial dentures. Unfilled resin can be analyzed by infrared spectroscopy. Detailed analysis of filled composite restorative resins has not yet been achieved in the as-set condition to permit discrimination between manufacturers' products. Future work will involve filler studies and pyrolysis of the composite resins by thermogravimetric analysis to determine percentage weight loss when the sample examined is subjected to a controlled heating regime. With these available techniques, corroborative evidence achieved from the scientific study of materials can augment standard forensic dental results to obtain a positive identification.

  16. Process Development of Porcelain Ceramic Material with Binder Jetting Process for Dental Applications

    Science.gov (United States)

    Miyanaji, Hadi; Zhang, Shanshan; Lassell, Austin; Zandinejad, Amirali; Yang, Li

    2016-03-01

    Custom ceramic structures possess significant potentials in many applications such as dentistry and aerospace where extreme environments are present. Specifically, highly customized geometries with adequate performance are needed for various dental prostheses applications. This paper demonstrates the development of process and post-process parameters for a dental porcelain ceramic material using binder jetting additive manufacturing (AM). Various process parameters such as binder amount, drying power level, drying time and powder spread speed were studied experimentally for their effect on geometrical and mechanical characteristics of green parts. In addition, the effects of sintering and printing parameters on the qualities of the densified ceramic structures were also investigated experimentally. The results provide insights into the process-property relationships for the binder jetting AM process, and some of the challenges of the process that need to be further characterized for the successful adoption of the binder jetting technology in high quality ceramic fabrications are discussed.

  17. Dental hard tissue characterization using laser-based ultrasonics

    Science.gov (United States)

    Blodgett, David W.; Massey, Ward L.

    2003-07-01

    Dental health care and research workers require a means of imaging the structures within teeth in vivo. One critical need is the detection of tooth decay in its early stages. If decay can be detected early enough, the process can be monitored and interventional procedures, such as fluoride washes and controlled diet, can be initiated to help re-mineralize the tooth. Currently employed x-ray imaging is limited in its ability to visualize interfaces and incapable of detecting decay at a stage early enough to avoid invasive cavity preparation followed by a restoration. To this end, non-destructive and non-contact in vitro measurements on extracted human molars using laser-based ultrasonics are presented. Broadband ultrasonic waves are excited in the extracted sections by using a pulsed carbon-dioxide (CO2) laser operating in a region of high optical absorption in the dental hard tissues. Optical interferometric detection of the ultrasonic wave surface displacements in accomplished with a path-stabilized Michelson-type interferometer. Results for bulk and surface in-vitro characterization of caries are presented on extracted molars with pre-existing caries.

  18. 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)

  19. Evaluation of Survival Time of Tooth Color Dental Materials in Primary Anterior Teeth

    Directory of Open Access Journals (Sweden)

    Behjat-Al-Molook Ajami

    2013-01-01

    Full Text Available Introduction: In restorative dentistry, selecting the proper material is an important factor for clinical success. The objective of this study was clinical evaluation of survival time of three tooth color materials in primary anterior teeth. Methods: In this interventional clinical trial study, 94 deciduous anterior teeth (36 teeth in boys, 58 teeth in girls belonging to 3-5 year old children in Pediatric Department of Mashhad Faculty of Dentistry, Iran were selected. Selective dental materials included compoglass, glass-ionomer Fuji II LC, and composite resin. The data were analyzed with Kaplan–Meyer and Log rank test. Results: compoglass had the highest survival time in comparison with composite and glass-ionomer. Nine months retention rate for teeth restored with compoglass, composite resin and glass-ionomer were estimated: 95%, 21%, and 12.5%, respectively. Conclusion: Compoglass can be a suitable material for anterior primary teeth restoration

  20. Evaluation of Survival Time of Tooth Color Dental Materials in Primary Anterior Teeth

    Directory of Open Access Journals (Sweden)

    Taraneh Movahhed

    2012-09-01

    Full Text Available Introduction: In restorative dentistry, selecting the proper material is an important factor for clinical success. The objective of this study was clinical evaluation of survival time of three tooth color materials in primary anterior teeth. Methods: In this interventional clinical trial study, 94 deciduous anterior teeth (36 teeth in boys, 58 teeth in girls belonging to 3-5 year old children in Pediatric Department of Mashhad Faculty of Dentistry, Iran were selected. Selective dental materials included compoglass, glass-ionomer Fuji II LC, and composite resin. The data were analyzed with Kaplan–Meyer and Log rank test. Results: compoglass had the highest survival time in comparison with composite and glass-ionomer. Nine months retention rate for teeth restored with compoglass, composite resin and glass-ionomer were estimated: 95%, 21%, and 12.5%, respectively. Conclusion: Compoglass can be a suitable material for anterior primary teeth restoration.

  1. Long Term Fatigue Behavior of Zirconia Based Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Moustafa N. Aboushelib

    2010-04-01

    Full Text Available This study evaluated the influence of cyclic loading on zirconia bar-shaped specimens after being subjected to three different surface treatments: particle abrasion with either 50 μm or 110 μm alumina and grinding with diamond points, while polished specimens served as a control. Statistical analysis revealed significant reduction (38-67% in flexure strength (P < 0.001 after three million cycles of dynamic loading for all surface treatments. Scanning electron imaging revealed grain boundary thickening, grain pull-out, and micro-cracking as the main structural defects. The results suggest that various surface treatments of zirconia based dental ceramics may significantly influence their long term fatigue resistance in the oral environment.

  2. Survey of attitudes, materials and methods employed in endodontic treatment by general dental practitioners in North Jordan

    OpenAIRE

    Al-Omari Wael M

    2004-01-01

    Abstract Background General dental practitioners provide the majority of endodontic treatment in Jordan. The aim of this study was to gather information on the methods, materials and attitudes employed in root canal treatment by dentists in North Jordan, in order to evaluate and improve the quality of current practice. Methods A questionnaire was posted to all registered general dental practitioners working in private practice in Irbid Governate in North Jordan (n = 181). The questionnaire in...

  3. Mechanochemically synthesized kalsilite based bioactive glass-ceramic composite for dental vaneering

    Science.gov (United States)

    Kumar, Pattem Hemanth; Singh, Vinay Kumar; Kumar, Pradeep

    2015-08-01

    Kalsilite glass-ceramic composites have been prepared by a mechanochemical synthesis process for dental veneering application. The aim of the present study is to prepare bioactive kalsilite composite material for application in tissue attachment and sealing of the marginal gap between fixed prosthesis and tooth. Mechanochemical synthesis is used for the preparation of microfine kalsilite glass-ceramic. Low temperature frit and bioglass have been prepared using the traditional quench method. Thermal, microstructural and bioactive properties of the composite material have been examined. The feasibility of the kalsilite to be coated on the base commercial opaque as well as the bioactive behavior of the coated specimen has been confirmed. This study indicates that the prepared kalsilite-based composites show similar structural, morphological and bioactive behavior to that of commercial VITA VMK95 Dentin 1M2.

  4. Ultrashort pulse laser processing of hard tissue, dental restoration materials, and biocompatibles

    Science.gov (United States)

    Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

    2007-07-01

    During the last few years, ultra-short laser pulses have proven their potential for application in medical tissue treatment in many ways. In hard tissue ablation, their aptitude for material ablation with negligible collateral damage provides many advantages. Especially teeth representing an anatomically and physiologically very special region with less blood circulation and lower healing rates than other tissues require most careful treatment. Hence, overheating of the pulp and induction of microcracks are some of the most problematic issues in dental preparation. Up till now it was shown by many authors that the application of picosecond or femtosecond pulses allows to perform ablation with very low damaging potential also fitting to the physiological requirements indicated. Beside the short interaction time with the irradiated matter, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of the required quality. One main reason for this can be seen in the fact that during scanning the time period between two subsequent pulses incident on the same spot is so much extended that no heat accumulation effects occur and each pulse can be treated as a first one with respect to its local impact. Extension of this advantageous technique to biocompatible materials, i.e. in this case dental restoration materials and titanium plasma-sprayed implants, is just a matter of consequence. Recently published results on composites fit well with earlier data on dental hard tissue. In case of plaque which has to be removed from implants, it turns out that removal of at least the calcified version is harder than tissue removal. Therefore, besides ultra-short lasers, also Diode and Neodymium lasers, in cw and pulsed modes, have been studied with respect to plaque removal and sterilization. The temperature increase during laser exposure has been experimentally evaluated in parallel.

  5. Supervising dentists' perspectives on the effectiveness of community-based dental education.

    Science.gov (United States)

    Nayar, Preethy; McFarland, Kimberly; Lange, Brian; Ojha, Diptee; Chandak, Aastha

    2014-08-01

    The Commission on Dental Accreditation recently implemented new predoctoral standards that require dental schools in the United States to provide students with community-based dental education (CBDE) experiences. The objective of this study was to examine the perspectives of supervising dentists (also known as dental preceptors) at rural CBDE sites regarding the University of Nebraska Medical Center program's effectiveness in improving the competencies of dental students. Surveys were sent to all forty-three preceptors in two subsequent years: nineteen responded to all questions in 2012 and sixteen in 2013, for a total of thirty-five participants. These preceptors evaluated the effectiveness of the program based on the American Dental Education Association (ADEA) Competencies for the New General Dentist. Overall, these preceptors rated the CBDE program as effective (excellent or very good) in improving the students' competence in five of the six ADEA domains: Critical Thinking, Professionalism, Communication and Interpersonal Skills, Health Promotion, Patient Care: Assessment, Diagnosis, and Treatment Planning, and Patient Care: Establishment and Maintenance of Oral Health. Practice Management and Informatics was found to be the least effective domain of competence. CBDE provides a unique opportunity to develop a competent dental workforce with an appreciation for the value of community service. Applying a competency-based framework to program evaluation can provide valuable information on program effectiveness to program administrators, educators, and the dental preceptors.

  6. Intelligent technique for knowledge reuse of dental medical records based on case-based reasoning.

    Science.gov (United States)

    Gu, Dong-Xiao; Liang, Chang-Yong; Li, Xing-Guo; Yang, Shan-Lin; Zhang, Pei

    2010-04-01

    With the rapid development of both information technology and the management of modern medical regulation, the generation of medical records tends to be increasingly intelligent. In this paper, Case-Based Reasoning is applied to the process of generating records of dental cases. Based on the analysis of the features of dental records, a case base is constructed. A mixed case retrieval method (FAIES) is proposed for the knowledge reuse of dental records by adopting Fuzzy Mathematics, which improves similarity algorithm based on Euclidian-Lagrangian Distance, and PULL & PUSH weight adjustment strategy. Finally, an intelligent system of dental cases generation (CBR-DENT) is constructed. The effectiveness of the system, the efficiency of the retrieval method, the extent of adaptation and the adaptation efficiency are tested using the constructed case base. It is demonstrated that FAIES is very effective in terms of reducing the time of writing medical records and improving the efficiency and quality. FAIES is also proven to be an effective aid for diagnoses and provides a new idea for the management of medical records and its applications.

  7. A Critical Review of Dental Implant Materials with an Emphasis on Titanium versus Zirconia

    Directory of Open Access Journals (Sweden)

    Reham B. Osman

    2015-03-01

    Full Text Available The goal of the current publication is to provide a comprehensive literature review on the topic of dental implant materials. The following paper focuses on conventional titanium implants and more recently introduced and increasingly popular zirconia implants. Major subtopics include the material science and the clinical considerations involving both implant materials and the influence of their physical properties on the treatment outcome. Titanium remains the gold standard for the fabrication of oral implants, even though sensitivity does occur, though its clinical relevance is not yet clear. Zirconia implants may prove to be promising in the future; however, further in vitro and well-designed in vivo clinical studies are needed before such a recommendation can be made. Special considerations and technical experience are needed when dealing with zirconia implants to minimize the incidence of mechanical failure.

  8. An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses

    Science.gov (United States)

    Sinescu, Cosmin; Negrutiu, Meda; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Mihai; Laissue, Philippe L.; Podoleanu, Adrian Gh.

    2008-04-01

    Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.

  9. Population-centered Risk- and Evidence-based Dental Interprofessional Care Team (PREDICT): study protocol for a randomized controlled trial

    OpenAIRE

    Cunha-Cruz, Joana; Milgrom, Peter; Shirtcliff, R. Michael; Bailit, Howard L.; Huebner, Colleen E; Conrad, Douglas; Ludwig, Sharity; Mitchell, Melissa; Dysert, Jeanne; Allen, Gary; Scott, JoAnna; Mancl, Lloyd

    2015-01-01

    Background To improve the oral health of low-income children, innovations in dental delivery systems are needed, including community-based care, the use of expanded duty auxiliary dental personnel, capitation payments, and global budgets. This paper describes the protocol for PREDICT (Population-centered Risk- and Evidence-based Dental Interprofessional Care Team), an evaluation project to test the effectiveness of new delivery and payment systems for improving dental care and oral health. Me...

  10. Influence of dental filling material type on the concentration of interleukin 9 in the samples of gingival crevicular fluid

    Directory of Open Access Journals (Sweden)

    Stefanović Vladimir

    2016-01-01

    Full Text Available Background/Aim. Several cytokines and lymphokines (IL1β, ENA78, IL6, TNFα, IL8 and S100A8 are expressed during dental pulp inflammation. Analysis of gingival crevicu-lar fluid (GCF offers a non-invasive means of studying gen-eral host response in oral cavity. Although GCF levels of various mediators could reflect the state of inflammation both in dental pulp and gingiva adjacent to a tooth, GCF samples of those without significant gingivitis could be inter-preted as reflection of pulpal process. The aim of this study was to investigate IL9 GCF values in patients with dental car-ies and to assess possible influence of various dental fillings materials on local IL9 production. Methods. The study group included 90 patients, aged 18–70, with inclusion and exclusion criteria in the prospective clinical study. Of the 6 types of material used for the restoration of prepared cavities, 3 were intended for temporary and 3 for definitive restora-tion. According to dental fillings weight, all the participants were divided into 3 groups: those with fillings lighter than 0.50 g, those with 0.50–1.00 g, and those with fillings heavier than 1.00 g. Samples were taken from gingival sulcus using the filter paper technique. Clinical parameters were deter-mined by bleeding index, plaque index (Silness-Lou, 0–3, gingival index (0–3, and gingival sulcus depth. Cytokine con-centrations were assessed using commercially available cy-tomix. Results. According to the weight of dental fillings, there was a clear decreament trend of IL9 values meaning that dental defects greater than 1.00 g of dental filling were associated with lower GCF IL9 concentration. The IL9 val-ues correlated with the degree of gingival index and depth of gingival sulcus, being higher with more advanced gingivitis and more pronounced anatomical changes in the tooth edge. Different filling materials exerted various local IL9 responses. Zink polycarbonate cement and amalgam fillings induced

  11. [Dental education for college students based on WeChat public platform].

    Science.gov (United States)

    Chen, Chuan-Jun; Sun, Tan

    2016-06-01

    The authors proposed a model for dental education based on WeChat public platform. In this model, teachers send various kinds of digital teaching information such as PPT,word and video to the WeChat public platform and students share the information for preview before class and differentiate the key-point knowledge from those information for in-depth learning in class. Teachers also send reference materials for expansive learning after class. Questionaire through the WeChat public platform is used to evaluate teaching effect of teachers and improvement may be taken based on the feedback questionnaire. A discussion and interaction based on WeCchat between students and teacher can be aroused on a specific topic to reach a proper solution. With technique development of mobile terminal, mobile class will come true in near future.

  12. [Dental education for college students based on WeChat public platform].

    Science.gov (United States)

    Chen, Chuan-Jun; Sun, Tan

    2016-06-01

    The authors proposed a model for dental education based on WeChat public platform. In this model, teachers send various kinds of digital teaching information such as PPT,word and video to the WeChat public platform and students share the information for preview before class and differentiate the key-point knowledge from those information for in-depth learning in class. Teachers also send reference materials for expansive learning after class. Questionaire through the WeChat public platform is used to evaluate teaching effect of teachers and improvement may be taken based on the feedback questionnaire. A discussion and interaction based on WeCchat between students and teacher can be aroused on a specific topic to reach a proper solution. With technique development of mobile terminal, mobile class will come true in near future. PMID:27609397

  13. Students' perceptions of materials and techniques used at European dental schools in the education of fixed prosthodontics.

    Science.gov (United States)

    Brand, Henk S; Kamell, Hassib; Kharbanda, Aron K; Dozic, Alma

    2013-09-01

    The aim of this study was to explore the materials and procedures used by students in dental schools across Europe for teaching fixed prosthodontics. An online questionnaire, containing twenty-eight dichotomous, multiple-choice, and Likert scale rating questions, was sent to students in forty dental schools. After excluding dental schools in which less than 10 percent of the students responded, 775 questionnaires from ten schools remained for statistical analysis. Among these respondents, acrylic resin teeth were said to be the most commonly used material during preclinical practice (46-96 percent), and use of extracted teeth varied from 8 to 65 percent. At nine of the ten institutions, metal-ceramic was reported to be most commonly used for fixed dental prostheses. There was large variation in the type of finish line for a metal-ceramic fixed dental prosthesis: students at five institutions reported using a shoulder finish line, three a chamfer finish line, and two a shoulder-bevel finish line. A similar variation was observed with regard to the final cementation of metal-ceramic fixed dental prostheses: students at four institutions reporting most frequently using glass ionomer cement, with three using zinc phosphate cement and three using carboxylate cement. The responding European dental students varied considerably in their opinions about whether they were preclinically properly trained for the first preparation on a patient and in their overall rating of their education in fixed prosthodontics. Responding students in the United Kingdom, Sweden, and Nijmegen, The Netherlands, rated their fixed prosthodontics training overall the highest. Overall, this study found a wide variation amongst dental schools with regard to their education in fixed prosthodontics and their rating of this teaching. PMID:24002851

  14. Measurement of absorbed doses near metal and dental material interfaces irradiated by x- and gamma-ray therapy beams

    International Nuclear Information System (INIS)

    Soft-tissue damage adjacent to dental restorations is a deleterious side effect of radiation therapy associated with low-energy electron scatter from dental materials of high electron density. This study was designed to investigate the enhancement of dose to soft tissue (or water) close to high electron-density materials and to measure the detailed lateral and depth-dose profiles in soft-tissue-simulating polymer adjacent to planar interfaces of several higher atomic-number materials: 18-carat gold dental casting alloy; Ag-Hg dental amalgam alloy; Ni-Cr dental casting alloy; and natural human tooth structure. Results indicate that the dose-enhancement in 'tissue' is as great as a factor of 2 on the backscatter side adjacent to gold and a factor of 1.2 adjacent to tooth tissue, but is insignificant on the forward-scatter side because of the predominant effect of attenuation by the high-density, high atomic-number absorbing material. (author)

  15. Evaluation of effects of ionizing radiation on materials used in dental restorations

    International Nuclear Information System (INIS)

    This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were submitted to X-ray beams of 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. The sample were submitted to Geiger-Mueller detectors and the ionization chambers in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a Germanium detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  16. Influence of dental resin material composition on cross-polarization-optical coherence tomography imaging

    Science.gov (United States)

    Lammeier, Carmen; Li, YuPing; Lunos, Scott; Fok, Alex; Rudney, Joel; Jones, Robert S.

    2012-10-01

    The purpose of this study was to investigate cross-polarization-optical coherence tomography (CP-OCT) signal attenuation through different resin material compositions. Four distinct composite systems were used: Filtek supreme ultra (FSU) (3M ESPE), IPS empress direct (EMD) (Ivoclar Vivadent), estelite sigma quick (SQK) (Tokuyama Dental), and Z100 (3M ESPE). Cross-sectional images of different composite-demineralized phantoms (n=108) were collected using a 1310-nm intraoral cross-polarization swept source OCT (CP-OCT) imaging system. %T quantified the CP-OCT signal attenuation. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive x-ray spectrometer chemical analysis was utilized to determine how different matrix/filler compositions affected attenuation of the near infrared (NIR) signal. CP-OCT imaging of dental resin composites showed enormous variation in signal attenuation. For each of our composite systems, there was not a consistent attenuation difference in the NIR signal for A to D shades. The four composites had similar measured backscattering values but attenuated the overall signal to different degrees. When comparing the A2 shades between the four different composite systems, the order of highest to lowest of %T was EMD>Z100, FSU>SQK (ANOVA, Tukey, p<0.0001). As a result, we demonstrate the importance of understanding how the constituents of composite materials affect CP-OCT signal attenuation.

  17. Determination of surface roughness and topography of dental resin-based nanocomposites using AFM analysis.

    Science.gov (United States)

    Lainović, Tijana; Vilotić, Marko; Blažić, Larisa; Kakaš, Damir; Marković, Dubravka; Ivanišević, Aljoša

    2013-02-01

    The aim of this study was to determine surface roughness and topography of polished dental resin-based nanocomposites. Four representative dental resin-based nanocomposites were tested in the study: two nanohybrids (Filtek Z550 and Tetric EvoCeram) and two nanofilled (Filtek Ultimate Body and Filtek Ultimate Translucent); and two reference materials: one microfilled (Gradia Direct) and one microhybrid (Filtek Z250). Polymerized cylindrical specimens (4 mm x 2 mm) were polished with multi-step polishing system- Super Snap. Immediately after the polishing, topography of each specimen was examined by Veeco di CP-II Atomic Force Microscope. Specimen's surface has been scanned in 6 points in contact mode with CONT20A-CP tips. 1 Hz scan rate and 256 × 256 resolution were used to obtain topography on a 90 µm × 90 µm scanning area. Measured topography data were processed by Image Processing and Data Analysis v2.1.15 software. Following parameters were compared among specimens: average roughness and maximum peak-to-valley distance. All of the tested materials had similar average surface roughness after finishing and polishing procedure. The lowest values occurred in the material Filtek Ultimate Body, and the highest in the Filtek Z550. When interpreting maximum peak-to-valley distance the larger differences in values (up to 100%) occurred in Filtek Z550, Filtek Z250 and Filtek Ultimate Body, which is a result of the deep polishing channels and tracks. Type, size, distribution of fillers and filler loading in tested materials, didn't influence average roughness values, but had an impact on maximum peak-to-valley distance values.

  18. Synthesis of partial stabilized cement–gypsum as new dental retrograde filling material

    International Nuclear Information System (INIS)

    The study describes the sol–gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)–gypsum by adding different weight percentage of gypsum (25% PSC + 75% gypsum, 50% PSC + 50% gypsum and 75% PSC + 25% gypsum) to the PSC. The crystalline phase and hydration products of PSC–gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC + 25% gypsum. The developed PSC–gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC–gypsum also had a remarkable antibacterial activity. - Highlights: ► A new dental retrograde filling material PSC–gypsum was developed. ► PSC–gypsum cement has shown excellent initial and final setting time as 15–35 min. ► It not only improved the setting time but also retain the viscosity, 2 Pa·s. ► High alkaline pH of the cement had a remarkable antibacterial activity. ► Cytotoxicity studies revealed that the synthesized material is highly biocompatible.

  19. 氧化锆牙科材料改性研究进展%Research Progress in Modification of Dental Zirconia Materials

    Institute of Scientific and Technical Information of China (English)

    朱香利; 方建强; 肖遂

    2015-01-01

    Zirconia ceramics were widely used as dental restorative materials due to its excellent biocompatibility, high strength, toughness and aesthetic. The purpose of this paper was to summary the research progress of the pigmentation and toughness of dental zirconia and zirconia-based bioactive materials in the field of prosthodontics. And also it prospected the future research and development of new zirconia based materials for dental application.%氧化锆因具良好的生物相容性、较高的强度、韧性以及美观效果,被广泛地用作牙科修复材料。随着科学技术的不断发展,氧化锆用于牙科修复材料的研究也有了较大的进展。该文从氧化锆增韧、氧化锆着色和氧化锆基生物活性材料3个方面概述了氧化锆作为牙科修复材料的研究进展,并对其做了进一步展望。

  20. 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

  1. Dental Implant Systems

    OpenAIRE

    Yoshiki Oshida; Tuna, Elif B.; Oya Aktören; Koray Gençay

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with...

  2. Emerging Ceramic-based Materials for Dentistry

    OpenAIRE

    Denry, I.; Kelly, J. R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appr...

  3. Emerging Ceramic-based Materials for Dentistry

    Science.gov (United States)

    Denry, I.; Kelly, J.R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance. PMID:25274751

  4. An estimation of fluoride release from various dental restorative materials at different pH: In vitro study

    Directory of Open Access Journals (Sweden)

    R N Bahadure

    2012-01-01

    Full Text Available Background: In the mid of 1980s, the cariostatic effect of fluoride ions on enamel caries had been demonstrated in many studies. The use of fluoride releasing dental restorative materials has seen increasing from many years for the specific purpose of leaching of fluoride into the surrounding tissues to inhibit secondary dental caries as well as prevention of caries in the newly erupted tooth. In the dental caries, acidic environment causes the demineralization of tooth structure and also affect the restorative margins of dental restoration. Aim: various restorative materials show different behavior in different pH conditions of oral cavity. Thus, the aim of this study was to evaluate the fluoride release of the various restorative materials at different pH. Design: In this in vitro study, 30 samples of each dental restorative material were prepared and grouped into five with six samples in each group as per the pH of the solution 4.3, 4.6, 5.0, 5.5, and 6.2. All the samples were subjected to alternate cycling of the demineralizing solution (6 h and remineralizing solution (18 h for 15 days. Results: the fluoride release was measured by using fluoride ion specific electrode and digital ion analyzer. The result showed that the fluoride release rate was significantly higher in first day and reduced after third day to nearly constant level. At pH 4.3, the fluoride release was highest and lowest at pH 6.2. Conclusion: the Amalgomer CR showed the highest fluoride release among all the experimental dental restorative materials.

  5. Fractographic features of glass-ceramic and zirconia-based dental restorations fractured during clinical function

    OpenAIRE

    Øilo, Marit; Hardang, Anne Dybdahl; Ulsund, Amanda Hembre; Gjerdet, Nils Roar

    2014-01-01

    Fractures during clinical function have been reported as the major concern associated with all-ceramic dental restorations. The aim of this study was to analyze the fracture features of glass-ceramic and zirconia-based restorations fractured during clinical use. Twenty-seven crowns and onlays were supplied by dentists and dental technicians with information about type of cement and time in function, if available. Fourteen lithium disilicate glass-ceramic restorations and 13 zirconia-based res...

  6. Restoration of noncarious tooth defects by dentists in The Dental Practice-Based Research Network

    DEFF Research Database (Denmark)

    Nascimento, Marcelle M; Gordan, Valeria V; Qvist, Vibeke;

    2011-01-01

    The authors conducted a study to quantify the reasons for restoring noncarious tooth defects (NCTDs) by dentists in The Dental Practice-Based Research Network (DPBRN) and to assess the tooth, patient and dentist characteristics associated with those reasons.......The authors conducted a study to quantify the reasons for restoring noncarious tooth defects (NCTDs) by dentists in The Dental Practice-Based Research Network (DPBRN) and to assess the tooth, patient and dentist characteristics associated with those reasons....

  7. Dental education and evidence-based educational best practices: bridging the great divide.

    Science.gov (United States)

    Masella, Richard S; Thompson, Thomas J

    2004-12-01

    Research about educational best practices is negatively perceived by many dental faculty. Separation between teaching and learning strategies commonly employed in dental education and evidence-based educational techniques is real and caused by a variety of factors: the often incomprehensible jargon of educational specialists; traditional academic dominance of research, publication, and grantsmanship in faculty promotions; institutional undervaluing of teaching and the educational process; and departmentalization of dental school governance with resultant narrowness of academic vision. Clinician-dentists hired as dental school faculty may model teaching activities on decades-old personal experiences, ignoring recent educational evidence and the academic culture. Dentistry's twin internal weaknesses--factionalism and parochialism--contribute to academic resistance to change and unwillingness to share power. Dental accreditation is a powerful impetus toward inclusion of best teaching and learning evidence in dental education. This article will describe how the gap between traditional educational strategies and research-based practices can be reduced by several approaches including dental schools' promotion of learning cultures that encourage and reward faculty who earn advanced degrees in education, regular evaluation of teaching by peers and educational consultants with inclusion of the results of these evaluations in promotion and tenure committee deliberations, creating tangible reward systems to recognize and encourage teaching excellence, and basing faculty development programs on adult learning principles. Leadership development should be part of faculty enrichment, as effective administration is essential to dental school mission fulfillment. Finally, faculty who investigate the effectiveness of educational techniques need to make their research more available by publishing it, more understandable by reducing educational jargon, and more relevant to the day

  8. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Science.gov (United States)

    Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

    2011-10-01

    Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (veneer on the Si3N4 specimens, the firing was performed in electric tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  9. Chipping fracture resistance of dental CAD/CAM restorative materials: Part 2. Phenomenological model and the effect of indenter type

    Science.gov (United States)

    Quinn, G.D.; Giuseppetti, A.A.; Hoffman, K.H.

    2014-01-01

    The edge chipping resistances of six CAD/CAM dental restoration materials are analyzed and correlated to other mechanical properties. A new quadratic relationship that is based on a phenomenological model is presented. Objective The purpose of this study was to further analyze the edge chipping resistance of the brittle materials evaluated in Part 1. One objective was to determine why some force-distance trends were linear and others were nonlinear. A second objective was to account for differences in chipping resistance with indenter type. Methods Edge chipping experiments were conducted with different indenters, including some custom-made sharp conical indenters. A new force – distance quadratic expression was correlated to the data and compared to the linear and power law trends. Results The new quadratic function was an excellent fit in every instance. It can account for why some materials can be fit by a linear trend, while others can be fit by the power law trend. The effects of indenter type are accounted for variations in crack initiation and by the wedging stresses once an indentation hole is created. Significance The new quadratic force – edge distance function can be used with edge chipping data for all brittle materials, not just those evaluated in this study. The data trends vary from linear to nonlinear depending upon the material’s hardness, fracture toughness, and elastic modulus. PMID:24685179

  10. Materials engineering data base

    Science.gov (United States)

    1995-01-01

    The various types of materials related data that exist at the NASA Marshall Space Flight Center and compiled into databases which could be accessed by all the NASA centers and by other contractors, are presented.

  11. Dental status and oral health-related quality of life. A population-based study.

    Science.gov (United States)

    Visscher, C M; Lobbezoo, F; Schuller, A A

    2014-06-01

    Oral health-related quality of life (OHRQoL) is associated with tooth wear and tooth loss. This study investigated the association between OHRQoL and dental status (in terms of natural dentition, partial or complete dentures, or edentulism). Sixteen hundred and twenty-two persons who participated in a large-scale Dutch dental survey were interviewed. Dentate persons (n = 1407) were additionally invited for a clinical examination (response rate: 69%). Dental status was based upon the combined data from this clinical examination and the questionnaire (seven dental status groups were defined). OHRQoL was measured by the Dutch translation of the short version of the Oral Health Impact Profile, the OHIP-NL14. Kruskal-Wallis tests and Mann-Whitney U tests were used to investigate differences in OHRQoL between the dental status groups. For all OHIP-NL14 scales, differences in OHRQoL were found between the dental status groups (all P-values edentulous persons with an overdenture had a more impaired OHRQoL than edentulous persons with non-supported complete dentures. The results demonstrated that impaired dental status is associated with deteriorations in OHRQoL, especially concerning functional limitations, physical pain and social disability. PMID:24698541

  12. Dental materials. Amorphous intergranular phases control the properties of rodent tooth enamel.

    Science.gov (United States)

    Gordon, Lyle M; Cohen, Michael J; MacRenaris, Keith W; Pasteris, Jill D; Seda, Takele; Joester, Derk

    2015-02-13

    Dental enamel, a hierarchical material composed primarily of hydroxylapatite nanowires, is susceptible to degradation by plaque biofilm-derived acids. The solubility of enamel strongly depends on the presence of Mg(2+), F(-), and CO3(2-). However, determining the distribution of these minor ions is challenging. We show—using atom probe tomography, x-ray absorption spectroscopy, and correlative techniques—that in unpigmented rodent enamel, Mg(2+) is predominantly present at grain boundaries as an intergranular phase of Mg-substituted amorphous calcium phosphate (Mg-ACP). In the pigmented enamel, a mixture of ferrihydrite and amorphous iron-calcium phosphate replaces the more soluble Mg-ACP, rendering it both harder and more resistant to acid attack. These results demonstrate the presence of enduring amorphous phases with a dramatic influence on the physical and chemical properties of the mature mineralized tissue.

  13. An unusual foreign body in the maxillary sinus: Dental impression material.

    Science.gov (United States)

    Deniz, Y; Zengin, A Z; Karli, R

    2016-01-01

    Foreign bodies in paranasal sinuses are very rare and most of them are encountered in the maxillary sinus. These foreign bodies may be organic or inorganic and can enter the maxillary sinus through an oro-antral fistula. The oro-antral fistula is formed by a break in the bony segment of the maxillary sinus floor and usually arises subsequent to maxillary premolar and molar extractions. A 63-year-old female patient evaluated for a nonhealing, left, toothless palate lesion and chronic headache occurring over 4 years. Radiography and computed tomography revealed bone discontinuity in the left floor of the maxillary sinus and calcifications within the antrum. A blue foreign body, later identified as dental impression material, was removed by intranasal endoscopy. A careful oral examination is recommended prior to prosthetic restorations. In addition, paranasal sinus foreign bodies should be surgically removed to prevent secondary soft tissue reactions.

  14. Microstructure and mechanical properties of Ti-15Zr alloy used as dental implant material.

    Science.gov (United States)

    Medvedev, Alexander E; Molotnikov, Andrey; Lapovok, Rimma; Zeller, Rolf; Berner, Simon; Habersetzer, Philippe; Dalla Torre, Florian

    2016-09-01

    Ti-Zr alloys have recently started to receive a considerable amount of attention as promising materials for dental applications. This work compares mechanical properties of a new Ti-15Zr alloy to those of commercially pure titanium Grade4 in two surface conditions - machined and modified by sand-blasting and etching (SLA). As a result of significantly smaller grain size in the initial condition (1-2µm), the strength of Ti-15Zr alloy was found to be 10-15% higher than that of Grade4 titanium without reduction in the tensile elongation or compromising the fracture toughness. The fatigue endurance limit of the alloy was increased by around 30% (560MPa vs. 435MPa and 500MPa vs. 380MPa for machined and SLA-treated surfaces, respectively). Additional implant fatigue tests showed enhanced fatigue performance of Ti-15Zr over Ti-Grade4. PMID:27258932

  15. Interdisciplinary, web-based, self-study, interactive programs in the dental undergraduate program: a pilot.

    Science.gov (United States)

    Cohen, Howard B; Walker, Stephanie R; Tenenbaum, Howard C; Spero, Lawrence

    2003-06-01

    The goal of this project was to encourage interdisciplinary, integrative health teaching and research in dental education through the development of web-accessible programs, collectively called the "StudyWeb." The specific objective of the project was the construction and integration of a series of prototypes of self-study modules. Four pilot modules were developed using existing teaching materials in histology, pharmacology, prosthodontics, and oral radiology and utilizing a variety of widely available software programs, including FrontPage and Photoshop. Low-end technological choices were made in order to facilitate compatibility with a wide range of hardware, software, and types of Internet access. Modules were tested for functionality, usability, and ease of navigation. The scope of the initial project was limited to development and functionality testing of the original modules. The next phase of this project will involve testing of the effectiveness of these web-based self-instruction tools.

  16. How does duration of curing affect the radiopacity of dental materials?

    Energy Technology Data Exchange (ETDEWEB)

    Bejeh Mir, Arash Poorsattar [School of Dentistry, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of); Bejeh Mir, Morvarid Poorsattar [Private Practice of Orthodontics, Montreal (Canada)

    2012-06-15

    Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs. One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm{sup 2} irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA. Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05). These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

  17. Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens : a co-culture study in vitro

    NARCIS (Netherlands)

    Zhao, Bingran; van der Mei, Henny C.; Rustema-Abbing, Minie; Busscher, Henk J.; Ren, Yijin

    2015-01-01

    Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration

  18. Dentists’ practice patterns regarding caries prevention: results from a dental practice-based research network

    OpenAIRE

    Yokoyama, Yoko; Kakudate, Naoki; Sumida, Futoshi; Matsumoto, Yuki; Gilbert, Gregg H.; Gordan, Valeria V.

    2013-01-01

    Objective The purposes of this study were to (1) quantify dentists' practice patterns regarding caries prevention and (2) test the hypothesis that certain dentists' characteristics are associated with these practice patterns. Design The study used a cross-sectional study design consisting of a questionnaire survey. Participants The study queried dentists who worked in outpatient dental practices who were affiliated with the Dental Practice-Based Research Network Japan, which seeks to engage d...

  19. Fracture toughness determination of ceramic and resin-based dental composites.

    Science.gov (United States)

    Kvam, K

    1992-01-01

    A new method has been developed for Klc determinations of brittle materials with precracks introduced by indentations. A reference glass, five ceramic materials, and one resin-based composite were tested. Knoop hardness indentations were made with a load of 49 N in a line from edge to edge vertical to the long axis on one surface of four-point flexure bars, to make a continuous crack under the indentations. Five specimens of each material were fractured in a four-point bend test with the line of indentations placed in the zone of constant and maximum tensile stress. Separate unfractured specimens were ground and polished to expose and measure the preformed continuous crack. The mean of six crack-depth measurements was used together with the fracture load and the dimensions of the bend specimens to calculate the fracture toughness, Klc of each material. The determined Klc value (x +/- SD) for the reference glass was 0.81 +/- .24 MPa m1/2 and corresponds to previous studies. The resin-based composite material, Silux Plus, had a value of 1.04 +/- 0.14 MPa m1/2. The Klc values (MPa m1/2) were 0.94 +/- 0.31 for Dicor, 1.41 +/- 0.18 for Cerestore, 1.50 +/- 0.29 for NBK-1000, 1.60 +/- 0.17 for Vitadur-N and 2.14 +/- 0.14 for Hi-Ceram. Hi-Ceram had significantly higher Klc values than the other materials. The new method seemed to be of value in determining the fracture toughness of non-metallic dental materials. PMID:1550892

  20. Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys.

    Science.gov (United States)

    Chen, Bo; Xia, Gang; Cao, Xin-Ming; Wang, Jue; Xu, Bi-Yao; Huang, Pu; Chen, Yue; Jiang, Qing-Wu

    2013-03-01

    This paper aims to investigate if the dental restoration of nickel-chromium based alloy (Ni-Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.

