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Sample records for canal wall dentine

  1. Clinical management of infected root canal dentin.

    Science.gov (United States)

    Love, R M

    1996-08-01

    Several hundred different species of bacteria are present in the human intraoral environment. Bacterial penetration of root canal dentin occurs when bacteria invade the root canal system. These bacteria may constitute a reservoir from which root canal reinfection may occur during or after endodontic treatment. The learning objective of this article is to review endodontic microbiology, update readers on the role of bacteria in pulp and periapical disease, and discuss the principles of management of infected root canal dentin. Complete debridement, removal of microorganisms and affected dentin, and chemomechanical cleansing of the root canal are suggested as being the cornerstones of successful endodontic therapy, followed by intracanal medication to remove residual bacteria, when required.

  2. Influence of the dentinal wall on the pH of sodium hypochlorite during root canal irrigation

    NARCIS (Netherlands)

    R.G. Macedo; N.P. Herrero; P. Wesselink; M. Versluis; L. van der Sluis

    2014-01-01

    Introduction The purpose of this study was to evaluate the influence of dentin on the pH levels of different concentrations of sodium hypochlorite (NaOCl) solutions over time and to evaluate if preconditioning of dentin with 17% EDTA or agitation of the NaOCl solution influences these pH levels. Met

  3. Influence of the Dentinal Wall on the pH of Sodium Hypochlorite during Root Canal Irrigation

    NARCIS (Netherlands)

    Macedo, Ricardo Gomes; Herrero, Noemi Pascual; Wesselink, Paul; Versluis, Michel; van der Sluis, Luc

    2014-01-01

    Introduction: The purpose of this study was to evaluate the influence of dentin on the pH levels of different concentrations of sodium hypochlorite (NaOCl) solutions over time and to evaluate if preconditioning of dentin with 17% EDTA or agitation of the NaOCl solution influences these pH levels. Me

  4. Ultrastructural investigation of root canal dentine surface after application of active ultrasonic method

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    Mitić Aleksandar

    2008-01-01

    Full Text Available INTRODUCTION The basic work principle of all ultrasonic techniques is the piezoelectric effect of producing high frequency ultrasounds of small length, which are transmitted over the endodontic extensions or canal instruments into the root canal. When in contact with the tissue, ultrasonic vibrations are converted into mechanical oscillations. Ultrasonic waves and the obtained oscillations along with the synergic effect of irrigation bring about the elimination of smear layer from the root canal walls. OBJECTIVE The aim of the study was to ultrastucturally examine the effect of smear layer removal from the walls of canals by the application of the active ultrasonic method without irrigation, that is by the application of ultrasound and irrigation using distilled water and 2.5% NaOCl. METHOD The investigation comprised 35 single-canal, extracted human teeth. After removal of the root canal content, experimental samples were divided into three groups. According to the procedure required, the first group was treated by ultrasound without irrigation; the second one by ultrasound with irrigation using distilled water; and the third group was treated by ultrasound and irrigation using 2.5% NaOCl solution. The control samples were treated by machine rotating instruments (Pro-File and were rinsed by distilled water. RESULTS The obtained results showed that the ultrasonic treatment of the root canal without irrigation did not remove the smear layer. The dentine canals are masked, and big dentine particles are scattered on the intertubular dentine. The ultrasonic treatment by using irrigation with distilled water provides cleaner dentine walls and open dentine tubules but with smaller particles on the intertubular dentine. The ultrasound treatment by using irrigation with 2.5% NaOCl solution provides a clean intertubular dentine surface without a smear layer and clearly open dentine tubules. CONCLUSION Instrumentation of the root canal by application of

  5. Canal Wall Reconstruction Mastoidectomy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the advantages of canal wall reconstruction (CWR) mastoidectomy, a single-stage technique for cholesteatoma removal and posterior external canal wall reconstruction, over the open and closed procedures in terms of cholesteatoma recurrence. Methods: Between June 2002 and December 2005, 38 patients (40 ears) with cholesteatoma were admited to Sun Yat-Sen Memorial Hospital and received surgical treatments. Of these patients, 25 were male with ages ranging between 11 and 60 years (mean = 31.6 years) and 13 were female with ages ranging between 20 and 65 years (mean = 38.8 years). Canal wall reconstruction (CWR)mastoidectomy was performed in 31 ears and canal wall down (CWD) mastoidectomy in 9 ears. Concha cartilage was used for ear canal wall reconstruction in 22 of the 31 CWR procedures and cortical mastoid bone was used in the remaining 9 cases. Results At 0.5 to 4 years follow up, all but one patients remained free of signs of cholesteatoma recurrence, i.e., no retraction pocket or cholesteatoma matrix. One patient, a smoker, needed revision surgery due to cholesteatoma recurrence 1.5 year after the initial operation. The recurrence rate was therefore 3.2% (1/31). Cholesteatoma recurrence was monitored using postoperative CT scans whenever possible. In the case that needed a revision procedure, a retraction pocket was identified by otoendoscopy in the pars flacida area that eventually evolved into a cholesteatoma. A pocket extending to the epitympanum filled with cholesteatoma matrix was confirmed during the revision operation, A decision to perform a modified mastoidectomy was made as the patient refused to quit smoking. The mean air-bone gap in pure tone threshold was 45 dB before surgery and 25 dB after (p < 0.05). There was no difference between using concha cartilage and cortical mastoid bone for the reconstruction regarding air-bone gap improvement, CT findings and otoendoscopic results. Conclusion CWR mastoidectomy can be used for

  6. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems.

    Science.gov (United States)

    Cabanillas, Cristina; Monterde, Manuel; Pallarés, Antonio; Aranda, Susana; Montes, Raquel

    2015-01-01

    Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p < 0.05). Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences.

  7. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems

    Directory of Open Access Journals (Sweden)

    Cristina Cabanillas

    2015-01-01

    Full Text Available Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique, ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p<0.05. Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences.

  8. Incidence of dentinal defects after root canal filling procedures

    NARCIS (Netherlands)

    Shemesh, H.; Wesselink, P.R.; Wu, M.K.

    2010-01-01

    Aim  To compare the incidence of dentinal defects (cracks and craze lines) after root canal preparation, lateral compaction and continuous wave compaction of gutta-percha and AH26 sealer. Methodology  Two hundred mandibular premolar teeth were divided into four groups with similar average canal diam

  9. Interactions between root canal irrigants, sealers and dentin

    NARCIS (Netherlands)

    Neelakantan, P.

    2016-01-01

    The objective of this thesis was to determine the interactions between root filling materials and root dentin and to investigate if root canal irrigating solutions had an impact on these interactions. The following outcomes were assessed in the studies encompassed in this thesis: (i) dislocation res

  10. Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

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    Cesar GAITAN-FONSECA

    2013-01-01

    Full Text Available Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS. Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA. The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT. Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

  11. Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems

    OpenAIRE

    Cristina Cabanillas; Manuel Monterde; Antonio Pallarés; Susana Aranda; Raquel Montes

    2015-01-01

    Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after inst...

  12. Effect of two contemporary root canal sealers on root canal dentin microhardness

    Science.gov (United States)

    2017-01-01

    Background Successful root canal treatment depends on proper cleaning, disinfecting and shaping of the root canal space. Pulpless teeth have lower dentin microhardness value compared to that of vital teeth. A material which can cause change in dentin composition may affect the microhardness. Thus the aim of this study was to evaluate and compare the effect of two root canal sealers on dentin microhardness. Material and Methods Forty two single rooted teeth were selected and divided into 3 equal groups; Apexit, iRootSP and control groups (n=14) Each group was then divided into 2 subgroups according to the post evaluation period; 1 week and 2 months (n=7). Root canal procedure was done in the experimental groups and obturation was made using either; Apexit, iRootSP or left unprepared and unobturated in the control group. Roots were sectioned transversely into cervical, middle and apical segments. The three sections of each root were mounted in a plastic chuck with acrylic resin. The coronal dentin surfaces of the root segments werepolished. Microhardness of each section was measured at 500 µm and 1000 µm from the canal lumen. Results Four way-ANOVA revealed that different tested sealer materials, canal third, measuring distance from the pulp and time as independent variables had statistically non significant effect on mean microhardness values (VHN) at p≤0.001. Among iRootSP groups there was a statistically significant difference between iRoot SP at coronal root portion (87.79±17.83) and iRoot SP at apical root portion (76.26±9.33) groups where (p=0.01). IRoot SP at coronal canal third had higher statistically significant mean microhardness value (87.79±17.83) compared to Apexit at coronal third (73.61±13.47) where (p=0.01). Conclusions Root canal sealers do not affect dentin microhardness. Key words:Root canal, dentin, sealers, microhardness, bioceramic. PMID:28149466

  13. Dentin Morphology of Root Canal Surface: A Quantitative Evaluation Based on a Scanning Electronic Microscopy Study

    OpenAIRE

    Giuseppe Lo Giudice; Giuseppina Cutroneo; Antonio Centofanti; Alessandro Artemisia; Ennio Bramanti; Angela Militi; Giuseppina Rizzo; Angelo Favaloro; Alessia Irrera; Roberto Lo Giudice; Marco Cicciù

    2015-01-01

    Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Ob...

  14. Bio-reconstruction of root canal using dentin post

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    Navin Mishra

    2013-01-01

    Full Text Available This case report describes the successful management of complicated crown fracture of left maxillary central incisor (#21 of 23-year-old male using dentin (biological post made from human tooth. Endodontic treatment was initiated and sectional obturation was done using ProTaper gutta-percha and AH Plus sealer. The coronal space was modified to receive a human dentin post. A two-step procedure comprising direct and indirect technique of post fabrication was done to achieve the accuracy of biological post. A maxillary cuspid from an institutional tooth bank was taken, sectioned mesiodistally using a diamond disc simulating the length and thickness of mock post. Dentin post was first verified on the plaster model and then cemented in tooth #21. Core build up was done with composite and porcelain fused to metal (PFM crown was luted. On the follow-up visits, patient was asymptomatic and radiographic evaluation revealed normal periradicular architecture. Biological posts may be good alternatives to conventional post systems as they preserve internal dentin walls, provide excellent adhesion, and resilience similar to natural tooth structure.

  15. Assessment of the wetting behavior of three different root canal sealers on root canal dentin

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    Muralidhar Tummala

    2012-01-01

    Full Text Available Aim: The objective of the present study was to evaluate and compare the wetting behavior of three different root canal sealers on the root canal dentin surface treated with irrigants and their combination. Materials and Methods: Decoronation and apical third resections of 27 extracted single-rooted human mandibular premolars were done. The roots were then split longitudinally into two halves, and randomly assigned into three treatment groups (n=18. The root dentin surfaces in Group1, Group 2 and Group 3 were treated with 17% ethylene diamine tetra acetic acid (EDTA, 3% sodium hypochlorite (NaOCl and combination of 17% EDTA and 3% NaOCl, respectively. Each group was subdivided into three subgroups of 6 specimens each, depending on the the sealer used, i.e. sub group A. zinc oxide (ZnOE, sub group B. AH plus, subgroup C. Guttaflow sealer, respectively. The contact angle was measured using First Ten Angstroms (FTA 200 dynamic contact angle analyzer. Results: The contact angle values for AH Plus sealer were significantly lower when compared to the other two sealer groups. Conclusion: The wettability of AH Plus sealer on the root surface dentin was found to be better than Gutta-Flow and ZnOE sealer.

  16. Effect of Imidazolium-Based Silver Nanoparticles on Root Dentin Roughness in Comparison with Three Common Root Canal Irrigants

    Science.gov (United States)

    Farshad, Melika; Abbaszadegan, Abbas; Ghahramani, Yasamin; Jamshidzadeh, Akram

    2017-01-01

    Introduction: The aim of this study was to evaluate the effect of a nanosilver-based irrigant on dentin roughness in comparison with three commonly used root canal irrigation solutions. Methods and Materials: Three common irrigants including 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA) and 2% chlorhexidine (CHX) and also an imidazolium-based silver nanoparticle solution (ImSNP) (5.7×10 -8 mol/L), were used. Distilled water was used as control. Roots of 25 human anterior teeth were sectioned longitudinally to obtain 50 dentin samples. Roughness values were evaluated by atomic force microscopy analysis on 5 groups (n=10) after each group was treated in one of the tested irrigant solutions for 10 min. Values were statistically analyzed by One-way analysis of variance, followed by a post hoc Tukey’s test for pair-wise comparison. Results: Dentin roughness significantly increased from 95.82 nm (control) to 136.02 nm, 187.07 nm, 142.29 nm and 150.92 nm with NaOCl, CHX, ImSNP and EDTA, respectively. CHX demonstrated a significantly higher roughness value compared to the other tested irrigants while no significant differences were seen in NaOCl, ImSNP and EDTA groups (P>0.242). Conclusion: ImSNP affected the physicochemical properties of dentin and raised its surface roughness; thus, this irrigant could impact bacterial and restorative material adhesion to root canal dentin walls. PMID:28179931

  17. Effects of the copper vapour laser radiation in the root canal wall dentine: in vitro experiment using scanning electron microscopy and stereoscopy; Efeitos da radiacao laser de vapor de cobre na parede de dentina de canais radiculares: estudo in vitro por meio de microscopia eletronica de varredura e microscopio estereoscopico

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Maria Claudia Garcia da

    2001-07-01

    Ten human uniradicular teeth had their crown removed along the cement-enamel junction and right away a proper chemical-surgical preparation of the radicular canals was done; the roots were longitudinally sectioned in order to allow the irradiation of the surfaces of the root canals wall dentine. The hemi-roots were separated in two groups: group I (control), with four hemi-roots, not irradiated; and group II, with 16 hemi-roots, subdivided in four sub-groups submitted to the following exposition time: 0,02 s; 0,05 s; 0,1 s and 0,5 s. A copper vapour laser was used with a 510,6 nm wavelength, total average power of 11 W in green and yellow emissions; average power of 6,5 W in green emission; pulse repetition rate of 16.000 Hz and pulse duration of 30 ns. The pulse energy (green line) is 0,4 mJ and the peak power 13,5 W. The laser cavity is unstable type (R{sub 1}=3.900 mm and R{sub 2}-250 mm). The focusing have focal length lens f{sub 1}=250 mm and f{sub 2}=150 mm. The beam quality is of the M{sup 2}=5. The results obtained by scanning electron microscopy analysis showed the appearance of a cavity in the region of the laser beam incidence in the edges of this cavity, dentin was melt and resolidified presenting also cracks due to heat diffusion. Based on these results, we concluded that the size of the cavity formed in the dentin is directly proportional to the rate of exposure and, the more laser emission in the same area, more damage in the root canals wall dentin occurs. More studies need to be done with different exposition's time in order to obtain a safety protocol that does not cause injury in dental and support tissue. (author)

  18. Uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in curved root canals

    NARCIS (Netherlands)

    Retsas, A.; Koursoumis, A.; Tzimpoulas, N.; Boutsioukis, C.

    2016-01-01

    Introduction: The aim of this study was to examine the effect of file type and activation time on the uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared curved root canals. Methods: Seventy-two curved mesial root canals of human mandibular molars were prepared

  19. Dentin Morphology of Root Canal Surface: A Quantitative Evaluation Based on a Scanning Electronic Microscopy Study

    Science.gov (United States)

    Lo Giudice, Giuseppe; Cutroneo, Giuseppina; Centofanti, Antonio; Artemisia, Alessandro; Bramanti, Ennio; Militi, Angela; Rizzo, Giuseppina; Favaloro, Angelo; Irrera, Alessia; Lo Giudice, Roberto; Cicciù, Marco

    2015-01-01

    Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Observations were conducted on 30 healthy premolar teeth extracted for orthodontic reasons in patients aged between 10 and 14. A SEM analysis of the data obtained in different canal portions showed that, in the coronal zone, dentinal tubules had a greater diameter (4.32 μm) than the middle zone (3.74 μm) and the apical zone (1.73 μm). The average number of dentinal tubules (in an area of 1 mm2) was similar in coronal zone (46,798 ± 10,644) and apical zone (45,192 ± 10,888), while in the middle zone they were lower in number (30,940 ± 7,651). However, intertubular dentin area was bigger going from apical to coronal portion. The differences between the analysed areas must be considered for the choice of the adhesive system. PMID:26413504

  20. Dentin Morphology of Root Canal Surface: A Quantitative Evaluation Based on a Scanning Electronic Microscopy Study

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    Giuseppe Lo Giudice

    2015-01-01

    Full Text Available Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Observations were conducted on 30 healthy premolar teeth extracted for orthodontic reasons in patients aged between 10 and 14. A SEM analysis of the data obtained in different canal portions showed that, in the coronal zone, dentinal tubules had a greater diameter (4.32 μm than the middle zone (3.74 μm and the apical zone (1.73 μm. The average number of dentinal tubules (in an area of 1 mm2 was similar in coronal zone (46,798±10,644 and apical zone (45,192±10,888, while in the middle zone they were lower in number (30,940±7,651. However, intertubular dentin area was bigger going from apical to coronal portion. The differences between the analysed areas must be considered for the choice of the adhesive system.

  1. Bio-reconstruction of root canal using dentin post

    OpenAIRE

    Navin Mishra; Isha Narang

    2013-01-01

    This case report describes the successful management of complicated crown fracture of left maxillary central incisor (#21) of 23-year-old male using dentin (biological) post made from human tooth. Endodontic treatment was initiated and sectional obturation was done using ProTaper gutta-percha and AH Plus sealer. The coronal space was modified to receive a human dentin post. A two-step procedure comprising direct and indirect technique of post fabrication was done to achieve the accuracy of bi...

  2. The ability of different nickel-titanium rotary instruments to induce dentinal damage during canal preparation

    NARCIS (Netherlands)

    Bier, C.A.S.; Shemesh, H.; Tanomaru-Filho, M.; Wesselink, P.R.; Wu, M.K.