  1. Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

    Directory of Open Access Journals (Sweden)

    Leticia Boldrin MESTIERI

    2015-10-01

    Full Text Available Mineral Trioxide Aggregate (MTA is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus.Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs.Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3 and kept in supplemented medium to obtain hDPCs adherent cultures. Cell characterization assays were performed to prove the osteogenic potential. The evaluated materials were: MTA Plus (MTAP; MTA Fillapex (MTAF and FillCanal (FC. Biocompatibility was evaluated with MTT and Neutral Red (NR assays, after hDPCs exposure for 24 h to different dilutions of each sealer extract (1:2, 1:3 and 1:4. Unexposed cells were the positive control (CT. Bioactivity was assessed by alkaline phosphatase (ALP enzymatic assay in cells exposed for one and three days to sealer extracts (1:4 dilution. All data were analyzed by ANOVA and Tukey post-test (p≤0.05%.Results MTT and NR results showed suitable cell viability rates for MTAP at all dilutions (90-135%. Cells exposed to MTAF and FC (1:2 and 1:4 dilutions showed significant low viability rate when compared to CT in MTT. The NR results demonstrated cell viability for all materials tested. In MTAP group, the cells ALP activity was similar to CT in one and three days of exposure to the material. MTAF and FC groups demonstrated a decrease in ALP activity when compared to CT at both periods of cell exposure.Conclusions The hDPCs were suitable for the evaluation of new endodontic materialsin vitro. MTAP may be considered a promising material for endodontic treatments.

  2. Materials properties data base computerization

    Science.gov (United States)

    Baur, R. G.; Donthnier, M. L.; Moran, M. C.; Mortman, I.; Pinter, R. S.

    1984-01-01

    Material property data plays a key role in the design of jet engine components. Consistency, accuracy and efficient use of material property data is of prime importance to the engineering community. The system conception, development, implementation, and future plans for computer software that captures the Material Properties Handbook into a scientific data base are described. The engineering community is given access to raw data and property curves, display of multiple curves for material evaluation and selection, direct access by design analysis computer programs, display of the material specification, and a historical repository for the material evolution. The impact of this activity includes significant productivity gains and cost reductions; all users have access to the same information nd provides consistent, rapid response to the needs of the engineering community. Future plans include incorporating the materials properties data base into a network environment to access information from other data bases and download information to engineering work stations.

  3. CHIPPING FRACTURE RESISTANCE OF DENTAL CAD/CAM RESTORATIVE MATERIALS: PART I, PROCEDURES AND RESULTS

    Science.gov (United States)

    Quinn, G. D.; Giuseppetti, A. A.; Hoffman, K. H.

    2014-01-01

    Objective The edge chipping test was used to measure the fracture resistance of CAD/CAM dental restoration ceramics and resin composites. Methods An edge chipping machine was used to evaluate six materials including one feldspathic porcelain, two glass ceramics, a filled resin-composite, a yttria-stabilized zirconia, and a new ceramic-resin composite material. Force versus edge distance data were collected over a broad range of forces and distances. Data were analyzed by several approaches and several chipping resistance parameters were evaluated. The effects of using different indenter types were explored. Results The force versus distance trends were usually nonlinear with good fits to a power law equation with exponents usually ranging from 1.2 to 1.9. The order of chipping resistance (from least to greatest) was: feldspathic porcelain and a leucite glass ceramic (which were similar), followed by the lithium disilicate glass ceramic and the two resin composites (which were similar), and finally the zirconia which had the greatest resistance to chipping. Chipping with a Vickers indenter required 28% to 45% more force than with the sharp conical 120° indenter. The two indenters rank materials approximately the same way. The power law exponents were very similar for the two indenters for a particular material, but the exponents varied with material. The Rockwell C indenter gives different power law trends and rankings. Significance Despite the variations in the trends and indenters, simple comparisons between materials can be made by chipping with sharp conical 120° or Vickers indenters at 0.50 mm. Broad distance ranges are recommended for trend evaluation. PMID:24685178

  4. Toxicity Testing of Restorative Dental Materials Using Brine Shrimp Larvae (Artemia salina

    Directory of Open Access Journals (Sweden)

    Manar M. Milhem

    2008-08-01

    Full Text Available This study investigated the effect of extracts of different composites, glass ionomer cement (GICs and compomers on the viability of brine shrimp larvae. Ethanolic extracts of four dental composites (Z-100; Solitaire 2; Filtek P60 and Synergy, a conventional GIC (Ketac-Fil, a resin-modified glass ionomer cement (Vitremer, two compomers (F2000; Dyract AP, and a flowable compomer (Dyract Flow were prepared from each material. Following evaporation of the ethanol, the extracts were resuspended in distilled water, which was then used to test the effects on the viability of brine shrimp larvae. For the composites, the extract of Synergy was the least toxic (88% viability followed by the extracts of Solitaire 2, Z100 and P60 (75%, 67.5% and 50% viability, respectively. One-way ANOVA revealed highly significant differences between the resin composite materials (p<0.001. Follow-up comparison between the composite groups by Tukey's pairwise multiple-comparison test (α =0.05 showed that the extract of Synergy was significantly less toxic than the extracts of all the other materials except that of Solitaire 2. The compomers showed 100% lethality, while the percentage of viable larvae for the extracts of Ketac-Fil, and Vitremer were 32.3%, and 37.0%, respectively. One-way ANOVA revealed highly significant differences between the groups of materials (p<0.001. Follow-up comparison between the groups by Tukey's test (α = 0.05 showed that the toxic effect of the extracts of the compomers were significantly greater than that of Ketac-Fil, and Vitremer. The differences in the toxic effects of Vitremer and Ketac-Fil were not statistically significant. In conclusion, the toxicity of composite materials varied according to their chemical composition. Compomers were the most lethal materials to brine shrimp larvae followed by GICs and then composites.

  5. Investigation of dental alginate and agar impression materials as a brain simulant for ballistic testing.

    Science.gov (United States)

    Falland-Cheung, Lisa; Piccione, Neil; Zhao, Tianqi; Lazarjan, Milad Soltanipour; Hanlin, Suzanne; Jermy, Mark; Waddell, J Neil

    2016-06-01

    Routine forensic research into in vitro skin/skull/brain ballistic blood backspatter behavior has traditionally used gelatin at a 1:10 Water:Powder (W:P) ratio by volume as a brain simulant. A limitation of gelatin is its high elasticity compared to brain tissue. Therefore this study investigated the use of dental alginate and agar impression materials as a brain simulant for ballistic testing. Fresh deer brain, alginate (W:P ratio 91.5:8.5) and agar (W:P ratio 81:19) specimens (n=10) (11×22×33mm) were placed in transparent Perspex boxes of the same internal dimensions prior to shooting with a 0.22inch caliber high velocity air gun. Quantitative analysis to establish kinetic energy loss, vertical displacement elastic behavior and qualitative analysis to establish elasticity behavior was done via high-speed camera footage (SA5, Photron, Japan) using Photron Fastcam Viewer software (Version 3.5.1, Photron, Japan) and visual observation. Damage mechanisms and behavior were qualitatively established by observation of the materials during and after shooting. The qualitative analysis found that of the two simulant materials tested, agar behaved more like brain in terms of damage and showed similar mechanical response to brain during the passage of the projectile, in terms of energy absorption and vertical velocity displacement. In conclusion agar showed a mechanical and subsequent damage response that was similar to brain compared to alginate. PMID:27131216

  6. Knowledge of evidence-based dentistry among academic dental practitioners of Bhopal, India: a preliminary survey

    Directory of Open Access Journals (Sweden)

    Aishwarya Singh

    2015-06-01

    Full Text Available This study aimed to characterize the knowledge of evidence-based dentistry (EBD among dental faculty members in the city of Bhopal in central India. A cross-sectional questionnaire was administered at two dental colleges in Bhopal City. All dental faculty members who were present on the day of the study and who agreed to participate were included in the study. A total of 50 dental faculty members returned the questionnaire. Six Likert-type questions were asked, and the percentages of various responses were used for analysis. Sixteen faculty members (32.0% strongly agreed that EBD is a process of making decisions based on scientifically proven evidence. Fifteen faculty members (30.0% strongly disagreed or disagreed with the item stating that the best and quickest way to find evidence is by reading textbooks or asking experienced colleagues. Thirteen faculty members (26.0% strongly agreed that EBD allows dentists to improve their scientific knowledge and clinical skills. It is recommended that EBD be included in undergraduate and postgraduate curricula and in intensive continuing dental education programs that are conducted for dental faculty members.

  7. 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

  8. Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

    Energy Technology Data Exchange (ETDEWEB)

    Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

  9. Dental radiology.

    Science.gov (United States)

    Woodward, Tony M

    2009-02-01

    Dental radiology is the core diagnostic modality of veterinary dentistry. Dental radiographs assist in detecting hidden painful pathology, estimating the severity of dental conditions, assessing treatment options, providing intraoperative guidance, and also serve to monitor success of prior treatments. Unfortunately, most professional veterinary training programs provide little or no training in veterinary dentistry in general or dental radiology in particular. Although a technical learning curve does exist, the techniques required for producing diagnostic films are not difficult to master. Regular use of dental x-rays will increase the amount of pathology detected, leading to healthier patients and happier clients who notice a difference in how their pet feels. This article covers equipment and materials needed to produce diagnostic intraoral dental films. A simplified guide for positioning will be presented, including a positioning "cheat sheet" to be placed next to the dental x-ray machine in the operatory. Additionally, digital dental radiograph systems will be described and trends for their future discussed. PMID:19410234

  10. Lignin-Based Thermoplastic Materials.

    Science.gov (United States)

    Wang, Chao; Kelley, Stephen S; Venditti, Richard A

    2016-04-21

    Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors. PMID:27059111

  11. Lignin-Based Thermoplastic Materials.

    Science.gov (United States)

    Wang, Chao; Kelley, Stephen S; Venditti, Richard A

    2016-04-21

    Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors.

  12. Dosimetric consideration for patients with dental filling materials undergoing irradiation of oral cavity using RapidArc: challenges and solution

    Science.gov (United States)

    Mail, Noor; Albarakati, Y.; Khan, M. Ahmad; Saeedi, F.; Safadi, N.; Al-Ghamdi, S.; Saoudi, A.

    2012-03-01

    In this study, we investigate the effect of dental filling materials (DFM) on RapidArcTM treatment plans and delivery in a patient undergoing radiotherapy treatment. The presence of DFM creates uncertainties in CT number and causes long streaking artifacts in the reconstructed images which greatly affect the dose distribution inside the oral cavity. The influence of extensive dental filling artifacts on dose distribution was performed using a geometrically well defined head and neck IMRT verification phantom (PTW, Freiburg, Germany) together with inserts from DFM (Amalgam, 11.3 g/cm3). The phantom was scanned using Siemens SOMATOM Sensation CT simulator (Siemens AG, Germany) under standard head and neck imaging protocol (120 kV, 120 mAs, voxel size 1×1×2 mm3). Three RapidArcTM plans were created in the Varian Eclipse treatment planning System (TPS) to treat oral cavity using the same CT dataset including; 1) raw CT image, 2) streaking artifacts replaced with a mask of 10 HU and 3) 2 cm thick 6000 HU virtual filter (a volume around the teeth in TPS to mimic extra attenuation). The virtual filter thickness optimization was purely based on measured PDD data acquired with DFM and the calculation in Eclipse Planning System using direct beam. The dose delivery and distribution for the three plans was verified using Gafchromic EBT2 (International Specialty Product, Wayne, NJ, USA) film measurements. The artifact mask and virtual filter around the teeth in the planning was found very useful to reduce the discrepancies between the dose plan and delivery. From clinical point of view, these results can be helpful to understand the increase of mucositis in patient having DFM, and further investigation is underway for clinical solution.

  13. Graphene-based Materials

    Science.gov (United States)

    Ruoff, Rodney

    2009-03-01

    Our top-down approaches [Lu et al.] inspired physicists to obtain graphene by micromechanical exfoliation. Another approach to individual layers involves converting graphite to graphite oxide (GO) to generate aqueous colloidal suspensions of `graphene oxide'(GO') sheets. (i) Reduced GO' (RGO') sheets were embedded in polymers such as polystyrene and their dispersion/morphology studied by SEM/TEM, and the conductivity/ percolation threshold of such composites was determined; (ii) individual GO' and RGO' sheets were studied to elucidate their chemical, optical, and electrical properties, (iii) GO' and RGO' sheets were embedded in thin glass films by a sol-gel route yielding conductive/transparent films, (iii) a `paper' material of stacked GO' sheets was made and characterized, (iv) powders composed of RGO' showed exceptional promise for use in ultracapacitors, and (v) C13-labeled GO was made and the detailed chemical structure of GO was determined with SS NMR. --Lu,Yu,Huang,Ruoff, ``Tailoring graphite with the goal of achieving single sheets'', Nanotechnology, 10, 269-272 (1999). See also http://bucky-central.me.utexas.edu/publications.htm 139, 146, 150, 155, 160, 164, 166, 168, 169, 174, 179-182, 184 where collaborators are shown as coauthors.

  14. Association between Black Stains and Dental Caries in Primary Teeth: Findings from a Brazilian Population-Based Birth Cohort

    OpenAIRE

    França-Pinto, C.C.; Cenci, M.S.; Correa, M.B.; Romano, A.R.; Peres, M.A.; Peres, K.G.; Matijasevich, A; Santos, I.S.; Barros, A.J.D.; Demarco, F.F.

    2012-01-01

    Lower dental caries experience has been observed in children and teenagers with the presence of black stains on dental structures. However, none of the previous investigations were population-based studies or adjusted the analysis for potential confounders. This study assessed the prevalence of black stains at the age of 5 in a population-based birth cohort from Pelotas, Brazil and investigated the association between black stains and dental caries. A total of 1,129 children from the 2004 Pel...

  15. Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields

    OpenAIRE

    Sheng-hui Liao; Shi-jian Liu; Bei-ji Zou; Xi Ding; Ye Liang; Jun-hui Huang

    2015-01-01

    An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most publi...

  16. Dental Amalgam

    Science.gov (United States)

    ... Devices Products and Medical Procedures Dental Devices Dental Amalgam Dental Amalgam Share Tweet Linkedin Pin it More sharing options ... a discussion with your dentist. More in Dental Amalgam About Dental Amalgam Fillings Alternatives to Dental Amalgam Related Resources ...

  17. Chemical or microbiological models of secondary caries development around different dental restorative materials.

    Science.gov (United States)

    Lobo, Maristela M; Gonçalves, Reginaldo B; Ambrosano, Gláucia Maria B; Pimenta, Luiz André F

    2005-08-01

    This study evaluated artificial secondary caries around restorative materials, induced by means of chemical or microbiological models. The following materials were used randomly to restore 130 dental blocks: (1) zinc-oxide eugenol-free temporary filling: Coltosol (Coltène/Whaledent Inc.; n = 30), (2) silver amalgam: Permite C (SDI Limited, n = 20), (3) composite resin: Filtek Z250 (3M ESPE; n = 20), (4) glass-ionomer cement: Fuji II (GC America Inc.; n = 20), (5) resin-modified glass ionomer: Vitremer (3M ESPE; n = 20), and (6) polyacid modified resin: Dyract AP (Dentsply; n = 20). Ten specimens of Group 1 were kept in humidity, and had no carious formation (NC). Ten specimens of each group were submitted to pH cycling (CG, n = 60), and the others were immersed in a medium containing Streptococcus mutans and sucrose (BG, n = 60). Mineral content was determined by microhardness assessment, and lesion depth was measured in polarized light photomicrographs. In the chemical model (CG), mineral content values in the vicinities of restoration were high for Groups 5 (75.7 +/- 11.9), 4 (70.8 +/- 14.2), and NC (95.4 +/- 3.8); intermediate for Groups 1 (55.8 +/- 18.5), 6 (45.6 +/- 11.0), and 2 (44.3 +/- 11.2); and reduced for Group 3 (34.7 +/- 9.7). In the microbiological model (BG), results were similar to CG, although there was less demineralization. The highest lesion depths were found for Groups 3 (182.3 +/- 33.2) in CG and 6 (126.5 +/- 42.8) in BG, when compared to Group 5 (114.6 +/- 26.0 and 56.2 +/- 33.2, respectively). In both models of caries induction, ionomeric materials showed a superior cariostatic effect when compared to the other restorative materials.

  18. Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields

    Directory of Open Access Journals (Sweden)

    Sheng-hui Liao

    2015-01-01

    Full Text Available An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most published methods in this area either are inaccurate or require lots of manual interactions. Motivated by the state-of-the-art general mesh segmentation methods that adopted the theory of harmonic field to detect partition boundaries, this paper proposes a novel, dental-targeted segmentation framework for dental meshes. With a specially designed weighting scheme and a strategy of a priori knowledge to guide the assignment of harmonic constraints, this method can identify teeth partition boundaries effectively. Extensive experiments and quantitative analysis demonstrate that the proposed method is able to partition high-quality teeth automatically with robustness and efficiency.

  19. Automatic Tooth Segmentation of Dental Mesh Based on Harmonic Fields.

    Science.gov (United States)

    Liao, Sheng-hui; Liu, Shi-jian; Zou, Bei-ji; Ding, Xi; Liang, Ye; Huang, Jun-hui

    2015-01-01

    An important preprocess in computer-aided orthodontics is to segment teeth from the dental models accurately, which should involve manual interactions as few as possible. But fully automatic partition of all teeth is not a trivial task, since teeth occur in different shapes and their arrangements vary substantially from one individual to another. The difficulty is exacerbated when severe teeth malocclusion and crowding problems occur, which is a common occurrence in clinical cases. Most published methods in this area either are inaccurate or require lots of manual interactions. Motivated by the state-of-the-art general mesh segmentation methods that adopted the theory of harmonic field to detect partition boundaries, this paper proposes a novel, dental-targeted segmentation framework for dental meshes. With a specially designed weighting scheme and a strategy of a priori knowledge to guide the assignment of harmonic constraints, this method can identify teeth partition boundaries effectively. Extensive experiments and quantitative analysis demonstrate that the proposed method is able to partition high-quality teeth automatically with robustness and efficiency. PMID:26413507

  20. 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...

  1. Effect of In-Office Carbamide Peroxide-Based Tooth Bleaching System on Wear Resistance of Silorane-Based and Methacrylate-Based Dental Composites

    Science.gov (United States)

    Hasani Tabatabaei, Masoumeh; Sheikhzadeh, Sedigheh; Ghasemi Monfared Rad, Hamidreza; Beygi, Ahmad

    2015-01-01

    Objectives: Several studies have assessed the characteristics and properties of silorane-based composites and adhesive systems. Considering the extensive application of tooth-whitening agents, possible deteriorative effects of tooth bleaching agents on these restorative materials must be studied. The aim of this study was to evaluate the effect of an in-office carbamide peroxide-based tooth bleaching agent on the wear resistance of a silorane-based and a conventional microhybrid dimethyl methacrylate-based dental composite with two different application times. Materials and Methods: Thirty cylindrical specimens were made of Z250 and P90 dental composite resins (n=15 for each composite). Samples made of each composite were divided into three groups (n=5) for immersion in an in-office bleaching agent (Opalescence® Quick 45%) for either three or eight hours or saline solution (control). Wear tests were conducted after bleaching using a pin-on disk apparatus under the load of 40N at a constant sliding speed of 0.5 ms−1 for a sliding distance of 300 m. The samples were weighed before and after the wear test. Repeated measures ANOVA was used to statistically analyze the obtained data (α=0.05). Results: There was a significant decrease in the weight of samples after the wear test (P0.05). Conclusion: Bleaching for three or eight hours using 45% carbamide peroxide had no deteriorative effect on the wear resistance of Z250 and P90 composites. PMID:27123014

  2. Polyphosphazine-based polymer materials

    Science.gov (United States)

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  3. The Developmental history of the dental filling materials%牙齿充填材料的改进

    Institute of Scientific and Technical Information of China (English)

    龚怡

    2008-01-01

    Caries may cause substantial defects in the hard tissue of teeth.The dental filling for de feets is an effective method to resume teeth complete form and masticatory function as well a8 aesthetic effects.The filling material is artificial restorative material to fill the dental defects.Tracing back the devel oping process of dental filling materials,we can see the advancement of stomotology of human beings.There was a revolutionary change in the filling materials from filling dental cavity with Chinese medicinal herbs to silver paste,from establishing the composition and proportion standardization of the silver amalgam filling materials to the application of new macromolecule compound resin.This is a continuous improvement and renewal in the idea and technology of dental filling treatment 80 that perfects the dental filling method and enables the retention of more healthy dental tissue.In addition,it pushes the development of dental aesthet ics,adhesives and technology.With the improvement of people's health standard,aesthetic demands and environmental awareness,compound resin restorative materials has become clinically preferred dental filling materials of doctors and patients in clinic.%龋病会造成牙体硬组织的实质性缺损,对缺损的充填是修复牙齿完整形态、恢复其咀嚼功能和美观的有效方法.充填材料是用于填补牙齿缺损的人工修复材料.追述牙齿充填材料的发展历程,可以看到人类口腔医学的进步.从中草药填塞牙洞到银膏补牙,从建立银汞合金充填材料成分与比例的标准化到新型高分子复合树脂的应用,牙齿充填材料发牛了革命性变化,使得牙齿充填治疗的理念与技术也在不断改进与更新,进一步完善了牙齿充填方法,使保留更多健康牙体组织成为可能,同时也推动了美学牙科、粘接材料和技术的发展.随着人们对健康标准和审美要求的不断提高,以及环保意识的增强,复合树脂修复

  4. Teeth and bones: applications of surface science to dental materials and related biomaterials

    Science.gov (United States)

    Jones, F. H.

    2001-05-01

    Recent years have seen a considerable upsurge in publications concerning the surface structure and chemistry of materials with biological or biomedical applications. Within the body, gas-solid interactions become relatively less significant and solid-liquid or solid-solid interfaces dominate, providing new challenges for the surface scientist. The current paper aims to provide a timely review of the use of surface analysis and modification techniques within the biomaterials field. A broad overview of applications in a number of related areas is given with particular attention focusing on those materials commonly encountered in dentistry and oral or maxillofacial implantology. Several specific issues of current interest are discussed. The interaction between synthetic and natural solids, both in the oral environment and elsewhere in the body is important in terms of adhesion, related stresses and strains and ultimately the longevity of a dental restoration, biomedical implant, or indeed the surrounding tissue. Exposure to body fluids, of course, can also affect stability, leading to the degradation or corrosion of materials within the body. Whilst this could potentially be harmful, e.g., if cytotoxic elements are released, it may alternatively provide a route to the preferential release of beneficial substances. Furthermore, in some cases, the controlled disintegration of a biomaterial is desirable, allowing the removal of an implant, e.g., without the need for further surgery. The presence of cells in the immediate bioenvironment additionally complicates the situation. A considerable amount of current research activity is targeted at the development of coatings or surface treatments to encourage tissue growth. If this is to be achieved by stimulating enhanced cell productivity, determination of the relationship between cell function and surface composition is essential.

  5. A community of learners in the evidence-based dental clinic

    NARCIS (Netherlands)

    M. Schoonheim-Klein; P.R. Wesselink; J.M. Vervoorn

    2012-01-01

    An increasing emphasis has been placed on the need for an evidence-based approach in dentistry. This calls for effort in dental education to develop and implement tools for the application of evidence in clinical decision-making (evidence-based decision-making, EBDM). Aim:  To evaluate whether the i

  6. The Development of LED-Based Dental Light Using a Multiplanar Reflector Design

    OpenAIRE

    Chi-Chang Hsieh; Yan-Huei Li

    2014-01-01

    A multiplanar reflector was designed to enhance the application efficiency of light-emitting diode (LED) light sources that can be employed as LED-based dental lights. This study used a high-power LED developed by Nichia, that is, a single LED capable of providing a total luminous flux of 120 lm, as the primarily light source to design and develop an LED-based dental light. This LED complies with the international standards and regulations stipulated in ISO 9680:2007. The light spots produced...

  7. Evaluation of conventional and digital radiography capacities for distinguishing dental materials on radiograms depending on the present radiopacifying agent

    Directory of Open Access Journals (Sweden)

    Antonijević Đorđe

    2014-01-01

    Full Text Available Bacgroun/Aim. The radiopacity of an endodontic material can considerably vary as measured on film and a digital sensor. Digital radiography offers numerous advantages over convential film-based radiography in dental clinical practice regarding both diagnostic capabilities and postintervention procedures. The aim of this study was to investigate the capacity of conventional and charge-conpled device (CCD based digital radiography to detect material on radiograph depending on the radio-pacifying agent present in the material. Methods. Experimental cements were formulated by mixing Portland cement with the following radiopacifying agents: zinc oxide (ZnO, zirconium oxide (ZrO2, titanium dioxide (TiO2, barium sulphate (BaSO4, iodoform (CHI3, bismuth oxide (Bi2O3 and ytterbium trifluoride (YbF3. In addition, 5 endodontic materials comprising Endomethasone®, Diaket®, N2®, Roth 801® and Acroseal® were investigated to serve as control. Per three specimens of each material were radiographed alongside an aluminum step wedge on film (Eastman Kodak Company®, Rochester, NY and a CCD-based digital sensor (Trophy Radiologie®, Cedex, France. Radiopacity values were calculated by converting the radiographic densities of the specimens expressed as a mean optical densities or mean grey scale values into equivalent thickness of aluminum. Results. Twoway ANOVA detected no significant differences with respect to the imaging system (p > 0.05, but the differences were significant with respect to radiopacifier (p < 0.001 and the interaction of the two factors (p < 0.05. Paired ttest revealed significant differences between the methods used for pure Portland cement, all concentrations of BaSO4 and CHI3, 10% and 20% additions of ZrO2 and Bi2O3 and 10% and 30% addition of YbF3 (p < 0.05. Conclusion. The materials which incorporate CHI3 or BaSO4 as radiopacifying agents are expected to be significantly more radiopaque on a digital sensor than on film. During clinical

  8. A Hyaluronan-Based Scaffold for the in Vitro Construction of Dental Pulp-Like Tissue

    Directory of Open Access Journals (Sweden)

    Letizia Ferroni

    2015-03-01

    Full Text Available Dental pulp tissue supports the vitality of the tooth, but it is particularly vulnerable to external insults, such as mechanical trauma, chemical irritation or microbial invasion, which can lead to tissue necrosis. In the present work, we present an endodontic regeneration method based on the use of a tridimensional (3D hyaluronan scaffold and human dental pulp stem cells (DPSCs to produce a functional dental pulp-like tissue in vitro. An enriched population of DPSCs was seeded onto hyaluronan-based non-woven meshes in the presence of differentiation factors to induce the commitment of stem cells to neuronal, glial, endothelial and osteogenic phenotypes. In vitro experiments, among which were gene expression profiling and immunofluorescence (IF staining, proved the commitment of DPSCs to the main components of dental pulp tissue. In particular, the hyaluronan-DPSCs construct showed a dental pulp-like morphology consisting of several specialized cells growing inside the hyaluronan fibers. Furthermore, these constructs were implanted into rat calvarial critical-size defects. Histological analyses and gene expression profiling performed on hyaluronan-DPSCs grafts showed the regeneration of osteodentin-like tissue. Altogether, these data suggest the regenerative potential of the hyaluronan-DPSC engineered tissue.

  9. The good toothbrushing game: a school-based dental hygiene program for increasing the toothbrushing effectiveness of children.

    OpenAIRE

    Swain, J J; Allard, G B; Holborn, S W

    1982-01-01

    There has been a serious lack of experimentally verified, effective dental hygiene programs in the schools. In and of themselves, the instruction-alone programs which comprise children's dental education do not produce proper toothbrushing skills. In the present study, a school-based contingency dental hygiene program designed to increase the effectiveness of children's toothbrushing skills at home was implemented with grade one and two classes. Each class was divided into teams and participa...

  10. ELECTROCHEMICAL AND MECHANICAL EVALUATION OF SOME DENTAL MATERIALS EMPLOYED FOR IMMOBILIZATION DEVICES

    Directory of Open Access Journals (Sweden)

    ANA MARIA FATU

    2016-03-01

    Full Text Available Measurement of corrosion potential is a relatively simple concept, an unanimously accepted notion in industry for the monitorization of steel corrosion, in building industry and in other structures. Equally, in the last decades, this parameter has been intensively utilized for characterizing dental alloys in either natural oral environment or in simulated solutions. The corrosion potential may be measured directly versus a reference electrode, characterized by a highly stable semi-cell potential. In this respect, a reference electrode (or a separated sensor of the material to be monitorized is introduced in the corrosive medium together with the metal or alloy under study, and the potential is measured directly with a millivoltmeter with very high input impedance. Additional details on the processes occurring in the system may be acquired if analyzing the curves of cyclic polarization, for whose obtaining the potential of the electrode formed with the investigated alloy is increased, at constant rate, in positive direction, up to a pre-established value, followed by its scavenging in reverse direction (towards negative values until reaching the initial value or some other value. During scavenging of the potential, the electric power passing through the solution between the working electrode and an auxilliary (platinum-made electrode is measured.

  11. Comparison of chemical composition of materials used in dental restorations 08 years after the irradiation

    International Nuclear Information System (INIS)

    The purpose of this work consisted of quantitative studies of the effects caused by ionizing radiation on the materials commonly used in dental restorations (amalgam, composite resin and Compomer), to mitigate the deleterious effects of radiotherapy when patients with tumors in head and neck, observed when the teeth are restored within the field of radiation. Samples were submitted to the beam of radiation from a source of cobalt-therapy, and analyzed by a X-ray fluorescence technique, by comparing the chemical composition of samples before and after irradiation. Gamma spectrometry was performed with detector of NaI and HPGe in the same samples. Then, the samples were kept in an appropriate place and after 08 years is repeated the same analysis. With these tests, it was possible to verify small changes in the composition of bodies of evidence due to the interaction 08 years after exposure to gamma radiation beams, simulating a patient who develops deleterious effects of radiation after the end radiotherapy treatment. (author)

  12. Comparison of chemical composition of materials used in dental restorations 08 years after the irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Maio, Mireia Florencio; Santos, Adimir dos, E-mail: mfmaio@ipen.b, E-mail: asantos@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP) Sao Paulo, SP (Brazil); Fernandes, Marco A.R., E-mail: marcosrf@salesiano-ata.b [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina

    2009-07-01

    The purpose of this work consisted of quantitative studies of the effects caused by ionizing radiation on the materials commonly used in dental restorations (amalgam, composite resin and Compomer), to mitigate the deleterious effects of radiotherapy when patients with tumors in head and neck, observed when the teeth are restored within the field of radiation. Samples were submitted to the beam of radiation from a source of cobalt-therapy, and analyzed by a X-ray fluorescence technique, by comparing the chemical composition of samples before and after irradiation. Gamma spectrometry was performed with detector of NaI and HPGe in the same samples. Then, the samples were kept in an appropriate place and after 08 years is repeated the same analysis. With these tests, it was possible to verify small changes in the composition of bodies of evidence due to the interaction 08 years after exposure to gamma radiation beams, simulating a patient who develops deleterious effects of radiation after the end radiotherapy treatment. (author)

  13. Heat generation caused by ablation of dental restorative materials with an ultra short pulse laser (USPL) system

    Science.gov (United States)

    Braun, Andreas; Wehry, Richard; Brede, Olivier; Frentzen, Matthias; Schelle, Florian

    2011-03-01

    The aim of this study was to assess heat generation in dental restoration materials following laser ablation using an Ultra Short Pulse Laser (USPL) system. Specimens of phosphate cement (PC), ceramic (CE) and composite (C) were used. Ablation was performed with an Nd:YVO4 laser at 1064 nm and a pulse length of 8 ps. Heat generation during laser ablation depended on the thickness of the restoration material. A time delay for temperature increase was observed in the PC and C group. Employing the USPL system for removal of restorative materials, heat generation has to be considered.

  14. Finite element modeling of dental restoration through multi-material laser densification

    Science.gov (United States)

    Dai, Kun

    To provide guidance for intelligent selection of various parameters in the Multi-Material Laser Densification (MMLD) process for dental restorations, finite element modeling (FEM) has been carried out to investigate the MMLD process. These modeling investigations include the thermal analysis of the nominal surface temperature that should be adopted during experiments in order to achieve the desired microstructure; the effects of the volume shrinkage due to transformation from a powder compact to dense liquid on the temperature distribution and the size of the transformation zone; the evolution of transient temperature, transient stresses, residual stresses and distortions; and the effects of laser processing conditions, such as fabrication sequences, laser scanning patterns, component sizes, preheating temperatures, laser scanning rates, initial porosities, and thicknesses of each powder layer, on the final quality of the component fabricated via the MMLD process. The simulation results are compared with the experiments. It is found that the predicted temperature distribution matches the experiments very well. The nominal surface temperature applied on the dental porcelain body should be below 1273 K to prevent the forming of the un-desired microstructure (i.e., a leucite-free glassy phase). The simplified models that do not include the volume shrinkage effect provide good estimations of the temperature field and the size of the laser-densified body, although the shape of the laser-densified body predicted is different from that obtained in the experiment. It is also fount that warping and residual thermal stresses of the laser-densified component are more sensitive to the chamber preheating temperature and the thickness of each powder layer than to the laser scanning rate and the initial porosity of the powder layer. The major mechanism responsible for these phenomena is identified to be related to the change of the temperature gradient induced by these laser

  15. The impacts of dental filling materials on RapidArc treatment planning and dose delivery: Challenges and solution

    Energy Technology Data Exchange (ETDEWEB)

    Mail, Noor; Al-Ghamdi, S.; Saoudi, A. [Princess Norah Oncology Center, National Guard Health Affairs, Jeddah 21423, Saudi Arabia and King Abdullah International Medical Research Center, Jeddah 21423 (Saudi Arabia); Albarakati, Y.; Ahmad Khan, M.; Saeedi, F.; Safadi, N. [Princess Norah Oncology Center, National Guard Health Affairs, Jeddah 21423 (Saudi Arabia)

    2013-08-15

    Purpose: The presence of high-density material in the oral cavity creates dose perturbation in both downstream and upstream directions at the surfaces of dental filling materials (DFM). In this study, the authors have investigated the effect of DFM on head and neck RapidArc treatment plans and delivery. Solutions are proposed to address (1) the issue of downstream dose perturbation, which might cause target under dosage, and (2) to reduce the upstream dose from DFM which may be the primary source of mucositis. In addition, an investigation of the clinical role of a custom-made plastic dental mold/gutter (PDM) in sparing the oral mucosa and tongue reaction is outlined.Methods: The influence of the dental filling artifacts on dose distribution was investigated using a geometrically well-defined head and neck intensity modulated radiation therapy (IMRT) verification phantom (PTW, Freiberg, Germany) with DFM inserts called amalgam, which contained 50% mercury, 25% silver, 14% tin, 8% copper, and 3% other trace metals. Three RapidArc plans were generated in the Varian Eclipse System to treat the oral cavity using the same computer tomography (CT) dataset, including (1) a raw CT image, (2) a streaking artifacts region, which was replaced with a mask of 10 HU, and (3) a 2 cm-thick 6000 HU virtual filter [a volume created in treatment planning system to compensate for beam attenuation, where the thickness of this virtual filter is based on the measured percent depth dose (PDD) data and Eclipse calculation]. The dose delivery for the three plans was verified using Gafchromic-EBT2 film measurements. The custom-made PDM technique to reduce backscatter dose was clinically tested on four head and neck cancer patients (T3, N1, M0) with DFM, two patients with PDM and the other two patients without PDM. The thickness calculation of the PDM toward the mucosa and tongue was purely based on the measured upstream dose. Patients’ with oral mucosal reaction was clinically examined

  16. The impacts of dental filling materials on RapidArc treatment planning and dose delivery: Challenges and solution

    International Nuclear Information System (INIS)

    Purpose: The presence of high-density material in the oral cavity creates dose perturbation in both downstream and upstream directions at the surfaces of dental filling materials (DFM). In this study, the authors have investigated the effect of DFM on head and neck RapidArc treatment plans and delivery. Solutions are proposed to address (1) the issue of downstream dose perturbation, which might cause target under dosage, and (2) to reduce the upstream dose from DFM which may be the primary source of mucositis. In addition, an investigation of the clinical role of a custom-made plastic dental mold/gutter (PDM) in sparing the oral mucosa and tongue reaction is outlined.Methods: The influence of the dental filling artifacts on dose distribution was investigated using a geometrically well-defined head and neck intensity modulated radiation therapy (IMRT) verification phantom (PTW, Freiberg, Germany) with DFM inserts called amalgam, which contained 50% mercury, 25% silver, 14% tin, 8% copper, and 3% other trace metals. Three RapidArc plans were generated in the Varian Eclipse System to treat the oral cavity using the same computer tomography (CT) dataset, including (1) a raw CT image, (2) a streaking artifacts region, which was replaced with a mask of 10 HU, and (3) a 2 cm-thick 6000 HU virtual filter [a volume created in treatment planning system to compensate for beam attenuation, where the thickness of this virtual filter is based on the measured percent depth dose (PDD) data and Eclipse calculation]. The dose delivery for the three plans was verified using Gafchromic-EBT2 film measurements. The custom-made PDM technique to reduce backscatter dose was clinically tested on four head and neck cancer patients (T3, N1, M0) with DFM, two patients with PDM and the other two patients without PDM. The thickness calculation of the PDM toward the mucosa and tongue was purely based on the measured upstream dose. Patients’ with oral mucosal reaction was clinically examined

  17. Biological characterization of a new silicon based coating developed for dental implants.

    Science.gov (United States)

    Martínez-Ibáñez, M; Juan-Díaz, M J; Lara-Saez, I; Coso, A; Franco, J; Gurruchaga, M; Suay Antón, J; Goñi, Isabel

    2016-04-01

    Taking into account the influence of Si in osteoblast cell proliferation, a series of sol-gel derived silicon based coating was prepared by controlling the process parameters and varying the different Si-alkoxide precursors molar rate in order to obtain materials able to release Si compounds. For this purpose, methyltrimethoxysilane (MTMOS) and tetraethyl orthosilicate (TEOS) were hydrolysed together and the sol obtained was used to dip-coat the different substrates. The silicon release ability of the coatings was tested finding that it was dependent on the TEOS precursor content, reaching a Si amount value around ninefolds higher for coatings with TEOS than for the pure MTMOS material. To test the effect of this released Si, the in vitro performance of developed coatings was tested with human adipose mesenchymal stem cells finding a significantly higher proliferation and mineralization on the coating with the higher TEOS content. For in vivo evaluation of the biocompatibility, coated implants were placed in the tibia of the rabbit and a histological analysis was performed. The evaluation of parameters such as the bone marrow state, the presence of giant cells and the fibrous capsule proved the biocompatibility of the developed coatings. Furthermore, coated implants seemed to produce a qualitatively higher osteoblastic activity and a higher number of bone spicules than the control (uncoated commercial SLA titanium dental implant). PMID:26936366

  18. Biological characterization of a new silicon based coating developed for dental implants.

    Science.gov (United States)

    Martínez-Ibáñez, M; Juan-Díaz, M J; Lara-Saez, I; Coso, A; Franco, J; Gurruchaga, M; Suay Antón, J; Goñi, Isabel

    2016-04-01

    Taking into account the influence of Si in osteoblast cell proliferation, a series of sol-gel derived silicon based coating was prepared by controlling the process parameters and varying the different Si-alkoxide precursors molar rate in order to obtain materials able to release Si compounds. For this purpose, methyltrimethoxysilane (MTMOS) and tetraethyl orthosilicate (TEOS) were hydrolysed together and the sol obtained was used to dip-coat the different substrates. The silicon release ability of the coatings was tested finding that it was dependent on the TEOS precursor content, reaching a Si amount value around ninefolds higher for coatings with TEOS than for the pure MTMOS material. To test the effect of this released Si, the in vitro performance of developed coatings was tested with human adipose mesenchymal stem cells finding a significantly higher proliferation and mineralization on the coating with the higher TEOS content. For in vivo evaluation of the biocompatibility, coated implants were placed in the tibia of the rabbit and a histological analysis was performed. The evaluation of parameters such as the bone marrow state, the presence of giant cells and the fibrous capsule proved the biocompatibility of the developed coatings. Furthermore, coated implants seemed to produce a qualitatively higher osteoblastic activity and a higher number of bone spicules than the control (uncoated commercial SLA titanium dental implant).