    2009-01-01

    The purpose of this study was to compare the incidence of dentinal defects (fractures and craze lines) after canal preparation with different nickel-titanium rotary files. Two hundred sixty mandibular premolars were selected. Forty teeth were left unprepared (n = 40). The other teeth were prepared e

  3. Comparison of Dentinal Crack Formation With Reciproc, Mtwo and ProTaper Root Canal Preparation Systems

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    Nazari Moghaddam

    2016-06-01

    Full Text Available Background Instrumentation with rotary instruments could potentially cause dentinal cracks possibly leading to tooth fracture. Reciproc files require a single file to finalize the root canal preparation and the effect of this procedure has not been compared with other systems. Objectives The aim of this study was to compare the incidence of dentinal micro-cracks following root canal preparations with ProTaper, Mtwo and Reciproc files. Materials and Methods In an experimental in vitro trial, 80 maxillary and mandibular first molars were selected and their crowns and distal roots were cut. The roots were then examined to remove any previous cracks and defects. An impression polyether material was used to simulate teeth periodontal ligament (PDL. The teeth were divided to four experimental groups (n = 20 and prepared using Reciproc, Mtwo and ProTaper or remained unprepared as a control group. The specimens were then sectioned horizontally on 3, 5 and 9 mm from the apex and number of micro-cracks was determined by stereomicroscope. The incidence of dentinal cracks on different systems or sections were statistically analyzed by means of the chi-square test. Results Dentinal defects on 3-mm, 5-mm and 9-mm sections from the apex were noted in 10 (5.6%; 7 (3.9% and 9 (5.0% samples of all, respectively. Following canal preparation using Reciproc, ProTaper and Mtwo systems, the defects were observed in 7 (3.9%, 12 (6.7% and 7 (3.9% the sections, respectively. No significant differences were observed regarding the defect incidence on the studied instrumentation files or sections. Conclusions Regarding the study limitations, dentinal cracks were observed in all files and distances from the apex. Although there was more crack incidence in ProTaper files, no significant differences were noted regarding the studied systems and sections from the apex.

  4. Computed Tomography Evaluation of Canal Transportation and Volumetric Changes in Root Canal Dentin of Curved Canals Using Mtwo, ProTaper and ProTaper Next Rotary System-An In-vitro Study

    Science.gov (United States)

    Shivashankar, Mayuri Biccodu; Jayasheel, Arun; Kenchanagoudra, Mallikarjun Goud

    2016-01-01

    Introduction Complete cleaning and shaping of root canal system is of paramount importance to achieve a successful root canal treatment. There are various rotary Ni-Ti systems available in the market to achieve mechanical goal of root canal preparation. But aggressive preparation of root canal with such systems would result in canal transportation and excess root dentin removal that would be one of the major reasons to decide the prognosis of root canal treated tooth. Aim The present study was conducted to compare the root canal preparation in terms of canal transportation and volumetric changes in the root canal dentin among three Ni-Ti file systems, namely Mtwo, ProTaper (PT) and ProTaper NEXT (PTN) file system, using Computed Tomography (CT). Materials and Methods A total of 45 mesiobuccal root canals of extracted first molar teeth with completely formed root apices and angle of curvature ranging between 10°- 35° were selected. These teeth were randomly divided into three experimental groups containing 15 teeth each, based on rotary system used. Group-I: Mtwo files, Group-II: PT files and Group-III: PTN files. Pre-instrumentation CT images were obtained at three cross-sectional planes – 3mm, 7mm and 11mm from apical end of the root. Similarly, post-instrumentation images were obtained. Shortest distance from the edge of the canal to the periphery of the root was analyzed by using Analysis of Variance. Results All three file systems tested in the present study presented similar behaviour with respect to the root canal transportation. Lesser canal transportation was recorded in Mtwo. But no statistically significant difference was seen in terms of canal transportation and volume of dentin removed between all three rotary systems (p>0.05). Conclusion Mtwo, PT and PTN rotary systems have similar behaviour with respect to canal transportation and volume of dentin removed. PMID:28050495

  5. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    Science.gov (United States)

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-12-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1: 13.8% chlorine dioxide, Group 2: 17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5 ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth.

  6. The Root Canal Biofilm

    NARCIS (Netherlands)

    Sluis, van der L.W.M.; Boutsioukis, C.; Jiang, L.M.; Macedo, R.; Verhaagen, B.; Versluis, M.; Chávez de Paz, E.; Sedgley, C.M.; Kishen, A.

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  7. Root canal irrigation

    NARCIS (Netherlands)

    L. van der Sluis; C. Boutsioukis; L.M. Jiang; R. Macedo; B. Verhaagen; M. Versluis

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  8. Comparison of 2 flushing methods used during passive ultrasonic irrigation of the root canal

    NARCIS (Netherlands)

    van der Sluis, Lucas; Wu, Min-Kai; Wesselink, Paul

    2009-01-01

    Objective: To determine the effect of irrigation time on the removal of dentin debris from root canals irrigated with passive ultrasonic irrigation comparing 2 flushing methods. Method and Materials: Root canals with a standardized groove in 1 canal wall, which was filled with dentin debris, were ir

  9. Influence of irrigation sequence on the adhesion of root canal sealers to dentin: a fourier transform infrared spectroscopy and push-out bond strength analysis

    NARCIS (Netherlands)

    P. Neelakantan; S. Sharma; H. Shemesh; P.R. Wesselink

    2015-01-01

    Introduction There is a lack of evidence on the chemical interaction between sealers and dentin. The influence of irrigation on the chemical interaction between root canal sealers and dentin was analyzed by using Fourier transform infrared spectroscopy (FTIRS) and measurement of dislocation resistan

  10. Effects of Self-Adjusting File, Mtwo, and ProTaper on the root canal wall

    NARCIS (Netherlands)

    Hin, E.S.; Wu, M.K.; Wesselink, P.R.; Shemesh, H.

    2013-01-01

    Introduction The purpose of this ex vivo study was to observe the incidence of cracks in root dentin after root canal preparation with hand files, self-adjusting file (SAF), ProTaper, and Mtwo. Methods One hundred extracted mandibular premolars with single canals were randomly selected. Two angulate

  11. Effect of the smear layer in the removal of calcium hydroxide from root canal walls

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    Hakan Arslan

    2012-01-01

    Full Text Available Background: The aim of this study was to investigate whether the smear layer influences the removal of calcium hydroxide from the root canal with manual or rotary instruments. Materials and Methods: The root canals of 48 freshly extracted single-rooted maxillary incisors were prepared to apical size 40 (n=40 and finally irrigated with sodium hypochlorite (group A, or ethylene diamine tetra acetic acid (EDTA followed by sodium hypo chlorite (group B. 20 teeth were assigned to each group, while the remaining eight teeth served as positive and negative controls. Each group was divided into two subgroups of 10 teeth (subgroup I - calcium hydroxide was removed with master apical file; subgroup II - with profile file; and, in all removal procedures, citric acid was used for irrigation. The percentage of calcium hydroxide-[Ca(OH [Ca(OH 2 ] coated surface area was calculated by image processing analysis. Results: Considering the root canal as a whole, the removal of Ca(OH 2 from the dentinal walls in group B showed significantly better results (P<0.05 as compared to group A. Conclusions: Under the conditions of this study, it can be concluded that the smear layer is important in the removal of calcium hydroxide.

  12. The influence of volume, type of irrigant and flushing method on removing artificially placed dentine debris from the apical root canal during passive ultrasonic irrigation

    NARCIS (Netherlands)

    van Der Sluis, LWM; Gambarini, G; Wu, MK; Wesselink, PR

    2006-01-01

    Aim To determine the influence of volume, irrigant and method of flushing on the removal of artificially-placed dentine debris from the apical part of root canals during passive ultrasonic irrigation. Methodolgy Access cavities were prepared in 15 canine teeth and their root canals instrumented to s

  13. Comparison of dentinal damage induced by different nickel-titanium rotary instruments during canal preparation: An in vitro study

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    Shiwani Garg

    2015-01-01

    Full Text Available Aim: To compare dentinal damage caused by hand and rotary nickel-titanium instruments using ProTaper, K3 Endo, and Easy RaCe systems after root canal preparation. Materials and Methods: One hundred and fifty freshly extracted mandibular premolars were randomly divided into five experimental groups of 30 teeth each and biomechanical preparation was done: Group 1 with unprepared teeth; Group 2 were prepared with hand files; Group 3 with ProTaper rotary instruments; Group 4 with K3 rotary; Group 5 with Easy RaCe rotary instruments. Then, roots were cut horizontally at 3, 6, and 9 mm from apex and were viewed under stereomicroscope. The presence of dentinal defects was noted. Statistical analysis: Groups were analyzed with the Chi-square test. Results: Significant difference was seen between groups. No defects were found in unprepared roots and those prepared with hand files. ProTaper, K3 rotary, and Easy RaCe preparations resulted in dentinal defects in 23.3%, 10%, and 16.7% of teeth, respectively. More defects were shown in coronal and middle sections, and no defect was seen in apical third. Conclusion: The present study revealed that use of rotary instruments could result in an increased chance for dentinal defects as compared to hand instrumentation.

  14. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

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    Niranjan Ashok Vatkar

    2016-01-01

    Conclusion: E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules.

  15. Demineralization of root canal dentine with EDTA and citric acid in different concentrations, pH and application times

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    Mr.Sc. Nexhmije Ajeti

    2011-12-01

    Full Text Available Abstract The aims of the study are: 1. Determination of the amount of extracted Ca ions from den-tine using 17% and 10% EDTA, at pH 7 and pH 9. 2. Determination of the amount of extracted Ca ions from  den-tine using citric acid 5% and 1%, at pH 7 and pH 9.  Methodology 30 extracted, single rooted, human teeth were tested. Their crowns were sectioned at CEJ using diamond disks. The root canals were manually prepared with K-files #50-60. After each instrument 2.5 ml of 5.25% NaOCl was used and 0.9 NaCl as final irrigation. All teeth were longitudinally sectioned and 8 samples of dentine taken from each sample. EDTA 10% and 17 % and citric acid 1% and 5% in neutral and alkaline pH were used.  Each sample was immersed in acid and then exposure time was evaluated after 1, 5, 10, 15 and 25 min. The release rate of calcium ions from root dentine was evaluated by atomic absorption spectrometer.  Results There were significant differences in the amount of extracted Ca by citric acid 1% and 5% or EDTA 10% and 17% in human teeth.  Conclusions It may be concluded that EDTA is a better chelating agent than citric acid. The decalcifying activity of these solutions is related to the duration of exposure, pH and their concentrations.

  16. Frequency of second mesiobuccal canal in permanent maxillary first molars using the operating microscope and selective dentin removal: A clinical study

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    Suroopa Das

    2015-01-01

    Full Text Available Purpose: The aim of this study was to investigate whether the combination of operating microscope and selective dentin removal increased the frequency of second mesiobuccal (MB2 canal detection in permanent maxillary first molar teeth. Materials and Methods: One hundred fifty permanent maxillary first molars indicated for root canal treatment were randomly selected from patients belonging to the age group of 18-45 years irrespective of gender. After access cavity preparation and location of main canals, the MB2 canal orifice was sought in all teeth with an endodontic explorer under direct vision (Stage I, then under magnification with the aid of operating microscope (Stage II and finally with the combined use of operating microscope and selective dentin removal (Stage III. Results: MB2 canals were detected in 36%, 54% and 72% of the teeth in Stages I-III, respectively. Conclusion: This study demonstrated that dental operating microscope when used along with adjunctive aids such as selective dentin removal/troughing and good clinical knowledge will increase the ability of dental clinician to locate MB2 canals.

  17. Comparison of dentinal and apical crack formation caused by four different nickel-titanium rotary and reciprocating systems in large and small canals.

    Science.gov (United States)

    Zhou, Xin; Jiang, Shan; Wang, Xiao; Wang, Shuai; Zhu, Xiaofei; Zhang, Chengfei

    2015-01-01

    This study compared dentinal and apical crack formation after instrumentation with different nickel-titanium systems at two different working lengths (WL) in large and small canals. Two hundred and eighty human teeth were randomly distributed into two control and 12 experimental groups (n=20 each). Large and small canals were instrumented by the WaveOne, Protaper Universal System (PTU), Twisted File (TF), or Twisted File Adaptive (TFA) at 1 mm shorter than canal length (CL-1 mm) or 1 mm beyond apical foreman (CL+1 mm). Horizontal sections were microscopically observed to evaluate the dentinal cracks (only large canals). Scanning electron microscopy images were taken before and after instrumentation to assess apical cracks. All file types caused more apical cracks in small canals than in large canals regardless of the WL. During over-instrumentation (WL=CL+1 mm), the WaveOne and PTU groups developed significantly more dentinal cracks at the 6 and 9 mm sections than the TF and TFA groups.

  18. Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths

    NARCIS (Netherlands)

    Liu, R.; Kaiwar, A.; Shemesh, H.; Wesselink, P.R.; Hou, B.; Wu, M.K.

    2013-01-01

    Introduction The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. Methods Two hundred forty mandibular incisors were mounted in resin blocks with simulated periodonta

  19. Root canal hydrophobization by dentinal silanization: improvement of silicon-based endodontic treatment tightness.

    Science.gov (United States)

    Collart Dutilleul, Pierre-Yves; Fonseca, Cesar Gaitán; Zimányi, László; Romieu, Olivier; Pozos-Guillén, Amaury J; Semetey, Vincent; Cuisinier, Frédéric; Pérez, Elías; Levallois, Bernard

    2013-07-01

    A new strategy to improve silicon-based endodontic treatment tightness by dentine hydrophobization is presented in this work: root dentine was silanized to obtain a hydrophobic dentine-sealer interface that limits fluid penetration. This strategy was based on the grafting of aliphatic carbon chains on the dentine through a silanization with the silane end groups [octadecyltrichlorosilane (OTS) and octadecyltriethoxysilane]. Dentine surface was previously pretreated, applying ethylenediaminetetraacetic acid and sodium hypochlorite, to expose hydroxyl groups of collagen for the silane grafting. Collagen fibers exposure after pretreatment was visible with scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy showed their correct exposition for the silanization (amide I and II, with 1630, 1580, and 1538 cm⁻¹ peaks corresponding to the vibration of C=O and C--N bonds). The grafting of aliphatic carbon chains was confirmed by FTIR (peaks at 2952 and 2923 cm⁻¹ corresponding to the stretching of C--H bonds) and by the increasing of the water contact angle. The most efficient hydrophobization was obtained with OTS in ethyl acetate, with a water contact angle turning from 51° to 109°. Gas and liquid permeability tests showed an increased seal tightness after silanization: the mean gas and water flows dropped from 2.02 × 10⁻⁸ to 1.62 × 10⁻⁸ mol s⁻¹ and from 10.8 × 10⁻³ to 5.4 × 10⁻³ µL min⁻¹, respectively. These results show clear evidences to turn hydrophilic dentine surface into a hydrophobic surface that may improve endodontic sealing.

  20. IERAPSI project: simulation of a canal wall-up mastoidectomy.

    Science.gov (United States)

    Neri, E; Sellari Franceschini, S; Berrettini, S; Caramella, D; Bartolozzi, C

    2006-03-01

    Among the various EU research projects concerning the medical application of virtual reality, the project Ist-1999-12175, called IERAPSI (Integrated Environment for the Rehearsal and Planning of Surgical Interventions), specifically addressed the creation of a virtual and interactive surgical field for the temporal bone using three-dimensional images derived from CT data. We report on the experience obtained in the IERAPSI project in simulating a canal wall-up mastoidectomy. A surgeon with extensive experience in surgery of the petrous bone performed the mastoidectomy. The operative field included the mastoid, with its substantial differences in density between the cortex and the pneumatized bone, together with soft tissue structures, both on the border and inside the bone. The simulation is better in the first part of the operation than in the second part, suffering from a lack of haptic feedback from soft tissue and the surgical tool in deeper contexts, and under-representation of the variability inherent in pneumatized bone. This said, the excellent representation of dust production and removal, 3D simulation through color, and very good visual and haptic feedback in the early stage of the procedure are impressive. IERAPSI represents a potential surgical planning theater for the training of students and young surgeons, but is also expected to aid expert surgeons in the preoperative planning of difficult cases.

  1. The effect of three different antioxidants on the dentinal tubular penetration of Resilon and Real Seal SE on sodium hypochlorite-treated root canal dentin: An in vitro study

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    Sarah Renjelina Christopher

    2016-01-01

    Full Text Available Objective: The effect of 10% ascorbic acid, 10% tannic acid, and 10% gallic acid on the dentinal tubular penetration of Resilon and Real Seal SE on sodium hypochlorite-treated root canal dentin was evaluated. Materials and Methods: Fifty human premolars were decoronated to attain 14-mm root length and divided into five groups of 10 teeth each. Biomechanical preparation was done with rotary instruments. Group I specimens were irrigated with saline and 17% ethylenediaminetetraacetic acid (EDTA. Specimens from groups II, III, IV, and V were irrigated with 5.25% sodium hypochlorite and 17% EDTA. Specimens from groups III, IV, and V underwent additional irrigation with antioxidants-10% ascorbic acid, 10% tannic acid, and 10% gallic acid, respectively. Following obturation with Resilon and Real Seal SE, scanning electron microscope (SEM analysis was done to note the maximum dentinal tubular penetration at the cervical, middle, and apical thirds of each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA, Post hoc and Dunnett′s test. Results: Maximum dentinal tubular penetration of Resilon and Real Seal SE was obtained following irrigation with 10% gallic acid. Conclusion: 10% gallic acid was superior among the antioxidant irrigants that enabled the increased dentinal tubular penetration of Resilon and Real Seal SE.

  2. Antimicrobial activity and substantivity of Uncaria tomentosa in infected root canal dentin.

    Science.gov (United States)

    Herrera, Daniel Rodrigo; Durand-Ramirez, Jorge Enrique; Falcão, Amanda; Silva, Emmanuel João Leal Nogueira da; Santos, Elizabete Brasil Dos; Gomes, Brenda Paula Figueiredo de Almeida

    2016-01-01

    The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat's claw, CC) in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212) and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP): CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX); NaOCl group: 5.25% sodium hypochlorite (NaOCl); and SS group: sterile saline (SS). Microbiological samples were collected before (S1) and after (S2) CMP and after 7 days (S3). Colony-forming units (CFU/mL) at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p 0.05) in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05) in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days.