  19. Optical approach in characterizing dental biomaterials

    Science.gov (United States)

    Demoli, Nazif; Vučić, Zlatko; Milat, Ognjen; Gladić, Jadranko; Lovrić, Davorin; Pandurić, Vlatko; Marović, Danijela; Moguš-Milanković, Andrea; Ristić, Mira; Čalogović, Marina; Tarle, Zrinka

    2013-04-01

    The purpose of this paper is to present the current activities of a research collaborative program between three institutions from Zagreb (School of Dental Medicine, Institute of Physics, and Institute Ruđer Bo\\vsković). Within the scope of this program, it is planned to investigate and find guidelines for the refinement of the properties of dental biomaterials (DBs) and of procedures in restorative dental medicine. It is also planned to identify and model the dominant mechanisms which control polymerization of DBs. The materials to be investigated include methacrylate based composite resins, new composite materials with amorphous calcium phosphate, silorane based composite resins, glass-ionomer cements, and giomer.

  20. Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys

    Institute of Scientific and Technical Information of China (English)

    Bo Chen; Gang Xia; Xin-Ming Cao; Jue Wang; Bi-Yao Xu; Pu Huang; Yue Chen; Qing-Wu Jiang

    2013-01-01

    This paper aims to investigate if the dental restoration of nickel-chromium based alloy (Ni-Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of 〈 1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of 〈1, 1 to 〈3 and 3 to 〈6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.

  1. Association between black stains and dental caries in primary teeth: findings from a Brazilian population-based birth cohort.

    Science.gov (United States)

    França-Pinto, C C; Cenci, M S; Correa, M B; Romano, A R; Peres, M A; Peres, K G; Matijasevich, A; Santos, I S; Barros, A J D; Demarco, F F

    2012-01-01

    Lower dental caries experience has been observed in children and teenagers with the presence of black stains on dental structures. However, none of the previous investigations were population-based studies or adjusted the analysis for potential confounders. This study assessed the prevalence of black stains at the age of 5 in a population-based birth cohort from Pelotas, Brazil and investigated the association between black stains and dental caries. A total of 1,129 children from the 2004 Pelotas birth cohort were examined at age 5, and their mothers were interviewed at their households. Dental examinations included a search for black stains and dental caries on the primary dentition through the dmf-s index. The mothers' questionnaire comprised data on demographic, social, and behavior aspects. Prevalence of black stains was 3.5% (95% CI 2.5-4.7) and the prevalence of dental caries was 48.4% (95% CI 45.4-51.4). Multivariable logistic regression analysis was performed to assess the association between black stains and dental caries. Adjusted analysis revealed that the presence of black stains was associated with lower levels of dental caries (OR = 0.51; 95% CI 0.26-0.99). The results of the present study suggest that black stains are a protective factor for dental caries development. PMID:22488298

  2. Dental age estimation based on third molar eruption in First Nation people of Canada.

    Science.gov (United States)

    Schmeling, A; Olze, A; Pynn, B R; Kraul, V; Schulz, R; Heinecke, A; Pfeiffer, H

    2010-12-01

    Forensic age estimation of living subjects has become an increasing focus of interest in modern society. One main criterion for dental age estimation in the relevant age group is the evaluation of third molar eruption. The importance of ethnic variation in dental development requires population specific data for dental age evaluation. In the present study, we determined the stages of third molar eruption in 347 female and 258 male First Nations people of Canada aged 11 to 29 years based on radiological evidence from 605 conventional orthopantomograms. The results presented here provide data on the age of alveolar, gingival, and complete eruption of the third molars in the occlusal plane that can be used for forensic estimation of the minimum and most probable ages of investigated individuals.

  3. How dentists diagnose and treat defective restorations: evidence from the dental practice-based research network

    DEFF Research Database (Denmark)

    Gordan, Valeria V; Garvan, Cynthia W; Richman, Joshua S;

    2009-01-01

    OBJECTIVES: To (1) identify and quantify the types of treatment that dentists use to manage defective dental restorations and (2) identify characteristics that are associated with these dentists' decisions to replace existing restorations. The Dental Practice-Based Research Network (DPBRN) consists...... of dentists in outpatient practices from five regions: AL/MS: Alabama/Mississippi; FL/GA: Florida/Georgia; MN: dentists employed by HealthPartners and private practitioners in Minnesota; PDA: Permanente Dental Associates in cooperation with Kaiser Permanente's Center for Health Research and SK: Denmark...... not intervene surgically when the restoration in the scenario was amalgam. Dentists participating in a solo or small private practice (SPP) chose surgical intervention more often than dentists participating in large group practices (LGP) or in public health practices (PHP) (p

  4. Developing a Competency-Based Curriculum for a Dental Hygiene Program.

    Science.gov (United States)

    DeWald, Janice P.; McCann, Ann L.

    1999-01-01

    Describes the three-step process used to develop a competency-based curriculum at the Caruth School of Dental Hygiene (Texas A&M University). The process involved development of a competency document (detailing three domains, nine major competencies, and 54 supporting competencies), an evaluation plan, and a curriculum inventory which defined the…

  5. Repair or replacement of defective restorations by dentists in The Dental Practice-Based Research Network

    DEFF Research Database (Denmark)

    Gordan, Valeria V; Riley, Joseph L; Geraldeli, Saulo;

    2012-01-01

    The authors aimed to determine whether dentists in practices belonging to The Dental Practice-Based Research Network (DPBRN) were more likely to repair or to replace a restoration that they diagnosed as defective; to quantify dentists' specific reasons for repairing or replacing restorations; and...

  6. Synthesis and ceramic processing of alumina and zirconia based composites infiltrated with glass phase for dental applications

    International Nuclear Information System (INIS)

    The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resin-based cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram systems. Considering that the improvement of powder's synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650 degree C in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400 degree C .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning electron

  7. Improved dental adhesive formulations based on reactive nanogel additives.

    Science.gov (United States)

    Morães, R R; Garcia, J W; Wilson, N D; Lewis, S H; Barros, M D; Yang, B; Pfeifer, C S; Stansbury, J W

    2012-02-01

    Current challenges in adhesive dentistry include over-hydrophilic bonding formulations, which facilitate water percolation through the hybrid layer and result in unreliable bonded interfaces. This study introduces nanogel-modified adhesives as a way to control the material's hydrophobic character without changing the basic monomer formulation (keeping water-chasing capacity and operatory techniques unaltered). Nanogel additives of varied hydrophobicity were synthesized in solution, rendering 10- to 100-nm-sized particles. A model BisGMA/HEMA solvated adhesive was prepared (control), to which reactive nanogels were added. The increase in adhesive viscosity did not impair solvent removal by air-thinning. The degree of conversion in the adhesive was similar between control and nanogel-modified materials, while the bulk dry and, particularly, the wet mechanical properties were significantly improved through nanogel-based network reinforcement and reduced water solubility. As preliminary validation of this approach, short-term micro-tensile bond strengths to acid-etched and primed dentin were significantly enhanced by nanogel inclusion in the adhesive resins. PMID:22019910

  8. Biocompatibility of Dental Amalgams

    OpenAIRE

    Yurdanur Uçar; Brantley, William A.

    2011-01-01

    Objective. The purpose of this review paper is to review the literature regarding the toxicology of mercury from dental amalgam and evaluate current statements on dental amalgam. Materials and Methods. Two key-words “dental amalgam” and “toxicity” were used to search publications on dental amalgam biocompatibility published in peer-reviewed journals written in English. Manual search was also conducted. The most recent declarations and statements were evaluated using information available on ...

  9. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator

    International Nuclear Information System (INIS)

    This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures such as posterior teeth and the two temporomandibular joints, moves with up to 6 degrees of freedom (DOF) in Cartesian space. The currently available wear simulators lack the ability to perform these chewing movements. In many cases, their lack of sufficient DOF enables them only to replicate the sliding motion of a single occlusal contact point by neglecting rotational movements and the motion along one Cartesian axis. The motion and forces of more than one occlusal contact points cannot accurately be replicated by these instruments. Furthermore, the majority of wear simulators are unable to control simultaneously the main wear-affecting parameters, considering abrasive mechanical wear, which are the occlusal sliding motion and bite forces in the constraint contact phase of the human chewing cycle. It has been shown that such discrepancies between the true in vivo and the simulated in vitro condition influence the outcome and the quality of wear studies. This can be improved by implementing biological features of the human masticatory system such as tooth compliance realized through the passive action of the periodontal ligament and active bite force control realized though the central nervous system using feedback from periodontal preceptors. The simulator described in this paper can be used for single- and multi-occlusal contact testing due to its kinematics and ability to exactly replicate human translational and rotational mandibular movements with up to 6 DOF without neglecting movements along or around the three Cartesian axes. Recorded human mandibular motion and occlusal force data are the reference inputs of the simulator

  10. Innovative Dental Stem Cell-Based Research Approaches: The Future of Dentistry

    Science.gov (United States)

    Mitsiadis, Thimios A.

    2016-01-01

    Over the past decade, the dental field has benefited from recent findings in stem cell biology and tissue engineering that led to the elaboration of novel ideas and concepts for the regeneration of dental tissues or entire new teeth. In particular, stem cell-based regenerative approaches are extremely promising since they aim at the full restoration of lost or damaged tissues, ensuring thus their functionality. These therapeutic approaches are already applied with success in clinics for the regeneration of other organs and consist of manipulation of stem cells and their administration to patients. Stem cells have the potential to self-renew and to give rise to a variety of cell types that ensure tissue repair and regeneration throughout life. During the last decades, several adult stem cell populations have been isolated from dental and periodontal tissues, characterized, and tested for their potential applications in regenerative dentistry. Here we briefly present the various stem cell-based treatment approaches and strategies that could be translated in dental practice and revolutionize dentistry.

  11. Evaluation of World Wide Web-based Lessons for a First Year Dental Biochemistry Course

    Directory of Open Access Journals (Sweden)

    Dr. Alan E. Levine

    2002-11-01

    Full Text Available First year dental students at The University of Texas Dental Branch at Houston (Dental Branch are required to take a basic biochemistry course. To facilitate learning and allow student self-assessment of their progress, WWW-based lessons covering intermediary metabolism were developed as a supplement to traditional lectures. Lesson design combined text, graphics, and animations and included learner control, links to other learning resources, and practice exercises and exams with immediate feedback. Results from an on-line questionnaire completed by students in two different classes showed that they completed 50% of the lessons and spent an average of 4 hrs. on-line. A majority of the students either agreed or strongly agreed that practice exercises were helpful, that the ability to control the pace of the lessons was important, that the lesson structure and presentation was easy to follow, that the illustrations, animations, and hyperlinks were helpful, and that the lessons were effective as a review. The very positive response to the WWW-based lessons indicates the usefulness of this approach as a study aid for dental students.

  12. Comparison of Dental Students' Self-Directed, Faculty, and Software-Based Assessments of Dental Anatomy Wax-Ups: A Retrospective Study.

    Science.gov (United States)

    Garrett, Pauline H; Faraone, Karen L; Patzelt, Sebastian B M; Keaser, Michael L

    2015-12-01

    Little is known about self-directed and self-reflective assessment in preclinical dental curricula. The aim of this study was to evaluate a visual dental anatomy teaching tool to train dental students to self-assess their dental anatomy wax carving practical examinations. The students self-assessed two waxing practical examinations (tooth #8 and tooth #19) using high-quality digital images in an assessment tool incorporated into a digital testing program. Student self-assessments were compared to the faculty evaluations and the results of a software-based evaluation tool (E4D Compare). Out of a total 130 first-year dental students at one U.S. dental school, wax-ups from 57 participants were available for this study. The assessment data were submitted to statistical analyses (p<0.05). For tooth #8, the student self-assessments were significantly different from the faculty and software assessments at a 400 micrometer level of tolerance (p=0.036), whereas the faculty assessment was not significantly different from the software assessment at a 300 micrometer level of tolerance (p=0.69). The evaluation of tooth #19 resulted in no significant differences between faculty members (p=0.94) or students (p=0.21) and the software at a level of tolerance of 400 micrometers. This study indicates that students can learn to self-assess their work using self-reflection in conjunction with faculty guidance and that it may be possible to use software-based evaluation tools to assist in faculty calibration and as objective grading tools.

  13. Mercury and Other Biomedical Waste Management Practices among Dental Practitioners in India

    OpenAIRE

    Raghuwar D Singh; Jurel, Sunit K.; Shuchi Tripathi; Agrawal, Kaushal K.; Reema Kumari

    2014-01-01

    Objectives. The objective of the study was to assess the awareness and performance towards dental waste including mercury management policy and practices among the dental practitioners in North India. Materials and Methods. An epidemiologic survey was conducted among 200 private dental practitioners. The survey form was composed of 29 self-administered questions frame based on knowledge, attitude, and those regarding the practices of dentists in relation to dental health-care waste management...

  14. Perceived sources of stress among dental college students: An Indian perspective

    OpenAIRE

    Tegbir Singh Sekhon; Simran Grewal; Ramandeep Singh Gambhir; Sumit Sharma

    2015-01-01

    Background: Identification of the potential sources of stress is important in dental education program, as it gives opportunity to take various measures to prevent stress in the dental school environment. The purpose of the present study was to address various sources of stress among dental school students and its relation with gender and year of the study. Materials and Methods: A questionnaire based cross-sectional study was conducted among 3 rd and 4 th year students of a dental school. Qu...

  15. Dental fitness classification in the Canadian forces.

    Science.gov (United States)

    Groves, Richard R

    2008-01-01

    The Canadian Forces Dental Services utilizes a dental classification system to identify those military members dentally fit for an overseas deployment where dental resources may be limited. Although the Canadian Forces Dental Services dental classification system is based on NATO standards, it differs slightly from the dental classification systems of other NATO country dental services. Data collected by dental teams on overseas deployments indicate a low rate of emergency dental visits by Canadian Forces members who were screened as dentally fit to deploy. PMID:18277717

  16. Development of the CEREC dental system and cutting materials%CEREC系统及切削材料进展

    Institute of Scientific and Technical Information of China (English)

    王林虎; 董青山; 马毅慧

    2012-01-01

    CEREC (chairside economical restoration of esthetic ceramic)是一种椅旁计算机辅助设计和计算机辅助制作(com-puter aided design/computer aided manufacturing,CAD/CAM)系统,它引领着牙科数字化发展方向.作为一种高便捷、高质量、高审美的的数字化牙科修复系统,吸引了无数牙医和患者的青睐,临床应用日趋广泛.文中就CEREC的CAD/CAM系统的发展过程、构成及工作原理、CEREC系统发展以及可切削材料改进作一综述.%The CEREC system is a chairside CAD/CAM (computer aided design /computer aided manufacturing) dental restoration system. It leads the dental digital development. As a high-convenient, high-quality, high-aesthetic digital dental restoration system, it attracts many dentists and patients to favor. There is an increasingly wide range of its clinical application. This article describes the development of the CEREC system, its work principle, the newest product of CEREC system and the cutting materials used to fabricate the restoration.

  17. 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.

  18. Conductive polymer-based material

    Science.gov (United States)

    McDonald, William F.; Koren, Amy B.; Dourado, Sunil K.; Dulebohn, Joel I.; Hanchar, Robert J.

    2007-04-17

    Disclosed are polymer-based coatings and materials comprising (i) a polymeric composition including a polymer having side chains along a backbone forming the polymer, at least two of the side chains being substituted with a heteroatom selected from oxygen, nitrogen, sulfur, and phosphorus and combinations thereof; and (ii) a plurality of metal species distributed within the polymer. At least a portion of the heteroatoms may form part of a chelation complex with some or all of the metal species. In many embodiments, the metal species are present in a sufficient concentration to provide a conductive material, e.g., as a conductive coating on a substrate. The conductive materials may be useful as the thin film conducting or semi-conducting layers in organic electronic devices such as organic electroluminescent devices and organic thin film transistors.

  19. Dental emergencies in a university-based pediatric dentistry postgraduate outpatient clinic: a retrospective study.

    Science.gov (United States)

    Agostini, F G; Flaitz, C M; Hicks, M J

    2001-01-01

    The purpose of this retrospective study was to determine the prevalence and types of dental emergencies occurring in a university-based, pediatric dentistry postgraduate outpatient clinic. All patients presenting for emergency dental care during scheduled clinic hours over a three year were identified, and their charts were retrieved. Each record was reviewed for demographic information, chief complaint and clinical diagnosis. Only those charts with both chief complaints and clinical diagnoses recorded were included in this study. A total of 816 patients received emergency care, representing 15.3 percent of all patient treated during the study period. The patient population had a slight female predilection (53 percent female, 47 percent male) and a mean age of 5.1 years (range 10 days to 15 years). Ethnicity (39 percent African-American, 36 percent Hispanic, 24 percent Caucasian space maintainers [10 percent]; and 6) lost restorations [2 percent]. Pain and bleeding were the most common reasons for seeking emergency dental care. Most causes for seeking outpatient emergency dental care are disease processes which may be avoided by infant oral health and preventive dentistry programs and early treatment intervention.

  20. Research of image enhancement of dental cast based on wavelet transformation

    Science.gov (United States)

    Zhao, Jing; Li, Zhongke; Liu, Xingmiao

    2010-10-01

    This paper describes a 3D laser scanner for dental cast that realize non-contact deepness measuring. The scanner and the control PC make up of a 3D scan system, accomplish the real time digital of dental cast. Owing to the complexity shape of the dental cast and the random nature of scanned points, the detected feature curves are generally not smooth or not accurate enough for subsequent application. The purpose of this p is to present an algorithm for enhancing the useful points and eliminating the noises. So an image enhancement algorithm based on wavelet transform and fuzzy set theory is presented. Firstly, the multi-scale wavelet transform is adopted to decompose the input image, which extracts the characteristic of multi-scale of the image. Secondly, wavelet threshold is used for image de-noising, and then the traditional fuzzy set theory is improved and applied to enhance the low frequency wavelet coefficients and the high frequency wavelet coefficients of different directions of each scale. Finally, the inverse wavelet transform is applied to synthesis image. A group of experimental results demonstrate that the proposed algorithm is effective for the dental cast image de-noising and enhancement, the edge of the enhanced image is distinct which is good for the subsequent image processing.

  1. Impact of Community-Based Dental Education on Attainment of ADEA Competencies: Students' Self-Ratings.

    Science.gov (United States)

    McFarland, Kimberly K; Nayar, Preethy; Ojha, Diptee; Chandak, Aastha; Gupta, Niodita; Lange, Brian

    2016-06-01

    Fourth-year dental students at the College of Dentistry, University of Nebraska Medical Center participate in a community-based dental education (CBDE) program that includes a four-week rotation in rural dental practices and community health clinics across Nebraska and nearby states. The aim of this study was to assess the impact of participation in the CBDE program on the self-rated competencies of these students. A retrospective survey was administered to students who participated in extramural rotations in two academic years. The survey collected demographic data and asked students to rate themselves on a scale from 1=not competent at all to 5=very competent on attainment of the American Dental Education Association (ADEA) Competencies for the New General Dentist for before and after the rotations. A total of 92 responses were obtained: 43 students for 2011-12 and 49 students for 2012-13 (95% response rate for each cohort). The results showed that the students' mean pre-program self-ratings ranged from 3.28 for the competency domain of Practice Management and Informatics to 3.93 for Professionalism. Their mean post-program self-ratings ranged from 3.76 for Practice Management and Informatics to 4.31 for Professionalism. The students showed a statistically significant increase in self-ratings for all six competency domains. The increase was greatest in the domain of Critical Thinking and least in Communication and Interpersonal Skills. Overall, these results suggest that the CBDE program was effective in improving the students' self-perceptions of competence in all six domains and support the idea that a competency-based evaluation of CBDE programs can provide valuable information to dental educators about program effectiveness. PMID:27251348

  2. Advances in polypropylene based materials

    International Nuclear Information System (INIS)

    Polypropylene is an extremely versatile thermoplastic polymer known for its good performance/price ratio, excellent heat, moisture and chemical resistance, favorable processing characteristics and recyclability. Due to its universal properties, polypropylene is applied in numerous industrial fields such as electronic and electrical, automobile, textile, pipeline, etc. Furthermore, the progress in its synthesis and property modification in the last decade has contributed to the development of new polypropylene based materials with advanced performance. This review aims at reporting on some recent developments in polypropylene based materials, such as nano fibers, natural fiber reinforced composites, self-reinforced polypropylene and polypropylene/clay hybrids, that have replaced many types of engineering thermoplastics in high-performance applications. (Author)

  3. Signal loss in magnetic resonance imaging caused by intraoral anchored dental magnetic materials; Signalloeschung im MRT-Bild, verursacht durch intraoral verankerte dentale Magnetwerkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Blankenstein, F.H.; Naumann, M. [Zentrum fuer Zahnmedizin (CVK), Charite - Universitaetsmedizin Berlin (Germany); Truong, B. [Zahnarztpraxis, Berlin (Germany); Thomas, A.; Schroeder, R.J. [Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin Berlin (Germany)

    2006-08-15

    Purpose: to measure the maximum extent of the signal loss areas in the center of the susceptibility artifacts generated by ferromagnetic dental magnet attachments using three different sequences in the 1.5 and 3.0 Tesla MRI. Materials and methods: five different pieces of standard dental magnet attachments with volumes of 6.5 to 31.4 mm{sup 3} were used: a NdFeB magnet with an open magnetic field, a NdFeB magnet with a closed magnetic field, a SmCo magnet with an open magnetic field, a stainless steel keeper (AUM-20) and a PdCo piece. The attachments were placed between two cylindrical phantoms and examined in 1.5 and 3.0 Tesla MRI using gradient echo and T1- and T2-weighted spin echoes. We measured the maximum extent of the generated signal loss areas parallel and perpendicular to the direction of B{sub O}. Results: in gradient echoes the artifacts were substantially larger and symmetrically adjusted around the object. The areas with total signal loss were mushroom-like with a maximum extent of 7.4 to 9.7 cm parallel to the direction of B{sub O} and 6.7 to 7.4 cm perpendicular to B{sub O}. In spin echoes the signal loss areas were obviously smaller, but not centered. The maximum values ranged between 4.9 and 7.2 cm (parallel B{sub O}) and 3.6 and 7.0 cm (perpendicular B{sub O}). The different ferromagnetic attachments had no clinically relevant influence on the signal loss neither in 1.5 T nor 3.0 T MRI. Conclusions: ferromagnetic materials used in dentistry are not intraorally standardized. To ensure, that the area of interest is not affected by the described artifacts, the maximum extent of the signal loss area should be assumed: a radius of up to 7 cm in 1.5 and 3.0 T MRI by T1 and T2 sequences, and a radius of up to 10 cm in T2* sequences. To decide whether magnet attachments have to be removed before MR imaging, physicians should consider both the intact retention of the keepers and the safety distance between the ferromagnetic objects and the area of

  4. Restorative treatment thresholds for interproximal primary caries based on radiographic images: findings from the Dental Practice-Based Research Network

    DEFF Research Database (Denmark)

    Gordan, Valeria V; Garvan, Cynthia W; Heft, Marc W;

    2009-01-01

    with restorative intervention in lesions that have penetrated only the enamel surface. This study surveyed dentists from the Dental Practice-Based Research Network (DPBRN) who had reported doing at least some restorative dentistry (n = 901). Dentists were asked to indicate the depth at which they would restore...

  5. Formulación de un material de impresión dental en forma de pasta

    OpenAIRE

    García, R; Wong, L.; A. Ferrer; García, A; Martínez, E.

    2000-01-01

    Los materiales de impresión dental (MID) basados en alginato son muy empleados en Estomatología. En la actualidad se plantea que los MID en forma de pasta tienen una mayor fidelidad de copia, mejor reproducción de detalles de la impresión y no desprenden polvos volátiles secos que sean inhalados por los especialistas en su utilización cotidiana, por lo que se decidimos estudiar una formulación de un MID en forma de pasta. En el presente trabajo se reporta un material formado po...

  6. The impact of three strains of oral bacteria on the surface and mechanical properties of a dental resin material.

    Science.gov (United States)

    Gregson, Karen S; Shih, Han; Gregory, Richard L

    2012-08-01

    The purpose of this study was to determine if three strains of bacteria could impact the mechanical or surface properties of a dental resin material. Resin material specimens were incubated at 37°C in sterile saline, tryptic soy broth supplemented with sucrose (TSBS), or TSBS inoculated with Streptococcus mutans, Streptococcus gordonii, or Streptococcus sanguis. The specimens were subjected to Fourier transform infrared spectroscopy before and after incubation. The flexural strength test was performed once a week for 6 weeks. Microhardness and scanning electron microscopy (SEM) was performed on specimens at 1 and 6 weeks. Differences in the area under the carbonyl peak were statistically significant for the specimens incubated in the media inoculated with either S. mutans or S. gordonii. To determine why S. sanguis did not produce changes as the other bacteria did, triethylene glycol dimethacrylate, methacrylic acid, and triethylene glycol were added to bacterial cultures at increasing concentrations. Both methacrylic acid and triethylene glycol reduced the number of colony-forming units of S. sanguis. Specimens incubated in TSBS, saline or in culture with S. sanguis demonstrated a decrease in peak stress in week 1 of the flexure strength test. SEM demonstrated that surface topology changed for those specimens incubated in culture with S. mutans or S. gordonii. The changes in surface topology demonstrated here could contribute to the secondary caries and changes in esthetic properties seen clinically with the use of resin materials in dental restorations.

  7. Non-Thermal Atmospheric Plasma: Can it Be Taken as a Common Solution for the Surface Treatment of Dental Materials?

    Science.gov (United States)

    Emre, Seker; Mehmet, Ali Kilicarslan; Serdar, Polat; Emre, Ozkir; Suat, Pat

    2016-04-01

    This study aimed to evaluate the surface roughness and wetting properties of various dental prosthetic materials after different durations of non-thermal atmospheric plasma (NTAP) treatment. One hundred and sixty discs of titanium (Ti) (n:40), cobalt chromium (Co-Cr) (n:40), yttrium stabilized tetragonal zirconia polycrystals (Y-TZP) (n:40) and polymethylmethacrylate (PMMA) (n:40) materials were machined and smoothed with silicon carbide papers. The surface roughness was evaluated in a control group and in groups with different plasma exposure times [1-3-5 s]. The average surface roughness (Ra) and contact angle (CA) measurements were recorded via an atomic force microscope (AFM) and tensiometer, respectively. Surface changes were examined with a scanning electron microscope (SEM). Data were analyzed with two-way analysis of variance (ANOVA) and the Tukey HSD test α=0.05). According to the results, the NTAP surface treatment significantly affected the roughness and wettability properties (P < 0.05). SEM images reveal that more grooves were present in the NTAP groups. With an increase in the NTAP application time, an apparent increment was observed for Ra, except in the PMMA group, and a remarkable reduction in CA was observed in all groups. It is concluded that the NTAP technology could enhance the roughening and wetting performance of various dental materials. supported by the Department of Scientific Research, Eskisehir Osmangazi University, Turkey (No. 201441045)

  8. Mechanistic aspects of fracture and fatigue in resin based dental restorative composites

    Science.gov (United States)

    Shah, Minalben B.

    For resin based dental restorative composites, one of the major challenges is to optimize the balance between mechanical and optical properties. Although fracture is the second leading cause of dental restorative failures, very limited mechanistic understanding exists on a microscopic level. In the present study, the fracture properties and mechanisms of two commercial dental resin composites with different microstructures are examined using double notched four point beam bending and pre-cracked compact-tension, C(T), specimens. Four point bend flexural strength was also measured using un-notched beam samples. The first material is a microhybrid composite that combines a range of nano and micro scale filler particles to give an average particle size of 0.6 mum, while the second is a nanofill composite reinforced entirely with nano particles and their agglomerates. The influences of 60 days water hydration and a post-cure heat treatment were also examined. Fracture resistance curve (R-curve) experiments have demonstrated the microhybrid composite to be more fracture resistant than the nanofill composite in both as-processed and hydrated conditions. Rising fracture resistance with crack extension was observed in all specimens, independent of the environmental conditions. Compared to the as-processed condition, a significant reduction in the peak toughness was observed for the nanofill composite after 60 days of water aging. Hydration lowered flexural strength of both composites which was attributed to hydrolytic matrix degradation with additional interfacial debonding causing larger strength decrease in the nanofill. Optical and SEM observations revealed an interparticle matrix crack path promoting crack deflection as a toughening mechanism in all cases except the hydrated nanofill which showed particle-matrix debonding. Crack bridging was another observed extrinsic toughening mechanism that was believed to be responsible for the rising fracture resistance curve (R

  9. 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.

  10. 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. PMID:18183523

  11. Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

    International Nuclear Information System (INIS)

    Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.

  12. Effect of an Experimental Direct Pulp-capping Material on the Properties and Osteogenic Differentiation of Human Dental Pulp Stem Cells

    Science.gov (United States)

    Yu, Fan; Dong, Yan; Yang, Yan-wei; Lin, Ping-ting; Yu, Hao-han; Sun, Xiang; Sun, Xue-fei; Zhou, Huan; Huang, Li; Chen, Ji-hua

    2016-01-01

    Effective pulp-capping materials must have antibacterial properties and induce dentin bridge formation; however, many current materials do not satisfy clinical requirements. Accordingly, the effects of an experiment pulp-capping material (Exp) composed of an antibacterial resin monomer (MAE-DB) and Portland cement (PC) on the viability, adhesion, migration, and differentiation of human dental pulp stem cells (hDPSCs) were examined. Based on a Cell Counting Kit-8 assay, hDPSCs exposed to Exp extracts showed limited viability at 24 and 48 h, but displayed comparable viability to the control at 72 h. hDPSC treatment with Exp extracts enhanced cellular adhesion and migration according to in vitro scratch wound healing and Transwell migration assays. Exp significantly upregulated the expression of osteogenesis-related genes. The hDPSCs cultured with Exp exhibited higher ALP activity and calcium deposition in vitro compared with the control group. The novel material showed comparable cytocompatibility to control cells and promoted the adhesion, migration, and osteogenic differentiation of hDPSCs, indicating excellent biocompatibility. This new direct pulp-capping material containing MAE-DB and PC shows promise as a potential alternative to conventional materials for direct pulp capping. PMID:27698421

  13. 21 CFR 872.3100 - Dental amalgamator.

    Science.gov (United States)

    2010-04-01

    ... and dental alloy particles, such as silver, tin, zinc, and copper. The mixed dental amalgam material... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  14. 21 CFR 872.3240 - Dental bur.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental bur. 872.3240 Section 872.3240 Food and... DENTAL DEVICES Prosthetic Devices § 872.3240 Dental bur. (a) Identification. A dental bur is a rotary... materials intended for use in the fabrication of dental devices. (b) Classification. Class I...

  15. The Validity of Subjects in Korean Dental Technicians' Licensing Examination

    Directory of Open Access Journals (Sweden)

    Woong-chul Kim

    2005-06-01

    Full Text Available This study prepared a basic framework for the development and improvement of Korean Dental Technicians' Licensing Examination, based on actual test questions. A peer review was conducted to ensure relevance to current practices in dental technology. For the statistical analysis, 1000 dental laboratory technicians were selected; specialists in dental laboratory technology (laboratory owners, educators, etc. were involved in creating valid and reliable questions. Results indicated that examination subjects should be divided into three categories: basic dental laboratory theory, dental laboratory specialties, and a practical examination. To ensure relevance to current practice, there should be less emphasis on basic dental laboratory theory, including health-related laws, and more emphasis on dental laboratory specialties. Introduction to dental anatomy should be separated from oral anatomy and tooth morphology; and fixed prosthodontics should be separated from crown and bridge technology and dental ceramics technology. Removable orthodontic appliance technology should be renamed 'orthodontic laboratory technology'. There should be less questions related to health related law, oral anatomy, dental hygiene, dental materials science and inlay, while the distribution ratio of questions related to tooth morphology should be maintained. There should be a decrease in the distribution ratio of questions related to crown and bridge technology, dental ceramics technology, complete dentures and removable partial dentures technology, and orthodontic laboratory technology. In the practical examination, the current multiple choice test should be replaced with tooth carving using wax or plaster. In dental laboratory specialties, subjects related to contemporary dental laboratory technology should be included in the test items.

  16. Dental amalgam: An update

    OpenAIRE

    Bharti Ramesh; Wadhwani Kulvinder; Tikku Aseem; Chandra Anil

    2010-01-01

    Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence with regard to its performance and offer predictions for the future of this material. The PubMed database was used initially; the reference list for dental amalgam featured 8641 articles and 13 publications dealing with recent advances in dental amalgam. A forward search was undertaken on selected articles and using...

  17. HLA-Association in Patients with Intolerance to Mercury and Other Metals in Dental Materials

    Directory of Open Access Journals (Sweden)

    J. Procházková

    2000-01-01

    Full Text Available A group of selected 25 patients with serious intolerance to heavy metals used for dental restoration were examined for HLA antigens. A significant increase for HLA – B37, B47 and DR4 was found. The value of the relative risk is not significant after correction for the number of antigens tested and therefore further studies of more patients are needed.

  18. FTIR spectroscopic study of an organic/mineral composite for bone and dental substitute materials.

    OpenAIRE

    Weiss, Pierre; Lapkowski, Mieczysław; Legeros, Raquel,; Bouler, Jean-Michel; Jean, Alain; Daculsi, Guy

    1997-01-01

    A new injectable biomaterial for bone and dental surgery is a composite consisting of a polymer as a matrix and bioactive calcium phosphate (CaP) ceramics as fillers. The stability of the polymer is essential in the production of a ready-to-use injectable sterilized biomaterial. The purpose of this study was to detect possible polymer degradation which may have been caused by the interaction with the fillers using Fourier transformed infrared spectroscopy. Composites containing CaP fillers (B...

  19. Association of cardiometabolic risk factors and dental caries in a population-based sample of youths

    Directory of Open Access Journals (Sweden)

    Kelishadi Roya

    2010-04-01

    Full Text Available Abstract Background Cardiovascular disease (CVD risk factors begin from early life and track onto adulthood. Oral and dental diseases share some risk factors with CVD, therefore by finding a clear relation between dental diseases and cardiometabolic risk factors; we can then predict the potential risk of one based on the presence of the other. This study aimed to compare the prevalence of dental caries between two groups of age-matched adolescents with and without CVD risk factors. Methods In this case-control study, the decayed, missing and filled surfaces (DMFS, based on the criteria of the World Health Organization, were compared in two groups of equal number (n = 61 in each group of population-based sample of adolescents with and without CVD risk factors who were matched for sex and age group. Results The study participants had a median age 13 y 5 mo, age range 11 y 7 mo to 16 y 1 mo, with male-to-female proportion of 49/51. We found significant difference between the mean values of DMFS, body mass index, waist and hip circumferences, as well as serum lipid profile in the case and control groups. Significant correlations were documented for DMFS with TC (r = 0.54, p = 0.02, LDL-C (r = 0.55, p = 0.01 and TG (r = 0.52, p = 0.04 in the case group; with LDL-C (r = 0.47, p = 0.03 in the whole study participants and with TC in control s(r = 0.45, p = 0.04. Conclusions Given the significant associations between dental caries and CVD risk factors among adolescents, more attention should be paid to oral health, as one of the topics to be taken into account in primordial/primary prevention of cardiometabolic disorders.

  20. Potential hazards and artifacts of ferromagnetic and nonferromagnetic surgical and dental materials and devices in nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    The risks to patients with metal surgical implants who are undergoing nuclear magnetic resonance (NMR) imaging and the artifacts caused by such implants were studied. Twenty-one aneurysm and other hemostatic clips and a variety of other materials (e.g., dental amalgam, 14 karat gold) were used. Longitudinal forces and torques were found to be exerted upon 16 of the 21 clips. With five aneurysm clips, forces and torques sufficient to produce risk of hemorrhage from dislocation of the clip from the vessel or aneurysm, or cerebral injury by clip displacement without dislodgement were identified. The induced ferromagnetism was shown to be related to the composition of the alloys from which the clips were manufactured. Clips with 10-14% nickel are evidently without sufficient induced ferromagnetism to cause hazard. The extent of NMR imaging artifacts was greater for materials with measurable ferromagnetic properties, but metals without measurable ferromagnetism in our tests also resulted in significant artifacts. Dental amalgam and 14 karat gold produced no imaging artifacts, but stainless steels in dentures and orthodontic braces produced extensive artifacts in the facial region

  1. Preparation and characterization of new dental porcelains, using K-feldspar and quartz raw materials. Effect of B2O3 additions on sintering and mechanical properties.