  3. Antimicrobial activity and substantivity of Uncaria tomentosa in infected root canal dentin

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    Daniel Rodrigo HERRERA

    2016-01-01

    Full Text Available Abstract The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat’s claw, CC in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212 and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP: CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX; NaOCl group: 5.25% sodium hypochlorite (NaOCl; and SS group: sterile saline (SS. Microbiological samples were collected before (S1 and after (S2 CMP and after 7 days (S3. Colony-forming units (CFU/mL at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p 0.05 in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05 in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days.

  4. Reinforcement of thin-walled root canal structures for placement of esthetic dowels: a clinical report.

    Science.gov (United States)

    Ayad, Mohamed F; Bahannan, Salma A; Rosenstiel, Stephen F

    2011-01-01

    Thin-walled root canals always present a challenge to dentists to select a restorative treatment that does not further weaken the thin tooth structure. The prognosis of dowel and core restorations can be unpredictable. This clinical report describes the treatment of a patient with extensive caries extending into the root canal of an endodontically treated maxillary central incisor. The use of a flowable composite resin in combination with a quartz fiber reinforced post is described, resulting in the rehabilitation of a structurally compromised root canal with satisfactory esthetic and functional outcomes.

  5. Evaluation in vitro of effects of Er:YAG and Nd:YAG lasers irradiation on root canal wall, by stereoscopy, scanning electron micrography and thermographic camera; Avaliacao in vitro dos efeitos da irradiacao laser de Er:YAG e Nd:YAG na parede dentinaria do canal radicular, sob observacao do estereoscopio, da micrografia eletronica e da camera termografica

    Energy Technology Data Exchange (ETDEWEB)

    Goya, Claudia

    2001-07-01

    This study was carried out to evaluate in vitro the effects of Nd:YAG laser and Er:YAG laser irradiation in the root canal wall by SEM, evaluating the apical leakage and the temperature changes during the laser irradiation. Seventy four extracted human teeth were used, they were instrumented and divided into seven groups of 10 teeth each. The teeth were evaluated through stereoscopy, by SEM, and with the thermographic camera. The Nd:YAG laser irradiation parameters were 100 mJ/p, 15 Hz, and Er:YAG laser were 160 mJ/p and 10 Hz, the irradiation was 4 times at 2 mm/sec speed, with 20 sec interval. The apical leakage was not observed in the teeth irradiated by Nd:YAG laser alone or in association with Er:YAG laser. However in the teeth irradiated only by the Er:YAG laser we observed a little leakage. By SEM observation the Nd:YAG laser irradiation showed melting and recrystallization in the dentin surface closing dentinal tubules, and in the samples irradiated by Er:Y AG laser a clean surface, opened dentinal tubules, and the combination by two lasers, showed melting covering some dentinal tubules The thermographic study found the temperature increase was not more than 6 deg C. This study showed the safety parameters applications of Er:YAG laser in association with Nd:YAG laser in root canal treatment, in order to not cause thermal damages to the periodontal tissues. (author)

  6. Defective anterior wall of inguinal canal and its role in the pathophysiology of direct inguinal hernias

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    Abdolvahabi SA

    2002-06-01

    Full Text Available Regrding pathophysiology of direct inguinal hernias the following are pointed our:1-Absence of contribution of fascia of transverses abdominis muscle along with fascia transversalis in making posterior wall of the inguinal canal causing defect point in Hesselbachs triangle.2- Defects in protectin mechanisms of the inguinal canal such as: I shutter like effect of the arch of internal oblique and transverses abdominis muscles. ii Sphincter like effect of fascia of oblique muscle (anterior wall of canl.During several years of observation and practice in the field of surgical repair of hernias, a new phenomenon was observed regarding the etiology of direct hernias.Evaluation of superficial ring and Ant. Wall of inguinal canal in 25 patients showed that the ant. Wall was not perfect and the defect was seen as a spectrum of moderate defect to complete absence of the wall. This phenomenon may be a newly observed mechanism in pathology of direct inguinal hernia that might help the operative repair. Taking this into account, i.e. repair of this defect, might help the classic herniorrhaphy techniques

  7. Techniques of the tympanomastoidectomy with reconstruction of the posterior bone wall of the external auditory canal

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    Dankuc Dragan

    2015-01-01

    Full Text Available A combined tympanoplasty method, the mobile-bridge tympanoplasty, has been applied at the Clinic for Ear, Nose and Throat Diseases in Novi Sad since 1998. Mobile-bridge tympanoplasty is performed at our Clinic by applying Feldmann’s procedure utilizing a microsurgical oscillating saw. It is a combination of closed and open techniques for surgical treatment of middle ear diseases. In addition to this technique, a method for reconstruction of the posterior bone wall of the external auditory canal was introduced. This procedure is applied in cases of damage or impairment of the bony ear canal wall using mastoid cortical temporal bone graft or modeled cartilage of the concha. Maintenance of general anatomical relations in the middle ear enables good ventilation of pneumatic spaces of the middle ear and Eustachian tube permeability, thus providing good conditions for ossicular chain reconstruction. The incidence of recurrent cholesteatoma in combined mobile-bridge tympanoplasty and tympanoplasty with reconstruction of the posterior bone wall was 6% in total. The incidence values for the recurrent cholesteatoma in closed tympanoplasty and in cases of open techniques were 10%. Mobile-bridge tympanoplasty and reconstruction of the posterior bone wall of external auditory canal are methods of choice in surgical treatment of middle ear cholesteatoma that progressed to the attic space, sinus tympani and facial recess.

  8. [The use of ultrasonic files in canal preparation].

    Science.gov (United States)

    Calas, P; Terrie, B

    1990-01-01

    The continuous high volume of irrigating solution delivered by the ultrasonic system facilitates the root canal debridement. An excellent cleaning of dentin wall is obtained even on surfaces unreached by the mechanical instrumentation. In order to obtain an efficacious preparation, the use of ultrasonic files were combined with instrumentation. This new technique is described in this article.

  9. Comparative evaluation of canal transportation, centering ability, and remaining dentin thickness between WaveOne and ProTaper rotary by using cone beam computed tomography: An in vitro study

    Science.gov (United States)

    Jain, Aditi; Asrani, Hemant; Singhal, Abhinav Chand; Bhatia, Taranjeet Kaur; Sharma, Vaibhav; Jaiswal, Pragya

    2016-01-01

    Aims: To compare the canal transportation, centering ability, and remaining dentin thickness of WaveOne and ProTaper systems using cone beam computed tomography. Subjects and Methods: Forty extracted human single-rooted premolars were used in the present study. Preinstrumentation scanning of all teeth was taken; canal curvatures were calculated, and the samples were randomly divided into two groups, with twenty samples in each group; one group was instrumented with WaveOne system and the other group with ProTaper rotary system. Postinstrumentation scans were performed, and the two scans were compared to determine canal transportation, centering ability, and remaining dentin thickness at 3 mm, 6 mm, and 9 mm from the root apex. Statistical Analysis Used: Student's unpaired t-test. Results: Using Student's unpaired t-test, results were as follows: for canal transportation, Group 1 showed significant difference at 3 mm and 6 mm and insignificant difference at 9 mm while Group 2 showed insignificant difference in all the three regions. For centering ability and remaining dentin thickness, Group 1 showed insignificant difference at 3 mm and 9 mm while significant difference at 6 mm was obtained. When comparison of remaining dentin thickness was done at three levels using two groups WaveOne and ProTaper, there was no significant difference between two groups. Conclusions: (1) WaveOne single reciprocation file system respected better canal anatomy better than ProTaper. (2) Individually, centering ability of WaveOne was better at 3 mm, 6 mm, and 9 mm levels. (3) However, ProTaper individually was better centered at 3 mm (apical third) and 9 mm (coronal 3rd) levels than 6 mm level (middle third). PMID:27656063

  10. Interfacial adaptation of an epoxy-resin sealer and a self-etch sealer to root canal dentin using the System B or the single cone technique.

    Science.gov (United States)

    Cavenago, Bruno Cavalini; Duarte, Marco Antonio Hungaro; Ordinola-Zapata, Ronald; Marciano, Marina Angélica; Carpio-Perochena, Aldo Enrique del; Bramante, Clovis Monteiro

    2012-01-01

    The aim of this laboratory study was to compare the interfacial adaptation of an epoxy-resin and a self-etch sealer in mesial root canals of mandibular molars filled using the System-B/Elements Obturation Unit. Sixty mesial root canals of mandibular molars were prepared using the K3 rotary system up to 35.04 instrument and then filled with the aid of the System-B/Elements Obturation Unit using either gutta-percha/ThermaSeal Plus (n=15) or Resilon/Real Seal SE (n=15). The single cone technique using both materials was used as control. The sealers were stained with Rhodamine B dye and the teeth were filled and sectioned at 2, 4 and 6 mm from the apex. The interfacial marginal adaptation of sealers was evaluated using confocal microscopy. Statistical analyses were performed by the Kruskall-Wallis test (α=0.05). In general, microscopic analysis showed a quite regular gap distribution pattern at sealer-dentin interfaces, mainly for the two groups filled with Real Seal SE. This means that both nonbonding root-filling groups (ThermaSeal Plus) showed significantly higher amount of gap-free regions regardless of the filling technique (pepoxy resin-based sealer using either the system B or the single cone technique.

  11. Dentin ablation-rate measurements in endodontics witj HF and CO2 laser radiation

    Science.gov (United States)

    Makropoulou, Mersini I.; Serafetinides, Alexander A.; Khabbaz, Marouan; Sykaras, Sotirios; Tsikrikas, G. N.

    1996-01-01

    Recent studies focused on the ability of the laser light to enlarge the root canal during the endodontic therapy. The aim of this research is the experimental and theoretical study of the ablation rate of two infrared laser wavelengths on dentin. Thirty freshly extracted human teeth were longitudinally sectioned at thicknesses ranged from 0.5 to 2 mm, and irradiated on the root canal dentin. The measured ablation rates in dentinal wall of the root canal showed that the HF laser at 2.9 micrometer can more effectively penetrate into the tissue, whereas the carbon dioxide laser at 10.6 micrometer leads to high thermal damage of the ablation crater surroundings.

  12. Comparison of canal wall incisions for tympanoplasty for large central perforations

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    Sohil I Vadiya

    2015-01-01

    Full Text Available Aim and Objective: To compare surgical outcomes with different canal wall incisions used in common practice for tympanoplasty for large perforations. Materials and Methods: Totally 88 patients included in the study and three groups formed. Group A consisted of 35 patients and the vascular strip incision with anterior tucking (VSAT technique used in these patients. Group B consisted of 31 patients and the tympanometal flap with anterior tucking (TMFAT technique used in these patients. Group C had 22 patients and the near full cuff (NFC technique used in them. Results: Success rate of 97.15% observed for Group A, 93.55% observed for Group B and 86.36% observed for Group C patients. Most of the patients in Group A had healing time <4 weeks, whereas most patients in Group C had more than 5 weeks of healing time. Granulations were not seen in Group A, whereas 3 among Group B and 4 among Group C patients developed granulations. Canal wall sagging was seen in 1 among Group A, 2 among Group B and 4 among Group C patients. The average hearing gain in terms of improvement in air-bone gap for Groups A, B and C have been 19.62, 19.25 and 17.35 db, respectively. Conclusion: The VSAT is the method of choice in terms of better success rates and minimum canal skin related complications in postoperative period. The VSAT also provides good exposure during surgery. Hearing gain in Group A is significantly better than Group C (P = 0.023.

  13. Topical application of Mitomycin C in the treatment of granulation tissue after Canal Wall Down mastoidectomy

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    Alireza Karimi-Yazdi

    2013-03-01

    Full Text Available Introduction: Otorrhea and granulation tissue in Canal Wall Down mastoidectomy (CWD is the common problem in cholesteatoma removal and leads to many discomfort for both the patient and the physician. The main objective in CWD is creating the dry cavity, so the topical antibiotic and acetic acid in variable saturations are used for this purpose. In this study we evaluate the effectiveness of topical MMC and chemical cautery by acetic acid.   Materials and Methods: Study population consists of 50 patients with cholesteatoma whom underwent CWD. All patient allocated randomly in two study groups, MMC and acetic acid. After 3 weeks, the first visit is planned, extension of granulation tissue and dryness of cavity are evaluated and topical drugs are used in blind fashion. MMC in 4% and acetic acid in 12.5% saturation are applied. Other visits are completed at next month and 3 months later.   Results: Both methods are effective in treatment of granulation tissue. In each group both treatment were effective too but MMC was more effective than acid acetic in the treatment of granulation tissue after 4 weeks.   Conclusion: Based on our findings, it is clear that topical MMC is very effective in the treatment of granulation tissue and in CWD. It results in dry cavity much better than acetic acid without any complication. 

  14. Clinical application of canal wall reconstruction with homograft cortical bone plate in canal wall down tympanoplasty%自体皮质骨外耳道重建在开放式鼓室成形术中的应用

    Institute of Scientific and Technical Information of China (English)

    马喆; 习国平; 张社江; 蔡爱军; 郝艳芳; 梁宝莲

    2012-01-01

    目的 对开放式鼓室成形术中利用自体皮质骨行外耳道重建的方法及疗效进行评价.方法 将接受手术治疗的胆脂瘤型中耳炎患者49例(49耳)分为两组.实验组,行开放式鼓室成形术+自体皮质骨外耳道重建术25例(耳);对照组,行常规开放式鼓室成形术+耳甲腔成形术24例(耳).术后随访6 ~ 36个月,观察两组患者术后听力结果、干耳率情况.结果 以术后语言频率气骨导差缩小>15 dB或气导听阈<40 dB为有效标准,实验组有效率68% (17/25),对照组有效率62.5% (15/24),组间比较无统计学意义(x2=0.1635,P>0.05).实验组干耳率为92.5%(23/25),明显高于对照组58.33%(14/24),差异有统计学意义(x2=4.363 6,P <0.05).实验组重建后的外耳道结构正常,无闭锁或狭窄情况发生.中耳乳突腔均接近正常.全部病例均无胆脂瘤复发.结论 开放式鼓室成形术加自体皮质骨外耳道重建术,能有效清除中耳病灶组织、恢复外耳道和中耳的结构,术后听力结果满意,干耳率高,是较为理想的手术方式.%Objective To evaluate the therapy of canal wall down tympanoplasty and canal reconstruction with homo-graft cortical bone plate. Methods Retrospective case review. 49 patients were divided into 2 groups. The experimental group that included 25 ears underwent canal wall down tympanoplasty and canal reconstruction with homograft cortical bone plate, while the control group that included 24 ears underwent regular canal wall down tympanoplasty with canal reconstruction. Follow up lasted 6-36 months and postoperative hearing and dry ear rate were evaluated. Results The criteria for success were defined as AB gap closure over 15 dB HL or air conduction threshold less than 40 dB HL (using the mean of 0. 5-, 1-, and 2-KHz threshold values). The experimental group's effective rate was 68% (17/25) and the control group's was 62. 5% (15/24). No significant difference was found between the

  15. Comparison of dentinal microcracks of oval shaped canal prepared with different nickel-titanium instruments%新型镍钛机动器械预备椭圆形根管牙本质微裂比较

    Institute of Scientific and Technical Information of China (English)

    伍婉翠; 吴补领; 陈广盛

    2014-01-01

    目的:通过观察3种新型镍钛机动器械预备椭圆形根管后牙根牙本质微裂情况,比较不同根管预备器械对根管预备后牙根抗折能力的影响。方法收集65个具有椭圆形单根管的下颌前牙,分为3个试验组(每组n=20)和对照组(n=5),试验组分别用自调节锉(SAF)、ProTaper Universal和ProTaper Next进行根管预备,对照组不进行根管预备。离根尖3、6、9 mm处横断牙根,体视显微镜下评估牙本质微裂情况。结果 ProTaper Universal组根折发生率高于 ProTaper Next组和 SAF组(P<0.05)。ProTaper Next组和SAF组的牙根折裂发生率比较,差异无统计学意义(P>0.05)。结论新型镍钛器械ProTaper Next和 SAF根管预备后牙本质微裂形成少,能降低根管治疗后牙根折裂风险。%Objective To compare the effect of different nickel-titanium rotary files on fracture resistance of teeth by observing status of dentinal microcracks after root canal preparation with.Methods 6 5 mandibular anterior teeth with single oval canal were randomly divided into three experimental groups (n=20)and a control group (n=5),SAF、ProTaper Universal and ProTaper Next system were used to prepare root canal in experimental groups,while the control group were left unprepared.Roots were sectioned from 3,6,9 mm to the apex,its status of dentinal microcracks was evaluated under a stereomicroscope.Results Root fracture inci-dence rate of group ProTaper Universal was significantly higher than that of group SAF and group ProTaper Next (P0.05).Conclusion Roots with oval shaped canal prepared with SAF and ProTaper Next produce less dentinal microc-racks,which decrease risk of vertical root fracture.

  16. Evolution of root canal sealers: An insight story

    Directory of Open Access Journals (Sweden)

    Sanjeev Tyagi

    2013-01-01

    Full Text Available Attainment of ideal root canal treatment comprises various essential factors such as proper instrumentation, biomechanical preparation, obturation, and ultimately depending upon the case, post-endodontic restoration. Main objective of the treatment is to get absolute rid of microbial entity and prevent any future predilection of re-infection. In order to achieve that, proper seal is required to cut down any chance of proliferation of bacteria and future occurrence of any pathology. Although gutta-percha has been the standard obturating material used in root canal treatment, it does not reinforce endodontically treated roots owing to its inability to achieve an impervious seal along the dentinal walls of the root canal. Gutta-percha does not from a monoblock even with the use of a resin-based sealer such as AH Plus because the sealer does not bind to gutta-percha. As a result, a monoblock is formed (consisting of Resilon core material, Resin sealer, bonding agent/primer, and dentin. Another reason of Resilon being a better obturating material could be that the removal of smear layer by ethylenediaminetetraacetic acid (EDTA after biomechanical preparation may have allowed the root canal filling material and root canal sealers to contact the canal wall and penetrate in the dentinal tubules, which may increase the strength of roots. New silicone-based sealers like Roekoseal automix and the most recent GuttaFlow have some affirmative results regarding solubility and biocompatibility, as compared to other sealers. Methacrylate resin-based sealers and mineral trioxide aggregate (MTA-based sealers have opened a new horizon for sealers.