    Science.gov (United States)

    Harabi, Abdelhamid; Guerfa, Fatiha; Harabi, Esma; Benhassine, Mohamed-Tayeb; Foughali, Lazhar; Zaiou, Soumia

    2016-08-01

    The aim of this work was to determine the effect of temperature and boric oxide (B2O3) addition on sintering and mechanical properties of a newly developed dental porcelain (DP) prepared from local Algerian raw materials. Based on a preliminary work, the new selected composition was 75wt.% feldspar, 20wt.% quartz and 5wt.% kaolin. It was prepared by sintering the mixture at different temperatures (1100-1250°C). The optimum sintering conditions gave a relatively higher density (2.47g/cm(3)) and excellent mechanical properties. The three point flexural strength (3PFS) and Martens micro-hardness of dental porcelains were 149MPa and 2600MPa, respectively. This obtained 3PFS value is more than four times greater than that of hydroxyapatite (HA) value (about 37MPa) sintered under the same conditions. However, the sintering temperature was lowered by about 25 and 50°C for 3 and 5wt.% B2O3 additions, respectively. But, it did not improve furthermore the samples density and their mechanical properties. It has also been found that B2O3 additions provoke a glass matrix composition variation which delays the leucite formation during sintering. PMID:27157725

  2. An interview study of persons who attribute health problems to dental filling materials--part two in a triangulation study on 65 and 75 years old Swedes.

    Science.gov (United States)

    Ståhlnacke, Katri; Söderfeldt, Björn

    2013-01-01

    Dental materials are perceived as a health problem by some people, although scientists do not agree about possible causes of such problems. The aim of this paper was to gain a deeper knowledge and understanding of experiences from living with health problems attributed to dental materials. Addressed topics were the type of problem, both as to general and oral health, perceived causes of the problems,their experienced effect on life, and reception by health professionals. Persons, who in a previous large questionnaire study had answered that they had experienced troubles from dental materials and also agreed to answer follow-up questions, were contacted with a request to take part in an interview study. Eleven individual interviews were held.The interviews were transcribed verbatim and the material was analysed according to the Qualitative Content Analysis method. Meaning units were extracted and condensed into a number of codes, which were combined into subcategories, categories, and themes. Four themes were identified: 1) Long-term oral, mental, and somatic difficulties of varying character, caused by dental amalgam. 2) Problems treated mainly by replacement of dental material in fillings. 3) Powerful effects on life, mostly negative. 4) The reception by health professionals was generally good, but with elements of encounters where they felt treated with nonchalance and lack of respect. In conclusion, people who attributed their health difficulties to dental materials had a complex range of problems and the perception was that amalgam/mercury was the cause of the troubles. The reception from health professionals was perceived as generally good, although with occasional negative experiences.

  3. A cone-beam CT based technique to augment the 3D virtual skull model with a detailed dental surface.

    Science.gov (United States)

    Swennen, G R J; Mommaerts, M Y; Abeloos, J; De Clercq, C; Lamoral, P; Neyt, N; Casselman, J; Schutyser, F

    2009-01-01

    Cone-beam computed tomography (CBCT) is used for maxillofacial imaging. 3D virtual planning of orthognathic and facial orthomorphic surgery requires detailed visualisation of the interocclusal relationship. This study aimed to introduce and evaluate the use of a double CBCT scan procedure with a modified wax bite wafer to augment the 3D virtual skull model with a detailed dental surface. The impressions of the dental arches and the wax bite wafer were scanned for ten patient separately using a high resolution standardized CBCT scanning protocol. Surface-based rigid registration using ICP (iterative closest points) was used to fit the virtual models on the wax bite wafer. Automatic rigid point-based registration of the wax bite wafer on the patient scan was performed to implement the digital virtual dental arches into the patient's skull model. Probability error histograms showed errors of 3D virtual augmented model of the skull with detailed dental surface.

  4. The Level of Dental Anxiety and Dental Status in Adult Patients

    OpenAIRE

    Dobros, Katarzyna; Hajto-Bryk, Justyna; Wnek, Anna; Zarzecka, Joanna; Rzepka, Dominik

    2014-01-01

    Background: The present study aimed to assess potential correlation between dental anxiety and overall dental status in adult patients, in consideration of the frequency of dental appointments and individual dental hygiene practices. Materials and Methods: Individual dental anxiety levels were assessed with the aid of the Corah’s dental anxiety scale (DAS). The study embraced 112 patients of the University Dental Clinic, Kraków. Following clinical and X-ray exams, r...

  5. Assessment of bacterial adhesion of different dental materials%几种常用口腔材料细菌粘附性能比较

    Institute of Scientific and Technical Information of China (English)

    丁宁; 张祖太; 何敏; 刘艳; 任蕾

    2014-01-01

    Objective To evaluate the difference of bacterial adhesion of different dental materials. Methods Five type of dental materials were selected, including self-curing denture base resin,composite resin, zirconia, titanium and nickel-cobalt alloy. 1. 3cm × 2. 0cm × 0. 2cm specimens of these dental materials were prepared and five test pieces in each material made. The surface of the specimens were polished. Sreptococcus mutans ATCC 25175 was selected, and the bacterial suspension was placed on the specimens and cultured at 37℃ for 48h. Then the bacteria that adhered to the specimens were eluted, cultured again and counted. The data were statistically analyzed. Results The amount of the bacteria that adhered to titanium was the least, followed by zirconia,resin,nickel-cobalt alloy and self-curing denture base resin( P<0. 05 ) . Conclusion Among the five types of dental materials, titanium had better antibacterial adhesion property.%目的:探讨5种口腔常用材料的抗细菌粘附性能。方法将自凝甲基丙烯酸甲酯基托树脂、Z250复合树脂、氧化锆陶瓷、纯钛和镍铬合金5种牙科常用修复材料,分别制备成3.0cm ×2.0cm ×0.2cm的板片试件,每组各5片。各组试件表面进行抛光处理,使试件表面粗糙度( Ra)值无显著性差异。实验菌株选用变形链球菌,用细菌悬浮液置试件表面,37℃培养48h,对粘附在材料表面的细菌再进行洗脱、培养、菌落计数,使用SPSSl7.0软件对试验结果进行统计分析。结果纯钛表面变形链球菌粘附量最低,依次为氧化锆陶瓷、Z250复合树脂、镍铬合金、自凝甲基丙烯酸甲酯基托树脂。结论不同口腔材料在同样粗糙度的条件下,抗细菌粘附性能存在差异,钛具有较好的抗细菌粘附性能。

  6. An intraoral miniature x-ray tube based on carbon nanotubes for dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jin; Kim, Hyun Nam; Raza, Hamid Saeed; Park, Han Beom; Cho, Sung Oh [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-06-15

    A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

  7. A pilot study combining individual-based smoking cessation counseling, pharmacotherapy, and dental hygiene intervention

    Directory of Open Access Journals (Sweden)

    Madrid Carlos

    2010-06-01

    Full Text Available Abstract Background Dentists are in a unique position to advise smokers to quit by providing effective counseling on the various aspects of tobacco-induced diseases. The present study assessed the feasibility and acceptability of integrating dentists in a medical smoking cessation intervention. Methods Smokers willing to quit underwent an 8-week smoking cessation intervention combining individual-based counseling and nicotine replacement therapy and/or bupropion, provided by a general internist. In addition, a dentist performed a dental exam, followed by an oral hygiene treatment and gave information about chronic effects of smoking on oral health. Outcomes were acceptability, global satisfaction of the dentist's intervention, and smoking abstinence at 6-month. Results 39 adult smokers were included, and 27 (69% completed the study. Global acceptability of the dental intervention was very high (94% yes, 6% mostly yes. Annoyances at the dental exam were described as acceptable by participants (61% yes, 23% mostly yes, 6%, mostly no, 10% no. Participants provided very positive qualitative comments about the dentist counseling, the oral exam, and the resulting motivational effect, emphasizing the feeling of oral cleanliness and health that encouraged smoking abstinence. At the end of the intervention (week 8, 17 (44% participants reported smoking abstinence. After 6 months, 6 (15%, 95% CI 3.5 to 27.2 reported a confirmed continuous smoking abstinence. Discussion We explored a new multi-disciplinary approach to smoking cessation, which included medical and dental interventions. Despite the small sample size and non-controlled study design, the observed rate was similar to that found in standard medical care. In terms of acceptability and feasibility, our results support further investigations in this field. Trial Registration number ISRCTN67470159

  8. Comparison of three evidence-based practice learning assessment methods in dental curricula.

    Science.gov (United States)

    Al-Ansari, Asim A; El Tantawi, Maha M A

    2015-02-01

    Incorporating evidence-based practice (EBP) training in dental curricula is now an accreditation requirement for dental schools, but questions remain about the most effective ways to assess learning outcomes. The purpose of this study was to evaluate and compare three assessment methods for EBP training and to assess their relation to students' overall course grades. Participants in the study were dental students from two classes who received training in appraising randomized controlled trials (RCTs) and systematic reviews in 2013 at the University of Dammam, Saudi Arabia. Repeated measures analysis of variance was used to compare students' scores on appraisal assignments, scores on multiple-choice question (MCQ) exams in which EBP concepts were applied to clinical scenarios, and scores for self-reported efficacy in appraisal. Regression analysis was used to assess the relationship among the three assessment methods, gender, program level, and overall grade. The instructors had acceptable reliability in scoring the assignments (overall intraclass correlation coefficient=0.60). The MCQ exams had acceptable discrimination indices although their reliability was less satisfactory (Cronbach's alpha=0.46). Statistically significant differences were observed among the three methods with MCQ exams having the lowest overall scores. Variation in the overall course grades was explained by scores on the appraisal assignment and MCQ exams (partial eta-squared=0.52 and 0.24, respectively), whereas score on the self-efficacy questionnaire was not significantly associated with overall grade. The results suggest that self-reported efficacy is not a valid method to assess dental students' RCT appraisal skills, whereas instructor-graded appraisal assignments explained a greater portion of variation in grade and had inherent validity and acceptable consistency and MCQ exams had good construct validity but low internal consistency. PMID:25640619

  9. Health promotion and dental caries

    Directory of Open Access Journals (Sweden)

    Marisa Maltz

    2010-01-01

    Full Text Available The central idea of the Brazilian health system is to prevent the establishment of disease or detect it as early as possible. Prevention and treatment of dental caries are related to behavioral factors, including dietary and oral hygiene habits, which are related to many chronic diseases. Dental health promotion therefore should be fully integrated into broadly based health-promoting strategies and actions such as food and health policies, and general hygiene (including oral hygiene, among others. For decades, a linear relationship between sugar consumption and caries has been observed. Recent data has indicated that this relationship is not as strong as it used to be before the widespread use of fluoride. However, diet is still a key factor acting in the carious process. Oral hygiene is a major aspect when it comes to caries, since dental biofilm is its etiological factor. Oral hygiene procedures are effective in controlling dental caries, especially if plaque removal is performed adequately and associated with fluoride. An alternative to a more efficient biofilm control in occlusal areas is the use of dental sealants, which are only indicated for caries-active individuals. If a cavity is formed as a consequence of the metabolic activity of the biofilm, a restorative material or a sealant can be placed to block access of the biofilm to the oral environment in order to prevent caries progress. The prevention of dental caries based on common risk-factor strategies (diet and hygiene should be supplemented by more disease-specific policies such as rational use of fluoride, and evidence-based dental health care.

  10. Evaluation of Training and Curriculum Materials Used in a Pilot Test of a Comprehensive Dental Health Program (TATTLETOOTH).

    Science.gov (United States)

    Fruchter, Dorothy A.

    Tattletooth was designed to help alleviate the physical, psychological and social problems associated with dental disease by teaching proper dental hygiene techniques and by stressing the importance of good dental health to the social and psychological well-being of the whole person. The program provided for the entire community with the provision…

  11. Bacteriostatic and anti-collagenolytic dental materials through the incorporation of polyacrylic acid modified CuI nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Renne, Walter George; Mennito, Anthony Samuel; Schmidt, Michael Gerard; Vuthiganon, Jompobe; Chumanov, George

    2015-05-19

    Provided are antibacterial and antimicrobial surface coatings and dental materials by utilizing the antimicrobial properties of copper chalcogenide and/or copper halide (CuQ, where Q=chalcogens including oxygen, or halogens, or nothing). An antimicrobial barrier is created by incorporation of CuQ nanoparticles of an appropriate size and at a concentration necessary and sufficient to create a unique bioelectrical environment. The unique bioelectrical environment results in biocidal effectiveness through a multi-factorial mechanism comprising a combination of the intrinsic quantum flux of copper (Cu.sup.0, Cu.sup.1+, Cu.sup.2+) ions and the high surface-to-volume electron sink facilitated by the nanoparticle. The result is the constant quantum flux of copper which manifests and establishes the antimicrobial environment preventing or inhibiting the growth of bacteria. The presence of CuQ results in inhibiting or delaying bacterial destruction and endogenous enzymatic breakdown of the zone of resin inter-diffusion, the integrity of which is essential for dental restoration longevity.

  12. Dental anxiety among adults: An epidemiological study in South India

    Directory of Open Access Journals (Sweden)

    Devapriya Appukuttan

    2015-01-01

    Full Text Available Background: Dental anxiety is a major barrier for dental care utilization. Hence, identifying anxious individuals and their appropriate management becomes crucial in clinical practice. Aim: The study aims to assess dental anxiety, factors influencing dental anxiety, and anxiety towards tooth extraction procedure among patients attending a dental hospital in India. Materials and Methods: The study sample consisted of 1,148 consecutive patients aged 18-70 years. The assessment tools consisted of a consent form, history form, a questionnaire form containing the Modified Dental Anxiety Scale (MDAS which was used to assess the level of dental anxiety, and an additional question on anxiety towards dental extraction procedure. Results: Among the study group, 63.7% were men and 36.3% were women. Based on the MDAS score, 45.2% of the participants were identified to be less anxious, 51.8% were moderately or extremely anxious, and 3% were suffering from dental phobia. Mean MDAS total score was 10.4 (standard deviation (SD = 3.91. Female participants and younger subjects were more anxious (P < 0.001. Subjects who were anxious had postponed their dental visit (P < 0.001. Participants who had negative dental experience were more anxious (P < 0.05. Notably, 82.6% reported anxiety towards extraction procedure. Significant association was seen between anxiety towards extraction procedure and the respondents gender (P < 0.05, age (P < 0.001, education level (P < 0.05, employment status (P < 0.001, income (P < 0.001, self-perceived oral health status (P < 0.05, and their history of visit to dentist (P < 0.05. Conclusion: Significant percentage of population was suffering from dental anxiety in this study population. A plethora of factors like age, gender, education level, occupation, financial stability, and previous bad dental experience influences dental anxiety to various levels. Extraction followed by drilling of tooth and receiving local anesthetic injection

  13. Application and safety evaluation of different dental implant materials%不同口腔种植材料的应用及安全性评价

    Institute of Scientific and Technical Information of China (English)

    宣永华

    2011-01-01

    背景:目前临床应用的牙种植体材料种类繁多,各有其优缺点,哪种材料更具临床应用价值及良好的生物相容性呢? 目的:综述不同口腔种植材料的研究进展,评价其种植后与宿主的相容性及临床应用前景.方法:应用计算机检索CNKI和PubMed数据库中2000-01/2011-03关于口腔种植材料应用的文章,在标题和摘要中以"口腔种植体;牙种植体;合金;陶瓷;高分子材料;复合材料"或"dental implant;polymer alloy composite material;ceramic/aluminum alloy"为检索词进行检索.选择内容与不同口腔种植材料的应用特点及安全性相关文章.初检得到126篇文献,根据纳入标准选择30篇文章进行综述.结果与结论:合金、陶瓷、高分子、复合材料及纳米材料在口腔种植方面发挥了重要作用.理想口腔植入材料的选择,需要对其生物相容性、生物力学性能、生物学形态、与周围组织的结合能力等各方面综合考虑,对细胞、组织等应无毒性、无刺激性、无致畸致突变性,同时与骨组织之间应形成骨性结合,具有良好的骨引导或骨诱导作用.%BACKGROUND: Currently, clinical dental implant materials are various with their own advantages and disadvantages, which one is better in clinical application and has good biocompatibility?OBJECTIVE: To review the progress of different dental implant materials and to evaluate the compatibility of dental implants with the host as well as their clinical prospect.METHODS: CNKI and PubMed (2000-01/2011-03) were retrieved for articles addressing application of dental implant materials using the keywords of “dental implant; polymer alloy composite material; ceramic/aluminum alloy” in English and “dental implant;tooth implant; alloy; ceramic; polymer material; composite material” in Chinese. Articles about application characteristics of different dental implant materials and their safety were retrieved and 126 articles were found

  14. Ni–Cr based dental alloys; Ni release, corrosion and biological evaluation

    International Nuclear Information System (INIS)

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10–15% for female adults and 1–3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni–Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni–Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: ► Nickel released was higher than the limits imposed in EU in contact with the skin. ► No direct relationship between the biological evaluation and chemical degradation.

  15. Ni-Cr based dental alloys; Ni release, corrosion and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Reclaru, L., E-mail: lucien.reclaru@pxgroup.com [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Unger, R.E.; Kirkpatrick, C.J. [Institute for Pathology, REPAIR Lab, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr.1, D-55101 Mainz (Germany); Susz, C.; Eschler, P.-Y.; Zuercher, M.-H. [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Antoniac, I. [Materials Science and Engineering Faculty, Politehnica of Bucharest, 060042 Bucharest (Romania); Luethy, H. [Institute of Dental Materials Science and Technology, University of Basel, Hebelstrasse 3, CH-4056 Basel (Switzerland)

    2012-08-01

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10-15% for female adults and 1-3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni-Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni-Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: Black-Right-Pointing-Pointer Nickel released was higher than the limits imposed in EU in contact with the skin. Black-Right-Pointing-Pointer No direct relationship between the

  16. Vanadium based materials as electrode materials for high performance supercapacitors

    Science.gov (United States)

    Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

    2016-10-01

    As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

  17. Radiology for dental assistants

    International Nuclear Information System (INIS)

    The book provides dental assistants with the knowledge they need to apply X-rays in a safe and economical manner. Starting from the theoretical fundamentals of radiophysics, the biologic effects of X-rays leading to the protective requirements of the new X-Ray Ordinance are explained. The main topics are the adjustment rules for dental film, panorama and cassette film images which are explained in detail and illustrated, the topics of materials and equipment, and processing up to the stage of a safe guarding. In chapters dealing with the practical points of view, the applications in paedodentistry and orthodontics, in endodonty, parodontology and in imaging the temporo-mandibular joints are described; these chapters also deal with recognizing and avoiding mistakes. An appendix with data worth knowing rounds up the contents. The book is based on numerous training seminars. (orig./MG)

  18. Crack tip fracture toughness of base glasses for dental restoration glass-ceramics using crack opening displacements.

    Science.gov (United States)

    Deubener, J; Höland, M; Höland, W; Janakiraman, N; Rheinberger, V M

    2011-10-01

    The critical stress intensity factor, also known as the crack tip toughness K(tip), was determined for three base glasses, which are used in the manufacture of glass-ceramics. The glasses included the base glass for a lithium disilicate glass-ceramic, the base glass for a fluoroapatite glass-ceramic and the base glass for a leucite glass-ceramic. These glass-ceramic are extensively used in the form of biomaterials in restorative dental medicine. The crack tip toughness was established by using crack opening displacement profiles under experimental conditions. The crack was produced by Vickers indentation. The crack tip toughness parameters determined for the three glass-ceramics differed quite significantly. The crack tip parameters of the lithium disilicate base glass and the leucite base glass were higher than that of the fluoroapatite base glass. This last material showed glass-in-glass phase separation. The discussion of the results clearly shows that the droplet glass phase is softer than the glass matrix. Therefore, the authors conclude that a direct relationship exists between the chemical nature of the glasses and the crack tip parameter.

  19. Dental Therapy Assistant: Attitudes of Army Dentists.

    Science.gov (United States)

    Heid, Theodore H.; Bair, Jeffrey H.

    The U. S. Army Dental Corps has implemented a formal program based on the concept that dental care can be more efficiently and effectively provided with treatment teams composed of one dental officer, two dental therapy assistants, one basic assistant, and the shared support of other auxiliary personnel. Such a team will use three dental treatment…

  20. Silica/quercetin sol-gel hybrids as antioxidant dental implant materials

    Science.gov (United States)

    Catauro, Michelina; Papale, Ferdinando; Bollino, Flavia; Piccolella, Simona; Marciano, Sabina; Nocera, Paola; Pacifico, Severina

    2015-06-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol-gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.

  1. Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens: a co-culture study in vitro.

    Science.gov (United States)

    Zhao, Bingran; van der Mei, Henny C; Rustema-Abbing, Minie; Busscher, Henk J; Ren, Yijin

    2015-12-01

    Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity. PMID:26674427

  2. In vitro and in vivo studies of ultrafine-grain Ti as dental implant material processed by ECAP.

    Science.gov (United States)

    An, Baili; Li, Zhirui; Diao, Xiaoou; Xin, Haitao; Zhang, Qiang; Jia, Xiaorui; Wu, Yulu; Li, Kai; Guo, Yazhou

    2016-10-01

    The aim of this study was to investigate the surface characterization of ultrafine-grain pure titanium (UFG-Ti) after sandblasting and acid-etching (SLA) and to evaluate its biocompatibility as dental implant material in vitro and in vivo. UFG-Ti was produced by equal channel angular pressing (ECAP) using commercially pure titanium (CP-Ti). Microstructure and yield strength were investigated. The morphology, wettability and roughness of the specimens were analyzed after they were modified by SLA. MC3T3-E1 osteoblasts were seeded onto the specimens to evaluate its biocompatibility in vitro. For the in vivo study, UFG-Ti implants after SLA were embedded into the femurs of New Zealand rabbits. Osseointegration was investigated though micro-CT analysis, histological assessment and pull-out test. The control group was CP-Ti. UFG-Ti with enhanced mechanical properties was produced by four passes of ECAP in BC route at room temperature. After SLA modification, the hierarchical porous structure on its surface exhibited excellent wettability. The adhesion, proliferation and viability of cells cultured on the UFG-Ti were superior to that of CP-Ti. In the in vivo study, favorable osseointegration occurred between the implant and bone in CP and UFG-Ti groups. The combination intensity of UF- Ti with bone was higher according to the pull-out test. This study supports the claim that UFG-Ti has grain refinement with outstanding mechanical properties and, with its excellent biocompatibility, has potential for use as dental implant material. PMID:27287096

  3. Social and dental status along the life course and oral health impacts in adolescents: a population-based birth cohort

    Directory of Open Access Journals (Sweden)

    Menezes Ana MB

    2009-11-01

    Full Text Available Abstract Background Harmful social conditions in early life might predispose individuals to dental status which in turn may impact on adolescents' quality of life. Aims To estimate the prevalence of oral health impacts among 12 yr-old Brazilian adolescents (n = 359 and its association with life course socioeconomic variables, dental status and dental services utilization in a population-based birth cohort in Southern Brazil. Methods Exploratory variables were collected at birth, at 6 and 12 yr of age. The Oral Impacts on Daily Performances index (OIDP was collected in adolescence and it was analyzed as a ranked outcome (OIDP from 0 to 9. Unadjusted and adjusted multivariable Poisson regression with robust variance was performed guided by a theoretical determination model. Results The response rate was of 94.4% (n = 339. The prevalence of OIDP = 1 was 30.1% (CI95%25.2;35.0 and OIDP ≥ 2 was 28.0% (CI95%23.2;32.8. The most common daily activity affected was eating (44.8%, follow by cleaning the mouth and smiling (15.6%, and 15.0%, respectively. In the final model mother schooling and mother employment status in early cohort participant's life were associated with OIDP in adolescence. As higher untreated dental caries at age 6 and 12 years, and the presence of dental pain, gingival bleeding and incisal crowing in adolescence as higher the OIDP score. On the other hand, dental fluorosis was associated with low OIDP score. Conclusion Our findings highlight the importance of adolescent's early life social environmental as mother schooling and mother employment status and the early and later dental status on the adolescent's quality of life regardless family income and use of dental services.

  4. A virtual sinogram method to reduce dental metallic implant artefacts in computed tomography-based attenuation correction for PET

    NARCIS (Netherlands)

    Abdoli, Mehrsima; Ay, Mohammad Reza; Ahmadian, Alireza; Zaidi, Habib

    2010-01-01

    Objective Attenuation correction of PET data requires accurate determination of the attenuation map (mu map), which represents the spatial distribution of linear attenuation coefficients of different tissues at 511 keV. The presence of high-density metallic dental filling material in head and neck X

  5. Unilateral and bilateral dental transpositions in the maxilla

    DEFF Research Database (Denmark)

    Danielsen, Jakob Christian; Karimian, K; Ciarlantini, R;

    2015-01-01

    AIM: This was to elucidate dental and skeletal findings in individuals with unilateral and bilateral maxillary dental transpositions. MATERIAL AND METHODS: The sample comprised of radiographic materials from 63 individuals with maxillary dental transpositions from the Departments of Odontology at...

  6. Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root-canal-filling materials.

    Science.gov (United States)

    Hauman, C H J; Love, R M

    2003-03-01

    Root-canal-filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root-canal-filling materials.

  7. Dental Abfraction - Case Report

    OpenAIRE

    Irina-Maria Gheorghiu; Loredana Mitran; M Mitran; Magdalena Mironiuc-Cureu; A. A. Iliescu; Ioana Suciu

    2015-01-01

    Dental abfraction is a pathological process which causes a loss of dental hard substance. Etiopathogenesis is related to occlusal stress that causes microfractures in enamel and dentin in the cervical region. The restoration treatment is made using aesthetic adhesive materials, but must take into account the causal factors and the specific area where the restoration is done.

  8. Dental Abfraction - Case Report

    Directory of Open Access Journals (Sweden)

    Irina-Maria Gheorghiu

    2015-01-01

    Full Text Available Dental abfraction is a pathological process which causes a loss of dental hard substance. Etiopathogenesis is related to occlusal stress that causes microfractures in enamel and dentin in the cervical region. The restoration treatment is made using aesthetic adhesive materials, but must take into account the causal factors and the specific area where the restoration is done.

  9. DENTAL HOT-COLD SENSITIVITY AND TRAUMATIC DENTAL INJURIES

    OpenAIRE

    Traebert, Jefferson; Martins, Luiz Gustavo Teixeira; Traebert, Eliane Silva de Azevedo; Bortoluzzi, Marcelo Carlos

    2014-01-01

    AIM: Although several studies have indicated negative impacts of traumatic dental injuries on children’s quality of life, virtually none of them have explored the possible association between them and the occurrence and dental hot-cold sensitivity. The aim of this study was to study the possible association of hot-cold dental sensitivity and history of traumatic dental injuries. MATERIAL AND METHODS: A cross-sectional study involving a representative sample of 11- to 14-year-old schoolchildre...

  10. Dentists' dietary perception and practice patterns in a dental practice-based research network.

    Directory of Open Access Journals (Sweden)

    Yoko Yokoyama

    Full Text Available Dental caries are largely preventable, and epidemiological evidence for a relationship between diet and oral health is abundant. To date, however, dentists' perceptions about the role of diet and dentists' practice patterns regarding diet counseling have not been clarified.THE PURPOSES OF THIS STUDY WERE TO: (1 examine discordance between dentists' perception of the importance of diet in caries treatment planning and their actual provision of diet counseling to patients, and (2 identify dentists' characteristics associated with their provision of diet counseling.The study used a cross-sectional study design consisting of a questionnaire survey in Japan.The study queried dentists working in outpatient dental practices who were affiliated with the Dental Practice-Based Research Network Japan (JDPBRN, which aims to allow dentists to investigate research questions and share experiences and expertise (n = 282.Dentists were asked about their perceptions on the importance of diet and their practice patterns regarding diet counseling, as well as patient, practice, and dentist background data.The majority of participants (n = 116, 63% recognized that diet is "more important" to oral health. However, among participants who think diet is "more important" (n = 116, only 48% (n = 56 provide diet counseling to more than 20% of their patients. Multiple logistic regression analysis suggested that several variables were associated with providing diet counseling; dentist gender, practice busyness, percentage of patients interested in caries prevention, caries risk assessment, and percentage of patients who receive blood pressure screening.Some discordance exists between dentists' perception of the importance of diet in caries treatment planning and their actual practice pattern regarding diet counseling to patients. Reducing this discordance may require additional dentist education, including nutritional and systemic disease concepts; patient

  11. Factors Influencing Dental Educators As They Develop Problem-Based Learning Cases.

    Science.gov (United States)

    Imai, Pauline H; Kresyman, Shelley; Asadoorian, Joanna

    2016-06-01

    In problem-based learning (PBL) environments, patient cases encourage students' development of critical thinking and problem-solving. Previous research has found that non-structured patient cases fostered students' critical thinking and problem-solving abilities; however, structured cases dominate in dental PBL. The aim of this study was to explore factors influencing educators as they developed cases for a hybrid PBL dental education program in Canada. In this phenomenological study, semi-structured interviews were used to collect seven educators' experiences with PBL case development. Content analyses with conceptual mapping were triangulated with field notes, researcher memos, and member checking to elucidate codes and themes. There were two major themes and 14 subthemes. The major theme-external factors-involved environmental parameters that influenced educators to develop PBL cases with a definitive problem-solving approach and preferred solution. Structured PBL cases dominated because of limited curricular time for students to explore identified learning issues within a three-session framework. The hybrid PBL dental curriculum further influenced educators to develop structured PBL cases such that content was not duplicated by corresponding lectures. The second major theme-internal factors-encompassed the educators' beliefs and values about teaching and student learning. These educators were enthusiastic about PBL as an instructional strategy, but did not appear to support the PBL philosophy wherein students engage in self-directed, self-exploratory learning. Structured PBL case development occurred when educators believed students needed content expert guidance. Structured PBL cases dominated in the hybrid PBL program because the educators felt students needed guidance in solving the cases to meet the learning objectives within the limited curricular time. PMID:27251356

  12. Dental Sealants

    Science.gov (United States)

    ... Internships for... High School and College Students Recent College Graduates Dental and Medical Students See All Careers & Training Opportunities Job Openings Loan Repayment Programs Careers in Dental Research ...

  13. Current Uses of Poly(lactic-co-glycolic acid in the Dental Field: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Maria Justina Roxana Virlan

    2015-01-01

    Full Text Available Poly(lactic-co-glycolic acid or PLGA is a biodegradable polymer used in a wide range of medical applications. Specifically PLGA materials are also developed for the dental field in the form of scaffolds, films, membranes, microparticles, or nanoparticles. PLGA membranes have been studied with promising results, either alone or combined with other materials in bone healing procedures. PLGA scaffolds have been used to regenerate damaged tissues together with stem cell-based therapy. There is solid evidence that the development of PLGA microparticles and nanoparticles may be beneficial to a wide range of dental fields such as endodontic therapy, dental caries, dental surgery, dental implants, or periodontology. The aim of the current paper was to review the recent advances in PLGA materials and their potential uses in the dental field.

  14. Comparison of the Surface Roughness of Gypsum (Dental Stone with three Types of Tissue Conditioner Impression Materials over Time

    Directory of Open Access Journals (Sweden)

    Nili M.

    2012-02-01

    Full Text Available Statement of Problems: Although the primary use of tissue conditioners is for healing the damaged mucosa but they can also be used as functional impression; it seems that its effeicasy depends on its viscoelastic features such as compatibility with gypsum and surface roughness.Purpose: The aim of this study is to compare the surface roughness of gypsum with several tissue conditioner impression materials avaliable in the market.Materials and Method: In this experimental study, three tissue conditioners (Acrosoft, viscogel & GC were used. Pars dental gypsum moldano Type III and a polyvinyl siloxane impression were used for the controls. The tissue conditioners powder liquid ratio was mixed according to the manufacturer’s recommendation and immediately poured in a mold with an internal diameter of 18 mm and depth of 2mm. The mold was completely filled. Then, a glass block with the mean roughness of 0.8 µm was placed on its surface for two hours. Then, the 5 samples were immediately placed in 37oC water for 0-24 hrs, 3, 7, and 14 days. After that, the specimens were beaded, boxed and poured with pars dental gypsum type III. The gypsum sample’s surface roughness was measured with profilometer with the length of 2.5 mm and cut-off of 0.8 mm. The results were analyzed using ANOVA and Tukey tests.Results: The results showed that surface roughness of Acrosoft in different storage times did not change significantly and there was no significant difference between Acrosoft and the control group. Viscogels surface roughness was significantly different with all other groups at zero time; with the increase of storage time the surface roughness decreases. The control group showed a significant difference with viscogel at zero time and with GC at 24 hrs and 3 days but it revealed no difference with the other groups. The least surface roughness belonged to GC at zero and 14 days and the highests surface roughness belonged to viscogel at zero time

  15. Dental students and faculty members' attitudes towards care for underserved patients and community service: do community-based dental education and voluntary service-learning matter?

    Science.gov (United States)

    Volvovsky, Mariya; Vodopyanov, Dmitry; Inglehart, Marita R

    2014-08-01

    The objectives of this study were to explore 1) how students across the four years of a dental curriculum differed in attitudes towards underserved patients and community service at the beginning and end of each school year; 2) how these attitudes changed as a function of participating in required vs. voluntary community-based activities; and 3) what attitudes faculty members held about the effects of community service-learning on students. Surveys were distributed to 440 students at one dental school at the beginning and end of the school year. The overall response rate for those surveys was 75 percent, with variations among classes: first year, 94 percent; second year, 92 percent; third year, 69 percent; and fourth year, 43 percent. Survey data were also collected from twenty-two students (out of a possible forty-seven) who participated in voluntary service-learning and from fifty-four faculty members (out of approximately 150). The results showed that, at the beginning of the year, the first-year students' attitudes were more positive than the responses of students in all other cohorts. However, at the end of the year, their attitudes were less positive. Participating in voluntary service-learning improved students' attitudes towards treating underserved patients only in the short run, and experiencing ten weeks of community-based dental education did not improve their attitudes. The faculty respondents' attitudes, however, were quite positive. The decrease in students' positive attitudes towards treating underserved patients and participating in community service should raise questions about why this loss of idealism occurred. PMID:25086145

  16. Effects of the Nd:YAG laser on amalgam dental restorative material: a preliminary study

    Science.gov (United States)

    Cernavin, Igor; Hogan, Sean P.

    1996-09-01

    The Nd:YAG laser has been marketed as an instrument for use on both hard and soft dental tissues. Its potential for use on hard tissues is limited but it may be the instrument of choice for use in certain soft tissue procedures. The aim of this study was to examine the effects of the Nd:YAG laser on amalgam restorations which frequently occur on tooth surfaces adjacent to areas of soft tissue which may be subjected to the laser. The amalgam used was Tytin. The laser firing was controlled by a computer and a constant repetition rate of 40 Hz was used. Energy per pulse was altered as follows, 30 mJ, 40 mJ, 60 mJ, 80 mJ, 120 mJ and 140 mJ. Exposure times of 0.05 sec, 0.125 sec, 0.25 sec, 0.5 sec, 1 sec, 2 sec, 3 sec, 4 sec, and 5 sec were used. The width of defect was measured using a Nikon measurescope with 10x magnification and it was established that the damage threshold lies between 0.125 sec and 0.25 sec for 30 mJ per pulse. The data was analyzed using a one way ANOVA statistical test. There was a significant correlation between the width of the defect and energy per pulse setting as well as exposure time. The findings indicate that amalgam restorations are prone to damage from inadvertent laser exposure and clinicians must take measures to protect such restorations during lasing of soft tissues.

  17. The Relationship between Biofilm and Physical-Chemical Properties of Implant Abutment Materials for Successful Dental Implants

    Directory of Open Access Journals (Sweden)

    Erica Dorigatti de Avila

    2014-05-01

    Full Text Available The aim of this review was to investigate the relationship between biofilm and peri-implant disease, with an emphasis on the types of implant abutment surfaces. Individuals with periodontal disease typically have a large amount of pathogenic microorganisms in the periodontal pocket. If the individuals lose their teeth, these microorganisms remain viable inside the mouth and can directly influence peri-implant microbiota. Metal implants offer a suitable solution, but similarly, these remaining bacteria can adhere on abutment implant surfaces, induce peri-implantitis causing potential destruction of the alveolar bone near to the implant threads and cause the subsequent loss of the implant. Studies have demonstrated differences in biofilm formation on dental materials and these variations can be associated with both physical and chemical characteristics of the surfaces. In the case of partially edentulous patients affected by periodontal disease, the ideal type of implant abutments utilized should be one that adheres the least or negligible amounts of periodontopathogenic bacteria. Therefore, it is of clinically relevance to know how the bacteria behave on different types of surfaces in order to develop new materials and/or new types of treatment surfaces, which will reduce or inhibit adhesion of pathogenic microorganisms, and, thus, restrict the use of the abutments with indication propensity for bacterial adhesion.

  18. 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.