  17. A novel type of developmental dentin defect.

    Science.gov (United States)

    Lukinmaa, P L; Waltimo, J; Hölttä, P; Risteli, L; Risteli, J; Alaluusua, S

    1996-01-01

    We describe a developmental dentin disorder distinct from dentin defects characterized thus far. The proband was a 9-year-old boy who was the only family member known to be affected in five generations. The dental defect was not associated with any general disease or developmental disorder. The teeth appeared normal with the exception of the pink hue seen in some primary teeth. Radiographs showed pathological resorption of primary teeth and abnormally shaped pulp chambers and denticles in permanent teeth. Root canals were wide in developing teeth, but appeared thin in erupted teeth. Histological examination of two primary molars revealed canal-like defects in dentin. In the crown, the canals appeared as clusters, which alternated with columns of normal tubular dentin, and in the virtually atubular root dentin they were haphazardly distributed. Scanning electron microscopic examination confirmed the distribution pattern of the canals. In transmission electron microscopy, the defects were found to contain symmetrically banded, segmental collagenous structures. The canal contents immunostained with antibodies to the N-terminal propeptide of type I procollagen, suggesting retention of the propeptide extension in type I collagen. Whereas type III collagen reactivity was barely detectable in the canal region, staining for type V collagen and the non-fibril-forming type VI collagen was strong. The findings imply that the pathogenesis of the defect could be related to a local failure of odontoblasts to produce normal dentin matrix.

  18. CBCT Assessment of Root Dentine Removal by Gates-Glidden Drills and Two Engine-Driven Root Preparation Systems

    Science.gov (United States)

    Harandi, Azade; Mohammadpour Maleki, Fatemeh; Moudi, Ehsan; Ehsani, Maryam; Khafri, Soraya

    2017-01-01

    Introduction: The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT). Methods and Materials: A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups (n=13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey’s post hoc tests were used for two-by-two comparisons. Results: Gates-Glidden drills with hand files removed significantly more (P0.05). Conclusion: The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls. PMID:28179920

  19. Ancient engineering geology projects in China; A canal system in Ganzu province and trenches along the Great Wall in Ningxia Hui Autonomous Region

    Science.gov (United States)

    Wallace, R.E.; Bucknam, R.C.; Hanks, T.C.

    1994-01-01

    Two major construction projects of ancient times in China involved what today would be considered engineering geology. We describe an ancient canal system in Gaotai County, Gansu province that was possibly begun in the Han dynasty (206 BC-220 AD). The canal system heads at the Dasha River and extends northwestward for about 55 km to the City of Camels and Xusanwan village. Four parallel canals are present at the local site we examined. The canals were likely built primarily to transport water but may also have served as defensive military barriers. A second project involves trenches and berms along the north side of the Great Wall, clearly part of the Great Wall defensive system. This site is in Ningxia Autonomous Region near the town of Shizuishan. ?? 1994.

  20. Effectiveness of simplified dentin bonding systems.

    Science.gov (United States)

    Imai, T; Itoh, K; Tani, C; Manabe, A; Yamashita, T; Hisamitsu, H; Wakumoto, S

    1998-03-01

    The effectiveness of newly developed commercial dentin bonding systems (SB, MB II and KB) was evaluated by measuring the contraction gap width of a resin composite restored into a cylindrical dentin cavity prepared in an extracted human molar and by measuring the tensile bond strength to the flat dentin surface. In addition, calcium loss during dentin conditioning was analyzed using electron microanalyses. An experimental dentin bonding system composed of EDTA conditioning, GM solution priming and a bonding agent containing 10-MDP was employed as a control in which it was presumed that contraction gap formation was prevented completely. However, gap formation was observed using the three commercial simplified dentin bonding systems. SEM observation showed that the gap was formed between the resin composite and the top surface of the dentin cavity wall indicating that the fracture occurred at the adhesive interface, but never inside the dentin nor inside the resin composite.

  1. Microporous, demineralized collagen matrices in intact radicular dentin created by commonly used calcium-depleting endodontic irrigants.

    Science.gov (United States)

    Tay, Franklin R; Gutmann, James L; Pashley, David H

    2007-09-01

    The use of calcium-depleting solutions in restorative dentistry results in demineralization of intact coronal dentin beneath smear layers. Likewise, application of calcium-depleting irrigants as final rinses might create demineralized collagen matrices in intact radicular dentin after removal of root canal wall smear layers created during canal shaping. These unsupported collagen matrices collapse on desiccation and might be difficult to detect in scanning electron microscopy dehydration techniques traditionally used in endodontic research. Demineralized collagen matrices were identified, by using a hexamethyldisilazane dehydration protocol, on the surface of smear layer-depleted radicular dentin when NaOCl was used as initial rinse, followed by the use of 17% ethylenediaminetetraacetic acid or BioPure MTAD as the final rinse. Compaction of conventional root filling materials over a demineralized collagen matrix in instrumented dentin is analogous to performing the same procedure against the predentin collagen network in the uninstrumented parts of root canals. The potential consequences of this process are, however, unknown.

  2. Evaluation of inactivation of intracanal antiseptics by dentin, demineralized dentin, dentin matrix and mineral component of dentin

    Directory of Open Access Journals (Sweden)

    Razmi H

    2007-01-01

    Full Text Available Background and Aim: Many studies have shown that microorganisms are the main cause of pulpal diseases and the main purpose of root canal therapy is their elimination from the root canal system. Antiseptic agents are used to reduce bacteria but their antibacterial activities differ from in vivo to in vitro studies and might be inactivated by dentin and its components in root canal space. This study was designed to investigate the effect of dentin on antibacterial activity of different antimicrobial agents. Materials and Methods: In this experimental study, two antibacterial agents (sodium hypochlorite and chlorhexidine with different concentrations were used in four experimental groups: Group 1: dentin, Group 2: demineralized dentin with EDTA, Group 3: dentin matrix and Group 4: dentin mineral component. The species used in this study was Entrococcus faecalis. Different concentration of agents were added to mixture of each experimental group and bacteria. At the baseline and after one and 24 hours, samples were collected and cultured. After incubation period, colonies were counted. Data were analyzed by Tukey test with p<0.05 as the limit of significance. Results: 2% and 0.2% chlorhexidine, and 5% sodium hypochlorite solutions at the three studied times eliminated Entrococcus faecalis completely. 1% sodium hypochlorite eliminated all bacteria in 1h and 24 hs. Statistical analysis showed significant differences between experimental and control groups (P<0.05. Sodium 1% hypochlorite at time 0, could reduce bacteria significantly (P<0.05 but didn’t eliminate them completely. Conclusion: Inactivation of intracanal antiseptics was not observed in this study. As elimination of bacteria occurred, application of these antibacterial agents are recommended in endodontic treatment. Further investigations on other antibacterial agents, other concentrations and shorter time intervals are recommended.

  3. 镍钛器械不同运动方式根管预备后牙根微裂的体外研究%Dentinal crack formation during root canal preparations using reciprocating and rotary files

    Institute of Scientific and Technical Information of China (English)

    于飞; 杨欣

    2016-01-01

    目的:比较Waveone与ProTaper Universal镍钛器械采用不同运动方式根管预备后牙根微裂的发生。方法:40颗离体下颌切牙随机分成4组(n=10),实验组分别使用Waveone Primary单支锉往复式运动、ProTaper Universal F2单支锉往复式运动、ProTaper Universal全序列至F2连续旋转运动模式预备根管,对照组不进行根管预备。根管预备后,距根尖孔3 mm、6 mm、9 mm处进行水平切盘,体视显微镜下观察牙根不同横截面牙根微裂的发生情况。结果:对照组未观察到牙根微裂。实验组中,Waveone Primary单支锉往复式运动组、ProTaper Universal F2单支锉往复式运动组和ProTaper Universal全序列连续旋转运动组产生根裂的比例分别为20%、30%和60%。往复式运动组和连续旋转运动组之间差异均有统计学意义(P0.05)。结论:机用镍钛器械采用往复式运动可减少牙根微裂的发生。%Objective:To compare the incidence of dentinal cracks after root canal preparation with instruments working in continuous rotation and reciprocating motion. Method:40 extracted mandibular central incisors with mature apices and straight root canals (5°~10°)were selected and kept in saline. Group A samples were prepared with WaveOne primary files,group B samples with single F2 ProTaper working in reciprocating motion,group C samples with sequential ProTaper until F2 working in continuous rotation motion,and group D samples were the negtive control. Roots were then horizontally sectioned 3,6,and 9 mm from the apex. The slices were viewed through a stereomicroscope at ×25 magnification. The samples were photographed with a camera to determine the presence of dentinal cracks. Result:The control group had no cracks. Waveone,single F2 ProTaper in reciprocating motion,and continuous ProTaper groups caused cracks in 20 %,30 %,and 60 % of samples,respectively. A statistically significant difference was found between 2

  4. Root dentine and endodontic instrumentation: cutting edge microscopic imaging.

    Science.gov (United States)

    Atmeh, Amre R; Watson, Timothy F

    2016-06-06

    Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments.

  5. Invasion of dentinal tubules by oral bacteria.

    Science.gov (United States)

    Love, R M; Jenkinson, H F

    2002-01-01

    Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.

  6. An in vitro comparative study of intracanal fluid motion and wall shear stress induced by ultrasonic and polymer rotary finishing files in a simulated root canal model.

    Science.gov (United States)

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

  7. A comparative study of intra canal stress pattern in endodontically treated teeth with average sized canal diameter and reinforced wide canals with three different post systems using finite element analysis

    Directory of Open Access Journals (Sweden)

    Kaur Amandeep

    2010-01-01

    Full Text Available Study methodology: This is a comparative study of intra canal stress patterns in endodontically treated maxillary central incisor with: average sized canal diameter and wide canals reinforced with three different post systems - cast post and core, carbon fiber post, stainless steel post; restored with ceramic crown using finite element analysis (FEA. All the models were subjected to a force of 100N applied at 450 to the long axis of the tooth at the middle third of the palatal surface of the restored ceramic crown. Results: The FEA revealed that all the post systems showed maximum stress in the coronal and middle third of the root. Maximum stress was seen on the inner dentinal wall in case of stainless steel post followed by cast gold and carbon fiber post, both in the models without reinforcement as well as in the reinforced models.

  8. Comparative evaluation of debris removal from root canal wall by using EndoVac and conventional needle irrigation: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vandana J Gade

    2013-01-01

    Full Text Available Context: Microbial control is of paramount importance in Clinical Endodontics. Therefore, cleaning and disinfection of root canals are essential to achieve endodontic success. Aims: The purpose of this study is to compare the efficacy of EndoVac irrigation system and conventional needle (30 gauges side venting needle irrigation for removal of debris from the root canal walls at coronal, middle and apical third by using the scanning electron microscopy (SEM. Settings and Design: An in vitro randomized control trial study. Materials and Methods: A total of 20 mandibular premolars with completely formed roots were selected and randomly divided into two groups - Group 1: Irrigation with the Conventional system and Group 2: EndoVac irrigation. After access opening and working length determination biomechanical preparation completed up to a rotary protaper F4 file. Groupwise irrigation with sodium hypochlorite and ethylenediaminetetraacetic acid was done with each canal in between instrumentation. Then, the teeth were sectioned in buccolingual direction and the halves were sputter-coated with gold palladium and coronal, middle and apical third were examined by SEM at x2000 magnification. Statistical Analysis: Mann-Whitney test for comparison between methods, Kruskal-Wallis test for comparison among thirds and Miller test for individual comparisons. Results: The apical, middle and cervical root canal thirds were evaluated and the results were analyzed statistically by the Mann-Whitney test for comparison between methods, Kruskal-Wallis test for comparison among thirds and Miller test for individual comparisons. Conclusions: EndoVac group resulted in significantly less debris at apical third compared with the conventional needle irrigation group. There was no statistical significant difference found in debris removal at coronal and middle third of root canal wall between the EndoVac group and conventional needle irrigation group.

  9. Uncontrolled removal of dentin during in vitro ultrasonic irrigant activation

    NARCIS (Netherlands)

    Boutsioukis, C.; Tzimpoulas, N.

    2016-01-01

    Introduction: The aim of this study was to evaluate uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared root canals using 2 different files. Methods: Fifty-four human single-rooted teeth with straight root canals were prepared to size 35/.06 taper. The specimens

  10. Antimicrobial Effect of Citrus Aurantifolia Extract on Enterococcus Faecalis Within the Dentinal Tubules in The Presence of Smear Layer

    Directory of Open Access Journals (Sweden)

    Sharifian MR

    2011-12-01

    Full Text Available Background and Aims: Instrumentation of the root canals results in formation of smear layer which covers the dentinal tubules. In infected teeth, it is ideal to achieve a material that has the ability to remove the smear layer besides antimicrobial activity. Therefore, this study was designed to evaluate the antimicrobial effect of Citrus aurantifolia extracts (lime juice and rind extract on Enterococcus faecalis within dentinal tubules in the presence of smear layer.Materials and Methods: One-hundred and forty dentin tubes were prepared from bovine incisors. After removal the smear layer, the specimens were infected with Enterococcus faecalis. Then, the smear layer was reformed. Test solutions were used as the irrigants in study roups as follows: group 1: 5.25% NaOCl; group 2: 17% EDTA; group 3: NaOCl+EDTA; group 4: Lime juice; group 5: ethanolic rind extract of C.aurantifolia; group 6: 96% ethanol. Dentin chips were collected from inner and outer layers of dentinal walls and optical density was measured. The data were analyzed using one-way ANOVA and Tamhane tests.Results: In outer layer of dentin, the efficacy of rind extract was less than that of NaOCl+EDTA (P<0.05. Also Lime juice was less effective than EDTA, NaOCl and NaOCl+EDTA (P<0.05. In inner layer of dentin, Lime juice was significantly less effective than NaOCl and NaOCl+EDTA (P<0.05. The efficacy of rind extract was less than that of NaOCl+EDTA (P<0.05.Conclusion: In the presence of smear layer, the antimicrobial activity of Lime juice was less than that of NaOCl but the efficacy of rind extract was similar to that of NaOCl.

  11. Inductively coupled plasma-emission spectroscopy and atomic absorption for the use of elemental analysis of a root canal after lasing with a holmium:YAG laser.

    Science.gov (United States)

    Deutsch, Allan S; Cohen, Brett I; Musikant, Barry Lee

    2003-06-01

    It has been reported in the literature that after lasing dentin the dentin surface has a glassy or globular appearance. Many authors believe this to be recrystallized hydroxyapatite. The purpose of this elemental analysis was to see if any of the silica fiber optic was melted and deposited as these globular structures on the canal wall. Two teeth were used. One was hand-instrumented with files and used as the control, the other was lased with a holmium:YAG laser. A 245-micro low OH- fiber was used with a power setting of 0.75 W, 5 Hz, 94.2 J, and 1134 V to lase the root. The roots were microanalyzed for oxygen, phosphorus, silicon, nitrogen, hydrogen, calcium, and carbon. The percentages for all elements tested were the same for both teeth. Therefore, there was no silicon deposited onto the canal wall of the tooth that was lased. It is concluded that the low OH- silica fiber optic was not melted and deposited onto the dentinal canal wall.

  12. Self-etching adhesives increase collagenolytic activity in radicular dentin.

    Science.gov (United States)

    Tay, Franklin R; Pashley, David H; Loushine, Robert J; Weller, R Norman; Monticelli, Francesca; Osorio, Raquel

    2006-09-01

    Endogenous matrix metalloproteinases (MMPs) release from crown dentin and their activation results in degradation of hybrid layers created by dentin adhesives. This study tested the hypothesis that instrumented intraradicular dentin possesses latent collagenolytic activity that is activated by mild self-etching adhesives. Root dentin shavings were produced from 50 cleaned and shaped, saline-irrigated root canals using Gates Glidden drills and rinsed with sodium azide to prevent bacterial growth. Dried dentin powder aliquots were treated with two clinically-relevant MMP inhibitors, 2% chlorhexidine for 10 minutes and 17% EDTA for 1 minute. Additional dentin powder was mixed with Clearfil Liner Bond 2V or Clearfil Tri-S Bond for 1 minute followed by extracting the adhesives with acetone. Dentin powder was also treated with 2% chlorhexidine for 10 minutes before or after adhesive application. Collagenolytic activities of the nine groups were assayed with a fluorometer in 96-well plates, by recording the changes in fluorescence before and after addition of fluorescein-labeled type I collagen. Epoxy resin-embedded powders were examined with TEM for the extent of demineralization. Instrumented, mineralized intraradicular dentin possessed low but detectable collagenolytic activity that was inhibited by chlorhexidine (p dentin powder and activated latent MMPs, with 14- to 15-fold increases in collagenolytic activities (p MMPs without denaturing these enzymes, and may adversely affect the longevity of bonded root canal fillings and posts.