  19. Nine years of DentEd--a global perspective on dental education.

    Science.gov (United States)

    Reynolds, P A; Eaton, K A; Paganelli, C; Shanley, D

    2008-08-23

    This paper describes the three successive and successful DentEd projects, funded by the European Union, that established a productive thematic network which identified common content within the dental curriculum. It then developed an agreed professional profile, with a defined set of competences and a modular curriculum for all new dental graduates based on the European Credit Transfer System and trends in learning and assessment. The three phases took nine years to complete. Phase one investigated all aspects of dental undergraduate education and included over 30 visits to different dental schools by teams of dental educators. Phase two built on this work and included further visits to dental schools. Phase three refined the competency framework that had been developed in phase two and culminated in a global dental conference which finalised position papers on all aspects of dental education. The work and recommendations of the ICT in dental education group are considered in detail in the paper. The projects provided the stimulus for a number of European and international collaborations, including the web-based International Federation of Dental Education and Associations (IFDEA) Knowledge Centre and the International Virtual Dental School (IVIDENT), both of which aim to make increasingly sophisticated ICT-based educational material available worldwide and to promote international understanding. PMID:18724340

  20. Implementation of a Web-Based Patient Simulation Program to Teach Dental Students in Oral Surgery.

    Science.gov (United States)

    Weiner, Carina Kruger; Skålén, Maya; Harju-Jeanty, Dick; Heymann, Robert; Rosén, Annika; Fors, Uno; Lund, Bodil

    2016-02-01

    The aim of this study was to evaluate a web-based simulation of patients (Web-SP) program on learning skills in clinical reasoning and patient evaluation in the oral surgery education of third-year dental students. A secondary aim was to investigate the program's effect on students' learning, knowledge, and attitudes towards virtual patient simulations. Authentic virtual oral surgery patient cases were created at a dental school in Sweden using the Web-SP platform. The Web-SP program was introduced in a two-hour seminar. A 20-minute pre-seminar test (test A) was administered to assess the students' knowledge of oral surgery prior to experiencing the Web-SP program. Ten days after the seminar, another test (test B) was administered to evaluate the increase in oral surgery knowledge as a result of using the program, and an emailed survey of the students was conducted. Of 70 students in the course, 67 (95.7%) agreed to participate in the study and took test A; of these, 59 (88%) took test B. Of the 59 students who took both tests, 28 (42%) completed the survey. The results of the two tests showed a statistically significant increase in knowledge, which was in accordance with the learning goals (pteaching method. In this study, Web-SP was found to be a valuable tool for teaching clinical reasoning and patient evaluation in an undergraduate oral surgery education setting by improving learning outcomes in comparison with traditional teaching alone. PMID:26834130

  1. Detection and quantification of dental plaque based on laser-induced autofluorescence intensity ratio values.

    Science.gov (United States)

    Joseph, Betsy; Prasanth, Chandra Sekhar; Jayanthi, Jayaraj L; Presanthila, Janam; Subhash, Narayanan

    2015-04-01

    The aim of this study was to evaluate the applicability of laser-induced autofluorescence (LIAF) spectroscopy to detect and quantify dental plaque. LIAF spectra were recorded in situ from dental plaque (0–3 grades of plaque index) in 300 patients with 404 nm diode laser excitation. The fluorescence intensity ratio of the emission peaks was calculated from the LIAF spectral data following which their scatter plots were drawn and the area under the receiver operating characteristics were calculated. The LIAF spectrum of clinically invisible grade-1 plaque showed a prominent emission peak at 510 nm with a satellite peak around 630 nm in contrast to grade 0 that has a single peak around 500 nm. The fluorescence intensity ratio (F510/F630) has a decreasing trend with increase in plaque grade and the ratio values show statistically significant differences (psensitivity and specificity of 100% each was achieved for discrimination between grade-0 and grade-1 plaque. The clinical significance of this study is that the diagnostic algorithm developed based on fluorescence spectral intensity ratio (F510/F630) would be useful to precisely identify minute amounts of plaque without the need for disclosing solutions and to convince patients of the need for proper oral hygiene and homecare practices.

  2. The Color Stability of Dental Prosthetic Material%口腔修复材料的颜色稳定性研究

    Institute of Scientific and Technical Information of China (English)

    杨桂梅

    2012-01-01

    目的:研究在唾液、茶、红酒等溶液中口腔修复材料的颜色稳定性.方法:制备树脂、烤瓷、聚合瓷试件各12个,进行稳定性检测,并对其进行对比分析.结果:不同时间、溶液、材料对口腔修复材料的颜色稳定性存在明显差异.结论:三组口腔修复材料中,树脂材料和聚合瓷材料均随时间增加而产生色差增加,并显示出初始色差增加明显的特征.%Objective: To study the total dental prosthetic material in the solution of the saliva, tea, red wine and other color stability. Method: Preparation of resin, porcelain, polymer ceramic specimen 12, stability testing, and comparative analysis. Result: The different time, solution, material for color stability of dental prosthetic material was significantly different. Conclusion: The three groups of dental prosthetic material , resin and polymer ceramic material increase in chromatic aberration increase with time, and shows the characteristics of the initial component increased significantly.

  3. Dental Therapy Assistant: Quality of Restorations Placed and Finished.

    Science.gov (United States)

    Heid, Theodore H.; Bair, Jeffrey H.

    The U.S. Army Dental Corps has implemented a new concept of dental care delivery, formally identified as the Improved Dental Care Delivery System. The concept is based on the conservation of professional manpower resources through the use of dental treatment teams employing expanded duty dental assistants. Dental Therapy Assistant (DTA) is the…

  4. Development of starch-based materials

    NARCIS (Netherlands)

    Habeych Narvaez, E.A.

    2009-01-01

    Starch-based materials show potential as fully degradable plastics. However, the current applicability of these materials is limited due to their poor moisture tolerance and mechanical properties. Starch is therefore frequently blended with other polymers to make the material more suitable for sp

  5. Survey of attitudes, materials and methods employed in endodontic treatment by general dental practitioners in North Jordan

    Directory of Open Access Journals (Sweden)

    Al-Omari Wael M

    2004-09-01

    Full Text Available Abstract Background General dental practitioners provide the majority of endodontic treatment in Jordan. The aim of this study was to gather information on the methods, materials and attitudes employed in root canal treatment by dentists in North Jordan, in order to evaluate and improve the quality of current practice. Methods A questionnaire was posted to all registered general dental practitioners working in private practice in Irbid Governate in North Jordan (n = 181. The questionnaire included information on methods, materials and techniques used in endodontic treatment. Results Reply rate was 72% (n = 131. The results demonstrated that only five dentists used rubber dam occasionally and not routinely. The majority used cotton rolls for isolation solely or in combination with a high volume saliva ejector (n = 116. The most widely used irrigants were sodium hypochlorite and hydrogen peroxide, which were used by 32.9% (n = 43 and 33.6% (n = 44 of the respondents, respectively. Forty eight percent of the respondents (n = 61 used the cold lateral condensation technique for canal obturation, 31.3% (n = 41 used single cone, 9.9% (n = 13 used vertical condensation and 12.2% (n = 16 used paste or cement only for the obturation. The majority used zinc oxide eugenol as a sealer (72.5%. All, but one, respondents used hand instruments for canal preparation and the technique of choice was step back (52.7%. More than 50% (n = 70 of the dentists took one radiograph for determining the working length, whilst 22.9% (n = 30 did not take any radiograph at all. Most practitioners performed treatment in three visits for teeth with two or more root canals, and in two visits for teeth with a single root canal. Conclusions This study indicates that dentists practicing in North Jordan do not comply with international quality standards and do not use recently introduced techniques. Many clinicians never take a radiograph for determining the working length and never

  6. Fracture resistance and failure mode of posterior fixed dental prostheses fabricated with two zirconia CAD/CAM systems

    OpenAIRE

    López Suárez, Carlos; Gonzalo, Esther; Peláez, Jesús; Rodríguez López, María Verónica; Suárez García, M. ª Jesús

    2015-01-01

    Background In recent years there has been an improvement of zirconia ceramic materials to replace posterior missing teeth. To date little in vitro studies has been carried out on the fracture resistance of zirconia veneered posterior fixed dental prostheses. This study investigated the fracture resistance and the failure mode of 3-unit zirconia-based posterior fixed dental prostheses fabricated with two CAD/CAM systems. Material and Methods Twenty posterior fixed dental prostheses were studie...

  7. Materiality in a practice-based approach

    DEFF Research Database (Denmark)

    Svabo, Connie

    2009-01-01

    The paper provides an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Common terms for materiality are 'artifact' and 'object'. The interaction between social and material realities is grasped as several processes: object......-oriented activity, symbolization, embodiment, performance, alignment and mediation. Material artifacts both stabilize and destabilize organizational action. They may ensure coordination, communication, and control, but they may also create disturbance and conflict....

  8. [Determinants of dental services utilization by adults: a population-based study in Florianópolis, Santa Catarina State, Brazil].

    Science.gov (United States)

    Miranda, Camila Dal-Bó Coradini; Peres, Marco Aurélio

    2013-11-01

    This study aimed to estimate the prevalence of dental services utilization by adults and to identify associated socioeconomic, demographic, behavioral, and self-awareness factors. A cross-sectional population-based study was conducted with adults living in the urban area of Florianópolis, Santa Catarina State, Brazil, in 2009. Associations were tested between use of dental services and predisposing, enabling, and needs-based variables. Multivariate analysis was conducted using Poisson regression with estimates of prevalence ratios and was stratified by place of last dental appointment. Prevalence of dental services utilization was 66% (95%CI: 62.9-70.7). Dental visits were 20% more frequent among women and 72% more frequent among individuals with more schooling (the latter in both public and private dental services). Individuals with private dental plans used dental services 13% more than those without. Schooling was the most important variable in predicting utilization. The study's results show the importance of monitoring associated factors in order to promote more equitable use of dental services.

  9. The Prevalence of Bruxism and Correlated Factors in Children Referred to Dental Schools of Tehran, Based on Parents Report

    OpenAIRE

    Bahman Seraj; Mehdi Shahrabi; Sara Ghadimi; Rahil Ahmadi; Jaleh Nikfarjam; Farid Zayeri; Fatemeh Pour-Taghi; Hadi Zare

    2010-01-01

    Objective: Bruxism is defined as the habitual nonfunctional forceful contact between occlusal tooth surfaces. The aim of this study was to determine the prevalence of bruxism and correlated factors in children referred to dental schools of Tehran, based on parents' report.Methods: This cross-sectional descriptive study was conducted on 600 4-12 year-old children with a mean age of 7.4±2.4 years, who were referred to four dental schools in Tehran. After collecting information with questionnair...

  10. Osteoporosis Detection using Important Shape-Based Features of the Porous Trabecular Bone on the Dental X-Ray Images

    Directory of Open Access Journals (Sweden)

    Enny Itje Sela

    2015-09-01

    Full Text Available Osteoporosis screening using dental X-Ray images has been growing an interesting research. Existing methods for osteoporosis screening have been performed using the dental periapical or panoramic in X-Ray images. There was limited research using both the periapical and panoramic due to the expensive cost of obtaining data. This paper presents a combination of the periapical and panoramic images for osteoporosis detection. The images processing was performed to obtain the shape-based features of the porous trabecular bone on both the dental radiograph images. The important features were selected from the extracted features. These selected features were chosen for osteoporosis detection using the decision tree. The quantitative evaluation used confusion matrix. It was found accuracy rate to be 73.33%, sensitivity rate to be 72.23, and specificity rate to be 72.23% for data testing.

  11. A radiological evaluation of marginal bone around dental implants: An in-vivo study

    OpenAIRE

    Nandal, Shikha; Ghalaut, Pankaj; Shekhawat, Himanshu

    2014-01-01

    Context: This article presents an original research conducted at Government Dental College, PGIDS, Rohtak. Aims: (1) To evaluate the marginal bone level changes around dental implants based on the radiological examination. (2) To evaluate the relationship of various parameters, i.e., gender, implant length, implant diameter and location of implants on the amount of bone loss around dental implants. Materials and Methods: An in-vivo study was undertaken to evaluate the crestal bone loss on mes...

  12. Wear resistance and hardness of dental prosthetics materials versus native teeth%齿科修复材料耐磨性及硬度与天然牙齿的比较

    Institute of Scientific and Technical Information of China (English)

    陈霜; 李国强

    2011-01-01

    BACKGROUND: There are frictions between native tooth and dental prosthetics materials. In order to protect the native tooth from wear out and lengthen the in-service life of dental prosthetic restorations simultaneously, it is necessary to understand tribological characteristics between native tooth and dental prosthetics materials. Accordingly, we can select the matching prosthetics materials.OBJECTIVE: To compare wear resistance and hard ness of native teeth and dental prosthetics materials.METHODS: A computer searched of PubMed database (http://www.ncbi.nlm.nih.gov/PubMed) and Wanfang database (http://www.wanfangdata.com.cn) from 2000 to 2010 was performed to retrieve articles about tribological characteristics between native tooth and dental prosthetics materials, with key words of "enamel, dental restorative material, zirconia, wear resistance,hardness" in English and in Chinese. A total of 46 articles were screened out, and 30 ones according to the inclusive criteria were involved for further summary.RESULTS AND CONCLUSION : The dental enamel has excellent tribology performance and wear resistance, but the dentin has poor wear resistance, once the dentin of native teeth exposes in wearing process, the abrasion will speed up. Therefore, it is extremely necessary to chose ideal dental prosthetic restoration materials which have similar wearing characteristic with native teeth. The abradability of dental enamel is fantastically higher than composite resin. The abradability of composite resin itself is not very good, so it wears little to the native tooth. The physical performance of new type composite resin is raising up unceasingly, and the abradability of some composite resins is approaching to the enamel. The specimens made from Bayer tooth,thermosetting plastic, copper base alloy, titanium and its alloy are thus idea prosthetic materials. Zirconium ceramics belong to biological inertia ceramics, and have good biocompatibility, strong intensity and tenacity

  13. The Dental Trauma Internet Calculator

    DEFF Research Database (Denmark)

    Gerds, Thomas Alexander; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg;

    2012-01-01

    Background/Aim Prediction tools are increasingly used to inform patients about the future dental health outcome. Advanced statistical methods are required to arrive at unbiased predictions based on follow-up studies. Material and Methods The Internet risk calculator at the Dental Trauma Guide......) in the period between 1972 and 1991. Subgroup analyses and estimates of event probabilities were based on the Kaplan-Meier and the Aalen-Johansen method. Results The Internet risk calculator shows individualized prognoses for the short and long-term healing outcome of traumatized teeth with the following...... were based on the tooth’s root development stage and other risk factors at the time of the injury. Conclusions This article explains the data base, the functionality and the statistical approach of the Internet risk calculator....

  14. Depth of cure of dental resin composites: ISO 4049 depth and microhardness of types of materials and shades.

    Science.gov (United States)

    Moore, B Keith; Platt, Jeffrey A; Borges, Gilberto; Chu, Tien-Min Gabriel; Katsilieri, Iphigenia

    2008-01-01

    The optimal degree of curing throughout the bulk of a visible light-activated dental resin composite is acknowledged to be important to the clinical success of a resin composite restoration. Unfortunately, the dentist has no means of monitoring the cure of the resin surfaces not directly exposed to the curing light. Techniques, such as the layered buildup of restorations in 2 mm increments with longer activation times than 20 seconds, have been suggested. This study investigated the depth of cure (DOC) of a commercial resin composite in three types: flowable, hybrid and packable and in three shades: B1, A3 and D3 after 20 second activation with a quartz halogen light (620 mW/cm2). Depth of cure was measured by scraping the uncured material and by using a Knoop Hardness profile, starting from the surface exposed to the light. Using a minimum Knoop Hardness ratio of 0.8 bottom/top only, the flowable in shade B1 achieved a 2 mm DOC. Using the less restrictive scraping test, only the B1 shade of flowable and hybrid significantly exceeded a 2 mm DOC. Knoop Hardness at the DOC obtained by scraping ranged from 55%-70% of the top surface hardness. These data suggest that a 2 mm buildup layering technique may not result in adequate curing of the bottom layer for such a wide range of materials and that manufacturers need to provide quantitative information about DOC at specific activation times and light intensities for their entire range of resin materials and shades so that the dentist can devise a placement technique that will ensure adequate cure of the bulk of a restoration.

  15. Dental implant materials. I. Some effects of preparative procedures on surface topography.

    Science.gov (United States)

    Smith, D C; Pilliar, R M; Chernecky, R

    1991-09-01

    The effect of different treatments for preparing implant materials was examined by scanning electron microscopy and by contact angle measurements. The materials examined were Ti6A14V alloy, Co-Cr-Mo alloy, A12O3, and synthetic hydroxyapatite. Samples were prepared with solid or porous surfaces of these materials. These were detergent-cleaned and then either autoclaved (steam sterilization), radiation-sterilized, nitric acid-etched, or plasma-cleaned. The results of wettability studies indicated marked changes in surface energy corresponding to the different preparation methods, and differences in surface morphology were also observed. These differences could have significant consequences on in vivo implant behaviour as mediated by tissue-implant interactions. PMID:1663951

  16. LDEF materials special investigation group's data bases

    Science.gov (United States)

    Strickland, John W.; Funk, Joan G.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) was composed of and contained a wide array of materials, representing the largest collection of materials flown for space exposure and returned for ground-based analyses to date. The results and implications of the data from these materials are the foundation on which future space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been tasked with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the space user community in an easily accessed, user-friendly form. The format and content of the data bases developed or being developed to accomplish this task are discussed. The hardware and software requirements for each of the three data bases are discussed along with current availability of the data bases.

  17. ISEF Based Identification of RCT/Filling in Dental Caries of Decayed Tooth

    OpenAIRE

    A. J. Solanki; K. R. Jain; N. P. Desai

    2013-01-01

    Dental image processing is one of the emerging fields in case of human identification in forensic sciences. Dental x-rays have been quiet effective for the diagnosis and detection of problems in tooth. This paper presents an add on approach in the same area of medical biometrics to detect and diagnose the dental caries in case of decayed tooth. The enhancement and segmentation of digital dental x-ray image is done by using Infinite Symmetric Exponential filter (Shen Castan Algorithm). The aim...

  18. EPR-based material modelling of soils

    Science.gov (United States)

    Faramarzi, Asaad; Alani, Amir M.

    2013-04-01

    In the past few decades, as a result of the rapid developments in computational software and hardware, alternative computer aided pattern recognition approaches have been introduced to modelling many engineering problems, including constitutive modelling of materials. The main idea behind pattern recognition systems is that they learn adaptively from experience and extract various discriminants, each appropriate for its purpose. In this work an approach is presented for developing material models for soils based on evolutionary polynomial regression (EPR). EPR is a recently developed hybrid data mining technique that searches for structured mathematical equations (representing the behaviour of a system) using genetic algorithm and the least squares method. Stress-strain data from triaxial tests are used to train and develop EPR-based material models for soil. The developed models are compared with some of the well-known conventional material models and it is shown that EPR-based models can provide a better prediction for the behaviour of soils. The main benefits of using EPR-based material models are that it provides a unified approach to constitutive modelling of all materials (i.e., all aspects of material behaviour can be implemented within a unified environment of an EPR model); it does not require any arbitrary choice of constitutive (mathematical) models. In EPR-based material models there are no material parameters to be identified. As the model is trained directly from experimental data therefore, EPR-based material models are the shortest route from experimental research (data) to numerical modelling. Another advantage of EPR-based constitutive model is that as more experimental data become available, the quality of the EPR prediction can be improved by learning from the additional data, and therefore, the EPR model can become more effective and robust. The developed EPR-based material models can be incorporated in finite element (FE) analysis.

  19. Factors for Increasing Adoption of E-Courses Among Dental and Dental Hygiene Faculty Members

    OpenAIRE

    DeBate, Rita D.; Cragun, Deborah; Severson, Herbert H; Shaw, Tracy; Christiansen, Steve; Koerber, Anne; Tomar, Scott; Brown, Kelli McCormack; Tedesco, Lisa A.; Hendricson, William

    2011-01-01

    The incorporation of web-based learning into the dental curriculum has been consistently recommended in the literature on reform in dental education. There has been growing support for web-based learning in dental and dental hygiene education as demonstrated by deans’ identifying this as a planned curricular innovation. The purpose of our study was to explore characteristics of e-courses that may serve to increase adoption among dental and dental hygiene faculty members. Eight ninety-minute f...

  20. A Therapeutic Strategy for Spinal Cord Defect: Human Dental Follicle Cells Combined with Aligned PCL/PLGA Electrospun Material

    Directory of Open Access Journals (Sweden)

    Xinghan Li

    2015-01-01

    Full Text Available Stem cell implantation has been utilized for the repair of spinal cord injury; however, it shows unsatisfactory performance in repairing large scale lesion of an organ. We hypothesized that dental follicle cells (DFCs, which possess multipotential capability, could reconstruct spinal cord defect (SCD in combination with biomaterials. In the present study, mesenchymal and neurogenic lineage characteristics of human DFCs (hDFCs were identified. Aligned electrospun PCL/PLGA material (AEM was fabricated and it would not lead to cytotoxic reaction; furthermore, hDFCs could stretch along the oriented fibers and proliferate efficiently on AEM. Subsequently, hDFCs seeded AEM was transplanted to restore the defect in rat spinal cord. Functional observation was performed but results showed no statistical significance. The following histologic analyses proved that AEM allowed nerve fibers to pass through, and implanted hDFCs could express oligodendrogenic lineage maker Olig2 in vivo which was able to contribute to remyelination. Therefore, we concluded that hDFCs can be a candidate resource in neural regeneration. Aligned electrospun fibers can support spinal cord structure and induce cell/tissue polarity. This strategy can be considered as alternative proposals for the SCD regeneration studies.

  1. New Cork-Based Materials and Applications

    Directory of Open Access Journals (Sweden)

    Luís Gil

    2015-02-01

    Full Text Available This review work is an update of a previous work reporting the new cork based materials and new applications of cork based materials. Cork is a material which has been used for multiple applications. The most known uses of cork are in stoppers (natural and agglomerated cork for alcoholic beverages, classic floor covering with composite cork tiles (made by the binding of cork particles with different binders, and thermal/acoustic/vibration insulation with expanded corkboard in buildings and some other industrial fields. Many recent developments have been made leading to new cork based materials. Most of these newly developed cork materials are not yet on the market, but they represent new possibilities for engineers, architects, designers and other professionals which must be known and considered, potentially leading to their industrialization. This paper is a review covering the last five years of innovative cork materials and applications also mentioning previous work not reported before.

  2. [Dissertations 25 years after date 44. Behaviour at high temperatures of palladium based dental alloys].

    Science.gov (United States)

    van der Zel, J M

    2016-02-01

    In the Netherlands in the 1980s palladium based dental alloys were often used in substructures of metal-ceramic restorations. However, after their introduction to the market some unexplained problems came to light: porosity on the metal-ceramic interface, frequent failure of solder joints, margin lift and distortion of bigger constructions. Later, palladium allergies could be added to the list. A 1989 dissertation investigated these problems and underlying causes and came up with answers and solutions. Recent problems like the breakage and chipping of porcelain on zirconia cores shows again that industry is sometimes unaware of adjustment problems at the moment that a new product is introduced to the market. PMID:26878716

  3. Whole Language-Based English Reading Materials

    Directory of Open Access Journals (Sweden)

    Dian Erlina

    2016-05-01

    Full Text Available This Research and Development (R&D aims at developing English reading materials for undergraduate EFL students of Universitas Islam Negeri (UIN Raden Fatah Palembang, Indonesia. Research data were obtained through questionnaires, tests, and documents. The results of the research show that the existing materials are not relevant to the students’ need, so there is a need for developing new materials based on whole language principles. In general, the new developed materials are considered reliable by the experts, students, and lecturers. The materials are also effective in improving students’ reading achievement. The final product of the materials consists of a course book entitled Whole Language Reading (WLR and a teacher’s manual. WLR provides rich input of reading strategies, variety of topics, concepts, texts, activities, tasks, and evaluations. Using this book makes reading more holistic and meaningful as it provides integration across language skills and subject areas.Keywords: materials development, reading materials, whole language

  4. Dental students--dental advocates.

    Science.gov (United States)

    Bensch, Brittany

    2010-01-01

    Student advocacy and involvement in the political process is built into the structure of the American Student Dental Association (ASDA), especially in its Legislative Grassroots Network and an internal communication network among students to ensure political awareness. Students are concerned with such issues as a universally accepted, non-patient-based licensure process, mid-level providers, loan availability and tax deductibility, financial support for schools, and service early in one's professional career (giving forward rather than giving back). Through collaboration with the American Dental Education Association and with many state associations, students participate in lobbying, awareness campaigns, and behind the scenes as legislative aids. Although students share the same love for the profession that animates established practitioners, they are perceived by legislators as being different. Students are involved in the legislative process because it represents their future.

  5. Dental students--dental advocates.

    Science.gov (United States)

    Bensch, Brittany

    2010-01-01

    Student advocacy and involvement in the political process is built into the structure of the American Student Dental Association (ASDA), especially in its Legislative Grassroots Network and an internal communication network among students to ensure political awareness. Students are concerned with such issues as a universally accepted, non-patient-based licensure process, mid-level providers, loan availability and tax deductibility, financial support for schools, and service early in one's professional career (giving forward rather than giving back). Through collaboration with the American Dental Education Association and with many state associations, students participate in lobbying, awareness campaigns, and behind the scenes as legislative aids. Although students share the same love for the profession that animates established practitioners, they are perceived by legislators as being different. Students are involved in the legislative process because it represents their future. PMID:21314046

  6. Bisphenol A in dental sealants and its estrogen like effect

    Directory of Open Access Journals (Sweden)

    Manu Rathee

    2012-01-01

    Full Text Available Bisphenol A or BPA-based epoxy resins are widely used in the manufacture of commercial products, including dental resins, polycarbonate plastics, and the inner coating of food cans. BPA is a precursor to the resin monomer Bis-GMA. During the manufacturing process of Bis-GMA dental sealants, Bisphenol A (BPA might be present as an impurity or as a degradation product of Bis-DMA through esterases present in saliva. Leaching of these monomers from resins can occur during the initial setting period and in conjunction with fluid sorption and desorption over time and this chemical leach from dental sealants may be bioactive. Researchers found an estrogenic effect with BPA, Bis-DMA, and Bis-GMA because BPA lacks structural specificity as a natural ligand to the estrogen receptor. It generated considerable concern regarding the safety of dental resin materials. This review focuses on the BPA in dental sealants and its estrogen-like effect.

  7. In vitro study of biofilm formation and effectiveness of antimicrobial treatment on various dental material surfaces.

    Science.gov (United States)

    Li, L; Finnegan, M B; Özkan, S; Kim, Y; Lillehoj, P B; Ho, C-M; Lux, R; Mito, R; Loewy, Z; Shi, W

    2010-12-01

    Elevated proportions of Candida albicans in biofilms formed on dentures are associated with stomatitis whereas Streptococcus mutans accumulation on restorative materials can cause secondary caries. Candida albicans, S. mutans, saliva-derived and C. albicans/saliva-derived mixed biofilms were grown on different materials including acrylic denture, porcelain, hydroxyapatite (HA), and polystyrene. The resulting biomass was analysed by three-dimensional image quantification and assessment of colony-forming units. The efficacy of biofilm treatment with a dissolved denture cleansing tablet (Polident(®)) was also evaluated by colony counting. Biofilms formed on HA exhibited the most striking differences in biomass accumulation: biofilms comprising salivary bacteria accrued the highest total biomass whereas C. albicans biofilm formation was greatly reduced on the HA surface compared with other materials, including the acrylic denture surface. These results substantiate clinical findings that acrylic dentures can comprise a reservoir for C. albicans, which renders patients more susceptible to C. albicans infections and stomatitis. Additionally, treatment efficacy of the same type of biofilms varied significantly depending on the surface. Although single-species biofilms formed on polystyrene surfaces exhibited the highest susceptibility to the treatment, the most surviving cells were recovered from HA surfaces for all types of biofilms tested. This study demonstrates that the nature of a surface influences biofilm characteristics including biomass accumulation and susceptibility to antimicrobial treatments. Such treatments should therefore be evaluated on the surfaces colonized by the target pathogen(s).

  8. The assessment of surface roughness and microleakage of eroded tooth-colored dental restorative materials

    Directory of Open Access Journals (Sweden)

    Thulfiqar Ali Hussein

    2014-01-01

    Full Text Available Objectives: To investigate the effect of acidic solution on surface roughness and microleakage of tooth-colored restorative materials. Materials and Methods: A 160 box-shaped cavities were prepared on the buccal surfaces of 160 human molars, and assigned to four groups: Group A restored with Ketac™ Molar Easymix, Group B with Fuji II™ LC, Group C with Ketac™N100, and Group D with Filtek™ Z250, and subdivided into study and control groups (n = 20. Study groups were immersed in lemon juice (pH = 2.79 for 24 h, whilst controlgroups in deionized distilled water. All samples were immersed in 2% methylene blue dye, sectioned into two equal halves for surface roughness, and microleakage tests. Data were analyzed using Mann-Whitney and Kruskal-Wallis tests at P < 0.05. Results: There was a significant difference in surface roughness of Ketac™ Molar, Fuji II™LC, and Ketac™N100. No significant difference was found in microleakage of Ketac™ Molar and Fuji II™LC; however, there were significant differences in the gingival margin of Ketac™N100, and the occlusal margin of Filtek™Z250. Conclusions: All glass ionomer cements were eroded after exposure to the acidic drink. Filtek™ Z250 and Ketac™ Molar Easymix showed more microleakage. All materials showed more microleakage at the gingival margins.

  9. Marketing applications for dental clinic

    OpenAIRE

    Čevela, Josef

    2010-01-01

    The essay deals with the marketing strategy of the dental clinic, more specifically the dental clinic Sorriso DENTAL s.r.o. It also analyses and describes the marketing mix. Based on these things, it offers certain recommendations for the clinic and its marketing conception.

  10. Dental Hygiene Realpolitik Affecting Education.

    Science.gov (United States)

    Bader, James D.

    1991-01-01

    Current conditions in dental hygiene influencing professional education are discussed. Workplace/practice issues include dental hygiene care as a component of dental practice, content, effects, and quality of care, hygienist supply and demand, and job satisfaction. Professional issues include the knowledge base, definitions of practice, and…

  11. Dental operatory design and equipment.

    Science.gov (United States)

    Floyd, M

    1993-08-01

    Improving and expanding the dental services of a practice can involve purchasing new equipment and even modifying or expanding the physical plant. Operatory design is important to the efficiency with which dental procedures can be performed. Equipment purchases to outfit the dental operatory should be made based on the specific needs and functions of a practice.

  12. METHACRYLATE AND ACRYLATE ALLERGY IN DENTAL STUDENTS.

    Directory of Open Access Journals (Sweden)

    Maya Lyapina

    2013-09-01

    Full Text Available A multitude of acrylic monomers is used in dentistry, and when dental personnel, patients or students of dental medicine become sensitized, it is of great importance to identify the dental ;acrylic preparations to which the sensitized individual can be exposed. Numerous studies confirm high incidence of sensitization to (meth acrylates in dentatal professionals, as well as in patients undergoing dental treatment and exposed to resin-based materials. Quite a few studies are available aiming to evaluate the incidence of sensitization in students of dental medicineThe purpose of the study is to evaluate the incidence of contact sensitization to some (meth acrylates in students of dental medicine at the time of their education, in dental professionals (dentists, nurses and attendants and in patients, the manifestation of co-reactivity.A total of 139 participants were included in the study, divided into four groups: occupationally exposed to (methacrylates and acrylic monomers dental professionals, 3-4 year-of-education students of dental medicine, 6th year–of-education students of dental medicine and patients with suspected or established sensitization to acrylates, without occupational exposure. All of them were patch-tested with methyl methacrylate (MMA, triethyleneglycol dimethacrylate (TREGDMA, ethyleneglycol dimethacrylate (EGDMA, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy phenyl]propane (bis-GMA, 2-hydroxyethyl methacrylate (2-HEMA, and tetrahidrofurfuril metacrylate. The overall sensitization rates to methacrylates in the studied population are comparative high – from 25.9% for MMA to 31.7% for TREGDMA. Significantly higher incidence of sensitization in the group of 3-4 course students compared to the one in the group of dental professionals for MMA and TREGDMA was observed. Highest was the incidence of sensitization to ethyleneglycol dimethacrylate, BIS-GMA, 2-HEMA and tetrahydrofurfuryl methacrylate in the group of patients, with

  13. Consensus statement by hospital based dentists providing dental treatment for patients with inherited bleeding disorders

    NARCIS (Netherlands)

    Hewson, I. D.; Daly, J.; Hallett, K. B.; Liberali, S. A.; Scott, C. L. M.; Spaile, G.; Widmer, R.; Winters, J.

    2011-01-01

    Avoidance of dental care and neglect of oral health may occur in patients with inherited bleeding disorders because of concerns about perioperative and postoperative bleeding, but this is likely to result in the need for crisis care, and more complex and high-risk procedures. Most routine dental car

  14. A contrast correction method for dental images based on histogram registration

    OpenAIRE

    Economopoulos, TL; Asvestas, PA; Matsopoulos, GK; Gröndahl, K; Gröndahl, H-G

    2010-01-01

    Contrast correction is often required in digital subtraction radiography when comparing medical data acquired over different time periods owing to dissimilarities in the acquisition process. This paper focuses on dental radiographs and introduces a novel approach for correcting the contrast in dental image pairs.

  15. ABSORBENT MATERIALS BASED ON KRAFT PULP: PREPARATION AND MATERIAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Fredrik Wernersson Brodin,

    2012-02-01

    Full Text Available Today, petroleum-based superabsorbents are widely used, but interest in renewable alternatives is on the rise. This study presents two wood-based absorbent materials suitable for various absorption applications as an alternative to petroleum-based products. Never-dried bleached kraft pulp was treated with TEMPO-oxidation, and new carboxylate and aldehyde groups were introduced. It was found that the aldehyde groups contributed to the wet integrity of the absorbent materials, possibly by the formation of hemiacetal bonds. After oxidation, the pulp fibers were gradually disintegrated, and size analysis showed that the disintegration rate was enhanced by an increase in the charge of the oxidant. Freeze drying produced a porous foam with a large surface area that enabled a rapid absorption rate as well as a reasonably high absorption capacity even for absorption under load. Air drying formed a compact film with a slow absorption rate but with a high final capacity for absorption.

  16. Efficacy of inter-dental mechanical plaque control in managing gingivitis - a meta-review

    NARCIS (Netherlands)

    S.A. Sälzer; D.E. Slot; F.A. van der Weijden; C.E. Dörfer

    2015-01-01

    Focused question What is the effect of mechanical inter-dental plaque removal in addition to toothbrushing, on managing gingivitis using various formats of inter-dental self-care in adults based on evidence gathered from existing systematic reviews? Material & Methods Three Internet sources were sea

  17. Polymeric vs hydroxyapatite-based scaffolds on dental pulp stem cell proliferation and differentiation

    Institute of Scientific and Technical Information of China (English)

    Arash; Khojasteh; Saeed; Reza; Motamedian; Maryam; Rezai; Rad; Mehrnoosh; Hasan; Shahriari; Nasser; Nadjmi

    2015-01-01

    AIM: To evaluate adhesion, proliferation and differentiation of human dental pulp stem cells(h DPSCs) on four commercially available scaffold biomaterials. METHODS: hD PSCs were isolated from human dental pulp tissues of extracted wisdom teeth and established in stem cell growth medium. h DPSCs at passage 3-5 were seeded on four commercially available scaffold biomaterials, SureO ss(Allograft), Cerabone(Xenograft), PLLA(Synthetic), and OSTEON Ⅱ Collagen(Composite), for 7 and 14 d in osteogenic medium. Cell adhesion and morphology to the scaffolds were evaluated by scanning electron microscopy(SEM). Cell proliferation and differentiation into osteogenic lineage were evaluated using DNA counting and alkaline phosphatase(ALP) activity assay, respectively. RESULTS: All scaffold biomaterials except Sure Oss(Allograft) supported h DPSC adhesion, proliferation and differentiation. hD PSCs seeded on PLLA(Synthetic) scaffold showed the highest cell proliferation and attachment as indicated with both SEM and DNA counting assay. Evaluating the osteogenic differentiation capability of hD PSCs on different scaffold biomaterials with ALP activity assay showed high level of ALP activity on cells cultured on PLLA(Synthetic) and OSTEON ⅡCollagen(Composite) scaffolds. SEM micrographs also showed that in the presence of Cerabone(Xenograft) and OSTEON Ⅱ Collagen(Composite) scaffolds, the h DPSCs demonstrated the fibroblastic phenotype with several cytoplasmic extension, while the cells on PLLA scaffold showed the osteoblastic-like morphology, round-like shape. CONCLUSION: PLLA scaffold supports adhesion, proliferation and osteogenic differentiation of hD PSCs. Hence, it may be useful in combination with hD PSCs for cell-based reconstructive therapy.

  18. Antibiotic prescribing for dental conditions: a community-based study in southern Italy.

    Science.gov (United States)

    Mazzaglia, G; Arcoraci, V; Blandino, G; Miragliotta, G; Schito, A M; Pasquantonio, G; Nicoletti, G; Caputi, A P

    2002-02-01

    The aim of this study was to investigate for which conditions antibiotics are being used in community dental practice, and which clinical features represent the most common reason for an antibacterial approach to the treatment of dental conditions. The study was carried out from November 1998 to June 1999. Dentists were selected according to the different areas of southern Italy, from a list provided by the Italian Society of Dentists. Out of 87 selected dentists, 33 agreed to participate and filled in 1615 questionnaires for each therapeutic intervention ending with antibiotic treatment. Analysis of data indicated that alveolar-gingival abscesses were the most commonly treated infection, accounting for 23.6% of total treatments, followed by acute periodontitis (20.6%) and disodontiasis of the 3rd molar (18.5%). Parenteral antibiotics were chosen in 7.8% of cases. Penicillins were the most commonly used group, 40.1% of total treatments, followed by macrolides (30.2%) and cephalosporins (13.4%). Moreover, penicillins were widely used for post-surgery therapy (52.1%) and disodontiasis of the 3rd molar (50.8%), while macrolides were the most commonly used group for gingivitis (44.1%) and parodontal diseases (55.0%). The choice of parenteral antibiotics was related to severe general symptoms (odds ratios [OR], 4.4; 95% CI: 2.2-9.0), pain (OR, 2.7; 95% CI: 1.2-6.1) and lymphonodal involvement (OR, 6.4; 95% CI: 2.7-15.1). In conclusion, our study demonstrates that antibiotic treatment is often based on the eradication of as many microorganisms as possible, and on the clinical assessment of the patients, rather than on any knowledge of the pathogens involved. PMID:11892902

  19. Development of starch-based materials

    OpenAIRE

    Habeych Narvaez, E.A.

    2009-01-01

    Starch-based materials show potential as fully degradable plastics. However, the current applicability of these materials is limited due to their poor moisture tolerance and mechanical properties. Starch is therefore frequently blended with other polymers to make the material more suitable for special or severe circumstances. By varying the components of the blend and the process conditions, the morphology and hence the properties can be controlled. A clear understanding over the structure fo...