  13. 软壁外耳道重建的鼓室成形术%Tympanoplasty with soft-wall reconstruction of ear canal

    Institute of Scientific and Technical Information of China (English)

    孙开; 管国芳; 金春顺; 刘瑶; 张德军; 都延茹; 娄玮; 史平; 孙丽丽

    2011-01-01

    目的:观察软壁外耳道重建的鼓室成形术治疗胆脂瘤中耳炎的疗效.方法:73例(76耳)胆脂瘤中耳炎患者行开放式乳突病变切除鼓室成形术,以耳后肌骨膜瓣行软壁外耳道重建,不做耳甲腔成形术,应用自体乳突皮质骨或砧骨雕刻后行听骨链重建.观察术后外耳道的形态和功能、术后听力以及有无并发症.结果:本组平均干耳时间为术后(21.1士3.1)d.术后外耳道形态基本正常,保持了正常的功能.随访6~24个月,术后气导听力平均改善(14.5士6.1) dB HL.结论:应用耳后肌骨膜瓣行软壁外耳道重建的鼓室成形术能使外耳道的形态和功能基本恢复正常,无需行耳甲腔成形术,听力改善满意.%Objective:To observe the therapeutic effect of tympanoplasty with soft-wall reconstruction of ear canal for chronic otitis media with cholesteatoma. Method: Seventy-three patients(76 ears) suffering from chronic otitis media with cholesteatoma were treated with canal wall down mastoidectomy with tympanoplasty. Postauricu-lar myo-periosteal flap was used to the soft-wall reconstruction of ear canal, and the cavityplasty of auricular con-cha was not performed. The auricular bone prosthesis was made of the autogeneic mastoid cortical bone or residual incus. The postoperative modality and the function of external auditory canal and the postoperative hearing and the postoperative complications were observed. Result:The mean dry ear time was(21. 1±3. 1) days after surgery in this study. The postoperative modality of external auditory canal was normal on the whole. The patients were fol-lowed up between 6 months and 24 months after surgery. The postoperative average air conduction hearing was improved by (14. 5±6. DdB HL. Conclusion: Tympanoplasty with soft-wall reconstruction of ear canal using the postauricular myo-periosteal flap can recover the modality and function of external auditory canal on the whole, and the cavityplasty of auricular

  14. Regional bond strengths of adhesive resins to pulp chamber dentin.

    Science.gov (United States)

    Belli, S; Zhang, Y; Pereira, P N; Ozer, F; Pashley, D H

    2001-08-01

    Microleakage of oral microorganisms, which can occur due to the lack of sealing ability of permanent restorative materials, may cause failure of root canal treatments. Although a great deal of research has been done on sealing enamel and coronal dentin with resins, little research has been done on the adhesion of resins to the walls of pulp chambers. The purpose of this study was to evaluate regional bond strengths of two adhesive systems to the walls of pulp chambers. A section was made horizontally through the middle of the pulp chamber of extracted human third molars to divide the chamber into upper and lower halves. The pulp tissue was removed and the tooth segments were then divided into treatment subgroups. The pulp chambers were bonded with C&B Metabond (Parkell) or One-Step (Bisco), with or without 5% NaOCI pretreatment. The microtensile bond strengths of these resins to four different pulp chamber regions (bottom, wall, roof, and pulp horn areas) were then measured using an Instron machine. The data were expressed in MPa and were analyzed by a three-way ANOVA. Statistically significant differences were found among the test groups (p < 0.001). One-Step produced higher bond strengths to all pulp chamber regions except the floor, compared with C&B Metabond. The results indicated that high bond strengths can be achieved between adhesive resins and the various regions of the pulp chamber. This should permit the use of a thick layer of unfilled resin along the floor of the pulp chamber and over the canal orifices as a secondary protective seal after finishing root canal therapy.

  15. Efficiency of final irrigation of root canal in removal of smear layer

    Directory of Open Access Journals (Sweden)

    Mitić Aleksandar

    2009-01-01

    Full Text Available Introduction A smear layer forms on the root canal walls as the consequence of root instrumentation. The smear layer formed in such a way considerably influences the quality of root obturation and endodontic treatment outcome. Objective The aim of this study was to ultrastructurally analyze the surface of intracanal dentine after removal of the smear layer by the solution of doxycycline, citric acid and detergent Tween-80 (MTAD. Methods The study involved 60 single-rooted, extracted, human teeth divided into four groups. All samples were instrumented by a step-back technique and manual K-files, and rinsed during instrumentation by 2% CHX and H2O2. The first group of samples was exclusively rinsed by CHX and H2O2; in the second group, besides using CHX and H2O2, MTAD solution was used for the final irrigation. The samples which were rinsed by distilled water (+ control and the samples rinsed by 5.25% NaOCl and 17% Na EDTA (-control served as control groups. All samples were observed under the scanning electronic microscope JEOL-JSM-5300. The coronary, middle and apex thirds of the radix region were analyzed. Results The obtained results of the SEM analysis showed that the application of 2% chlorhexidine and hydrogen peroxide did not give clear dentine walls, and the smear layer could not be removed completely. The application of the same combination (CHX and H2O2, added by the final MTAD irrigation solution, led to the efficient removal of the smear layer, while the morphological structure of dentine surface remained unchanged. Statistical analysis showed that canal walls in the experimental group with MTAD as the final irrigation were significantly clearer compared to the control group (p<0.001. Conclusion Based on the obtained results, it can be concluded that MTAD is an efficient solution for the final irrigation of the canal system.

  16. Comparative evaluation of canal cleaning ability of various rotary endodontic filesin apical third: A scanning electron microscopic study

    Science.gov (United States)

    Jadhav, Ganesh Ranganath; Mittal, Priya; Kulkarni, Anish; Syed, Shibli; Bagul, Ravikiran; Elahi, Saina; Kalra, Dheeraj

    2016-01-01

    Background: The purpose of this study was to evaluate the canal cleaning ability of three novel endodontic rotary instruments and compare with ProTaper files as a control in apical third of root canals under scanning electron microscopy (SEM). Materials and Methods: Eighty freshly extracted mandibular premolars were selected according to inclusion criteria. Buccal cusp tips were ground to ensure having a flat coronal reference point with a total tooth length of 16 mm for all samples. Teeth were divided equally into four groups: Group I (ProTaper group), Group II (ProTaper next group), Group III (variable taper group), and Group IV (self-adjusting file [SAF] group). Using SEM, the dentinal surfaces were observed and rated at apical thirds with a magnification of ×1000 for the presence/absence of smear layer and debris. Descriptive analysis was performed, and analysis of variance with Bonferroni post hoc test was carried out for comparison between the groups, at a significance level of 0.05. Results: There was statistically significant difference between Group II and Group IV for debris (P = 0.047) and smear layer (P = 0.037). Conclusion: In apical third of root canal, SAF showed statistically significant canal cleaning ability due to combined effect of continuous streaming irrigation with effectively replacing the irrigant from the apical portion of the root canal, irrigants activation through the creation of turbulence, and its self-adapting design to root canal anatomy with a scrubbing motion on the canal walls. PMID:28182065

  17. Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

    Directory of Open Access Journals (Sweden)

    Jussaro Alves DUQUE

    Full Text Available Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU and Controlled Memory NiTi (ProTaper Gold PTG instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05. There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU and Controlled Memory NiTi (PTG instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

  18. Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

    Science.gov (United States)

    DUQUE, Jussaro Alves; VIVAN, Rodrigo Ricci; CAVENAGO, Bruno Cavalini; AMOROSO-SILVA, Pablo Andrés; BERNARDES, Ricardo Affonso; de VASCONCELOS, Bruno Carvalho; DUARTE, Marco Antonio Hungaro

    2017-01-01

    Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion. PMID:28198973

  19. Coinvasion of dentinal tubules by Porphyromonas gingivalis and Streptococcus gordonii depends upon binding specificity of streptococcal antigen I/II adhesin.

    Science.gov (United States)

    Love, R M; McMillan, M D; Park, Y; Jenkinson, H F

    2000-03-01

    Cell wall-anchored polypeptides of the antigen I/II family are produced by many species of oral streptococci. These proteins mediate adhesion of streptococci to salivary glycoproteins and to other oral microorganisms and promote binding of cells to collagen type I and invasion of dentinal tubules. Since infections of the root canal system have a mixed anaerobic bacterial etiology, we investigated the hypothesis that coadhesion of anaerobic bacteria with streptococci may facilitate invasive endodontic disease. Porphyromonas gingivalis ATCC 33277 cells were able to invade dentinal tubules when cocultured with Streptococcus gordonii DL1 (Challis) but not when cocultured with Streptococcus mutans NG8. An isogenic noninvasive mutant of S. gordonii, with production of SspA and SspB (antigen I/II family) polypeptides abrogated, was deficient in binding to collagen and had a 40% reduced ability to support adhesion of P. gingivalis. Heterologous expression of the S. mutans SpaP (antigen I/II) protein in this mutant restored collagen binding and tubule invasion but not adhesion to P. gingivalis or the ability to promote P. gingivalis coinvasion of dentin. An isogenic afimbrial mutant of P. gingivalis had 50% reduced binding to S. gordonii cells but was unaffected in the ability to coinvade dentinal tubules with S. gordonii wild-type cells. Expression of the S. gordonii SspA or SspB polypeptide on the surface of Lactococcus lactis cells endowed these bacteria with the abilities to bind P. gingivalis, penetrate dentinal tubules, and promote P. gingivalis coinvasion of dentin. The results demonstrate that collagen-binding and P. gingivalis-binding properties of antigen I/II polypeptides are discrete functions. Specificity of antigen I/II polypeptide recognition accounts for the ability of P. gingivalis to coinvade dentinal tubules with S. gordonii but not with S. mutans. This provides evidence that the specificity of interbacterial coadhesion may influence directly the etiology

  20. Effect of endodontic procedures on root dentin permeability.

    Science.gov (United States)

    Tao, L; Anderson, R W; Pashley, D H

    1991-12-01

    The purpose of this study was to quantitate the sequential effects of endodontic procedures on the permeability of human root dentin in vitro. Forty single-rooted teeth were used. Both the crown and the apical 2 mm of the root were removed. The hydraulic conductance of the root before and after various endodontic procedures was measured using a fluid filtration method. Measurements were also made of dentin thickness, intracanal diameter changes, and changes in intracanal surface area. The results showed that instrumentation by K files alone or in combination with Gates Glidden drills did not alter radicular dentin permeability when the cementum remained intact. After removing the cementum, the creation of a smear layer and smear plugs on the canal surface tended to offset the expected increase in dentin permeability created by increasing the intracanal surface area and decreasing root dentin thickness. EDTA treatment inside the instrumented canal to remove the smear layer did not increase permeability significantly. The use of K files followed by Gates Glidden drills tended to remove more cervical dentin, increased the intracanal surface area, and increased the hydraulic conductance of root dentin more than the use of K files alone.

  1. Mechanical or cold lateral compaction: The incidence of dentinal defects

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Hasheminia

    2015-01-01

    Full Text Available Background: The incidence of dentinal defects may influence the outcome of root canal treatment. The aims of this study were to evaluate and compare the incidence of dentinal defects following root canal obturation with two different techniques. Materials and Methods: A total of 110 mesial roots of human mandibular first molars were selected. Twenty-seven roots were left unprepared as negative controls (NCs. The mesiobuccal canals of 83 roots were prepared using rotary instruments. Twenty-seven roots were left unobturated as positive controls (PCs. Twenty-eight roots were obturated with cold lateral compaction (CLC technique and the others were obturated with mechanical lateral compaction (MLC technique. In the CLC and MLC groups, spreader penetration depth was measured by an electromechanical testing machine in canals containing master Gutta-percha cones. After root canal obturation, all the roots were sectioned horizontally at four levels from the apex and evaluated under a stereomicroscope at a magnification of ×40. The presence of dentinal defects was noted. Data were analyzed using the Chi-square and t-tests. Results: The number of defects was not significantly different between the CLC, MLC, and PC groups. The CLC, MLC, and PC groups had significantly more defects compared to the NC group. Conclusion: According to the results of this study, the MLC and CLC techniques were the same in producing dentinal defects.

  2. Effects of adsorbed and templated nanosilver in mesoporous calcium-silicate nanoparticles on inhibition of bacteria colonization of dentin

    Directory of Open Access Journals (Sweden)

    Fan W

    2014-11-01

    Full Text Available Wei Fan,1,* Daming Wu,1,* Franklin R Tay,2 Tengjiao Ma,1 Yujie Wu,1 Bing Fan1 1The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, People’s Republic of China; 2Department of Endodontics, Georgia Regents University, Augusta, Georgia, USA *These authors contributed equally to this work Abstract: Mesoporous calcium-silicate nanoparticles (MCSNs are advanced biomaterials for controlled drug delivery and mineralization induction. Nanosilver-incorporated MCSNs (Ag-MCSNs were prepared in the present study using both the adsorption and template methods. Both versions of Ag-MCSNs showed characteristic morphology of mesoporous materials and exhibited sustained release of ions over time. In antibacterial testing against planktonic Enterococcus faecalis, Ag-MCSNs showed significantly better antibacterial effects when compared with MCSNs (P<0.05. The Ag-MCSNs aggregated on the dentin surface of root canal walls and infiltrated into dentinal tubules after ultrasound activation, significantly inhibiting the adherence and colonization of E. faecalis on dentin (P<0.05. Despite this, Ag-MCSNs with templated nanosilver showed much lower cytotoxicity than Ag-MCSNs with adsorbed nanosilver (P<0.05. The results of the present study indicated that nanosilver could be incorporated into MCSNs using the template method. The templated nanosilver could release silver ions and inhibit the growth and colonization of E. faecalis both in the planktonic form and as biofilms on dentin surfaces as absorbed nanosilver. Templated Ag-MCSNs may be developed into a new intracanal disinfectant for root canal disinfection due to their antibacterial ability and low cytotoxicity, and as controlled release devices for other bioactive molecules to produce multifunctional biomaterials. Keywords: antibacterial effect, mesoporosity

  3. The effect of an Nd-YAG pulsed laser on the cleaning of the root canal and the formation of a fused apical plug.

    Science.gov (United States)

    Saunders, W P; Whitters, C J; Strang, R; Moseley, H; Payne, A P; McGadey, J

    1995-07-01

    A Neodymium-yttrium aluminium garnet (Nd-YAG) pulsed laser was used in vitro to determine whether various laser energy levels from 0.75 W to 1.7 W at 15 pulses s(-1) (pps) were able to (i) remove debris from the walls of prepared root canals (ii) remove pulpal tissue from unprepared canals and (iii) create a fused apical plug from dentine chips, hydroxyapatite (HAP) or low-fusing dental porcelain. Single-rooted teeth were sectioned at the amelocemental junction and the crowns discarded. The root canals of 50 teeth were prepared chemomechanically and allocated to four groups of 10 teeth for laser treatment. One group was left unlased as a control. After lasing, the teeth were split longitudinally, stained and examined for residual debris. Results showed that there was no statistically significant difference between the groups (Plaser energy was applied to dentine chips, HAP and low-fusing porcelain in an attempt to produce a fused apical plug. The laser was unable to melt the dentine chips but some hardening of HAP occurred when combined with blue food-colouring, with or without glycerine, at energy levels of 1.0 W, at 15 pps for 30 s. Superficial hardening of low-fusing porcelain occurred at 1.0 W, 15 pps for 30 s.

  4. Capacidade de remoção da smear layer das paredes do canal radicular utilizando o vinagre de álcool e o vinagre de maçã como soluções irrigadoras durante a terapia endodôntica

    OpenAIRE

    Luis Eduardo Duarte Irala; Renata Grazziotin Soares; Alcebíades Nunes Barbosa; Alice Rorig; Jaqueline Peter

    2009-01-01

    The authors analyzed by scanning electron microscopy (SEM) the capacity to remove smear layer of dentin root canal wall after endodontic treatment. The study used premolars extracted human teeth. ProTaper System (Dentsply Maillefer) was used to endodontic instrumentation helpful by five irrigants solutions: sodium hypochlorite 1% + EDTA; sodium hypochlorite 1% + vinegar of apple; vinegar of apple; sodium hypochlorite 1% + vinegar of alcohol and vinegar of alcohol. Root longitudinal-sections w...

  5. Anatomical evaluation of the root canal diameter and root thickness on the apical third of mesial roots of molars.

    Science.gov (United States)

    Martos, Josué; Tatsch, Gustavo Henrique; Tatsch, Augusto César; Silveira, Luiz Fernando Machado; Ferrer-Luque, Carmen María

    2011-09-01

    The purpose was to determine the diameter of the main root canal and wall thickness in the apical dentin in mesial roots of maxillary and mandibular molars. Forty mesiobuccal and mesial root specimens were sectioned horizontally at 1, 2 and 3 mm from the apex, and measured at each top surface by using optical microscopy to an accuracy of ×20 magnification. The anatomical parameters were established as the following points of reference: AB, two points connected by a line from the outer edge of the mesial wall to the outer edge of the distal one through the center of the root canal to measure the thickness of the root and mesiodistal diameter of the root canal (CD). A second line (EF) was designed to evaluate the diameter of the root canal in the buccolingual direction. All data were summarized, and values were assessed statistically by ANOVA and Bonferroni multiple comparisons. The buccolingual (BL) root canal diameters at 1, 2 and 3 mm in the mandibular and maxillary molars were greater than in the mesiodistal (MD), showing statistically significant differences (p maxillary molars were statistically significant (p maxillary molars was 1.741 mm. The BL diameters in maxillary and mandibular molars were higher than the MD diameter. The thickness (MD) of maxillary and mandibular molars decreased as a function of apical proximity.

  6. 再治疗根管再预备过程对根管壁损伤的影响%Influence of root canal retreatment procedures on the appearance of defects on the root canal walls

    Institute of Scientific and Technical Information of China (English)

    张凌; 朱琳琳; 成超; 张梦龙

    2015-01-01

    Objective To explore the influence of root canal retreatment procedures on the appearance of defects on the root canal walls. Methods One hundred and sixty premolars extracted for orthodontics were randomly divided into two groups with 80 in each group. They were treated and retreated a month(A group)and half a year(B group)after extraction. Forty teeth (A1 group)in A group were treated and the other 40 (A2 group)were retreated at random,and B group was divided into B1 group and B2 group in the same way. Among retreated teeth,twenty teeth filling materials were removed by ProTaper retreatment files only(A21 group,B21 group)and the other twenty teeth were removed by ProTaper retreatment files with chloroform(A22 group,B22 group). Roots were then sectioned and inspected under a microscope. Results Retreatment groups showed significantly more defects than the initial treatment group. There was difference in the appearance of defects after retreatment between ProTaper retreatment files only group and chloroform-sup-plied group. Conclusions Retreatment procedures result in more defects than initial treatment. When assessing the outcomes of endo-dontic retreatment,the substantial damage to the root canal walls should be considered.%目的:研究再治疗术根管再预备对根管壁损伤的影响。方法160颗正畸拔除的前磨牙随机分为2组,各80颗,分别在拔除1个月(A 组),半年后(B 组)行根管治疗、再治疗;A 组再随机分为根管治疗组(A1组)再治疗组(A2组),每组40颗,B 组同样分为根管治疗组(B1组)再治疗组(B2组);A2和B2组又分为单独ProTaper 再治疗锉组(A21、B21)、ProTaper再治疗锉辅助使用氯仿组(A22、B22)。牙根在显微镜下切断并检查。结果再治疗组的根管壁损伤明显高于根管治疗组;与ProTaper 再治疗锉单独使用比较,辅助使用氯仿组有明显的差异,使用氯仿可以减少再预备过程对根管壁的

  7. In vitro evaluation of the cleansing working time and analysis of the amount of gutta-percha or Resilon remnants in the root canal walls after instrumentation for endodontic retreatment.