  20. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  1. Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Fabiola Galbiatti de; Fucio, Suzana Beatriz Portugal de; Correr-Sobrinho, Lourenco [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Dental Materials; Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Puppin-Rontani, Regina Maria [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Pedriatric Dentistry], e-mail: rmpuppin@fop.unicamp.br

    2009-07-01

    This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm{sup 2} area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 deg C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials. (author)

  2. Materiality in a Practice-Based Approach

    Science.gov (United States)

    Svabo, Connie

    2009-01-01

    Purpose: The paper aims to provide an overview of the vocabulary for materiality which is used by practice-based approaches to organizational knowing. Design/methodology/approach: The overview is theoretically generated and is based on the anthology Knowing in Organizations: A Practice-based Approach edited by Nicolini, Gherardi and Yanow. The…

  3. Dental practice network of U.S. dental schools.

    Science.gov (United States)

    Fisher, Monica A; Beeson, Dennis C; Hans, Mark G

    2009-12-01

    As dental schools incorporate training in evidence-based dentistry (EBD) into their curricula, students must learn how to critically evaluate systematic reviews and meta-analyses. It is important that dental education in the United States support the American Dental Association's position statement on EBD, which defines "best evidence" as data obtained from all study designs. Given that much evidence is missing when EBD is derived from Cochrane Systematic Reviews' randomized clinical trials, we propose the creation of a dental practice network of U.S. dental schools. We developed an electronic clinical dentistry research database for EBD using Epi-Info (available at www.cdc.gov/epiinfo/downloads.htm). As a free, public use software, Epi-Info provides the foundation for the development of clinical research databases that can increase the research capacity through multisite studies designed to generate outcomes data on the effectiveness of dental treatment. The creation of a dental practice network of dental schools with their large number of patients would expand the research capacity for EBD practice and advance the EBD science regarding the effectiveness of dental treatment. The next step is to link clinical dental researchers/educators at multiple dental schools through a collaborative clinical research network, so that the findings can be applied to the EBD component of problem-based learning curricula of dental education. PMID:20007494

  4. Material Recognition for Content Based Image Retrieval

    NARCIS (Netherlands)

    J.M. Geusebroek

    2002-01-01

    One of the open problems in content-based Image Retrieval is the recognition of material present in an image. Knowledge about the set of materials present gives important semantic information about the scene under consideration. For example, detecting sand, sky, and water certainly classifies the im

  5. INTELLIGENT MATERIALS BASED ON CERAMIC COMPOSITES

    OpenAIRE

    Maximov, Y.; Merzlikin, V.; Sidorov, O.; Suttugin, V.

    2010-01-01

    The paper examines the possibility to design intellectual materials based on film composites. Ferroelectric composites are offered to use as the film composites. The authors discuss ferroelectric composites of different structures. Sensors and intellectual materials on the basis of the obtained composites are considered.

  6. Effect of artificial saliva contamination on adhesion of dental restorative materials.

    Science.gov (United States)

    Shimazu, Kisaki; Karibe, Hiroyuki; Ogata, Kiyokazu

    2014-01-01

    The purpose of this study was to evaluate the effects of artificial saliva contamination on three restorative materials, namely, a glass ionomer cement (GIC), a resin-modified GIC (RMGIC), and a composite resin (CR), for which two different etching adhesive systems were used. Thus, three surface conditions were created on bovine teeth using artificial saliva: control, mild saliva contamination, and severe saliva contamination. The dentin bond strength for CR was significantly lower after artificial saliva contamination. There were, however, no significant differences among the three surface conditions in terms of the dentin and enamel bond strengths of GIC and RMGIC. Moreover, CR exhibited significantly greater microleakage after artificial saliva contamination, whereas no significant differences were found in GIC and RMGIC. The results showed that artificial saliva contamination did not affect the shear bond strengths of GIC and RMGIC or their degrees of microleakage.

  7. Graphene-based Composite Materials

    Science.gov (United States)

    Rafiee, Mohammad Ali

    We investigated the mechanical properties, such as fracture toughness (KIc), fracture energy (GIc), ultimate tensile strength (UTS), Young¡¦s modulus (E), and fatigue crack propagation rate (FCPR) of epoxy-matrix composites with different weight fractions of carbon-based fillers, including graphene platelets (GPL), graphene nanoribbons (GNR), single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), and fullerenes (C60). Only ˜0.125 wt.% GPL was found to increase the KIc of the pure epoxy by ˜65% and the GIc by ˜115%. To get similar improvement, CNT and nanoparticle epoxy composites required one to two orders of magnitude greater weight fraction of nanofillers. Moreover, ˜0.125% wt.% GPL also decreased the fatigue crack propagation rate in the epoxy by ˜30-fold. The E value of 0.1 wt.% GPL/epoxy nanocomposite was ˜31% larger than the pure epoxy while there was only an increase of ˜3% for the SWNT composites. The UTS of the pristine epoxy was improved by ˜40% with GPLs in comparison with ˜14% enhancement for the MWNTs. The KIc of the GPL nanocomposite enhanced by ˜53% over the pristine epoxy compared to a ˜20% increase for the MWNT-reinforced composites. The results of the FCPR tests for the GPL nanocomposites showed a different trend. While the CNT nanocomposites were not effective enough to suppress the crack growth at high values of the stress intensity factor (DeltaK), the reverse behavior is observed for the GPL nanocomposites. The advantage of the GPLs over CNTs in terms of mechanical properties enhancement is due to their enormous specific surface area, enhanced adhesion at filler/epoxy interface (because of the wrinkled surfaces of GPLs), as well as the planar structure of the GPLs. We also show that unzipping of MWNTs into graphene nanoribbons (GNRs) enhances the load transfer effectiveness in epoxy nanocomposites. For instance, at ˜0.3 wt.% of fillers, the Young's modulus (E) of the epoxy nanocomposite with GNRs increased

  8. THE EFFECT OF BEYOND FLUORIDE-REMOVING MATERIAL ON BLEACHING DENTAL FLUOROSIS%Beyond祛氟剂治疗氟斑牙的效果观察

    Institute of Scientific and Technical Information of China (English)

    王孟博; 邓婧

    2008-01-01

    目的 观察Beyond祛氟剂治疗氟斑牙的临床疗效.方法 将20例着色型氟斑牙病人的左、右侧氟斑牙分别作为该研究的实验组和对照组,实验组用Beyond祛氟剂漂白治疗,对照组采用Beyond祛氟剂联合Beyond冷光美白治疗.用Vita比色板进行美白治疗前后颜色的对比.结果 实验组与对照组的脱色显效率有显著性差异(χ2=4.556,P0.05).结论 Beyond祛氟剂对治疗着色型氟斑牙有较好的美白效果,并且无明显副作用.Beyond祛氟剂联合冷光美白治疗的疗效更显著.%Objective To evaluate the clinical effect of fluoride-removing material on bleaching dental fluorosis. MethodsThe left teeth of 20 patients treated with fluoride-removing material served as experimental group, and the right teeth of the same patients treated with fluoride-removing material combined with Beyond cold light-bleaching technique as controls. The changes of tooth color were evaluated by VITA shade guide matching after treatment. Results The effective rate of experimental group was higher than that of the controls (χ2= 4.556,P0.05). Conclusion Beyond fluoride-removing material is proved to be effective and safe for bleaching discolored dental fluorosis. A combination of Beyond fluoride-removing material and Beyond cold light-bleaching technique is better than using Beyond fluoride-removing material alone for bleaching dental fluorosis.

  9. Self-medication practices among dental, midwifery and nursing students

    OpenAIRE

    Osarobo Ehigiator; Azodo, Clement C; Ehizele, Adebola O.; Ezeja, Ejike B; Laura Ehigiator; Ikechukwu U Madukwe

    2013-01-01

    Objective: To determine the pattern of self-medication among dental, midwifery and nursing students and to evaluate the factors associated with self-medication. Materials and Methods: A questionnaire-based cross-sectional of dental, nursing and midwifery students undergoing clinical training in University of Benin Teaching Hospital, Nigeria was conducted in 2010. The elicited data include demography, use of drug without doctor′s prescription, type of drug used (pain relievers, antibiotics, an...

  10. Dental Therapy Assistant: Effect on Team Productivity.

    Science.gov (United States)

    Heid, Theodore H.

    The U.S. Army Dental Corps has implemented a formal program based on the concept that dental care can be more efficiently and effectively provided with treatment teams composed of one dental officer, two dental therapy assistants (DTAs), one basic assistant, and the shared support of other auxiliary personnel. Such a team will use three dental…

  11. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns...

  12. ITER blanket, shield and material data base

    International Nuclear Information System (INIS)

    As part of the summary of the Conceptual Design Activities (CDA) for the International Thermonuclear Experimental Reactor (ITER), this document describes the ITER blanket, shield, and material data base. Part A, ''ITER Blanket and Shield Conceptual Design'', discusses the need for ITER of a tritium breeding blanket to supply most of the tritium for the fuel cycle of the device. Blanket and shield combined must be designed to operate at a neutron wall loading of 1MW/m2, and to provide adequate shielding of the magnets to meet the neutron energy fluence goal of 3MWa/m2 at the first wall. After a summary of the conceptual design, the following topics are elaborated upon: (1) function, design requirement, and critical issues; (2) material selection; (3) blanket and shield segmentation; (4) blanket design description; (5) design analysis; (6) shield; (7) radiation streaming analysis; and (8) a summary of benchmark calculations. Part B, ''ITER Materials Evaluation and Data Base'', treats the compilation and assessment of the available materials data base used for the selection of the appropriate materials for all major components of ITER, including (i) structural materials for the first wall, (ii) Tritium breeding materials for the blanket, (iii) plasma facing materials for the divertor and first wall armor, and (4) electric insulators for use in the blanket and divertor. Refs, figs and tabs

  13. Spatially-oriented EMR for Dental Surgery

    OpenAIRE

    Wu, Min; Koenig, Lisa; Lynch, John; Wirtz, Thomas

    2006-01-01

    As digital dental images become widely available, a new Electronic MR system (EMR) will be critical for the success of applying new technology to dental care. This project is designed an image-based and spatially-oriented EMR for dental surgery. A new panoramic image-based annotation model will be developed, which will complement dental charting precisely locating specific spatial findings for each patient. A spatially-oriented, multilayered data model for dental EMR will be developed using G...

  14. The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy

    Science.gov (United States)

    Lin, Mu-Han; Li, Jinsheng; Price, Robert A., Jr.; Wang, Lu; Lee, Chung-Chi; Ma, C.-M.

    2013-02-01

    This work aims to investigate the dosimetric impact of dental implants on volumetric modulated arc therapy (VMAT) for head-and-neck patients and to evaluate the effectiveness of using the material's electron-density ratio for the correction. An in-house Monte Carlo (MC) code was utilized for the dose calculation to account for the scattering and attenuation caused by the high-Z implant material. Three different dental implant materials were studied in this work: titanium, Degubond®4 and gold. The dose perturbations caused by the dental implant materials were first investigated in a water phantom with a 1 cm3 insert. The per cent depth dose distributions of a 3 × 3 cm2 photon field were compared with the insert material as water and the three selected dental implant materials. To evaluate the impact of the dental implant on VMAT patient dose calculation, four head-and-neck cases were selected. For each case, the VMAT plan was designed based on the artifact-corrected patient geometry using a treatment planning system (TPS) that was typically utilized for routine patient treatment. The plans were re-calculated using the MC code for five situations: uncorrected geometry, artifact-corrected geometry and artifact-corrected geometry with one of the three different implant materials. The isodose distributions and the dose-volume histograms were cross-compared with each other. To evaluate the effectiveness of using the material's electron-density ratio for dental implant correction, the implant region was set as water with the material's electron-density ratio and the calculated dose was compared with the MC simulation with the real material. The main effect of the dental implant was the severe attenuation in the downstream. The 1 cm3 dental implant can lower the downstream dose by 10% (Ti) to 51% (Au) for a 3 × 3 cm2 field. The TPS failed to account for the dose perturbation if the dental implant material was not precisely defined. For the VMAT patient dose calculation

  15. In vitro toothbrushing abrasion of dental resin composites: packable, microhybrid, nanohybrid and microfilled materials

    Directory of Open Access Journals (Sweden)

    Rafael Ratto de Moraes

    2008-06-01

    Full Text Available This study evaluated weight loss and surface roughening after toothbrushing of different resin composites: one packable (Solitaire 2, Heraeus Kulzer, one microhybrid (Charisma, Heraeus Kulzer, one nanohybrid (Simile, Pentron and one microfilled (Durafill VS, Heraeus Kulzer. Cylindrical specimens (n = 20 were prepared. Half of the samples were submitted to 60,000 strokes, at 4 Hz, with a dentifrice-water slurry. Control samples (n = 10 remained stored at 37°C. Pre- and post-abrasion parameters for weight (mg and surface roughness (Ra, µm were determined on an analytical balance and a surface profilometer. Data were separately submitted to Repeated Measures ANOVA and Tukey's test (a = 0.05. Percentages of weight loss were analyzed by ANOVA and Tukey's test (a = 0.05. The relationship between both evaluations was assessed by Pearson's test (a = 0.05. The means (% for weight loss (standard deviation were 0.65(0.2, 0.93(0.2, 1.25(0.6 and 1.25(0.4 for Simile, Durafill, Charisma and Solitaire, respectively. Baseline roughness means ranged from 0.065(0.01, 0.071(0.01, 0.066(0.02 and 0.074(0.01 for Simile, Durafill, Charisma and Solitaire, respectively, to 0.105(0.04, 0.117(0.03, 0.161(0.03 and 0.214(0.07 after testing. The composites with larger fillers presented higher weight loss and roughening than the finer materials (p < 0.05. For both evaluations, control specimens showed no significant alteration. No significant relationship between loss of weight and roughness alteration was detected (r = 0.322, p = 0.429.

  16. Surface texture measurement for dental wear applications

    Science.gov (United States)

    Austin, R. S.; Mullen, F.; Bartlett, D. W.

    2015-06-01

    The application of surface topography measurement and characterization within dental materials science is highly active and rapidly developing, in line with many modern industries. Surface measurement and structuring is used extensively within oral and dental science to optimize the optical, tribological and biological performance of natural and biomimetic dental materials. Although there has historically been little standardization in the use and reporting of surface metrology instrumentation and software, the dental industry is beginning to adopt modern areal measurement and characterization techniques, especially as the dental industry is increasingly adopting digital impressioning techniques in order to leverage CAD/CAM technologies for the design and construction of dental restorations. As dental treatment becomes increasingly digitized and reliant on advanced technologies such as dental implants, wider adoption of standardized surface topography and characterization techniques will become evermore essential. The dental research community welcomes the advances that are being made in surface topography measurement science towards realizing this ultimate goal.

  17. Saliva and dental erosion

    OpenAIRE

    Marília Afonso Rabelo Buzalaf; Angélicas Reis Hannas; Melissa Thiemi Kato

    2012-01-01

    Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective: This review discusses the role of salivary factors on the development of dental erosion. Material and Methods: A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the re...

  18. Mechanical Properties of a new Dental all-ceramic Material-zirconia Toughened Nanometer-ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    CHAI Feng; XU Ling; CHAO Yong-lie; LIAO Yun-mao; ZHAO Yi-min

    2003-01-01

    Objectives:All-ceramic dental restorations are attractive to the dental community because of their advantages.But they're also challenged by relatively low flexural strength and intrinsic poor resistance to fracture.This paper aims to investigate mechanical properties of a new dental all-ceramic material, i.e. zirconia toughened nanometer-ceramic composite (α-Al2O3/nZrO2).Methods:α-Al2O3/nZrO2 ceramics powder (W) was processed with combined methods of chemical co-precipitation method and ball milling. Scanning electron microscopy (SEM)was used to determine the particle size distribution and to characterize the particle morphology of the powders. Four kinds of powders with different ZrO2 content (5wt%, 10wt%, 15wt% and 20wt%) were prepared by using α-Al2O3 powder to dilute the higher ZrO2 content powder (W). The ceramic matrix compacts were made by slip-casting technique and sintering to 1 200~1 600 ℃. The flexural strength and the fracture toughness of the matrix materials were measured via three-point bending test and single-edge notch beam methods, respectively.Results:1) The particle distribution of the Al2O3/nZrO2 powder ranged from 0.02~3.0 μm, with the superfine particles almost accounting for 20%;2) There is a significant difference of flexural strength (P<0.05) between the groups with 1 450 ℃ and 1 600 ℃ sintering temperature and 1 200 ℃;3) There is a significant difference of flexural strength (P<0.05) between different zirconia volume fraction groups with the same sintering temperature, the ceramic matrix samples with higher nZrO2 (W) content had much better mechanical properties than those of pure α-Al2O3 ceramics.Conclusions:The studied nanometer α-Al2O3/nZrO2 powder was homogeously distributed within the matrix and had reasonable powder-size gradation to improve mechanical properties of ceramics.%目的:口腔全瓷修复体以其独特优越性受到医患青睐,但脆性问题一直限制其应用范围及使用可靠性.本研

  19. Inequity in a market-based health system: evidence from Canada's dental sector

    OpenAIRE

    Michel Grignon; Jeremiah Hurley; Li Wang; Sara Allin

    2008-01-01

    We study the extent and drivers of income-related inequity in utilization of dental services in Canada using the concentration-index approach that has been widely applied to study equity in physician and hospital services. Because dental care is almost wholly privately financed in Canada, our estimates provide a benchmark for income-related inequity of utilization in private health systems. Although a number of studies document a link between income and utilization, our study is one of the fe...

  20. Association between dental pain and tooth loss with health-related quality of life: the Korea national health and nutrition examination survey: A population-based cohort study.

    Science.gov (United States)

    Yang, Sung-Eun; Park, Yong-Gyu; Han, Kyungdo; Kim, Sin-Young

    2016-08-01

    Dental pain and tooth loss are global public health concerns. However, there have been no large cross-sectional epidemiologic studies of a representative sample of an entire country's populations. The purpose of this study was to evaluate the relationships between dental pain and tooth loss with health-related quality of life (HRQOL) using a well characterized, nationally representative, population-based study.This study analyzed data of 3924, representing 21,836,566 adults from the 2012 Korea National Health and Nutrition Examination Survey. Subjects were divided into 4 groups as follows: tooth loss of up to 8 teeth without dental pain, tooth loss of up to 8 teeth with dental pain, tooth loss of 8 to 28 teeth without dental pain, and tooth loss of 8 to 28 teeth with dental pain. Logistic regression was applied to estimate the adjusted odds ratios (ORs) and 95% confidence intervals (CI), controlling for a range of covariates.Among the 3924 subjects, representing an estimated 21,836,566 adults, the prevalence of tooth loss of 8 to 28 teeth was 24.6% and the prevalence of dental pain was 35%. The tooth loss of 8 to 28 teeth with dental pain group showed the highest level of impaired HRQOL in all 5 dimensions, and the tooth loss up to 8 teeth without dental pain group showed the lowest level. The proportion of both groups without dental pain decreased significantly from the younger age to older age group. After adjustment for sociodemographic factors, the ORs (95% CI) of mobility, self-case, usual activity, pain/discomfort, and anxiety/depression were 1.93 (1.32-2.84), 1.90 (1.25-2.90), 1.46 (0.88-2.43), 1.48 (0.88-2.49), and 1.46 (0.85-2.51) in tooth loss of 8 to 28 teeth with dental pain group. Although the ORs of tooth loss of 8 to 28 teeth without dental pain group did not significantly increase.Dental pain and tooth loss has a considerable impact of HRQOL in the Korean adult population. In our study, HRQOL is more closely associated with dental pain than with

  1. Effect of filler type on 3-body abrasion of dental composite

    OpenAIRE

    Yasini E.; Ataei M; Amini M

    2005-01-01

    Statement of Problem: The relatively poor wear resistance of dental composite in stress bearing posterior situations has restricted wider clinical application of this restorative material. Purpose: The aim of this study was to evaluate the three body abrasive wear of a dental composite based on a new filler (leucite: KAl Si2O6) and to compare it with the wear resistance of a composite based on commonly used Aluminium – Barium Silicate filler. Materials and Methods: This research was an interv...

  2. Dental caries: Therapeutic possibilities

    Directory of Open Access Journals (Sweden)

    Perić Tamara

    2008-01-01

    Full Text Available Contemporary tendencies in dentistry are based on the concept of maximal protection of healthy tooth tissues. Caries removal has been done traditionally with mechanical rotary instruments that are fast and precise. However, conventional cavity preparation has potential adverse effects to the pulp due to heat, pressure and vibrations. Moreover, drilling often causes pain and requires local anaesthesia, and these procedures are frequently perceived as unpleasant. Etiology, development and prevention of dental caries are better understood today and new restorative materials that bond micromechanically and/or chemically to dental tissues have been introduced. Thus, development of a new, less destructive caries removal technique is allowed. In the last decades, many alternative methods have been introduced in an attempt to replace rotary instruments. These are claimed to be efficient and selective for diseased tissues and to offer comfortable treatment to the patients. New methods include air abrasion, air polishing, ultrasonic, polymer burs, enzymes, systems for chemo-mechanical caries removal, and lasers. The aim of this paper was to discuss various caries removal techniques and possibilities of their use in clinical practice. Based on the literature review it can be concluded that none of the new caries removal methods can completely replace conventional rotary instruments.

  3. Quality of linear incisions performed by dental students using Er:YAG laser in soft tissue

    Science.gov (United States)

    Novelli, Moacyr Domingos; Vasques, Mayra Torres; Meneguzzo, Daiane Thaís; Aranha, Ana Cecília Corrêa; Corrêa, Luciana

    2008-02-01

    Introduction: New technologies in dental practice, such as laser, have enabled new strategies to be established in dental education. The aim of this study was to analyze the difficulties that dental students encountered with performing surgical incisions using Er:YAG laser (LE), and the morphology of these incisions. Material and Methods: Sixteen undergraduate dental students and ten dental professionals (DP) enrolled at The Master of Science Program in Laser Dentistry were asked to perform 15 incisions using an LE and 15 with a conventional scalpel. The incisions were compared, based on the shape factor (relation between area and perimeter), which was obtained by a digital image system and by a morphometry software. Data was submitted to statistical analysis of variance (p 0.05). Results: Considering the incisions performed by scalpel, DP showed statistically significant differences (p dental professionals that specialize in laser.

  4. Risk in the management of dental amalgam in dental medium and small entities in the department of Antioquia, Colombia

    Directory of Open Access Journals (Sweden)

    Jairo A. Ruiz

    2009-08-01

    Full Text Available This article is based on the applied research “Environmental Management of the Dental Amalgam in Antioquia, Colombia”, which was financed by the company New Stetic S. A. and the University of Antioquia. The research was carried out between 2005 and 2007 by the following groups: Biomedical Science and Technology, Precious Materials, and Pyrometallurgical and Materials Researches, and the Research and Development Division of the mentioned company. Objetive: to describe and characterize the activities about handling mercury, dental amalgam and its waste in 107 dental offices defined as medium and small, that is to say those with less than five dental chairs in the same workplace. Methodology: a poll was made in each institution filling a questionnaire about personal details of the interviewee, mercury and amalgam handling, occupational health, training, environmental conditions, and waste management. Each dental office was visited by a research engineer and an advanced engineering student who were trained in advance in order to collect the information. Results: a reflection aimed to establish integral actions and safe methodologies in the short term to promote a better quality service and a minimum risk for the people exposed to mercury and the ecosystem must be encouraged by dental and administrative staff, as well as by surveillance and control institutions and the educational institutions devoted to the formation of dental professionals.

  5. Effect of disinfection of irreversible hydrocolloid impression materials with 1% sodium hypochlorite on surface roughness and dimensional accuracy of dental stone casts

    Directory of Open Access Journals (Sweden)

    Andressa Rodrigues Dorner

    2014-01-01

    Full Text Available Aim: The aim of this study was to evaluate the effect of disinfection of commercially available irreversible hydrocolloid impression materials with 1% sodium hypochlorite on the surface roughness and dimensional accuracy of dies produced using type IV dental stone. Materials and Methods: Four different brands of irreversible hydrocolloid impression materials were used as follows: Jeltrate Plus without disinfection (GJ, Jeltrate Plus with disinfection (GJD, Hydrogum without disinfection (GH, Hidrogun with disinfection (GHD, Hidrogum 5 Days without disinfection (GH5, Hidrogum 5 Days with disinfection (GH5D, Cavex without disinfection (GC, and Cavex with disinfection (GCD. A total of 80 dies were poured using type IV dental stone and their mean surface roughness was evaluated using rugosimeter (Mitutoyo SJ-400. To conduct the dimensional alteration analysis, type IV dental stone casts were obtained from a matrix made of chemically-activated resin. They were analyzed in a coordinate-measuring machine (Brown and Sharpe. Statistics Analysis: Numerical data were analyzed using analysis of variance (ANOVA with Tukey′s post hoc test at 5% confi dence interval. Results: Hidrogun 5 Days and Cavex showed the least surface roughness value even after 5 days. There were no significant differences in the dimensional alteration of Jeltrate (GJ and GJD and Hidrogum (GH and GHD in relation to the "new brands" Hidrogum 5 (GH5 and GH5D and Cavex (GC and GCD, even after 5 days of storage. Conclusion: Considering the results obtained, it can be concluded that there was a roughness increase in the die stones poured from irreversible hydrocolloids disinfected with sodium hypochlorite.

  6. Dentists' use of caries risk assessment in children: findings from the Dental Practice-Based Research Network

    DEFF Research Database (Denmark)

    Riley, Joseph L; Qvist, Vebeke; Fellows, Jeffrey L;

    2010-01-01

    group practice model were the most likely to use a special form for caries risk assessment. Recent graduates from dental school were more likely to use a caries risk assessment compared to older graduates. Current oral hygiene, decreased salivary flow, and the presence of active caries were rated...... as the most important caries factors. Some differences by region were also evident for the risk factor ratings. These results suggest that not all community dentists assess caries risk. The results of this study also indicate considerable variability in dentists' views concerning the importance of specific......This study surveyed Dental Practice-Based Research Network (DPBRN) member dentists (from four regions in the U.S. and Scandinavia) who perform restorative dentistry in their practices. The survey asked a range of questions about caries risk assessment in patients aged 6 to 18. Among respondents, 73...

  7. Microemulsion-based synthesis of nanocrystalline materials.

    Science.gov (United States)

    Ganguli, Ashok K; Ganguly, Aparna; Vaidya, Sonalika

    2010-02-01

    Microemulsion-based synthesis is found to be a versatile route to synthesize a variety of nanomaterials. The manipulation of various components involved in the formation of a microemulsion enables one to synthesize nanomaterials with varied size and shape. In this tutorial review several aspects of microemulsion based synthesis of nanocrystalline materials have been discussed which would be of interest to a cross-section of researchers working on colloids, physical chemistry, nanoscience and materials chemistry. The review focuses on the recent developments in the above area with current understanding on the various factors that control the structure and dynamics of microemulsions which can be effectively used to manipulate the size and shape of nanocrystalline materials. PMID:20111772

  8. Research on giving antibacteria activity of tailored dental materials; Gin ion ni yoru shikayo zairyo no kokinsei fuyo ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The secondary dental caries easily occur by breeding of bacteria in cavities between living body and composite resin, false tooth or root of tailored tooth as tooth repairing materials. The antibacteria activity of tailored dental materials was thus studied by implanting Ag ion. The antibacteria effect with time after culture of caries bacteria was studied by implanting Ag ion into SiO2 powder, PMMA samples and Ti alloy samples at 20 and 200keV in energy of ion. In addition, the antibacteria activity of SiO2 powder as composite material was found at 25keV which was previously effective for the antibacteria activity. This SiO2 filler (Ag{sup +} filler) showed the antibacteria activity on every bacteria sample after 2h, and in particular, could kill all of 3 kinds of bacteria obtained from a composite resin surface after 12h. The number of living S. salivarius was reduced by half after 12h. The application of the composite resin filler implanted with Ag{sup +} is significant to prevent recurrence of caries. 5 refs., 27 figs., 7 tabs.

  9. Morphology of polyethylene ski base materials.

    Science.gov (United States)

    Fischer, Jörg; Wallner, Gernot M; Pieber, Alois

    2010-03-01

    We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.

  10. Problem-based learning and the workplace: do dental hygienists in Hong Kong continue to use the skills acquired in their studies?

    Science.gov (United States)

    Cheng, Brenda Siu Shan

    2009-08-01

    Problem-based learning (PBL) has been implemented in the dental hygiene program at the University of Hong Kong since 2001, but research is lacking to address the level of retention in the workplace. The purpose of this study was to explore whether dental hygienists continue to use their PBL skills and how well those skills are being applied in the workplace. A total of eighteen dental hygienists from the 2006 program were invited to participate in this study. A survey was conducted and follow-up group interviews carried out in 2008. The results revealed that dental hygienists continue to use the PBL skills of communication with the patient, patient education, and independent learning, but seldom use dental knowledge, teamwork, and communication with colleagues. Critical thinking, self-evaluation, and lifelong learning skills showed contradictory results. Besides, stressors under individual work environments, including certain Chinese cultural values, affect the way in which dental hygienists utilize PBL skills. This study concludes that the PBL approach is a worthwhile learning process for dental hygiene. However, many different variables affect the effectiveness of applying PBL skills after academic training, especially under the influence of Chinese culture in Hong Kong. PMID:19648570

  11. 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.

  12. Towards long lasting zirconia-based composites for dental implants. Part I: innovative synthesis, microstructural characterization and in vitro stability.

    Science.gov (United States)

    Palmero, Paola; Fornabaio, Marta; Montanaro, Laura; Reveron, Helen; Esnouf, Claude; Chevalier, Jérôme

    2015-05-01

    In order to fulfill the clinical requirements for strong, tough and stable ceramics used in dental applications, we designed and developed innovative zirconia-based composites, in which equiaxial α-Al2O3 and elongated SrAl12O19 phases are dispersed in a ceria-stabilized zirconia matrix. The composite powders were prepared by an innovative surface coating route, in which commercial zirconia powders were coated by inorganic precursors of the second phases, which crystallize on the zirconia particles surface under proper thermal treatment. Samples containing four different ceria contents (in the range 10.0-11.5 mol%) were prepared by carefully tailoring the amount of the cerium precursor during the elaboration process. Slip cast green bodies were sintered at 1450 °C for 1 h, leading to fully dense materials. Characterization of composites by SEM and TEM analyses showed highly homogeneous microstructures with an even distribution of both equiaxial and elongated-shape grains inside a very fine zirconia matrix. Ce content plays a major role on aging kinetics, and should be carefully controlled: sample with 10 mol% of ceria were transformable, whereas above 10.5 mol% there is negligible or no transformation during autoclave treatment. Thus, in this paper we show the potential of the innovative surface coating route, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites; moreover, its processing costs and environmental impacts are limited, which is beneficial for further scale-up and real use in the biomedical field.

  13. Superconductivity in dense carbon-based materials

    Science.gov (United States)

    Lu, Siyu; Liu, Hanyu; Naumov, Ivan I.; Meng, Sheng; Li, Yinwei; Tse, John S.; Yang, Bai; Hemley, Russell J.

    2016-03-01

    Guided by a simple strategy in search of new superconducting materials, we predict that high-temperature superconductivity can be realized in classes of high-density materials having strong sp3 chemical bonding and high lattice symmetry. We examine in detail sodalite carbon frameworks doped with simple metals such as Li, Na, and Al. Though such materials share some common features with doped diamond, their doping level is not limited, and the density of states at the Fermi level in them can be as high as that in the renowned Mg B2 . Together with other factors, this boosts the superconducting temperature (Tc) in the materials investigated to higher levels compared to doped diamond. For example, the Tc of sodalitelike Na C6 is predicted to be above 100 K. This phase and a series of other sodalite-based superconductors are predicted to be metastable phases but are dynamically stable. Owing to the rigid carbon framework of these and related dense carbon materials, these doped sodalite-based structures could be recoverable as potentially useful superconductors.

  14. Photodetectors based on two dimensional materials

    Science.gov (United States)

    Zheng, Lou; Zhongzhu, Liang; Guozhen, Shen

    2016-09-01

    Two-dimensional (2D) materials with unique properties have received a great deal of attention in recent years. This family of materials has rapidly established themselves as intriguing building blocks for versatile nanoelectronic devices that offer promising potential for use in next generation optoelectronics, such as photodetectors. Furthermore, their optoelectronic performance can be adjusted by varying the number of layers. They have demonstrated excellent light absorption, enabling ultrafast and ultrasensitive detection of light in photodetectors, especially in their single-layer structure. Moreover, due to their atomic thickness, outstanding mechanical flexibility, and large breaking strength, these materials have been of great interest for use in flexible devices and strain engineering. Toward that end, several kinds of photodetectors based on 2D materials have been reported. Here, we present a review of the state-of-the-art in photodetectors based on graphene and other 2D materials, such as the graphene, transition metal dichalcogenides, and so on. Project supported by the National Natural Science Foundation of China (Nos. 61377033, 61574132, 61504136) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

  15. Synthesis and ceramic processing of alumina and zirconia based composites infiltrated with glass phase for dental applications; Sintese e processamento de compositos a base de alumina e zirconia com infiltracao de fase vitrea para aplicacoes odontologicas

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Daniel Gomes

    2009-07-01

    The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resin-based cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram systems. Considering that the improvement of powder's synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650 degree C in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400 degree C .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning

  16. Dental Chairside Technique. Student's Manual.

    Science.gov (United States)

    Apfel, Maura; Weaver, Trudy Karlene

    This manual is part of a series dealing with skills and information needed by students in dental assisting. The individualized student materials are suitable for classroom, laboratory, or cooperative training programs. This student manual contains four units covering the following topics: local anesthesia; dental office emergencies; oral hygiene;…

  17. Graphene based materials for biomedical applications

    Directory of Open Access Journals (Sweden)

    Yuqi Yang

    2013-10-01

    Full Text Available Graphene, a single layer 2-dimensional structure nanomaterial with unique physicochemical properties (e.g. high surface area, excellent electrical conductivity, strong mechanical strength, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization, has received increasing attention in physical, chemical and biomedical fields. This article selectively reviews current advances of graphene based materials for biomedical applications. In particular, graphene based biosensors for small biomolecules (glucose, dopamine etc., proteins and DNA detection have been summarized; graphene based bioimaging, drug delivery, and photothermal therapy applications have been described in detail. Future perspectives and possible challenges in this rapidly developing area are also discussed.

  18. Graphene-based materials for energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Nanda Gopal [Energy Research Institute, Nanyang Technological University (Singapore); Pan, Yongzheng; Li, Lin; Chan, Siew Hwa [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

    2012-08-08

    With the depletion of conventional energy sources, the demand for renewable energy and energy-efficient devices continues to grow. As a novel 2D nanomaterial, graphene attracts considerable research interest due to its unique properties and is a promising material for applications in energy conversion and storage devices. Recently, the fabrication of fuel cells and solar cells using graphene for various functional parts has been studied extensively. This research news summarizes and compares the advancements that have been made and are in progress in the utilization of graphene-based materials for energy conversion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Fracture resistance curves and toughening mechanisms in polymer based dental composites

    DEFF Research Database (Denmark)

    De Souza, J.A.; Goutianos, Stergios; Skovgaard, M.;

    2011-01-01

    The fracture resistance (R-curve behaviour) of two commercial dental composites (Filtek Z350® and Concept Advanced®) were studied using Double Cantilever Beam sandwich specimens loaded with pure bending moments to obtain stable crack growth. The experiments were conducted in an environmental...... significantly higher fracture resistance than the composite with the coarser microstructure. The fracture properties were related to the flexural strength of the dental composites. The method, thus, can provide useful insight into how the microstructure enhances toughness, which is necessary for the future...

  20. Barriers to the Production of Scientific Dental Articles in Dental Schools in Iran; the View of Postgraduate Students

    Directory of Open Access Journals (Sweden)

    Hadi Ghasemi

    2012-02-01

    Full Text Available Background and Aims: The present study aimed to evaluate the barriers to the production of scientific dental articles in dental schools in Iran based on the opinions of dental postgraduate students.Materials and Methods: A self-administered questionnaire was distributed among postgraduate students of all Iranian dental schools in June 2010. The respondents rated their agreement with eight sentences about what hinder them from producing scientific dental articles based on a 5-grade Likert scale. The data were analyzed usingChi-square test.Results: Totally, 270 filled questionnaires from 14 dental schools were received. Of all respondents, 53% were male, the mean age were 29.6 ± 3.8. About half of the respondents reported at least one published article. Less than half of the respondents reported producing an article from undergraduate thesis; more women than men and more younger than older students (P<0.03. About two-third of the respondents rated absence of an English editing center, no financial incentives, no appropriate environment, and no competency for scientific writing as most prevalent barriers to the production of scientific dental articles.Conclusion: To expand the share of Iran in the production of scientific dental documents, the potential of postgraduate dental students must be regarded and suitable condition for scientific writing must be provided. Specifically, based on the findings of the present study, provision of an English editing facility, establishing financial incentives, and providing the students with appropriate environment and efficient scientific writing education are of utmost importance.

  1. Dental Forensics: Bitemark Analysis

    OpenAIRE

    Elza Ibrahim Auerkari

    2013-01-01

    Forensic odontology (dental forensics) can provide useful evidence in both criminal and civil cases, and therefore remains a part of the wider discipline of forensic science. As an example from the toolbox of forensic odontology, the practice and experience on bitemark analysis is reviewed here in brief. The principle of using visible bitemarks in crime victims or in other objects as evidence is fundamentally based on the observation that the detailed pattern of dental imprints tend to be pra...

  2. Agave Chewing and Dental Wear: Evidence from Quids.

    Science.gov (United States)

    Hammerl, Emily E; Baier, Melissa A; Reinhard, Karl J

    2015-01-01

    Agave quid chewing is examined as a potential contributing behavior to hunter-gatherer dental wear. It has previously been hypothesized that the contribution of Agave quid chewing to dental wear would be observed in communities wherever phytolith-rich desert succulents were part of subsistence. Previous analysis of coprolites from a prehistoric agricultural site, La Cueva de los Muertos Chiquitos in Durango, Mexico, showed that Agave was a consistent part of a diverse diet. Therefore, quids recovered at this site ought to be useful materials to test the hypothesis that dental wear was related to desert succulent consumption. The quids recovered from the site were found to be largely derived from chewing Agave. In this study, the quids were found to be especially rich in phytoliths, and analysis of dental casts made from impressions left in the quids revealed flat wear and dental attrition similar to that of Agave-reliant hunter-gatherers. Based on evidence obtained from the analysis of quids, taken in combination with results from previous studies, it is determined that Agave quid chewing was a likely contributing factor to dental wear in this population. As such, our method provides an additional avenue of dental research in areas where quids are present. PMID:26230855

  3. Agave Chewing and Dental Wear: Evidence from Quids.

    Directory of Open Access Journals (Sweden)

    Emily E Hammerl

    Full Text Available Agave quid chewing is examined as a potential contributing behavior to hunter-gatherer dental wear. It has previously been hypothesized that the contribution of Agave quid chewing to dental wear would be observed in communities wherever phytolith-rich desert succulents were part of subsistence. Previous analysis of coprolites from a prehistoric agricultural site, La Cueva de los Muertos Chiquitos in Durango, Mexico, showed that Agave was a consistent part of a diverse diet. Therefore, quids recovered at this site ought to be useful materials to test the hypothesis that dental wear was related to desert succulent consumption. The quids recovered from the site were found to be largely derived from chewing Agave. In this study, the quids were found to be especially rich in phytoliths, and analysis of dental casts made from impressions left in the quids revealed flat wear and dental attrition similar to that of Agave-reliant hunter-gatherers. Based on evidence obtained from the analysis of quids, taken in combination with results from previous studies, it is determined that Agave quid chewing was a likely contributing factor to dental wear in this population. As such, our method provides an additional avenue of dental research in areas where quids are present.

  4. Environmental assessment of biomass based materials

    DEFF Research Database (Denmark)

    Jørgensen, Susanne Vedel

    the potential mitigation value of this in relation to avoid crossing dangerous climatic target levels. CTP characterization factors for several GHG development scenarios and a number of other important model parameters are given, making the approach operational for direct inclusion in LCA. Influence of selected...... with temporary carbon storage in biomaterials, in a way that quantifies the potential climate change benefit in relation to avoiding crossing near-term climatic targets. The geographical scope in this PhD project is global, as the focus is on methodology development and assessment of biomaterials at a global...... materials. Background The society today is highly dependent on fossil oil and gas for producing fuels, chemicals and materials, however many of those can alternatively be produced from biomass. The potential of biomaterials to substitute fossil based materials receives increased attention, and their global...

  5. A Review of Dental Implant Treatment Planning and Implant Design Based on Bone Density

    Directory of Open Access Journals (Sweden)

    Torkzaban

    2013-06-01

    Full Text Available Context A key determinant for clinical success is the diagnosis of the bone density in a potential implant site. The percentage of bone-implant contact is related to bone density, and the axial stress contours around an implant are affected by the density of bone. Evidence Acquisition A number of reports have emphasized the importance of the quality of bone on the survival of dental implants. The volume and density of the recipient bone have also been shown to be determining criteria to establish proper treatment plans with adequate number of implants and sufficient surface area. Previous clinical reports that did not alter the protocol of treatment related to bone density had variable survival rates. To the contrary, altering the treatment plan to compensate for soft bone types has provided similar survival rates in all bone densities. Results When bone density decreases and bone become softer, the implant surface in contact with the bone decreases, therefore treatment plan should be modified by changing the drilling protocol, using gradual loading and reducing the force on the prosthesis or increasing the loading area with increasing implant number, implant position, implant size, implant design (deeper and more threads with more pitch, squared shape and implant body surface condition. Conclusions Once the prosthetic option, key implant position, and patient force factors have been determined, the bone density in the implant sites should be evaluated to modify the treatment plan. Inappropriate implant number or design in poor quality bone results in higher failure rates. Changing the treatment plan and implant design is suggested, based on bone density to achieve higher survival rates.

  6. Influence of bioactive material coating of Ti dental implant surfaces on early healing and osseointegration of bone

    International Nuclear Information System (INIS)

    The dental implant surface type is one of many factors that determine the long-term clinical success of implant restoration. The implant surface consists of bioinert titanium oxide, but recently coatings with bioactive calcium phosphate ceramics have often been used on Ti implant surfaces. Bio-active surfaces are known to significantly improve the healing time of the human bone around the inserted dental implant. In this study, we characterized two types of coated implant surfaces by scanning electron microscopy, energy dispersive spectrometry, and surface roughness testing. The effect of surface modification on early bone healing was then tested by using the rabbit tibia model to measure bone-to-implant contact ratios and removal torque values. These modified surfaces showed different characteristics in terms of surface topography, chemical composition, and surface roughness. However, no significant differences were found in the bone-to-implant contact and the resistance to removal torque between these surfaces. Both the coated implants may induce similar favorable early bone responses in terms of the early functioning and healing of dental implants even though they differed in their surface characteristics.

  7. Evaluation of effects of ionizing radiation on materials used in dental restorations;Avaliacao dos efeitos da radiacao ionizante em materiais utilizados em restauracoes dentarias

    Energy Technology Data Exchange (ETDEWEB)

    Maio, Mireia Florencio

    2009-07-01

    This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were submitted to X-ray beams of 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. The sample were submitted to Geiger-Mueller detectors and the ionization chambers in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a Germanium detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  8. Saliva and dental erosion

    Directory of Open Access Journals (Sweden)

    Marília Afonso Rabelo Buzalaf

    2012-10-01

    Full Text Available Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective: This review discusses the role of salivary factors on the development of dental erosion. Material and Methods: A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results: Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions: Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects.

  9. DISR: Dental Image Segmentation and Retrieval

    OpenAIRE

    Pilevar, Abdol Hamid

    2012-01-01

    In this paper, we propose novel algorithms for retrieving dental images from databases by their contents. Based on special information of dental images, for better content-based dental image retrieval and representation, the image attributes are used. We propose Dental Image Segmentation and Retrieval (DISR), a content-based image retrieval method that is robust to translation and scaling of the objects in the images. A novel model is used to calculate the features of the image. We implemente...

  10. Evaluation of the effect of tooth and dental restoration material on electron dose distribution and production of photon contamination in electron beam radiotherapy.

    Science.gov (United States)

    Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Akbari, Fatemeh; Mehrpouyan, Mohammad; Sobhkhiz Sabet, Leila

    2016-03-01

    The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam's energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided. PMID:26581762

  11. Evaluation of the effect of tooth and dental restoration material on electron dose distribution and production of photon contamination in electron beam radiotherapy.

    Science.gov (United States)

    Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Akbari, Fatemeh; Mehrpouyan, Mohammad; Sobhkhiz Sabet, Leila

    2016-03-01

    The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam's energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided.

  12. Implementation of Portfolio Assessment in a Competency-based Dental Hygiene Program.

    Science.gov (United States)

    Gadbury-Amyot, Cynthia C.; Holt, Lorie P.; Overman, Pamela R.; Schmidt, Colleen R.

    2000-01-01

    Describes the implementation of a portfolio assessment program in the dental hygiene program at the University of Missouri School of Dentistry. Tables provide examples of program competencies and related portfolio entries, the complete scoring rubric for portfolios, and the student portfolio evaluation survey. Concludes that although portfolio…

  13. Measuring the development of insight by dental health professionals in training using workplace-based assessment.

    NARCIS (Netherlands)

    Prescott-Clements, L.E.; Vleuten, C.P.M. van der; Schuwirth, L.; Gibb, E.; Hurst, Y.; Rennie, J.S.

    2011-01-01

    INTRODUCTION: For health professionals, the development of insight into their performance is vital for safe practice, professional development and self-regulation. This study investigates whether the development of dental trainees' insight, when provided with external feedback on performance, can be

  14. Dental status and oral health-related quality of life. A population-based study

    NARCIS (Netherlands)

    Visscher, C. M.; Lobbezoo, F.; Schuller, A. A.

    2014-01-01

    Oral health-related quality of life (OHRQoL) is associated with tooth wear and tooth loss. This study investigated the association between OHRQoL and dental status (in terms of natural dentition, partial or complete dentures, or edentulism). Sixteen hundred and twenty-two persons who participated in

  15. Dental status and oral health-related quality of life. A population-based study

    NARCIS (Netherlands)

    Visscher, C.M.; Lobbezoo, F.; Schuller, A.A.

    2014-01-01

    Summary: Oral health-related quality of life (OHRQoL) is associated with tooth wear and tooth loss. This study investigated the association between OHRQoL and dental status (in terms of natural dentition, partial or complete dentures, or edentulism). Sixteen hundred and twenty-two persons who partic

  16. Dental status and oral health-related quality of life: a population-based study

    NARCIS (Netherlands)

    C.M. Visscher; F. Lobbezoo; A.A. Schuller

    2014-01-01

    Oral health-related quality of life (OHRQoL) is associated with tooth wear and tooth loss. This study investigated the association between OHRQoL and dental status (in terms of natural dentition, partial or complete dentures, or edentulism). Sixteen hundred and twenty-two persons who participated in

  17. Constraints on the performance of school-based dental program in Yogyakarta, Indonesia: A qualitative study

    Directory of Open Access Journals (Sweden)

    Rosa Amalia

    2011-06-01

    Full Text Available Background: A high prevalence of caries at ages ≥ 12 in Yogyakarta province (DMFT = 6.5, raises the question of the effectiveness of the school-based dental program (SBDP which, as a national oral health program in schools, is organized by community health centers (CHCs. Purpose: The aim of this study is to explore the possible constraints on work processes which might affect the performance of SBDPs in controlling caries. Methods: In-depth interviews was conducted in twelve CHCs, covering all five districts both in urban and rural areas. Subjects were 41 dentists and dental nurses working in these CHCs. The interviews were structured according to the following themes: resources and logistics; program planning; target achievement; monitoring and evaluation; and suggestions for possible improvements. The data were analyzed using content analysis. Results: The main constraints identified were limited resources and inflexible regulations for resource allocation in the CHC, and inadequate program planning and program evaluation. Inadequate participation of parents was also identified. Another constraint is thatpolicy at the district level orientates oral health towards curative intervention rather than prevention. Suggestions from interviewees include encouraging a policy for oral health, task delegation, a funding program using school health insurance, and a reorientation towards prevention. Conclusion: The weakness of management processes and the unsupported policy of the SBDP at the local level result in a lack of effectiveness. The constraints identified and suggestions for improvements could constitute a basis for improving program quality.Latar Belakang: Tingginya prevalensi karies pada usia ≥ 12 tahun (DMFT = 6.5 di Provinsi Daerah Istimewa Yogyakarta (DIY menimbulkan pertanyaan akan efektifitas Usaha Kesehatan Gigi Sekolah (UKGS. UKGS adalah salah satu program nasional di bidang kesehatan gigi dan mulut yang dilaksanakan oleh Puskesmas

  18. Lorentz contact resonance spectroscopy for nanoscale characterisation of structural and mechanical properties of biological, dental and pharmaceutical materials.

    Science.gov (United States)

    Khanal, Dipesh; Dillon, Eoghan; Hau, Herman; Fu, Dong; Ramzan, Iqbal; Chrzanowski, Wojciech

    2015-12-01

    Scanning probe microscopy has been widely used to obtain topographical information and to quantify nanostructural properties of different materials. Qualitative and quantitative imaging is of particular interest to study material-material interactions and map surface properties on a nanoscale (i.e. stiffness and viscoelastic properties). These data are essential for the development of new biomedical materials. Currently, there are limited options to map viscoelastic properties of materials at nanoscale and at high resolutions. Lorentz contact resonance (LCR) is an emerging technique, which allows mapping viscoelasticity of samples with stiffness ranging from a few hundred Pa up to several GPa. Here we demonstrate the applicability of LCR to probe and map the viscoelasticity and stiffness of 'soft' (biological sample: cell treated with nanodiamond), 'medium hard' (pharmaceutical sample: pMDI canister) and 'hard' (human teeth enamel) specimens. The results allowed the identification of nanodiamond on the cells and the qualitative assessment of its distribution based on its nanomechanical properties. It also enabled mapping of the mechanical properties of the cell to demonstrate variability of these characteristics in a single cell. Qualitative imaging of an enamel sample demonstrated variations of stiffness across the specimen and precise identification of enamel prisms (higher stiffness) and enamel interrods (lower stiffness). Similarly, mapping of the pMDI canister wall showed that drug particles were adsorbed to the wall. These particles showed differences in stiffness at nanoscale, which suggested variations in surface composition-multiphasic material. LCR technique emerges as a valuable tool for probing viscoelasticity of samples of varying stiffness's. PMID:26518012

  19. Reliance on social security benefits by Swedish patients with ill-health attributed to dental fillings: a register-based cohort study

    Directory of Open Access Journals (Sweden)

    Naimi-Akbar Aron

    2012-08-01

    Full Text Available Abstract Background Some people attribute their ill health to dental filling materials, experiencing a variety of symptoms. Yet, it is not known if they continue to financially support themselves by work or become reliant on different types of social security benefits. The aim of this study was to analyse reliance on different forms of social security benefits by patients who attribute their poor health to dental filling materials. Methods A longitudinal cohort study with a 13-year follow up. The subjects included were 505 patients attributing their ill health to dental restorative materials, who applied for subsidised filling replacement. They were compared to a cohort of matched controls representing the general population (three controls per patient. Annual individual data on disability pension, sick leave, unemployment benefits, and socio-demographic factors was obtained from Statistics Sweden. Generalized estimating equations were used to test for differences between cohorts in number of days on different types of social security benefits. Results The cohort of dental filling patients had a significantly higher number of days on sick leave and disability pension than the general population. The test of an overall interaction effect between time and cohort showed a significant difference between the two cohorts regarding both sick leave and disability pension. In the replacement cohort, the highest number of sick-leave days was recorded in the year they applied for subsidised replacement of fillings. While sick leave decreased following the year of application, the number of days on disability pension increased and peaked at the end of follow-up. Conclusions Ill health related to dental materials is likely to be associated with dependence on social security benefits. Dental filling replacement does not seem to improve workforce participation.

  20. 21 CFR 872.3640 - Endosseous dental implant.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant. 872.3640 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3640 Endosseous dental implant. (a) Identification. An endosseous dental implant is a device made of a material such as titanium or titanium alloy,...

  1. Biomechanics of the press-fit phenomenon in dental implantology: an image-based finite element analysis

    Directory of Open Access Journals (Sweden)

    Frisardi Gianni

    2012-05-01

    Full Text Available Abstract Background A fundamental pre-requisite for the clinical success in dental implant surgery is the fast and stable implant osseointegration. The press-fit phenomenon occurring at implant insertion induces biomechanical effects in the bone tissues, which ensure implant primary stability. In the field of dental surgery, the understanding of the key factors governing the osseointegration process still remains of utmost importance. A thorough analysis of the biomechanics of dental implantology requires a detailed knowledge of bone mechanical properties as well as an accurate definition of the jaw bone geometry. Methods In this work, a CT image-based approach, combined with the Finite Element Method (FEM, has been used to investigate the effect of the drill size on the biomechanics of the dental implant technique. A very accurate model of the human mandible bone segment has been created by processing high resolution micro-CT image data. The press-fit phenomenon has been simulated by FE analyses for different common drill diameters (DA = 2.8 mm, DB = 3.3 mm, and DC = 3.8 mm with depth L = 12 mm. A virtual implant model has been assumed with a cylindrical geometry having height L = 11 mm and diameter D = 4 mm. Results The maximum stresses calculated for drill diameters DA, DB and DC have been 12.31 GPa, 7.74 GPa and 4.52 GPa, respectively. High strain values have been measured in the cortical area for the models of diameters DA and DB, while a uniform distribution has been observed for the model of diameter DC . The maximum logarithmic strains, calculated in nonlinear analyses, have been ϵ = 2.46, 0.51 and 0.49 for the three models, respectively. Conclusions This study introduces a very powerful, accurate and non-destructive methodology for investigating the effect of the drill size on the biomechanics of the dental implant technique. Further studies could aim at understanding how different drill

  2. Zirconia in dental implantology: A review

    OpenAIRE

    Apratim, Abhishek; Eachempati, Prashanti; Krishnappa Salian, Kiran Kumar; Singh, Vijendra; Chhabra, Saurabh; Shah, Sanket

    2015-01-01

    Background: Titanium has been the most popular material of choice for dental implantology over the past few decades. Its properties have been found to be most suitable for the success of implant treatment. But recently, zirconia is slowly emerging as one of the materials which might replace the gold standard of dental implant, i.e., titanium. Materials and Methods: Literature was searched to retrieve information about zirconia dental implant and studies were critically analyzed. PubMed databa...

  3. A Cognitive Task Analysis for Dental Hygiene.

    Science.gov (United States)

    Cameron, Cheryl A.; Beemsterboer, Phyllis L.; Johnson, Lynn A.; Mislevy, Robert J.; Steinberg, Linda S.; Breyer, F. Jay

    2000-01-01

    As part of the development of a scoring algorithm for a simulation-based dental hygiene initial licensure examination, this effort conducted a task analysis of the dental hygiene domain. Broad classes of behaviors that distinguish along the dental hygiene expert-novice continuum were identified and applied to the design of nine paper-based cases…

  4. Intraoral radiology in general dental practices. A comparison of digital and film-based X-ray systems with regard to radiation protection and dose reduction

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to gain insight into the distribution and application of digital intraoral radiographic techniques within general dental practices and to compare these with film-based systems in terms of patient dose reduction. Materials and Methods: 1100 questionnaires were handed out to general dental practitioners. Data was analyzed with respect to the type of system by using descriptive statistics and nonparametric tests, i.e. Kruskal-Wallis, Mann-Whitney and chi-square test (SPSS 20). Results: 64% of the questioned dentists still use film-based radiology, 23% utilize storage phosphor plate (SPP) systems and 13% use a charge-coupled device (CCD). A strong correlation between the number of dentists working in a practice and the use of digital dental imaging was observed. Almost 3/4 of the film users work with E- or F-speed film. 45% of them refuse to change to a digital system. The use of lead aprons was popular, while only a minority preferred thyroid shields and rectangular collimators. A fourfold reduction of exposure time from D-speed film to CCD systems was observed. Due to detector size and positioning errors, users of CCD systems take significantly more single-tooth radiographs in total. Considering the number of radiographs per patient, there is only a slight tendency towards more X-rays with CCD systems. Up to image generation, digital systems seem to be as or even more difficult to handle than film-based systems, while their handling was favored after radiographic exposure. Conclusion: Despite a slight increase of radiographs taken with CCD systems, there is a significant dosage reduction. Corresponding to the decrease in exposure time, the patient dose for SPP systems is reduced to one half compared to film. The main issues in CCD technology are positioning errors and the size of the X-ray detectors which are difficult to eliminate. The usage of radiation protection measures still needs to be improved. (orig.)

  5. 牙科可切削硅藻土全瓷材料的初步研究%Pilot Study on Dental Machinable Diatomite- based Ceramic.

    Institute of Scientific and Technical Information of China (English)

    刘梅; 殷雪萌; 章非敏; 梁慧; 顾宁

    2011-01-01

    Objective: To study the relationship between stracture and properties of a new type of dental machinable ceramic based on diatomite.Methods: By adding nanometer reinforcing agent, the new diatomite based dental machinable ceramic was fabricated.X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to characterize the crystal form and microstructure.The mechanical properties and the maehinability of this new ceramic were evaluated.Results: The color of the ceramic after sintering was oyster white and its surface was smooth.SEM images presented polycrystalline structure and the grain edge was clear with decreased porosities.The flexure strength, mierohardness and fracture toughness of the new ceramic reached 177.23±7.02MPa, 9.73±0.64 GPa and 3.93±0.58MPa · m1/2 respectively.The machinability of the material sintered at 700 degrees was good.Conclusion: The mechanical and esthetic properties of the new type of diatomite-based dental machinable ceramic were acceptable but the mechanical strength still needs to be enhanced.%目的:制备一种新型的牙科可切削硅藻土陶瓷材料,探讨其结构和性能的关系.方法:选取硅藻土为原料,通过添加纳米增韧剂制备陶瓷材料.采用X射线衍射仪分析陶瓷的晶相成分,扫描电镜观察陶瓷的显微结构,并测量材料的机械性能和切削性能.结果:硅藻土全瓷材料表面光滑,呈现乳白色;电镜下观察材料内部呈现致密多晶结构,晶界清晰,气孔较少;其三点弯曲强度(177.23±7.02)MPa,显微硬度(9.73±0.64)GPa,断裂韧性(3.93±0.58)MPa·m1/2.初烧结的陶瓷材料中烧结温度为700℃的切削性能较好.结论:该材料符合牙科可切削陶瓷材料的基本要求,但强度仍需进一步提高.

  6. Intraoral radiology in general dental practices. A comparison of digital and film-based X-ray systems with regard to radiation protection and dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Anissi, H.D. [Ulm Univ. (Germany). Dentistry; Geibel, M.A. [Ulm Univ. (Germany). Dept. of Dentomaxillofacial Surgery

    2014-08-15

    Purpose: The purpose of this study was to gain insight into the distribution and application of digital intraoral radiographic techniques within general dental practices and to compare these with film-based systems in terms of patient dose reduction. Materials and Methods: 1100 questionnaires were handed out to general dental practitioners. Data was analyzed with respect to the type of system by using descriptive statistics and nonparametric tests, i.e. Kruskal-Wallis, Mann-Whitney and chi-square test (SPSS 20). Results: 64% of the questioned dentists still use film-based radiology, 23% utilize storage phosphor plate (SPP) systems and 13% use a charge-coupled device (CCD). A strong correlation between the number of dentists working in a practice and the use of digital dental imaging was observed. Almost 3/4 of the film users work with E- or F-speed film. 45% of them refuse to change to a digital system. The use of lead aprons was popular, while only a minority preferred thyroid shields and rectangular collimators. A fourfold reduction of exposure time from D-speed film to CCD systems was observed. Due to detector size and positioning errors, users of CCD systems take significantly more single-tooth radiographs in total. Considering the number of radiographs per patient, there is only a slight tendency towards more X-rays with CCD systems. Up to image generation, digital systems seem to be as or even more difficult to handle than film-based systems, while their handling was favored after radiographic exposure. Conclusion: Despite a slight increase of radiographs taken with CCD systems, there is a significant dosage reduction. Corresponding to the decrease in exposure time, the patient dose for SPP systems is reduced to one half compared to film. The main issues in CCD technology are positioning errors and the size of the X-ray detectors which are difficult to eliminate. The usage of radiation protection measures still needs to be improved. (orig.)

  7. Voxel-based registration of simulated and real patient CBCT data for accurate dental implant pose estimation

    Science.gov (United States)

    Moreira, António H. J.; Queirós, Sandro; Morais, Pedro; Rodrigues, Nuno F.; Correia, André Ricardo; Fernandes, Valter; Pinho, A. C. M.; Fonseca, Jaime C.; Vilaça, João. L.

    2015-03-01

    The success of dental implant-supported prosthesis is directly linked to the accuracy obtained during implant's pose estimation (position and orientation). Although traditional impression techniques and recent digital acquisition methods are acceptably accurate, a simultaneously fast, accurate and operator-independent methodology is still lacking. Hereto, an image-based framework is proposed to estimate the patient-specific implant's pose using cone-beam computed tomography (CBCT) and prior knowledge of implanted model. The pose estimation is accomplished in a threestep approach: (1) a region-of-interest is extracted from the CBCT data using 2 operator-defined points at the implant's main axis; (2) a simulated CBCT volume of the known implanted model is generated through Feldkamp-Davis-Kress reconstruction and coarsely aligned to the defined axis; and (3) a voxel-based rigid registration is performed to optimally align both patient and simulated CBCT data, extracting the implant's pose from the optimal transformation. Three experiments were performed to evaluate the framework: (1) an in silico study using 48 implants distributed through 12 tridimensional synthetic mandibular models; (2) an in vitro study using an artificial mandible with 2 dental implants acquired with an i-CAT system; and (3) two clinical case studies. The results shown positional errors of 67+/-34μm and 108μm, and angular misfits of 0.15+/-0.08° and 1.4°, for experiment 1 and 2, respectively. Moreover, in experiment 3, visual assessment of clinical data results shown a coherent alignment of the reference implant. Overall, a novel image-based framework for implants' pose estimation from CBCT data was proposed, showing accurate results in agreement with dental prosthesis modelling requirements.

  8. Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors

    Science.gov (United States)

    Ottevaere, H.; Tabak, M.; Chah, K.; Mégret, P.; Thienpont, H.

    2012-04-01

    Polymerization shrinkage of dental composite materials is recognized as one of the main reasons for the development of marginal leakage between a tooth and filling material. As an alternative to conventional measurement methods, we propose optical fiber Bragg grating (FBG) based sensors to perform real-time strain and shrinkage measurements during the curing process of dental resin cements. We introduce a fully automated set-up to measure the Bragg wavelength shift of the FBG strain sensors and to accurately monitor the linear strain and shrinkage of dental resins during curing. Three different dental resin materials were studied in this work: matrix-filled BisGMA-based resins, glass ionomers and organic modified ceramics.

  9. 口腔修复膜材料在牙种植中引导骨再生中的应用%Clinical Observation of Dental Restorations Membrane Materials in the Application of Dental Implants in Guided Bone Regeneration

    Institute of Scientific and Technical Information of China (English)

    吴喆; 王涛

    2015-01-01

    目的:观察口腔修复膜材料在牙种植中引导骨再生中的应用效果及安全性。方法:选择行牙种植再生的患者106例,按照随机数字对照表法平均分为两组,对照组(53例)采用钛膜引导骨再生,研究组(53例)采用海奥口腔修复膜引导骨再生,观察两组修复成功率及1周骨厚度、植骨厚度,并评价安全性。结果:研究组修复成功率为94.3%,明显高于对照组的83.0%,差异有统计学意义(P<0.05)。研究组患者1周骨厚度和植骨厚度均显著高于对照组,差异有统计学意义(P<0.05)。研究组不良反应发生率为3.8%,明显低于对照组的13.2%,差异有统计学意义(P<0.05)。结论:海奥口腔修复膜在牙种植中引导骨再生中效果良好,修复成功率高,有效促进骨和植骨的发育,值得临床推广和普及。%Objective:To observe clinical of dental restorations membrane materials in the application of dental implants in guided bone regeneration.Method:Teeth plant regeneration of 106 patients were selected and divided into two groups according to random number table method, control group (53 cases) used titanium membrane guided bone regeneration, reserach group (53 cases) used the oral repair membrane guided bone regeneration,Repair success rate and 1 week bone thickness, thickness of bone graft, and evaluation of safety of two groups was observed.Result: The repair success rate of reserach group was 94.3%, significantly higher than 83.0% of the control group, (P<0.05). The 1 week bone thickness and thickness of the bone graft of reserach group were significantly higher than that of control group (P<0.05).The incidence of adverse reactions of reserach group was 3.8%, significantly lower than 13.2% of the control group,there was statistically significant difference(P<0.05).Conclusion:The haiao dental restorations membrane guided bone regeneration in the dental implants is good effect, and

  10. Predictors of Dental caries among children 7–14 years old in Northwest Ethiopia: a community based cross-sectional study

    Directory of Open Access Journals (Sweden)

    Ayele Fenta A

    2013-01-01

    Full Text Available Abstract Background Dental caries in children remains a significant public health problem. It is a disease with multifactorial causes. The aim of the study was to assess the prevalence and associated factors of dental caries among children between 7 to 14 years old. Methods A community based cross-sectional study was conducted in Gondar town from June 2011 to September 2011. A total of 842 children were involved in the study. Multi-stage sampling technique was used to select the children. Pretested and structured questionnaires were used to collect data from mothers. Clinical examination of children was done using dental caries criteria set by world health organization. Data were entered, cleaned and edited using EPI Info version 3.5.1 and exported to SPSS version 16.0 for analysis. Binary multiple logistic regression analyses was applied to test the association. Results Four hundred sixty three (55% children were females. The prevalence of dental caries was 306(36.3%.The educational status of children’s father (AOR=0.3, 95%CI, 0.17, 0.80, monthly household income (AOR=0.59, 95%CI, 0.01, 0.45, regular teeth brushing (AOR=0.08, 95% CI, 0.03, 0.20 and using mouth rinsing (AOR=0.40, 95% CI, 0.2, 0.80 were found statistically significantly associated with dental caries. Conclusions Dental caries were high among children in Gondar town. Low socioeconomic status and poor oral hygiene practices were the influencing factors for dental caries. Oral hygiene, dietary habits and access to dental care services are supreme important for the prevention of the problem.

  11. Prevalence of dental caries and periodontal diseases, and their association with socio-demographic risk factors among older persons in Delhi, India: a community-based study.

    Science.gov (United States)

    Srivastava, Rahul; Gupta, Sanjeev Kumar; Mathur, Vijay Prakash; Goswami, Anil; Nongkynrih, Baridalyne

    2013-05-01

    Dental health is often neglected in the older persons, and dental conditions associated with aging are complex, adversely affecting the quality of life. The present study was undertaken to estimate the prevalence of dental caries and periodontal diseases among older persons from Delhi, India, and to study their association with selected socio-behavioral risk factors. We conducted a community-based cross sectional study among persons aged > or = 60 years from Delhi during 2009-2010. A questionnaire was used to interview elderly regarding dental health. The World Health Organization (WHO) oral health assessment form was used for examining the study participants. A total of 448 participants were examined and included in the study. Of the dentate, 47.1% had active dental caries. The mean decayed, missing and filled teeth (DMFT) score for the study population was 14.4. The prevalence of gingival bleeding, periodontal pockets and loss of attachment was 96.6, 89.1, and 80.3%, respectively. The prevalence of tobacco use was 47.9%. Age, frequency of teeth cleaning, and method used for teeth cleaning were statistically associated with the DMFT score. The prevalence of dental caries and periodontal disease was high in the study population, and warrants intervention.

  12. How to estimate dental age in paleodontology?

    Directory of Open Access Journals (Sweden)

    Vedran Šebečić

    2010-06-01

    Full Text Available Nowadays there are many methods available for dental age estimation: morphological, radiological, biochemical. Some methods require sample sectioning while other non-destructive methods are more appropriate for use in paleodontology. Children’s dental age assessment is based on phases in growth and development of the deciduous and permanent dentition, while age assessment in the adult dentition is based upon changes in the structure of hard dental tissue caused by aging. Dental age calculating software enables automated age calculations.

  13. How to estimate dental age in paleodontology?

    OpenAIRE

    Vedran Šebečić; Andrea Hoch; Maja Sabalić

    2010-01-01

    Nowadays there are many methods available for dental age estimation: morphological, radiological, biochemical. Some methods require sample sectioning while other non-destructive methods are more appropriate for use in paleodontology. Children’s dental age assessment is based on phases in growth and development of the deciduous and permanent dentition, while age assessment in the adult dentition is based upon changes in the structure of hard dental tissue caused by aging. Dental age calculati...

  14. Association between Dental Erosion and Diet in Brazilian Adolescents Aged from 15 to 19: A Population-Based Study

    OpenAIRE

    Yêska Paola Costa Aguiar; Fábio Gomes dos Santos; Eline Freitas de Farias Moura; Fernanda Clotilde Mariz da Costa; Sheyla Marcia Auad; Saul Martins Paiva; Alessandro Leite Cavalcanti

    2014-01-01

    Dental erosion is a pathological condition resulting from the irreversible dissolution of the mineralized portion of the teeth, being recognized in modern society as an important cause of loss of tooth structure. The aim of this study was to assess the prevalence and its association with diet in Brazilian adolescents of Campina Grande, PB, Brazil. A population-based study was conducted on a stratified sample of 675 adolescents aged from 15 to 19 of both sexes using the index proposed by O'Sul...

  15. Racking strength of paperboard based sheathing materials

    Directory of Open Access Journals (Sweden)

    Bi, W.

    2007-02-01

    Full Text Available Small-scale racking testers were developed for use as a means to evaluate paperboard-based sheathing materials used in framed wall-construction. For the purpose of evaluating the performance of different sheathing materials, the tester provides an economic alternative to standard full-scale racking tests. In addition, results from testing provide practical insight into the racking response of framed and sheathed walls. The load-deformation responses of three commercial sheathing boards were measured, and initial racking stiffness and racking strength were proposed as parameters for characterizing the board. The racking test results showed that the initial paperboard racking stiffness correlated to elastic modulus and caliper, but the response was insensitive to paperboard orientation or test dimensions. Observations and results showed that both panel buckling and paperboard cutting at the staples affected the racking response, but the dominating factor influencing the racking response appears to be load transfer through the staples.

  16. Bibliographic data base for low activation materials

    Energy Technology Data Exchange (ETDEWEB)

    Alenina, M.V.; Kolotov, V.P. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation); Ivanov, L.I. [A.A. Baikov Institute of Metallurgy and Science of Materials, Russian Academy of Sciences, Moscow (Russian Federation)

    2007-07-01

    Full text of publication follows: The analysis of the publications dealing with development of low-activation materials for fusion technology demonstrates that the period of information doubling is about 5-6 years. Such high rate usually is characteristic of the actively developing field of science. To develop an useful instrument for analysis and systematization of the available data a computer based bibliographic system has been developed some time ago. Recently the engine of the system has been significantly modernized. The bibliographic system is based on using of MS SQL server data base which includes main bibliographic information including abstracts. The most important feature of the system is that full-text abstracts searching capabilities are appended with indexing of information by experts to increase its definition. The experts indexes cover the following topics: - Main problems; - Software and methods for calculation; - Libraries of nuclear data; - Spectrum of neutrons for different construction parts of fusion reactor; - Low activation materials; - Technology of production; - Radiation effects; - Utilization of radiation waste; - Estimation of risks; - Designs of fusion reactor; - Nuclear transmutations; - Equipment used for investigations. The primary data base is filling/appending by periodical queries to different bibliographic data bases (INIS, COMPEMDEX and others) via suitable Internet providers including strict analysis of the income information to remove a possible 'information noise' and following data indexing by experts. The data base contains references since 1976 year (when first works in this area have been fulfilled) and until now. The bibliographic system is accessible by means of Internet using different forms developed for queries (http://www.geokhi.ru/{approx}lam{sub d}b). (authors)

  17. Dental amalgam: is this the end?

    Science.gov (United States)

    Taut, Cristina

    Dental amalgam is a reliable and effective restorative material with a well-established role in modern dentistry. Throughout the years its mercury content and the risks posed to human health were main topics of interest for many scientists. This paper offers a review of the scientific literature on the health and environmental impact of mercury in dentistry published over the last decade. A variety of peer-reviewed, epidemiological and large-scale clinical studies on dental amalgam, as well as published reports of professional and governmental bodies, were organised thematically and analysed. The most relevant findings of the aforementioned literature are reported. No reliance has been placed on unpublished work or publicly available opinions that are not scientifically based. In order to offer an appropriate view on the topic the toxicology, health impacts and possible environmental threats are briefly presented in relation to the relevant literature published in the last ten years. It is almost unanimously accepted that dental amalgam is a safe material, with little or insignificant adverse effect on general health. However, current and mostly unfounded environmental concerns may result in the implementation of new across the board legislation that could lead to a global dental amalgam "phase out".

  18. Clinical analysis of biocompatibility of different dental restorative materials and 3 kinds of materials to ifll the proximal dental caries of accessional teeth%不同牙科修复材料生物相容性及3种材料充填恒磨牙邻面龋的临床分析

    Institute of Scientific and Technical Information of China (English)

    马海英

    2016-01-01

    ObjectiveTo analyze the clinical effect of different dental restorative materials on the proximal dental caries of accessional teeth.MethodA retrospective analysis of clinical data of 444 patients with proximal dental caries of accessional teeth treated in our hospital from May 2010 to May 2012 was performed, according to the different iflling materials, the patients were divided into group A (glass-ionomer cement), group B (light-cured composite resin) and group C (silver amalgam), analyzed the success rate of different dental restorative materials.ResultFollowed-up 1 and 3 years respectively, the success rate of group A was signiifcantly lower than that of group B and group C (P0.05); after 3 years of restoration, the success rate of group B was higher than group C (P<0.05).ConclusionLight-cured composite resin is helpful to improve the success rate of proximal dental caries of accessional teeth, and it is worth to be popularized in clinic.%目的:研究并分析不同牙科修复材料充填恒磨牙邻面龋的临床效果。方法回顾性分析2010年5月至2012年5月收治的444例恒磨牙邻面龋患者的临床资料。按照充填材料不同将入选患者分为A组(玻璃离子水门汀充填)、B组(光固化复合树脂充填)、C组(银汞合金充填),分析不同牙科修复材料对患牙的修复成功率。结果修复后1年和3年复诊,A组患牙修复成功率明显低于B组和C组(P<0.05)。修复后1年,B组与C组患牙修复成功率比较差异无显著性(P>0.05);修复后3年,B组患牙修复成功率高于C组(P<0.05)。结论光固化复合树脂有助于提高恒磨牙邻面龋的修复成功率,值得临床推广。

  19. Micro-computed tomography (CT) based assessment of dental regenerative therapy in the canine mandible model

    Science.gov (United States)

    Khobragade, P.; Jain, A.; Setlur Nagesh, S. V.; Andreana, S.; Dziak, R.; Sunkara, S. K.; Sunkara, S.; Bednarek, D. R.; Rudin, S.; Ionita, C. N.

    2015-03-01

    High-resolution 3D bone-tissue structure measurements may provide information critical to the understanding of the bone regeneration processes and to the bone strength assessment. Tissue engineering studies rely on such nondestructive measurements to monitor bone graft regeneration area. In this study, we measured bone yield, fractal dimension and trabecular thickness through micro-CT slices for different grafts and controls. Eight canines underwent surgery to remove a bone volume (defect) in the canine's jaw at a total of 44 different locations. We kept 11 defects empty for control and filled the remaining ones with three regenerative materials; NanoGen (NG), a FDA-approved material (n=11), a novel NanoCalcium Sulfate (NCS) material (n=11) and NCS alginate (NCS+alg) material (n=11). After a minimum of four and eight weeks, the canines were sacrificed and the jaw samples were extracted. We used a custombuilt micro-CT system to acquire the data volume and developed software to measure the bone yield, fractal dimension and trabecular thickness. The software used a segmentation algorithm based on histograms derived from volumes of interest indicated by the operator. Using bone yield and fractal dimension as indices we are able to differentiate between the control and regenerative material (p<0.005). Regenerative material NCS showed an average 63.15% bone yield improvement over the control sample, NCS+alg showed 55.55% and NanoGen showed 37.5%. The bone regeneration process and quality of bone were dependent upon the position of defect and time period of healing. This study presents one of the first quantitative comparisons using non-destructive Micro-CT analysis for bone regenerative material in a large animal with a critical defect model. Our results indicate that Micro-CT measurement could be used to monitor invivo bone regeneration studies for greater regenerative process understanding.

  20. Development of Preventive Measures Based on the Aetiology of Dental Caries: A Review

    OpenAIRE

    Hamada, Shigeyuki; Ooshima, Takashi; Fijiwara, Taku; Minami, Takahiro; Kimura, Shigenobu

    2011-01-01

    Mutans streptococci including Streptococcus mutans and Streptococcus sobrinus are aetiologically associated with the development of dental caries in humans and experimental animals. These organisms produce glucosyltransferases (GTases), which catalyse the synthesis of adherent glucan from sucrose, promoting the adherence of the organisms to the tooth surface. In addition, they release large quantities of acids from various dietary sugars. These are the essential virulence factors of mutans st...