    Science.gov (United States)

    Cunha, Rodrigo Sanches; De Martin, Alexandre Sigrist; Barros, Pedro Paulo; da Silva, Fabiola Mendonça; Jacinto, Rogério de Castilho; Bueno, Carlos Eduardo da Silveira

    2007-12-01

    The present study assessed the obturation removal and reinstrumentation working time of canals filled with Resilon/Real Seal in comparison with canals filled with gutta-percha/AH Plus. Thirty human extracted canines were instrumented. In group 1 (n = 15) root canals were filled with Resilon/Real Seal and in group 2 (n = 15) with gutta-percha/AH Plus sealer. The obturations were removed from both by using chloroform and irrigation with 2.5% NaOCl, and the canals were manually reinstrumented. The teeth were radiographically analyzed. Specimens without obturation material remnants visible in the radiographic examination were selected for analysis under scanning electron microscopy. The Resilon/Real Seal system was removed in greater quantities from the canal walls compared with the gutta-percha cones and the AH Plus cement. Time was not a significant factor. Under scanning electron microscopy analysis, the teeth presented material remnants in the 3 analyzed thirds. Resilon was better removed from the canal than the gutta-percha cones and the AH Plus.

  8. 完壁式乳突根治鼓室成形术的发展及应用%Development and Application of Canal Wall up Mastoid-tympanoplasty

    Institute of Scientific and Technical Information of China (English)

    宋昱(综述); 马芙蓉(审校)

    2015-01-01

    慢性化脓性中耳炎严重影响患者生活质量,伴胆脂瘤者可能因颅内外并发症危及生命,手术目的为彻底清除病灶,并尽可能保存和重建听力。手术方式主要包括开放式及完壁式乳突根治鼓室成形术,前者在清除病灶方面具有较为广阔的视野,后者术后胆脂瘤复发可能性较高,但因外耳道后壁的保存使患者术后有更高的生活质量。本文对完壁式乳突根治鼓室成形术的术式、手术疗效、术后复发率及手术适应证进行概述,旨在为该术式的选择提供参考。%[Summary] Chronic suppurative otitis media affects patients ’ quality of life, and is life-threatening in patients with cholesteatoma which causes intracranial or extracranial complications .The purpose of surgery is to clear up all the lesions and to reconstruct hearing function .Tympanoplasty is the main surgical method , which includes basically canal wall down ( CWD) and canal wall up (CWU) styles.CWD provides lager surgical field but impairs normal auditory canal structure ; CWU preserves the posterior wall of external auditory canal and provides better quality of life although it has higher possibility of recurrence of cholesteatoma .We reviewed the surgical methods , surgical effects , recurrence rates , and surgical indications of canal wall up mastoid-tympanoplasty , hoping to provide meaningful reference for clinical application .

  9. 完壁式乳突切开鼓室成形术%Intact canal wall mastoidectomy and tympanoplasty in the treatment of chronic suppurative otitis media

    Institute of Scientific and Technical Information of China (English)

    余坤飞; 张松; 熊武; 袁佛良; 吴淑献; 潘松

    2015-01-01

    Objective To report outcomes in patients with active chronic suppurative otitis media treat-ed with intact canal wall mastoidectomy and tympanoplasty. Methods Data from 57 cases treated with intact canal wall mastoidectomy and tympanoplasty were retrospectively reviewed. Result Regarding the tympanic membrane, primary healing was achieved in 48 ears;residual perforation was seen with delayed (2-3 weeks) healing in 5 ears with transplanted fascia;and surgical sites was infected with no tympanic membrane healing in 4 ears. There were no recurrent cases found during the follow-up period of 10 to 34 months. Air-conductive average threshold over 0.5, 1.0, 2.0 and 4.0 kHz improved from 49.7±9.4 dB HL pre-operatively to 30.3±8.0 dB HL postoperatively, with the average air-bone gap reduced by 15 dB. Hearing improvement was reported by the patient in 48 cases. Conclusion Intact canal wall mastoidectomy can be used in active chronic suppura-tive otitis media to effectively remove middle ear lesions and reconstruct middle ear conduction structures, while retaining the normal morphology of ear, improving hearing and enhancing quality of life.%目的:介绍完壁式乳突切开鼓室成形术治疗活动期慢性化脓性中耳炎的临床效果。方法回顾分析我院采用完壁式乳突切开鼓室成形术治疗的57例(耳)活动期慢性化脓性中耳炎的临床资料。结果48耳术后鼓膜一期愈合,5耳移植筋膜边缘残留裂隙,2-3周后延期愈合,4耳术后感染鼓膜穿孔未愈合;随访10个月至34个月,无复发病例,57耳的0.5、1.0、2.0、4.0kHz气导听阈平均值由术前的49.7±9.4 dBHL恢复到30.3±8.0 dBHL,气骨导差平均缩小15 dBHL,其中48耳听力有改善。结论采用完壁式乳突切开鼓室成形术治疗活动期慢性化脓性中耳炎,亦可有效清除中耳乳突病灶,重建中耳传导结构,且能保留耳部正常形态,提升患者听力及生活质量。

  10. Investigations of radicular dentin permeability and ultrastructural changes after irradiation with Er,Cr:YSGG laser and dual wavelength (2780 and 940 nm) laser.

    Science.gov (United States)

    Al-Karadaghi, Tamara Sardar; Franzen, Rene; Jawad, Hussein A; Gutknecht, Norbert

    2015-11-01

    The aim of this study was to assess the effectiveness of dual wavelength (2780 nm Er,Cr:YSGG, 940 nm diode) laser in elimination of smear layer comparing it with Er,Cr:YSGG laser in terms of radicular dentin permeability and ultrastructural changes of root canal walls. Fifty-one sound single-rooted extracted teeth were instrumented up to size F4 and divided into three groups: group Co, non-irradiated samples; group A, irradiated with Er,Cr:YSGG laser; group B, irradiated with the dual wavelength laser. Afterward, the roots were made externally impermeable, filled with 2% methylene blue dye, divided horizontally into three segments reflecting the cervical, middle, and apical thirds then examined under microscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Additionally, scanning electron microscope investigations were accomplished. Analysis of variance (ANOVA) showed significant differences between all groups over the three root thirds. Dye permeation in dual wavelength laser group was significantly higher over the whole root length: cervical, middle, and apical compared to Er,Cr:YSGG laser group and non-irradiated samples (p laser root canal irradiation produced uneven removal of smear layer, in efficient cleanliness especially in the apical third. There was no sign of melting and carbonization. Within the studied parameters, root canal irradiation with dual wavelength laser increased dentin permeability.

  11. Comparative Evaluation of Microshear Bond Strength of 5th, 6th and 7th Generation Bonding Agents to Coronal Dentin Versus Dentin at Floor of Pulp Chamber: An In vitro Study

    OpenAIRE

    Deepa, Velagala Lakshmi; Damaraju, Bhargavi; Priyadharsini, Bollu Indira; Subbarao, Vummidisetti V; Raju, K Rama Krishna

    2014-01-01

    Background: Lack of seal and adhesion between the final restoration and tooth structure adversely affects the results of root canal treatment. Lots of adhesive bonding agents are marketed to overcome this deficiency and achieve successful restoration. So the study compares and evaluates the micro shear bond strength of coronal dentin and pulp chamber dentin using three different generation dentin bonding systems and to know clinical efficiency for clinical use. Materials and Methods: Differen...

  12. Mesenchymal dental pulp cells attenuate dentin resorption in homeostasis.

    Science.gov (United States)

    Zheng, Y; Chen, M; He, L; Marão, H F; Sun, D M; Zhou, J; Kim, S G; Song, S; Wang, S L; Mao, J J

    2015-06-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  13. High speed imaging of an Er,Cr:YSGG laser in a model of a root canal

    Science.gov (United States)

    Verdaasdonk, Rudolf; Blanken, Jan; van Heeswijk, Hans; de Roode, Rowland; Klaessens, John

    2007-02-01

    Laser systems of various wavelengths and pulse characteristics have been introduced in dentistry. At present, the range of applications for the different systems is being investigated mainly differentiating between soft and hard tissue applications. For the preparation of root canals both hard and soft tissues are involved. Ideally, one would like to use one laser system for the whole treatment. In this study, we studied the characteristics of the pulsed 2,78 Er,Cr:YSGG laser (Biolase, Waterlase Millenium), in view of root canal cleaning and desinfection. The laser energy was fiber delivered with fiber tip diameters from 400 μm down to 200 μm. Special thermal and high speed imaging techniques were applied in a transparent model of a tapered root canal and slices cut from human teeth. High speed imaging revealed the dynamics of an explosive vapor bubble at the tip of the Er laser in water and the root canal model. Typically for Erbium lasers, within a time span of several hundred μs, a longitudinal bubble expanded to maximum size of 5 mm length and 2 mm diameter at 100 mJ and imploded afterwards. In the root canal, the explosive bubble created turbulent high speed water streaming which resects soft tissue from the hard tissue. Thermal imaging showed the dynamics of all lasers heating of the canal wall up to several mm depending on the wavelength and energy settings. The mechanism of smear layer removal and sterilization in the root canal, is attributed to cavitation effects induced by the pulsed laser. The heat generation into the dentine wall was minimal.

  14. Tissue engineering in endodontics: root canal revascularization.

    Science.gov (United States)

    Palit Madhu Chanda; Hegde, K Sundeep; Bhat, Sham S; Sargod, Sharan S; Mantha, Somasundar; Chattopadhyay, Sayan

    2014-01-01

    Root canal revascularization attempts to make necrotic tooth alive by the use of certain simple clinical protocols. Earlier apexification was the treatment of choice for treating and preserving immature permanent teeth that have lost pulp vitality. This procedure promoted the formation of apical barrier to seal the root canal of immature teeth and nonvital filling materials contained within root canal space. However with the success of root canal revascularization to regenerate the pulp dentin complex of necrotic immature tooth has made us to rethink if apexification is at the beginning of its end. The objective of this review is to discuss the new concepts of tissue engineering in endodontics and the clinical steps of root canal revascularization.

  15. Dentine tubule infection and endodontic therapy implications.

    Science.gov (United States)

    Oguntebi, B R

    1994-07-01

    A critical review of the literature suggests that the microenvironment of dentinal tubules appears to favour the selection of relatively few bacterial types irrespective of the aetiology of the infection process; coronal dental caries or pulpar necrosis. These bacteria may constitute an important reservoir from which root canal infection and reinfection may occur following pulp necrosis or during and after endodontic treatment. Previous studies of this microflora have utilized microbiological culture techniques which need to be supplemented by those that allow in situ demonstration as well as identification of the bacteria. Newer treatment strategies that are designed to eliminate this microflora must include agents that can penetrate the dentinal tubules and destroy these microorganisms, since they are located in an area beyond the host defence mechanisms where they cannot be reached by systemically administered antimicrobial agents.

  16. Dynamic intratubular biomineralization following root canal obturation with pozzolan-based mineral trioxide aggregate sealer cement.

    Science.gov (United States)

    Yoo, Yeon-Jee; Baek, Seung-Ho; Kum, Kee-Yeon; Shon, Won-Jun; Woo, Kyung-Mi; Lee, WooCheol

    2016-01-01

    The application of mineral trioxide aggregates (MTA) cement during the root canal obturation is gaining concern due to its bioactive characteristic to form an apatite in dentinal tubules. In this regard, this study was to assess the biomineralization of dentinal tubules following root canal obturation by using pozzolan-based (Pz-) MTA sealer cement (EndoSeal MTA, Maruchi). Sixty curved roots (mesiobuccal, distobuccal) from human maxillary molars were instrumented and prepared for root canal obturation. The canals were obturated with gutta-percha (GP) and Pz-MTA sealer by using continuous wave of condensation technique. Canals obturated solely with ProRoot MTA (Dentsply Tulsa Dental) or Pz-MTA sealer were used for comparison. In order to evaluate the biomineralization ability under different conditions, the PBS pretreatment before the root canal obturation was performed in each additional samples. At dentin-material interfaces, the extension of intratubular biomineralization was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. When the root canal was obturated with GP and Pz-MTA sealer, enhanced biomineralization of the dentinal tubules beyond the penetrated sealer tag was confirmed under the SEM observation (p cement can be used as a promising bioactive root canal sealer to enhance biomineralization of dentinal tubules under controlled environment.

  17. In vivo model for microbial invasion of tooth root dentinal tubules

    Directory of Open Access Journals (Sweden)

    Jane L. BRITTAN

    2016-04-01

    Full Text Available ABSTRACT Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF. DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0 to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine.

  18. In vivo model for microbial invasion of tooth root dentinal tubules.

    Science.gov (United States)

    Brittan, Jane L; Sprague, Susan V; Macdonald, Emma L; Love, Robert M; Jenkinson, Howard F; West, Nicola X

    2016-04-01

    Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF). DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0) to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine.

  19. Effect of delayed light curing of a resin composite on marginal integrity in cylindrical dentine cavities.

    Science.gov (United States)

    Manabe, A; Debari, K; Itoh, K; Hisamitsu, H; Wakumoto, S

    1993-12-01

    The effect of delayed light curing of resin composite on marginal adaptation has been examined by measuring the wall-to-wall polymerization contraction gap when using a commercial resin composite together with experimental dentine bonding systems to restore cylindrical preparations in dentine. Morphological changes in dentine during dentine bonding procedures were observed using a scanning electron microscope. In a previous report, the contraction gap width for a resin composite increased when irradiation of the resin system was delayed, despite the use of a dentine bonding system considered to be 'contraction' gap free. Such deterioration in marginal adaptation was minimized by use of an experimental dentine primer, 40% erythritol methacrylate aqueous solution (EM), followed by the use of a commercial dual- or autocured dentine bonding agent. Under scanning electron microscopy, the dentine surface microstructure became unclear after EM priming, and a polymer film was detected after polymerization of the dual-cured dentine bonding agent. The hydrogelled primer and the formation of a polymer network on the dentine surface may prevent the flow of fluid from the pulp through the dentine tubules, and maintain marginal integrity if there is delay in light curing of light-activated resin composite systems.

  20. Dentin sialoprotein and dentin phosphoprotein overexpression during amelogenesis.

    Science.gov (United States)

    Paine, Michael L; Luo, Wen; Wang, Hong-Jun; Bringas, Pablo; Ngan, Amanda Y W; Miklus, Vetea G; Zhu, Dan-Hong; MacDougall, Mary; White, Shane N; Snead, Malcolm L

    2005-09-09

    The gene for dentin sialophosphoprotein produces a single protein that is post-translationally modified to generate two distinct extracellular proteins: dentin sialoprotein and dentin phosphoprotein. In teeth, dentin sialophosphoprotein is expressed primarily by odontoblast cells, but is also transiently expressed by presecretory ameloblasts. Because of this expression profile it appears that dentin sialophosphoprotein contributes to the early events of amelogenesis, and in particular to those events that result in the formation of the dentino-enamel junction and the adjacent "aprismatic" enamel. Using a transgenic animal approach we have extended dentin sialoprotein or dentin phosphoprotein expression throughout the developmental stages of amelogenesis. Overexpression of dentin sialoprotein results in an increased rate of enamel mineralization, however, the enamel morphology is not significantly altered. In wild-type animals, the inclusion of dentin sialoprotein in the forming aprismatic enamel may account for its increased hardness properties, when compared with bulk enamel. In contrast, the overexpression of dentin phosphoprotein creates "pitted" and "chalky" enamel of non-uniform thickness that is more prone to wear. Disruptions to the prismatic enamel structure are also a characteristic of the dentin phosphoprotein overexpressing animals. These data support the previous suggestion that dentin sialoprotein and dentin phosphoprotein have distinct functions related to tooth formation, and that the dentino-enamel junction should be viewed as a unique transition zone between enamel and the underlying dentin. These results support the notion that the dentin proteins expressed by presecretory ameloblasts contribute to the unique properties of the dentino-enamel junction.

  1. The effective concentration of red betel leaf (Piper crocatum infusion as root canal irrigant solution

    Directory of Open Access Journals (Sweden)

    Fani Pangabdian

    2012-03-01

    Full Text Available Background: Smear layer is a debris consisting of organic and inorganic particles of calcified tissue, necrotic tissue, pulp tissue, and dentinoblast and microorganism processes that can close the entrance to the dentin tubuli. Smear layer, will not only inhibit the penetration of disinfection materials and sealers to the dentin tubuli, but will also reduce the attachment of root canal filling material so that root canal irrigation solution is needed to dissolve the smear layer. Red betel leaf (Piper crocatum infusion, on the other hand, contains saponin characterized as “surfactants” which can dissolve smear layer. Nevertheless, the effective concentration of the red betel leaf infusion has still not been known clearly. Purpose: This study is aimed to determine the effective concentration of the red betel leaf infusion for cleaning root canal walls from smear layer. Methods: Fiveteen extracted human teeth with straight single roots were randomized into 5 groups (n=3. The specimens were then shaped by using rotary instruments up to a size of 25/.07. During instrumentation, each canal was irrigated with 10, 20, 30 and, 40% red betel leaf infusion for treatment groups, while another was irrigated with aquadest for the control group. Root canal cleanliness was observed by using scanning electron microscope (SEM. Results: There were significant differences among treatment groups (p<0.05, except in the treatment groups irrigated with red betel leaf infusion with concentrations of 30% and 40% (p>0.05. Conclusion: It can be concluded that red betel leaf infusion with a concentration of 30% is effective for cleaning the root canal walls from the smear layer.Latar belakang: Smear layer adalah suatu debris yang mengandung partikel organik dan anorganik dari jaringan terkalsifikasi, jaringan nekrotik, proses dentinoblas, jaringan pulpa dan mikroorganisme yang dapat menutup jalan masuk ke tubuli dentin. Smear layer akan menghalangi penetrasi dari bahan

  2. A COMPARATIVE EVALUATION OF EFFECT OF SODIUM HYPOCHLORITE ON MICROTENSILE BOND STRENGTH OF THREE DIFFERENT BONDING AGENTS TO THE LATERAL WALLS OF PULP CHAMBER: AN IN VITRO STUDY

    Directory of Open Access Journals (Sweden)

    Bhat Gowrish S.