  1. Introducing and evaluating MorphoDent, a Web-based learning program in dental morphology.

    Science.gov (United States)

    Mitov, Gergo; Dillschneider, Timo; Abed, Mohammad Rabbo; Hohenberg, Gregor; Pospiech, Peter

    2010-10-01

    MorphoDent, a computer-assisted learning program designed to teach the anatomy of the adult dentition, was introduced into the curriculum of dentistry at the University of Saarland in Homburg, Germany. Thirty-six second-year students of the School of Dentistry were introduced to morphoDent alongside the traditional lectures of dental anatomy. Questionnaires that evaluated the students' perceptions of virtual learning as well as aspects of the functionality of the program educational objectives were developed and distributed to the students. Online tests were performed and compared with a traditional examination. All questionnaires were returned. A wide variety of aspects dealing the pedagogic implications of e-learning were evaluated by the students, with the overall result being that students are aware of the needed hardware and technical skills and expect the quality of their studies to improve by implementation of e-learning. All sophomores except one felt that morphoDent had helped them in learning dental morphology and reported enjoying the virtual anatomical examination. One-third reported technical difficulties in operating the program. The average exam score was 2.53 (SD: 0.66) for the traditional and 2.23 (SD: 0.59) for the online dental anatomy test. Students expressed their positive attitude towards e-learning in general and indicated that the use of photorealistic 3D models of human teeth supported the process of individual learning of dental anatomy. The online test could be rated as a good option for students' self-performance rating.

  2. High energy X-ray diffraction study of a dental ceramics–titanium functional gradient material prepared by field assisted sintering technique

    Energy Technology Data Exchange (ETDEWEB)

    Witte, K., E-mail: kerstin.witte@uni-rostock.de [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany); Bodnar, W. [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany); Schell, N. [Institute of Materials Research, Helmholtz-Center Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Lang, H. [Department of Operative Dentistry and Periodontology, University of Rostock, Strempelstr. 13, 18057 Rostock (Germany); Burkel, E. [Institute of Physics, University of Rostock, August-Bebel-Str. 55, 18055 Rostock (Germany)

    2014-09-15

    A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is α-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. The crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1) Å, while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2) Å. The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable. - Highlights: • High energy XRD studies of dental ceramics–Ti gradient material consolidated by FAST. • Phase composition, crystallinity and lattice parameters are determined. • Crystallinity increases stepwisely along the gradient following weight fraction of Ti. • Lattice mismatch leading to internal stress is calculated over the whole gradient. • Internal stress in α-Ti embedded in the gradient is smaller than its yield strength.

  3. American Dental Association

    Science.gov (United States)

    ... site Partnerships and Commissions Joint Commission on National Dental Examinations Learn about the examinations used in licensing dentists and dental hygienists Commission on Dental Accreditation Explore CODA's role ...

  4. [Hardening of dental instruments].

    Science.gov (United States)

    Gerasev, G P

    1981-01-01

    The possibility of prolonging the service life of stomatological instruments by the local hardening of their working parts is discussed. Such hardening should be achieved by using hard and wear-resistant materials. The examples of hardening dental elevators and hard-alloy dental drills are given. New trends in the local hardening of instruments are the treatment of their working parts with laser beams, the application of coating on their surface by the gas-detonation method. The results of research work and trials are presented.

  5. Quantum Mechanics Based Multiscale Modeling of Materials

    Science.gov (United States)

    Lu, Gang

    2013-03-01

    We present two quantum mechanics based multiscale approaches that can simulate extended defects in metals accurately and efficiently. The first approach (QCDFT) can treat multimillion atoms effectively via density functional theory (DFT). The method is an extension of the original quasicontinuum approach with DFT as its sole energetic formulation. The second method (QM/MM) has to do with quantum mechanics/molecular mechanics coupling based on the constrained density functional theory, which provides an exact framework for a self-consistent quantum mechanical embedding. Several important materials problems will be addressed using the multiscale modeling approaches, including hydrogen-assisted cracking in Al, magnetism-controlled dislocation properties in Fe and Si pipe diffusion along Al dislocation core. We acknowledge the support from the Office of Navel Research and the Army Research Office.

  6. Radiation detectors based by polymer materials

    International Nuclear Information System (INIS)

    Scintillation counters make use of the property of certain chemical compounds to emit short light pulses after excitation produced by the passage of charged particles or photons of high energy. These flashes of light are detected by a photomultiplier tube that converts the photons into a voltage pulse. The light emitted from the detector also can be collected, focussed and dispersed by a CCD detector. The study of the evolution of the light emission and of the radiation damage under irradiation is a primary topic in the development of radiation hard polymer based scintillator. Polymer scintillator thin films are used in monitoring radiation beam intensities and simultaneous counting of different radiations. Radiation detectors have characteristics which depend on: the type of radiation, the energy of radiation, and the material of the detector. Three types of polymer thin films were studied: a polyvinyltoluene based scintillator, fluorinated polyimide and PMMA. (authors)

  7. From acid etching treatments to tribocorrosive properties of dental implants: do some experimental results on surface treatments have an influence on the tribocorrosion behaviour of dental implants?

    International Nuclear Information System (INIS)

    Surface treatments of dental implants aim at promoting osseointegration, i.e. the anchorage of the metallic part. Titanium-, grade II–V, based material is used as a bulk material for dental implants. For promoting the anchorage of this metallic biomaterial in human jaw, some strategies have been applied for improving the surface state, i.e. roughness, topography and coatings. A case study, experimental study, is described with the method of acid etching on titanium grade 4, CpTi. The main goal is to find the right proportion in a mixture of two acids in order to obtain the best surface state. Finally, a pure theoretical prediction is quite impossible and some experimental investigations are necessary to improve the surface state. The described acid etching is compared with some other acid etching treatments and some coatings available on dental implants. Thus, the discussion is focused on the tribocorrosion behaviour of titanium-based materials. The purpose of the coating is that the lifetime under tribocorrosion is limited. Moreover, the surgery related to the implantation has a huge impact on the stability of dental implants. Thus, the performance of dental implants depends on factors related to surgery (implantation) that are difficult to predict from the biomaterial characteristics. From the tribocorrosion point of view, i.e. during the mastication step, the titanium material is submitted to some deleterious factors that cause the performance of dental implants to decrease. (paper)

  8. Dental radiology

    International Nuclear Information System (INIS)

    Since dental radiology has become a subject of the final examinations in dental medicine, there is a demand for literature presenting the basic principles of this subject field. The textbook in hand is primarily intended as an introduction for students attending the roentgenography lessons, or for students preparing for their dental medicine examinations. The book discusses the following aspects: physical principles and fundamentals; technical fundamentals of X-ray generation; image formation; X-ray films and film processing; intraoral imaging techniques; extraoral imaging techniques; special methods; panoramic technique; biological radiation effects; basic principles of radiation protection; legal aspects (X-ray Ordinance). (orig.)

  9. Solution-based nanoengineering of materials.

    Energy Technology Data Exchange (ETDEWEB)

    Criscenti, Louise Jacqueline; Spoerke, Erik David; Liu, Jun; Voigt, James A.; Cygan, Randall Timothy; Machesky, Michael L. (Illinois State Water Survey, Champaign, IL); Tian, Zhengrong Ryan; McKenzie, Bonnie Beth

    2005-02-01

    Solution-based synthesis is a powerful approach for creating nano-structured materials. Although there have been significant recent successes in its application to fabricating nanomaterials, the general principles that control solution synthesis are not well understood. The purpose of this LDRD project was to develop the scientific principles required to design and build unique nanostructures in crystalline oxides and II/VI semiconductors using solution-based molecular self-assembly techniques. The ability to synthesize these materials in a range of different nano-architectures (from controlled morphology nanocrystals to surface templated 3-D structures) has provided the foundation for new opportunities in such areas as interactive interfaces for optics, electronics, and sensors. The homogeneous precipitation of ZnO in aqueous solution was used primarily as the model system for the project. We developed a low temperature, aqueous solution synthesis route for preparation of large arrays of oriented ZnO nanostructures. Through control of heterogeneous nucleation and growth, methods to predicatively alter the ZnO microstructures by tailoring the surface chemistry of the crystals were established. Molecular mechanics simulations, involving single point energy calculations and full geometry optimizations, were developed to assist in selecting appropriate chemical systems and understanding physical adsorption and ultimately growth mechanisms in the design of oxide nanoarrays. The versatility of peptide chemistry in controlling the formation of cadmium sulfide nanoparticles and zinc oxide/cadmium sulfide heterostructures was also demonstrated.

  10. Negative Dielectric Constant Material Based on Ion Conducting Materials

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2014-01-01

    Metamaterials or artificial negative index materials (NIMs) have generated great attention due to their unique and exotic electromagnetic properties. One exemplary negative dielectric constant material, which is an essential key for creating the NIMs, was developed by doping ions into a polymer, a protonated poly(benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at megahertz (MHz) frequencies due to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency were tunable by doping concentration. The highly doped PBI showed larger absolute magnitude of negative dielectric constant at just above its resonance frequency than the less doped PBI.

  11. Factors for increasing adoption of e-courses among dental and dental hygiene faculty members.

    Science.gov (United States)

    DeBate, Rita D; Cragun, Deborah; Severson, Herbert H; Shaw, Tracy; Christiansen, Steve; Koerber, Anne; Tomar, Scott; Brown, Kelli McCormack; Tedesco, Lisa A; Hendricson, William

    2011-05-01

    The incorporation of web-based learning into the dental curriculum has been consistently recommended in the literature on reform in dental education. There has been growing support for web-based learning in dental and dental hygiene education as demonstrated by deans' identifying this as a planned curricular innovation. The purpose of our study was to explore characteristics of e-courses that may serve to increase adoption among dental and dental hygiene faculty members. Eight ninety-minute focus groups (three dental; five dental hygiene) were conducted with dental (n=27) and dental hygiene (n=23) faculty members from six academic institutions. The resulting data were analyzed to identify two overarching themes and associated subthemes with regard to benefits and barriers influencing adoption of e-courses. A working conceptual framework, based on the Diffusion of Innovations, was developed from these themes to understand the characteristics that may influence the rate of adoption of e-courses among dental and dental hygiene faculty members. Analysis of the data revealed four main adoption barriers: 1) low perceived relative advantage to faculty members; 2) low compatibility with current curriculum; 3) high perceived time commitment; and 4) complexity of e-course development. This exploratory assessment identifies leverage points for facilitating the adoption and sustainability of e-courses in dental and dental hygiene education. PMID:21546592

  12. Scientific fundamentals for the development of dental implants

    Directory of Open Access Journals (Sweden)

    Lyasnikov V.N.

    2013-09-01

    Full Text Available The article deals with topical issues of development, production and application of modern biocompatible materials and coatings based on them to clinical practice. Particular attention is paid to the intraosseous dental implants, which considered to be the most popular and well established methods to address the defects of dentition with partial and fully edentulous state.

  13. Dental esthetic satisfaction, received and desired dental treatments for improvement of esthetics

    OpenAIRE

    Akarslan Zuhre; Sadik Burak; Erten Hulya; Karabulut Erdem

    2009-01-01

    Aim: The purposes of this research were to investigate factors influencing patients′ satisfaction with their present dental esthetic, received previous dental treatments on anterior teeth and basic treatments that they wanted to undergo to improve their dental appearance. Materials and Methods: A total of 1014 patients who attended a dental school in a major city in Turkey participated in the study. The participants were surveyed with a questionnaire containing questions about gende...

  14. 77 FR 12517 - VA Dental Insurance Program

    Science.gov (United States)

    2012-03-01

    ... AFFAIRS 38 CFR Part 17 RIN 2900-AN99 VA Dental Insurance Program AGENCY: Department of Veterans Affairs...) proposes to amend its regulations to establish a pilot program to offer premium-based dental insurance to... insurer through the Federal contracting process to offer dental insurance, and the private insurer...

  15. Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens:a co-culture study in vitro

    Institute of Scientific and Technical Information of China (English)

    Bingran Zhao; Henny C van der Mei; Minie Rustema-Abbing; Henk J Busscher; Yijin Ren

    2015-01-01

    Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.

  16. Image Post-Processing in Dental Practice

    OpenAIRE

    Gormez, Ozlem; Yilmaz, Hasan Huseyin

    2009-01-01

    Image post-processing of dental digital radiographs, a function which used commonly in dental practice is presented in this article. Digital radiography has been available in dentistry for more than 25 years and its use by dental practitioners is steadily increasing. Digital acquisition of radiographs enables computer-based image post-processing to enhance image quality and increase the accuracy of interpretation. Image post-processing applications can easily be practiced in dental office by ...

  17. 不同种齿科修复材料与牙釉质磨损性能的临床评价%Different types of dental restoration materials and clinical evaluation of enamel wear performance

    Institute of Scientific and Technical Information of China (English)

    马福军; 王占红

    2011-01-01

    背景:冠修复体的严重磨耗会失去咬合功能甚至被磨穿,直接影响修复效果.目的:评价不同种类常用的牙齿修复材料与牙釉质之间的磨耗性能,寻求与天然牙釉质适应性较好的材料.方法:由第一作者检索1990-01/2010-02 PubMed数据及万方数据库有关牙齿修补材料及不同修复材料与牙釉质磨损性能关系的相关文献,英文检索词为"dental materials;composite resins; dental enamel;abrasive wear",中文检索词为"牙釉质;修复材料;磨损;烤瓷;纳米复合体".根据纳入标准,排除重复性研究,保留20篇文献进行分析.结果与结论:口腔是一个复杂的电解质环境,酸性饮食,茵斑堆积,细菌新陈代谢作用产生酸性物质,不论是无机酸还是有机酸,都会对金属的耐腐蚀性能产生不良影响.金属材料的化学稳定性好,耐腐蚀性强,与其表面形成的钝化膜有关,而非金属材料的耐腐蚀性则出现很大不同,参差不齐.磨耗性能牙科材料性能优良与否的主要因素,很多实验从牙科材料结构本身、牙齿磨损测量等多方面进行了深入研究,但对牙科材料的磨损机制研究还有待进一步深入.%BACKGROUND: Severe wear can lead to the loss of occlusal function or the crown restoration will be worn out, which directlyaffects the restoration results.OBJECTIVE: To evaluate the wear property between different types of dental restoration materials and dental enamel, and toseek a material adapting to natural enamel.METHODS: The first author retrieved PubMed database and Wanfang database from 1990 to 2010 for studies about dentalrepair materials and their wear relationships with dental enamel. English key words were “dental materials; composite resins;dental enamel; abrasive wear”, and Chinese key words were “enamel; repair materials; wear; porcelain; nanocomposite”. Therepetitive research was excluded. Twenty papers meeting the inclusion criteria were included in further

  18. Evidence-Based Practice Knowledge, Perceptions, and Behavior: A Multi-Institutional, Cross-Sectional Study of a Population of U.S. Dental Students

    Science.gov (United States)

    Straub-Morarend, Cheryl L.; Wankiiri-Hale, Christine R.; Blanchette, Derek R.; Lanning, Sharon K.; Bekhuis, Tanja; Smith, Becky M.; Brodie, Abby J.; Oliveira, Deise Cruz; Handy-sides, Robert A.; Dawson, Deborah V.; Spallek, Heiko

    2016-01-01

    The aim of this study was to help inform faculty and curriculum leaders in academic dental institutions about the knowledge, skills, perceptions, and behavior of an institutionally diverse population of dental students with respect to evidence-based practice (EBP). A survey utilizing the validated Knowledge, Attitudes, Access, and Confidence Evaluation instrument developed by Hendricson et al. was conducted in 2012 with fourth-year dental students at seven geographically dispersed U.S. dental schools. The survey addressed elements of EBP knowledge, attitudes toward EBP, behavior in accessing evidence, and perceptions of competence in statistical analysis. A total of 138 students from the seven schools participated. A slight majority of these students correctly responded to the knowledge of critical appraisal questions. While the students demonstrated positive attitudes about EBP, they did not report high levels of confidence in their critical appraisal skills. The findings also showed that the students accessed various sources of evidence with differing frequencies. The most frequently accessed resources were colleagues, the Internet (excluding Cochrane Database of Systematic Reviews), and textbooks. The results of this study help to identify areas for improvement in EBP education in order to advance dental students’ preparation to become evidence-based practitioners. PMID:27037451

  19. Agreement between parents and adolescents on dental fluorosis: a population-based study.

    Science.gov (United States)

    Almeida, Maria Eneide Leitão de; Teixeira, Ana Karine Macedo; Alencar, Carlos Henrique; Paiva, Saul Martins; Abreu, Mauro Henrique Nogueira Guimarães de

    2013-01-01

    This study evaluated the prevalence and severity of dental fluorosis and compared the reports from adolescents aged 12 to 18 years with those of their parents regarding the perceptions and concerns arising from this disease. The study was conducted in the cities of Viçosa and Sobral and the District of Rafael Arruda (Sobral), Ceará. A cross-sectional study was conducted from October 2010 to March 2011, with 891 students examined and 780 parents or guardians interviewed. Dental fluorosis was measured using the Dean's Index, and the Child's and Parent's Questionnaire about Teeth Appearance was used to assess the reports from parents and adolescents. A chi-squared test for trends was used to compare the opinions of parents and adolescents about fluorosis, and the agreement was measured using the weighted kappa. For the dichotomous variables, we used the unweighted kappa coefficient. The prevalence of fluorosis was 29.7%, but in the District of Rafael Arruda, evidence of very mild and mild fluorosis was found in 32.5% of the subjects, and moderate and severe fluorosis was found in 28.7%. There was poor agreement between the data reported by the adolescents and their parents or guardians regarding areas of concern and their perceived satisfaction with the appearance and color of their teeth. The prevalence of dental fluorosis was high in one of the communities studied, but the clinical diagnosis of this condition should not necessarily equate with concern and dissatisfaction with aesthetic appearances among teenagers and their parents.

  20. Agreement between parents and adolescents on dental fluorosis: a population-based study

    Directory of Open Access Journals (Sweden)

    Maria Eneide Leitão de Almeida

    2013-04-01

    Full Text Available This study evaluated the prevalence and severity of dental fluorosis and compared the reports from adolescents aged 12 to 18 years with those of their parents regarding the perceptions and concerns arising from this disease. The study was conducted in the cities of Viçosa and Sobral and the District of Rafael Arruda (Sobral, Ceará. A cross-sectional study was conducted from October 2010 to March 2011, with 891 students examined and 780 parents or guardians interviewed. Dental fluorosis was measured using the Dean's Index, and the Child's and Parent's Questionnaire about Teeth Appearance was used to assess the reports from parents and adolescents. A chi-squared test for trends was used to compare the opinions of parents and adolescents about fluorosis, and the agreement was measured using the weighted kappa. For the dichotomous variables, we used the unweighted kappa coefficient. The prevalence of fluorosis was 29.7%, but in the District of Rafael Arruda, evidence of very mild and mild fluorosis was found in 32.5% of the subjects, and moderate and severe fluorosis was found in 28.7%. There was poor agreement between the data reported by the adolescents and their parents or guardians regarding areas of concern and their perceived satisfaction with the appearance and color of their teeth. The prevalence of dental fluorosis was high in one of the communities studied, but the clinical diagnosis of this condition should not necessarily equate with concern and dissatisfaction with aesthetic appearances among teenagers and their parents.

  1. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns.

    Science.gov (United States)

    Hickel, Reinhard; Roulet, Jean-François; Bayne, Stephen; Heintze, Siegward D; Mjör, Ivar A; Peters, Mathilde; Rousson, Valentin; Randall, Ros; Schmalz, Gottfried; Tyas, Martin; Vanherle, Guido

    2007-01-01

    clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the Journal of Adhesive Dentistry and Clinical Oral Investigations. Additionally, an extended abstract will be published in the International Dental Journal, giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community.

  2. Infant dental care (image)

    Science.gov (United States)

    ... sugar water. As the child grows, establishing proper dental hygiene will promote healthy teeth and gums which are essential to overall good health. Poor dental development, dental disease, and dental trauma can result ...

  3. An algorithm of dental/dentofacial-based options for managing patients with obstructive sleep apnoea referred to a dentist/dental specialist by a physician.

    Science.gov (United States)

    Kılınç, D D; Didinen, S

    2016-07-01

    There are so many documents in the literature discoursing the aetiology, nature, diagnosis and treatment planning of obstructive sleep apnoea (OSA). Almost all of them mention that OSA has to be evaluated and treated through the multidisciplinary teamwork of physicians and dentists. Due to a lack in the literature, this article focuses on dentists' and dental specialists' role in the treatment algorithm of OSA. PMID:27388089

  4. Utilization of dental care: An Indian outlook

    Science.gov (United States)

    Gambhir, Ramandeep Singh; Brar, Prabhleen; Singh, Gurminder; Sofat, Anjali; Kakar, Heena

    2013-01-01

    Oral health has a significant impact on the quality of life, appearance, and self-esteem of the people. Preventive dental visits help in the early detection and treatment of oral diseases. Dental care utilization can be defined as the percentage of the population who access dental services over a specified period of time. There are reports that dental patients only visit the dentist when in pain and never bother to return for follow-up in most cases. To improve oral health outcomes an adequate knowledge of the way the individuals use health services and the factors predictive of this behavior is essential. The interest in developing models explaining the utilization of dental services has increased; issues like dental anxiety, price, income, the distance a person had to travel to get care, and preference for preservation of teeth are treated as barriers in regular dental care. Published materials which pertain to the use of dental services by Indian population have been reviewed and analyzed in depth in the present study. Dental surgeons and dental health workers have to play an adequate role in facilitating public enlightenment that people may appreciate the need for regular dental care and make adequate and proper use of the available dental care facilities. PMID:24082719

  5. [Dental prostheses and dental impressions from a hygienic viewpoint].

    Science.gov (United States)

    Engelhardt, J P

    1986-12-01

    Dentures, dental impressions, removable orthodontic appliances and all dental technical devices, which are part of any dental treatment are parts as well of a potential crosscontamination chain in dental treatment. Most of those items do not tolerate heat as a sure sterilization medium. For disinfection, chemical disinfectant solutions may be used as far as they work properly and as they are tolerated by the materials in question. Though, one can report some progress in disinfection of dentures and impressions, there are still questions open depending on safety and/or compatibility of the particular materials. For disinfection of removable dentures chlorine-yielding preparations such as Maranon can be recommended. Peracid preparations, such as Sekusept, Sekusept steril and Dentavon may be useful for disinfection of dental impressions. To do the possible means to reduce the infection risk for all persons involved in the dental treatment, patient, dentist, dental technician and all auxiliary persons. This includes both, active hygiene provisions as sterilization and disinfection, as well as possible passive self protection.

  6. Mercury contamination: occupational risk of the dental surgeon

    Directory of Open Access Journals (Sweden)

    Cristiane K. KAMETANI

    2009-12-01

    Full Text Available Introduction and objective: Mercury is a widely used material in dental practice. However, it is one of the most dangerous environmental and occupational pollutants. Thus, the aim of this study is to analyze several aspects of mercury contamination, based on a literature review, in order to demonstrate the risks related to mishandling of mercury. Literature review: Some recommendations are stated regarding the handling and application of mercury in the dental office environment, once aesthetic materials have been replacing a large number of amalgam restorations. This could lead to mercury vapor exposure, a chemical risk to the health that many dental professionals do not always consider. Conclusion: Mercury can produce local or systemic toxic effects on the organism through vapor inhalation during amalgam preparation or during its replacement.

  7. Registration of the Cone Beam CT and Blue-Ray Scanned Dental Model Based on the Improved ICP Algorithm

    Directory of Open Access Journals (Sweden)

    Xue Mei

    2014-01-01

    Full Text Available Multimodality image registration and fusion has complementary significance for guiding dental implant surgery. As the needs of the different resolution image registration, we develop an improved Iterative Closest Point (ICP algorithm that focuses on the registration of Cone Beam Computed Tomography (CT image and high-resolution Blue-light scanner image. The proposed algorithm includes two major phases, coarse and precise registration. Firstly, for reducing the matching interference of human subjective factors, we extract feature points based on curvature characteristics and use the improved three point’s translational transformation method to realize coarse registration. Then, the feature point set and reference point set, obtained by the initial registered transformation, are processed in the precise registration step. Even with the unsatisfactory initial values, this two steps registration method can guarantee the global convergence and the convergence precision. Experimental results demonstrate that the method has successfully realized the registration of the Cone Beam CT dental model and the blue-ray scanner model with higher accuracy. So the method could provide researching foundation for the relevant software development in terms of the registration of multi-modality medical data.

  8. Base-metal dental casting alloy biocompatibility assessment using a human-derived three-dimensional oral mucosal model.

    LENUS (Irish Health Repository)

    McGinley, E L

    2012-01-01

    Nickel-chromium (Ni-Cr) alloys used in fixed prosthodontics have been associated with type IV Ni-induced hypersensitivity. We hypothesised that the full-thickness human-derived oral mucosa model employed for biocompatibility testing of base-metal dental alloys would provide insights into the mechanisms of Ni-induced toxicity. Primary oral keratinocytes and gingival fibroblasts were seeded onto Alloderm™ and maintained until full thickness was achieved prior to Ni-Cr and cobalt-chromium (Co-Cr) alloy disc exposure (2-72 h). Biocompatibility assessment involved histological analyses with cell viability measurements, oxidative stress responses, inflammatory cytokine expression and cellular toxicity analyses. Inductively coupled plasma mass spectrometry analysis determined elemental ion release levels. We detected adverse morphology with significant reductions in cell viability, significant increases in oxidative stress, inflammatory cytokine expression and cellular toxicity for the Ni-Cr alloy-treated oral mucosal models compared with untreated oral mucosal models, and adverse effects were increased for the Ni-Cr alloy that leached the most Ni. Co-Cr demonstrated significantly enhanced biocompatibility compared with Ni-Cr alloy-treated oral mucosal models. The human-derived full-thickness oral mucosal model discriminated between dental alloys and provided insights into the mechanisms of Ni-induced toxicity, highlighting potential clinical relevance.

  9. Dental Trauma Guide

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Lauridsen, Eva; Gerds, Thomas Alexander;

    2012-01-01

    Diagnosis and treatment for traumatic dental injuries are very complex owing to the multiple trauma entities represented by six luxation types and nine fracture types affecting both the primary and the permanent dentition. When it is further considered that fracture and luxation injuries are often...... combined, the result is that more than 100 trauma scenarios exist, when the two dentitions are combined. Each of these trauma scenarios has a specific treatment demand and prospect for healing. With such a complexity in diagnosis and treatment, it is obvious that even experienced practitioners may have...... problems in selecting proper treatment for some of these trauma types. To remedy this situation, an Internet-based knowledge base consisting of 4000 dental trauma cases with long-term follow up is now available to the public and the professions on the Internet using the address http://www.DentalTrauma...

  10. Surface Functionalization of Graphene-based Materials

    Science.gov (United States)

    Mathkar, Akshay

    Graphene-based materials have generated tremendous interest in the past decade. Manipulating their characteristics using wet-chemistry methods holds distinctive value, as it provides a means towards scaling up, while not being limited by yield. The majority of this thesis focuses on the surface functionalization of graphene oxide (GO), which has drawn tremendous attention as a tunable precursor due to its readily chemically manipulable surface and richly functionalized basal plane. Firstly, a room-temperature based method is presented to reduce GO stepwise, with each organic moiety being removed sequentially. Characterization confirms the carbonyl group to be reduced first, while the tertiary alcohol is reduced last, as the optical gap decrease from 3.5 eV down to 1 eV. This provides greater control over GO, which is an inhomogeneous system, and is the first study to elucidate the order of removal of each functional group. In addition to organically manipulating GO, this thesis also reports a chemical methodology to inorganically functionalize GO and tune its wetting characteristics. A chemical method to covalently attach fluorine atoms in the form of tertiary alkyl fluorides is reported, and confirmed by MAS 13C NMR, as two forms of fluorinated graphene oxide (FGO) with varying C/F and C/O ratios are synthesized. Introducing C-F bonds decreases the overall surface free energy, which drastically reduces GO's wetting behavior, especially in its highly fluorinated form. Ease of solution processing leads to development of sprayable inks that are deposited on a range of porous and nonporous surfaces to impart amphiphobicity. This is the first report that tunes the wetting characteristics of GO. Lastly as a part of a collaboration with ConocoPhillips, another class of carbon nanomaterials - carbon nanotubes (CNTs), have been inorganically functionalized to repel 30 wt% MEA, a critical solvent in CO 2 recovery. In addition to improving the solution processability of CNTs

  11. Zirconia-based dental crown to support a removable partial denture: a three-dimensional finite element analysis using contact elements and micro-CT data.

    Science.gov (United States)

    Rocha, Eduardo Passos; Anchieta, Rodolfo Bruniera; de Almeida, Erika Oliveira; Freitas, Amilcar Chagas; Martini, Ana Paula; Sotto-Maior, Bruno Sales; Luersen, Marco Antonio; Ko, Ching Chang

    2015-01-01

    Veneer fracture is the most common complication in zirconia-based restorations. The aim of this study was to evaluate the mechanical behavior of a zirconia-based crown in a lower canine tooth supporting removable partial denture (RPD) prosthesis, varying the bond quality of the veneer/coping interface. Microtomography (μCT) data of an extracted left lower canine were used to build the finite element model (M) varying the core material (gold core - MAu; zirconia core - MZi) and the quality of the veneer/core interface (complete bonded - MZi; incomplete bonded - MZi-NL). The incomplete bonding condition was only applied for zirconia coping by using contact elements (Target/Contact) with 0.3 frictional coefficients. Stress fields were obtained using Ansys Workbench 10.0. The loading condition (L = 1 N) was vertically applied at the base of the RPD prosthesis metallic support towards the dental apex. Maximum principal (σmax) and von Mises equivalent (σvM) stresses were obtained. The σmax (MPa) for the bonded condition was similar between gold and zirconia cores (MAu, 0.42; MZi, 0.40). The incomplete bonded condition (MZi-NL) raised σmax in the veneer up to 800% (3.23 MPa) in contrast to the bonded condition. The peak of σvM increased up to 270% in the MZi-NL. The incomplete bond condition increasing the stress in the veneer/zirconia interface.

  12. Effect of prophylactic treatments on the superficial roughness of dental tissues and of two esthetic restorative materials Efeito de tratamentos profiláticos na rugosidade superficial de tecidos dentais e de dois materiais restauradores estéticos

    Directory of Open Access Journals (Sweden)

    Daniele Salami

    2003-03-01

    Full Text Available Dental prophylaxis is a common way to remove dental plaque and stain, both undesirable factors in most dentistry procedures. However, besides cleaning the tooth surface, prophylactic techniques may increase the surface roughness of restorations and dental tissues, which, in turn, may result in plaque accumulation, superficial staining and superficial degradation. This study evaluated the effect of three prophylactic techniques - sodium bicarbonate jet, pumice paste and whiting paste - on the superficial roughness of two restorative materials - a composite resin and a compomer - and on the superficial roughness of two dental surfaces - enamel and cementum/dentin - through rugosimetric and scanning electron microscopy (SEM analysis. Statistical analysis of the rugosimetric data showed that the use of pumice paste on enamel produced a significantly smoother surface than the natural surface. However, comparing the effect of the three techniques, prophylaxis with the pumice paste produced a rougher surface than did the other techniques as regards enamel and cementum/dentin probably due to its abrasiveness. On composite resin, the pumice paste only produced a rougher surface than did the whiting paste. On compomer, all of the applied treatments produced similar results. Based on rugosimetric and SEM analysis, we could conclude that the prophylactic treatments employed did not improve roughness of the studied surfaces. As to the effects of the techniques, they were different depending on the surfaces on which the prophylactic treatments were applied.A profilaxia dental é uma prática comum para a remoção de placa bacteriana e outros indutos que dificultam a realização dos procedimentos restauradores. Entretanto, como efeito secundário à limpeza, pode-se ter uma superfície mais rugosa e sujeita a manchamentos e degradações. O presente estudo avaliou os efeitos de três técnicas de profilaxia - jato de bicarbonato de sódio, pasta de pedra

  13. Novel Ag nanocrystals based dental resin composites with enhanced mechanical and antibacterial properties

    Institute of Scientific and Technical Information of China (English)

    Fengwei Liu; Ruili Wang; Yuyuan Shi; Xiaoze Jiang; Bin Sun; Meifang Zhu

    2013-01-01

    The aim of this work was to investigate the effect of trace addition of oleic acid coated Ag nanocrystals (Ag NCs) on mechanical and antibacterial properties of dental resin composites. Composites (70 wt%of silica loading) with 25 ppm, 50 ppm, 75 ppm and 100 ppm (wt) Ag NCs were prepared and the composite without Ag NCs served as a control. The experimental results showed that the addition of Ag NCs significantly improved the strength and modulus of the resin composite without compromising the shade. For the composite with 50 ppm Ag NCs, flexural strength (140.3 MPa), modulus (13.2 GPa) and compressive strength (347.2 MPa) were increased by 4.1%, 22.2%, 13.3%, respectively, compared with the control. The antibacterial test demonstrated that trace Ag NCs provided the resin composites with an antibacterial effect. Such strong and antibacterial dental resin composites might be advantageous to prevent secondary caries and be potential for future clinical applications.

  14. Chelating resin-based extraction of DNA from dental pulp and sex determination from incinerated teeth with Y-chromosomal alphoid repeat and short tandem repeats.

    Science.gov (United States)

    Tsuchimochi, Tsukasa; Iwasa, Mineo; Maeno, Yoshitaka; Koyama, Hiroyoshi; Inoue, Hiroyuki; Isobe, Ichiro; Matoba, Ryoji; Yokoi, Motoo; Nagao, Masataka

    2002-09-01

    A procedure utilizing Chelex 100, chelating resin, was adapted to extract DNA from dental pulp. The procedure was simple and rapid, involved no organic solvents, and did not require multiple tube transfers. The extraction of DNA from dental pulp using this method was as efficient, or more so, than using proteinase K and phenol-chloroform extraction. In this study, the Chelex method was used with amplification and typing at Y-chromosomal loci to determine the effects of temperature on the sex determination of the teeth. The extracted teeth were incinerated in a dental furnace for 2 minutes at 100 degrees C, 200 degrees C, 300 degrees C, 400 degrees C, and 500 degrees C. After the isolation of DNA from the dental pulp by the Chelex method, alphoid repeats, and short tandem repeats, the human Y chromosome (DYZ3), DYS19, SYS389, DYS390, and DYS393 could be amplified and typed in all samples incinerated at up to 300 degrees C for 2 minutes. The DYS389 locus in some samples could not be amplified at 300 degrees C for 2 minutes. An autopsy case is described in which genotypings of DYS19, DYS390, and DYS393 from dental pulp obtained from a burned body were needed. The data presented in this report suggest that Chelex 100-based DNA extraction, amplification, and typing are possible in burned teeth in forensic autopsy cases.

  15. Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

    OpenAIRE

    MANGANO, F; Chambrone, L.; van Noort, R; Miller, C.; Hatton, P.; Mangano, C.

    2014-01-01

    Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and his...

  16. Development of anti-bacterial, re-mineralising and selfadhesive dental composites

    OpenAIRE

    Aljabo, A. F. H.

    2015-01-01

    The project aim was characterisation of antibacterial releasing, remineralising and self-adhesive novel dental composites. Commercially available bulk filling and flowable composites were tested in order to provide benchmark properties for successful dental composite materials. 20 wt. % of light curable urethane dimethacrylate based liquid was mixed with 80 wt. % glass filler containing 10 wt. % CHX and 0 - 40 wt. % CaP. Conversion versus depth with 20 or 40 s light exposure was assessed by F...

  17. The effects of an interactive software application on the self-assessment ability of dental students

    DEFF Research Database (Denmark)

    Mattheos, N.; Nattestad, A.; Christersson, C.;

    2004-01-01

    examination, self-assessment, interactive, internet-based software, undergraduate dental education......examination, self-assessment, interactive, internet-based software, undergraduate dental education...

  18. Maintenance of an Adequate Dental Hygiene Education System.

    Science.gov (United States)

    Ley, Eugene; And Others

    1984-01-01

    Administrative decisions about the future of dental hygiene programs are often based on inadequate information about employment trends and about the importance of the dental hygienist in dental practices. Studies indicate that demand for dental hygiene services will remain high in the 1980s. (Author/MLW)

  19. Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

    Science.gov (United States)

    Damodaran, Vani; Rao, Suresh Ranga; Vasa, Nilesh J.

    2016-08-01

    In this paper, a study of in-house built optical coherence tomography (OCT) system with a wavelength of 840 nm for imaging of dental caries, progress in demineralisation and cavity restoration is presented. The caries when imaged with the 840 nm OCT system showed minute demineralisation in the order of 5 μm. The OCT system was also proposed to study the growth of lesion and this was demonstrated by artificially inducing caries with a demineralisation solution of pH 4.8. The progress of carious lesion to a depth of about 50-60 μm after 60 hours of demineralisation was clearly observed with the 840 nm OCT system. The tooth samples were subjected to accelerated demineralisation condition at pH of approximately 2.3 to study the adverse effects and the onset of cavity formation was clearly observed. The restoration of cavity was also studied by employing different restorative materials (filled and unfilled). In the case of restoration without filler material (unfilled), the restoration boundaries were clearly observed. Overall, results were comparable with that of the widely used 1310 nm OCT system. In the case of restoration with filler material, the 1310 nm OCT imaging displayed better imaging capacity due to lower scattering than 840 nm imaging.

  20. Is there an association between the presence of dental fluorosis and dental trauma amongst school children?

    Science.gov (United States)

    Oliveira, Lorenna Fonseca Braga de; Souza, João Gabriel Silva; Mendes, Rafael Inácio Pompeu; Oliveira, Rodrigo Caldeira Nunes; Oliveira, Carolina de Castro; Lima, Carolina Veloso; Martins, Andréa Maria Eleutério de Barros Lima

    2016-03-01

    Our objective was to evaluate whether there is an association with the different levels of dental fluorosis and the presence of dental trauma amongst school children. A transversal study was conducted amongst school children from the age of 12. Dental examinations were conducted by 24 well trained and fully qualified dental surgeons. Data was collected from 36 randomly selected public schools amongst 89 schools in a municipality. The criteria used to diagnose dental fluorosis was based on the Dean's fluorosis Index and for diagnosing dental trauma we looked for clinical signs of crown fractures and dental avulsions. Multiple descriptive analysis, which was bivariate, was carried out. Amongst the 2,755 school children that took part in the study 1,089 (39.6%) were diagnosed with dental fluorosis and 106 (3.8%) had one tooth or more with dental trauma. We noted a high prevalence of dental fluorosis, independent of the level of severity, amongst individuals with one tooth or more who had dental trauma. This association was even more evident where there were severely high levels of fluorosis. We also noted that the presence of fluorosis was greater amongst those that actively paid more attention to discoloration on their teeth and who received treatment from a dental professional at their schools. Nevertheless dental fluorosis was associated with the presence of dental trauma, independent of its severity. PMID:26960108