    2013-03-01

    Full Text Available The advent of adhesive materials has revolutionized the field of restorative dentistry. Lack of adhesion and sealing between the final restoration and tooth structure may lead to microleakage and ultimate failure of the restoration. These adhesive restorations are also being used in the field of endodontics. A good coronal seal is very important, since the penetration of microorganisms from a coronal direction can reinfect the root canal system and affect the prognosis of the non-surgical root canal therapy. Coronal leakage is particularly significant in multi rooted teeth, in which accessory canal may allow inflammatory change to occur in the periodontal tissues from the pulp chambers. Improper restoration can lead to loss of endodontically treated teeth more than actual failure of endodontic therapy. The restorations with adhesive systems offer the advantage of transmission of functional stresses across the bonded interface to the tooth (mono bloc restoration and potentially reinforce the weakened tooth structure. Bonding to pulp chamber lateral walls is different from bonding other dentinal surface. The structure of pulp chamber wall is complicated and not much is known about the bonding characteristics of pulp chamber, it becomes essential to study the same. This study was done evaluate the effect of sodium hypochlorite on bond strength of bonding agent to the lateral walls of the pulp chamber. However, chemical irrigants, such as sodium hypochlorite used in the endodontic treatment have been shown to affect the bond strength of resin composite to dentin adversely.

  3. Laser-activated irrigation within root canals: cleaning efficacy and flow visualization

    NARCIS (Netherlands)

    de Groot, S.D.; Verhaagen, B.; Versluis, M.; Wu, M.K.; Wesselink, P.R.; van der Sluis, L.W.M.

    2009-01-01

    Aim  To test ex vivo the efficiency of laser-activated irrigation in removing dentine debris from the apical part of the root canal and to visualize in vitro the fluid dynamics during the activation of the irrigant by laser, using high-speed imaging at a relevant timescale. Methodology  Root canals

  4. Laser-activated irrigation within root canals : cleaning efficacy and flow visualization

    NARCIS (Netherlands)

    de Groot, S. D.; Verhaagen, B.; Versluis, M.; Wu, M. -K.; Wesselink, P. R.; van der Sluis, L. W. M.

    2009-01-01

    P>Aim To test ex vivo the efficiency of laser-activated irrigation in removing dentine debris from the apical part of the root canal and to visualize in vitro the fluid dynamics during the activation of the irrigant by laser, using high-speed imaging at a relevant timescale. Methodology Root canals

  5. Dynamic intratubular biomineralization following root canal obturation with pozzolan‐based mineral trioxide aggregate sealer cement

    Science.gov (United States)

    Yoo, Yeon‐Jee; Baek, Seung‐Ho; Kum, Kee‐Yeon; Shon, Won‐Jun; Woo, Kyung‐Mi

    2015-01-01

    Summary The application of mineral trioxide aggregates (MTA) cement during the root canal obturation is gaining concern due to its bioactive characteristic to form an apatite in dentinal tubules. In this regard, this study was to assess the biomineralization of dentinal tubules following root canal obturation by using pozzolan‐based (Pz‐) MTA sealer cement (EndoSeal MTA, Maruchi). Sixty curved roots (mesiobuccal, distobuccal) from human maxillary molars were instrumented and prepared for root canal obturation. The canals were obturated with gutta‐percha (GP) and Pz‐MTA sealer by using continuous wave of condensation technique. Canals obturated solely with ProRoot MTA (Dentsply Tulsa Dental) or Pz‐MTA sealer were used for comparison. In order to evaluate the biomineralization ability under different conditions, the PBS pretreatment before the root canal obturation was performed in each additional samples. At dentin‐material interfaces, the extension of intratubular biomineralization was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. When the root canal was obturated with GP and Pz‐MTA sealer, enhanced biomineralization of the dentinal tubules beyond the penetrated sealer tag was confirmed under the SEM observation (p cement can be used as a promising bioactive root canal sealer to enhance biomineralization of dentinal tubules under controlled environment. SCANNING 38:50–56, 2016. © 2015 The Authors. Scanning Published by Wiley Periodicals, Inc. PMID:26179659

  6. Regional variation in root dentinal tubule infection by Streptococcus gordonii.

    Science.gov (United States)

    Love, R M

    1996-06-01

    The purpose of this study was to investigate the pattern of bacterial invasion of dentinal tubules at different regions in human roots. Specimens were obtained from single-rooted teeth that had their root canals prepared in a standard manner. Roots were then sectioned longitudinally through the canals and the resulting specimens chemically treated to remove the smear layers. Specimens were immersed in a suspension of Streptococcus gordonii for 3 weeks and then prepared for histological analysis. Sections from the cervical, midroot, and apical areas were examined. The pattern of bacterial infection of the cervical and midroot areas was similar, characterized as a heavy infection with bacteria penetrating as deep as 200 microns. Invasion of the apical dentin was significantly different, with a mild infection and maximum penetration of 60 microns.

  7. canal24

    Data.gov (United States)

    California Department of Resources — Canal system center lines in the Central Valley of California and adjacent areas captured from 1:24,000-scale USGS topographic maps. Updates and modifications made...

  8. Morphology of bacterial flora in root canals associated with apical abscesses

    Institute of Scientific and Technical Information of China (English)

    Guo Huijie; Gao Chengzhi; Zhang Chengfei; Zheng Shuying; Yue Lin

    2014-01-01

    Background Apical abscess is an inflammatory process in the peri-radicular tissues caused by biofllms in the necrotic root canal systems.Therefore,a comprehensive analysis of the bacterial colonization is required for a better understanding of the pathogenesis.This study aimed to investigate the patterns of bacterial infection of root canals of teeth with apical abscesses and to determine whether histological and microbiological findings correlated with clinical conditions.Methods Eighteen samples from 18 teeth with apical pathological lesions were analyzed.Nine patients with acute apical abscesses experienced severe pain,and nine patients were asymptomatic with a sinus tract.After extraction,each affected root was divided into two halves.One half was processed for histobacteriologic analysis and examined using light microscopy,and the other half was analyzed using scanning electron microscopy (SEM) to determine the patterns of microbial colonization of the root canals.Results The appearance of each sample subjected to SEM was consistent with the histobacteriologic findings despite the presence or absence of clinical symptoms.Intraradicular biofilms comprising cocci,rods,and/or filaments of amorphous materials were observed in the apical third of the main root canals in all samples.The bacterial biofilms covering the main root canal walls also penetrated the dentinal tubules to varying depths.The morphologies of biofilms varied,and a unique pattern of intraradicular infection was not identified.Conclusion Intraradicular infections formed complex and variable multispecies biofilms and their presence did not correlate with clinical symptoms.

  9. In vitro study of caries detection through sound dentin using a laser fluorescence device, DIAGNOdent.

    Science.gov (United States)

    Iwami, Yukiteru; Shimizu, Ayako; Yamamoto, Hiroko; Hayashi, Mikako; Takeshige, Fumio; Ebisu, Shigeyuki

    2003-02-01

    The objective of this study was to investigate the feasibility of proximal surface caries detection using a laser fluorescence device, DIAGNOdent, through the sound dentin surrounding the cavity wall after removal of occlusal caries. Extracted sound human molars were ground to prepare horizontal and vertical dentin plates 1.4 mm thick. Extracted carious human molars were reduced in thickness horizontally from the occlusal surfaces until exposure of the dentin caries. The dentin plate was placed on the carious tooth. Before and after gradual thinning of the dentin plate from approximately 1.4 mm to 0.2 mm thick, the dentin caries was measured 10 times through the plate by the laser fluorescence device with a cone-shaped tip or a broad tip. When the dentin plate was reduced to less than 0.3 mm thick (using a combination of a horizontal plate and cone-shaped tip) or 0.2 mm thick (using the other combinations), the values measured with the laser fluorescence device were significantly larger than the values before reducing the thickness of the dentin. Based on these results, the device offers potential use as one of the screening tests for proximal surface caries detection through sound dentin when the sound dentin between tip and caries is thin.

  10. Damage to root dentin during retreatment procedures

    NARCIS (Netherlands)

    Shemesh, H.; Roeleveld, A.C.; Wesselink, P.R.; Wu, M.K.

    2011-01-01

    Introduction: The aim of this study was to explore the influence of retreatment procedures on the appearance of defects on the root canal walls. Methods: Two hundred mandibular premolars were divided into 4 groups. One group was left unprepared. The rest of the teeth were prepared with ProTaper file

  11. DE CANALES

    Directory of Open Access Journals (Sweden)

    Roberto Carlos Guevara C.

    2013-01-01

    Full Text Available La amplia utilización de redes WiFi en los diversos escenarios sociales está generando una especie de saturación de canales, que a su vez ocasiona interferencia entre estas redes. Esta situación genera solapamiento de canales, lo que hace que las tasas de trasferencia se reduzcan. En este artículo se detalla esta situación, y se estructura y aplica un experimento para encontrarle solución al problema. También se presentan los resultados tabulados y graficados utilizando la herramienta de software libre inSSider.

  12. The effect of endodontic regeneration medicaments on mechanical properties of radicular dentin

    Science.gov (United States)

    Yassen, Ghaeth H.

    Endodontic regeneration treatment of necrotic immature teeth has gained popularity in recent years. The approach suggests a biological alternative to induce a continuous root development. In this project, three in vitro experiments were conducted to investigate the effect of three medicaments used in endodontic regeneration on mechanical properties and chemical structure of radicular dentin. In the first experiment, we investigated longitudinally the effect of medicaments on the indentation properties of the root canal surface of immature teeth using a novel BioDent reference point indenter. A significant difference in the majority of indentation parameters between all groups was found after one-week and one-month application of medicaments (p double antibiotic paste (DAP) > control > calcium hydroxide [Ca(OH)2]. The four-week exposure of dentin to TAP and DAP caused 43% and 31% increase in total indentation distance outcome, respectively. In the second experiment, we investigated longitudinally the effect of medicaments on the chemical structure of immature radicular dentin by measuring the phosphate/amide I ratios of dentin using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy. Phosphate/amide I ratios were significantly different between the four groups after one week, two weeks and four week application of medicaments (p untreated dentin > DAP-treated dentin > TAP-treated dentin. In the third experiment, we investigated longitudinally the effect of medicaments on root fracture resistance and microhardness of radicular dentin. For the microhardness, the two-way interaction between group and time was significant (pintegrity of the superficial radicular dentin and significantly affected the indentation properties of the root canal surface. Furthermore, the three month intracanal application of medicaments significantly reduced the fracture resistance of roots.

  13. 开放式乳突根治鼓室成形术中乳突术腔复合填塞方法的应用%The combined mastoid cavity obliteration in canal wall down tympanomastoidectomy

    Institute of Scientific and Technical Information of China (English)

    刘稳; 神平; 曹恒明; 李巍; 樊可成; 李培华; 孙海清

    2012-01-01

    目的 探讨开放式乳突根治、鼓室成形术中联合使用自体骨粉、颞肌筋膜、耳后肌骨膜瓣、外耳道皮瓣来缩小术腔容积的方法.方法 回顾性分析179例施行开放式乳突根治、鼓室成形术的患者.研究对象分为2组:复合缩容123例(A组),使用健康骨粉填充上鼓室、鼓窦、窦脑膜角,颞肌筋膜覆盖骨粉及术腔骨质,耳后肌骨膜瓣填充术腔,外耳道皮瓣覆盖下部术腔;常规处理56例(B组),术中仅用颞肌筋膜修补鼓膜、覆盖术腔,未使用骨粉、肌骨膜瓣、皮瓣行术腔复合缩容.随访比较2组术后术腔大小、干耳时间以及术后痂皮生成情况等.结果 A组的术腔容积明显缩小,术后平均干耳时间(6.6±2.3)周,较B组(8.4±2.4)周明显缩短(P<0.01),术后随访基本无痂皮形成,无需反复清理术腔.结论 开放式乳突根治、鼓室成形术中联合使用自体骨粉、颞肌筋膜、耳后肌骨膜瓣、外耳道皮瓣来缩小术腔体积,能够缩短干耳时间、减少术后痂皮形成.%Objective To describe the technique for mastoid cavity obliteration in canal wall down tympanomastoid ectomy using autologous bone chips , temporal myofascial flap, musculoperiosteal flap , and ear canal skin flap. Methods Retrospective analysis based on 179 cases of chronic otitis media treated with canal wall down tympanomastoidectomy . Subjects were divided into 2 groups by the methods of mastoid cavity obliteration . 123 cases (group A) were treated with combined mastoid cavity obliteration using autologous bone chips , temporal myofascial flap, musculoperiosteal flap, and ear canal skin flap; 56 cases ( group B) were treated with routine therapy without combined mastoid cavity obliteration . Postoperative dry ear time and mastoid cavity size were compared between the two groups . Results The mastoid cavity size of group A was much smaller than group B and the average dry ear time of group A was much shorter than group B

  14. The cleanliness differences of root canal irrigated with 0.002% saponin of mangosteen peel extract and 2.5% NaOCl

    Directory of Open Access Journals (Sweden)

    Anis Sakinah

    2015-06-01

    Full Text Available Background: Root canal treatment consists of preparation, sterilization, and obturation. During root canal preparation, debris is smeared over the dentinal surface forming a smear layer. Smear layer will reduce the attachment of root canal filling materials. Organic material in smear layer can be substrated for microorganism. Preparation of root canal should be followed by irrigation. NaOCl is common irrigation solution in endodontics. It has been very effective for their disinfecting and tissue-dissolving properties, but it is incapable of removing the smear layer. On the other hand, saponin of mangosteen peel extract has an ability as a surfactant to lower the surface tension, and it can dissolve debris containing of anorganic and organic materials. Purpose: This study aims to know the differences between 2.5% NaOCl and 0.002% saponin of mangosteen peel extract in removing the debris in the root canal after the preparation procedure. Method: Three groups of teeth (7 teeth in each were instrumented with K-file and irrigated as follow: group 1 (control with aquadest; group 2 with 2.5% NaOCl; and group 3 with 0.002% saponin of mangosteen peel extract. Furthermore, those teeth were split horizontally and longitudinally 4mm above the apical. The apical third of root canal walls was observed by a scanning electron microscope (SEM. Result: There were significant differences between each group (p<0.05. Median value of the group 3 was score 1 considered as the smallest value. It indicates that Group 3 with 0.002% saponin of mangosteen peel extract was the cleanest group. Conclusion:It can be concluded that 0.002% saponin of mangosteen peel extract can clean the smear layer of the root canal better than 2.5% NaOCl.

  15. Scalloping at the lumbosacral canal

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, R.

    1987-07-01

    Scalloping is an indentation of the dorsal side of the vertebral body (anterior wall of the lumbosacral or sacral canal) which typically involves several adjacent lumbal vertebral body segments and the anterior wall of the canalis sacralis. Occurrence without underlying disease is rare; it occurs most frequently with chondrodystrophy, neurofibromatosis, Morquio's syndrome, Hurler's syndrome, acromegaly, Ehlers-Danlos syndrome, Marfan's syndrome, cysts, tumors and in peridural lipomas.

  16. Assessment of three root canal preparation techniques on root canal geometry using micro-computed tomography: In vitro study

    Directory of Open Access Journals (Sweden)

    Shaikha M Al-Ali

    2012-01-01

    Full Text Available Aim: To assess the effects of three root canal preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. Materials and Methods: Thirty extracted Human Maxillary Molars having three separate roots and similar root shape were randomly selected from a pool of extracted teeth for this study and stored in normal saline solution until used. A computed tomography scanner (Philips Brilliance CT 64-slice was used to analyze root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using stainless steel K-Files, Ni-Ti rotary ProTaper and rotary SafeSiders instruments. Differences in dentin volume removed, the surface area, the proportion of unchanged area and canal transportation were calculated using specially developed software. Results: Instrumentation of canals increased volume and surface area. Statistical analysis found a statistically significant difference among the 3 groups in total change in volume (P = 0.001 and total change in surface area (P = 0.13. Significant differences were found when testing both groups with group III (SafeSiders. Significant differences in change of volume were noted when grouping was made with respect to canal type (in MB and DB (P < 0.05. Conclusion: The current study used computed tomography, an innovative and non destructive technique, to illustrate changes in canal geometry. Overall, there were few statistically significant differences between the three instrumentation techniques used. SafeSiders stainless steel 40/0.02 instruments exhibit a greater cutting efficiency on dentin than K-Files and ProTaper. CT is a new and valuable tool to study root canal geometry and changes after preparation in great details. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

  17. 开放式鼓室成形术听力重建效果的分析%Analysis of auditory outcomes in canal wall down tympanoplasty with ossiculoplasty

    Institute of Scientific and Technical Information of China (English)

    郭敛容; 胡洪义; 苏永进

    2011-01-01

    目的 比较自体骨及钛金属两种听力重建材料在开放式鼓室成形术后的听力改善状况.方法 对2007年10月~2010年5月接受开放式鼓室成形术的21例(21耳)进行回顾性分析,根据听骨链重建材料分为自体骨组和金属钛组,听力统计以0.5,1,2,4 kHz的平均气骨导差值计算.结果 自体骨组术后平均气骨导差和术前比较无明显统计学差异,金属钛组术后平均气骨导差较术前缩小(27.5±7.25)dB,两组比较差异有统计学意义.结论 在开放式鼓室成形术中,使用金属钛重建听力链的听力改善较自体骨好.%Objective To compare the hearing improvement in canal wall down tympanoplasty with autologous bone or titanium prostheses. Methods The data of 2 1 cases underwent canal wall down tympanoplasty since October 2007 to May 2010 was retrospectively analysed. The patients were divided into 2 groups : autologous bone group and titanium prostheses group. The average postoperative air - bone gaps (A - BC ) of four frequencies : 0.5,1, 2 , 4 kHz were measured. Results There was no significant hearing improvement in autologous bone group . The postoperative A - BC in titanium prostheses group significantly reduced by 2 7 . 5 ± 7.25 dB. Conclusions The hearing improvement in canal wall down tympanoplasty with titanium prostheses was better than with autologous bone.

  18. 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.

  19. Effects of dentin depth and cavity configuration on bond strength.

    Science.gov (United States)

    Yoshikawa, T; Sano, H; Burrow, M F; Tagami, J; Pashley, D H

    1999-04-01

    During polymerization of resin composites, shrinkage stresses compete with resin-dentin bonds in a manner that can cause failure of the bond, depending upon the configuration of the cavity, its depth, and the restorative technique. The hypothesis tested in this study was that the effect of cavity configuration (C) and remaining dentin thickness (RDT) influence resin bond strength to the dentin of Class I cavity floors. The occlusal enamel was ground to expose a flat superficial dentin surface as a control (superficial dentin, C-factor = 1) in human extracted third molars. Cavities 3 mm long x 4 mm wide were prepared to a depth 2 mm below the ground dentin surfaces (deep dentin within cavity floor, C-factor = 3). To assess the relationship between C-factor and RDT, we removed the walls of cavities, making a deep flat surface for bonding (deep dentin, C-factor = 1). The teeth were restored with either Clearfil Liner Bond II (LB II), One-Step (OS), or Super-Bond D Liner (DL), followed by Clearfil Photo Posterior resin composite. After 24 hrs' storage in water, the teeth were sectioned vertically into 3 or 4 slabs (0.7 mm thick) and trimmed for the micro-tensile bond test so that we could determine the strength of the resin bonds to the pulpal floor. All groups gave high bond strengths to superficial dentin, but OS and DL gave significantly lower bond strengths to flat deep dentin when the C-factor was 1. When the C-factor was increased to 3 by the creation of a three-dimensional cavity preparation, the bond strengths of all materials fell (range, 21 to 35%), but the difference was significant (p bond strengths tended to exhibit cohesive failures within the hybrid layer, while specimens exhibiting low bond strengths showed failures at the top of the hybrid layer. Some adhesives do not bond well to deep dentin, making them more susceptible to polymerization shrinkage stress that develops in cavities with high C-factors.

  20. Holmium:YAG laser in dentistry: photoconditioning of dentinal surfaces

    Science.gov (United States)

    Holt, Raleigh A.; Nordquist, Robert E.

    1994-09-01

    This in vitro study was undertaken to determine energy levels necessary to produce tubule closure and surface smoothing on dentinal surfaces of human teeth and their resultant temperature increases within the pulpal canals with the Holmium:YAG laser. An optimal working spot size and even absorption pattern were produced by defocusing the laser beam and evaluated by images produced on light exposed and developed photographic paper. The surface effects on dentin were examined by scanning electron microscopy. A thermocouple was positioned in the canals of fresh dissected dog jaws and attached to a recorder which produced a graph of the temperature changes. The in vitro research model for intrapulpal temperatures changes was verified by comparing premortem and postmortem temperature readings. The same protocol was used to evaluate temperature changes in fresh human extracted teeth. In vivo histological studies were conducted to evaluate the effects of HO:YAG laser energy on pulpal tissues. The results of these studies indicate the HO:YAG laser at a wavelength of 2.12 microns can be safely and effectively used for photoconditioning of the dentinal surfaces of teeth in clinical conditions.

  1. Fiber-post bond strength in canals obturated with a cross-linked gutta-percha core obturator.

    Science.gov (United States)

    Scotti, Nicola; Coero Borga, Francesco A; Alovisi, Mario; Bergantin, Emanuele; Marchionni, Silvia; Pasqualini, Damiano; Berutti, Elio

    2014-04-01

    The aim of this in-vitro study was to evaluate the bond strength of fiber posts cemented in a root canal filled using various root-canal obturation techniques. A total of 33 monoradicular samples, treated endodontically, were randomly assigned to three groups according to the root-canal obturation technique: group 1, continuous-wave technique; group 2, plastic-obturator-core technique; and group 3, cross-linked gutta-percha obturator-core technique. Fiber posts were luted in each sample and each was sectioned perpendicular to the post axis. The push-out test was performed using a universal machine and the maximum failure load was recorded in MPa mm(-2) . Several samples were randomly chosen for scanning electron microscopy evaluation. The mean debris and dentinal tubule-opening scores were calculated separately in the coronal and apical portions. Bond strength was significantly higher in group 1 than in groups 2 and 3. Debris scores were significantly higher in the apical portion of groups 2 and 3 than in group 1. Within the limitations of this study it can be affirmed that thermoplasticized alpha gutta-percha seemed to worsen the cleaning of post-space walls and hence reduced fiber-post bond strength.

  2. Canal-wall-down mastoidectomy and tympanoplasty surgery preserving chorda tympani nerve integrality%保留鼓索神经的开放式乳突根治鼓室成形术

    Institute of Scientific and Technical Information of China (English)

    王林娥; 张汝祥; 张道行

    2012-01-01

    目的:报告开放式乳突根治鼓室成形术中寻找鼓索神经的方法和保留鼓索神经的意义.方法:66例慢性化脓性中耳炎或中耳胆脂瘤患者,术中以砧骨短突为标志,磨低外耳道后壁,沿面神经垂直段找到鼓索嵴(鼓索神经出骨管处),沿鼓索嵴找到游离于鼓室内的鼓索神经,仔细清理鼓索神经表面的病变组织,保持其完整性.结果:24例中耳胆脂瘤患者和42例慢性化脓性中耳炎患者鼓索神经表面胆脂瘤上皮及肉芽彻底清理,无一例鼓索神经断裂,患者术后味觉无明显变化.结论:开放式乳突根治鼓室成形术中彻底清理病变的同时保持鼓索神经的完整性,保留了鼓索神经的结构和功能,可以减低移植于镫骨头上的听小骨膺复物脱落的危险,且可对移植筋膜起支架作用.%Objective:To report the way for searching the chorda tympani nerve and the significance for preserving the chorda tympani nerve during canal'wall-down mastoidectomy and tympanoplasty surgery. Method:Sixty-six cases with chronic suppurative otitis media underwent canal-wall-down mastoidectomy and tympanoplasty surgery. According to the marker of the short crus of incus, the posterior wall of auditory canal was lowered and crista of the chorda tympani nerve was found through tracing the facial nerve contour. The chorda tympani nerve was preserved after clearing the surrounding tissue. Result: Among the 66 cases, 24 cases had middle ear chol-esteatoma,42 cases had granulation in middle ear. The cholesteatoma and granulation on the surface of the chorda tympani nerve were cleared thoroughly. No neurotmesis or obvious change of taste occurred after operation. Conclu sion: Canal-wall-down mastoidectomy and tympanoplasty surgery preserving chorda tympani nerve integrality may preserve the structure and function of the chorda tympani nerve , reduce the risk of ossicle extrusion above the head of stapes and serve as a frame for transplanting

  3. 下颌第二恒磨牙C型根根管壁厚度的显微CT分析%A micro-CT analysis of the wall thickness of C-shaped canals in permanent mandibular second molars

    Institute of Scientific and Technical Information of China (English)

    顾永春; 朱琦; 张燕萍; 周培刚; 丁月峰; 陈花花; 周涛

    2014-01-01

    Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.%目的:测量下颌第二恒磨牙 C 型根的根管壁厚度。方法:采集到中国汉族患者拔除的 C 形根下颌第二恒磨牙40颗。显微 CT 扫描后采用 Mimics 10.01软件进行三维重建;沿着牙体长轴从釉牙骨质界(CEJ)到根尖顶每隔1 mm 连续虚拟横切牙根模型,观测牙根横截面上 C 形根管的类型(范兵分型)

  4. Effects of dentin on the antimicrobial properties of endodontic medicaments.

    Science.gov (United States)

    Haapasalo, Markus; Qian, Wei; Portenier, Isabelle; Waltimo, Tuomas

    2007-08-01

    Successful treatment of apical periodontitis is dependent on the elimination of the infective microflora from the necrotic root canal system. Antimicrobial irrigating solutions and other locally used disinfecting agents and medicaments have a key role in the eradication of the microbes. While most if not all presently used disinfecting agents rapidly kill even the resistant microbes when tested in vitro in a test tube, the effectiveness of the same agents is clearly weaker in the in vivo conditions. Recent studies have given valuable information about the interaction of endodontic disinfecting agents with dentin and other compounds present in the necrotic root canal. As a result of such interactions the antimicrobial effectiveness of several of our key disinfectants may be weakened, or even eliminated under certain circumstances. Different disinfectants show different sensitivity to the action by the various potential inactivators, such as dentin, serum proteins, hydroxyapatite, collagen derived from different sources, and microbial biomass. This review is a summary of our present knowledge of the mostly negative interactions between endodontic disinfecting agents and the various compounds present in the root canal environment.

  5. The dentinal surface: its influence on dentinal adhesion. Part I.

    Science.gov (United States)

    Eick, J D; Cobb, C M; Chappell, R P; Spencer, P; Robinson, S J

    1991-12-01

    Three categories of dentinal adhesive are proposed: category I includes adhesives with shear bond strength values between 5 and 7 MPa; category II includes dentinal adhesives with shear bond strengths between 8 and 14 MPa; and category III includes adhesives with shear bond strength values up to 20 MPa. In part I of this article, photomicrographs of the dentinal smear layer and three category I first-generation dentin-adhesive interfaces are presented. The photomicrographs show that the wetting and penetration of the first-generation dentinal adhesives were not adequate to produce high shear bond strengths. When the category I adhesives were tested for shear bond strength, failures occurred at the interface or in the resin adhesive. Future articles will explain wetting and adhesive performance of category II and III adhesives.

  6. Dentinal tubules driven wetting of dentin: Cassie-Baxter modelling

    Science.gov (United States)

    Ramos, S. M. M.; Alderete, L.; Farge, P.

    2009-10-01

    We investigate the wetting properties of dentin surfaces submitted to a phosphoric acid etching followed by an air drying procedure, as in clinical situations of adhesive dentistry. The surface topography of the etched surfaces was characterized by AFM, and the wetting properties of water on these rough and heterogeneous surfaces were studied, by contact angle measurements. We showed that the contact angle increases with the acid exposure time and consequently with both surface roughness and the organic-mineral ratio of the dentin components. From the whole results, obtained on dentin and also on synthesized hydroxyapatites samples, we inferred a water contact angle of ˜ 133° on the dentinal tubule. These experimental results may be described by the Cassie-Baxter approach, and it is suggested that small air pockets could be formed inside the dentinal tubules.

  7. Effect of three different calcium hydroxide mixtures (calcium hydroxide with glycerine, normal saline and distilled water on root dentin microhardness

    Directory of Open Access Journals (Sweden)

    Hasheminia SM

    2007-06-01

    Full Text Available Background and Aim: During root canal therapy, it is necessary to remove as many bacteria as possible from the root canal. The use of medicaments is recommended to reduce the microbial population prior to root filling. Calcium hydroxide pastes have been used because of their antibacterial effects and the ability of tissue dissolving. The aim of this study was to evaluate the effect of calcium hydroxide/glycerine mixture, calcium hydroxide/normal saline mixture and calcium hydroxide/distilled water mixture on root dentin microhardness in storage times of 7 and 14 days.Materials and Methods: In this in vitro study, fifteen extracted maxillary canines and central incisors were selected. The crowns of the teeth were removed and the canals were prepared. Teeth were sectioned transversally to produce a total of 30 dentin discs from the middle third of the roots. Specimens were divided into three groups of 10 discs each. Dentin samples were subjected to calcium hydroxide/glycerine, calcium hydroxide/normal saline and calcium hydroxide/distilled water mixtures for 7 and 14 days. Dentin microhardness was measured by a Vickers indenter with a load of 200 g for 15 seconds. Data were analyzed using ANOVA, Paired t-test and LSD with p<0.05 as the level of significance.Results: Statistical analysis showed that all three mixtures decreased dentin microhardness. After 7 days, reduction in dentin microhardness by calcium hydroxide/glycerine combination was significantly higher than calcium hydroxide/normal saline and calcium hydroxide/distilled water combinations. After 14 days, reduction in dentin microhardness by calcium hydroxide/distilled water combination was significantly higher than the other two groups.Conclusion: Based on the results of this study, the use of calcium hydroxide combinations for intracanal dressing reduces dentin microhardness. After 7 days calcium hydroxide/glycerine combination and after 14 days calcium hydroxide/distilled water

  8. Effect of cleaning methods on bond strength of self-etching adhesive to dentin

    Directory of Open Access Journals (Sweden)

    Juliana Delatorre Bronzato

    2016-01-01

    Full Text Available Aim: The aim of this study was to investigate the influence of cleaning methods to remove zinc oxide-eugenol-based root canal sealer (Endomethasone on the bond strength of the self-etching adhesive to dentin. Materials and Methods: Twenty crowns of bovine incisors were cut to expose the pulp chamber. A zinc oxide- and eugenol-based sealer was placed for 10 min in contact with the pulp chamber dentin. Specimens were divided into four groups according to the cleaning method of dentin used: G1, no root canal sealer (control; G2, 0.9% sodium chlorite (NaCl; G3, ethanol; and G4, followed by diamond drill. After cleaning, the teeth were restored with composite resin and Clearfil SE Bond. All specimens were sectioned to produce rectangular sticks and dentin/resin interface was submitted to microtensile bond testing. The mean bond strengths were analyzed using ANOVA/Tukey (α = 0.05. Results: G3 and G4 showed bond strengths similar to the G1 (P > 0.05. A significant decrease in the bond strength in the G2 was observed (P < 0.05. G1, G3, and G4, the predominant failure mode was the mixed type. The prevalence of adhesive failure mode was verified in the G2. Conclusion: The cleaning methods affected the bond strength of the self-etching adhesive to dentin differently.

  9. Dentin permeability: determinants of hydraulic conductance.

    Science.gov (United States)

    Reeder, O W; Walton, R E; Livingston, M J; Pashley, D H

    1978-02-01

    A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.

  10. Diffusion of calcitonin through the wall of the root canal Avaliação da difusão da calcitonina através da dentina radicular

    Directory of Open Access Journals (Sweden)

    Selma Cristina Cury Camargo

    2004-03-01

    Full Text Available The aim of this study was to evaluate the in vitro diffusion of synthetic salmon calcitonin (CT, used as an intracanal medication, to the external root surface, with or without the presence of intact root cementum. Fifty-four human central incisors were used in the experiment, and were divided into two groups of 21 (test groups and two groups of 6 teeth (control groups. After root canal preparation, 10 ml of calcitonin was inserted within the root canal chamber. The root was sealed and made externally impermeable. Specimens were then placed in tubes with saline solution buffered with phosphates and stored at 37°C. The diffusion of calcitonin was measured after 1, 4 and 7 days. To count calcitonin present at the external media (PBS, ELISA test (an antigen-antibody reaction was used. Results showed that there was calcitonin diffusion through dentin in all of the test samples. The absence of cementum increased the diffusion of calcitonin (p=0.05. The highest counts of CT were obtained on day 7 for groups with or without cementum - showing a direct relation between time and diffusion of the medication.O presente estudo determinou in vitro a difusão da calcitonina sintética de salmão, como medicação intracanal, até a superfície externa radicular, com e sem a presença de cemento radicular. Foram utilizados cinqüenta e quatro incisivos centrais humanos, divididos em dois grupos com 21 dentes cada e dois grupos com 6 dentes cada (controle negativo. Após o preparo endodôntico, os dentes receberam 10 ml de calcitonina como medicação intracanal. Feitos o selamento e a impermeabilização externa da raiz, os espécimes foram acondicionados em tubos com solução salina tamponada com fosfatos e incubados em estufa a 37°C. Foram colhidas amostras da solução salina nos períodos de 1, 4 e 7 dias. Para a análise das soluções teste, utilizou-se teste ELISA. Os resultados mostram que existe a difusão da medicação testada até a superf

  11. Canals in the Roof of the Pharynx :Anatomic Study and their Clinical Meaning

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionThe palatovaginal canal and the vomerovaginal canal are small canals which connect the roof of the nasopharynx to the posterior wall of the pterygopalatine fossa. The pterygopalatine fossa represents a major pathway for spread of malignant tumors and infections. In most of the classic anatomy texts brief descriptions of the palatovaginal canal and the vomerovaginal canal are provided. There is still a scarcity of studies comparing the radiologic and microdissection findings~([1]). The aim of t...

  12. Mineral trioxide aggregate root canal filling of traumatized immature tooth

    OpenAIRE

    Maha A Kanfar; Al-Nazhan, Saad A.

    2013-01-01

    An 8-year-old female patient reported to the dental clinic seeking a help to save her traumatized maxillary left central incisor. The tooth had been treated with a temporary filling by a general dentist. The coronal tooth structure was intact, discolored, and a temporary filling was placed on the access opening. She gave a history of trauma about 3 years back. An intraoral periapical radiograph revealed an open apex and dentin bridge in the middle of the root canal. The root canal and the acc...

  13. [Electronic determination of the length of the root canal].

    Science.gov (United States)

    Dehon, P; Van Nieuwenhuysen, J P

    1999-01-01

    The endpoint of an endodontic treatment must be situated at the cemen-to-dentinal junction to preserve the biological potential of the periapical area and to realize a complete disinfection of the principal root canal system. Thus, the determination of working length is a crucial factor in endodontic therapy. The conventional radiographic method cannot provide the accurate location of the apical constriction. For this reason, the electronic apex locators have been developed. Now, the last generation of apex locators has become more sophisticated and the electronic measurements seem to be accurate and reliable with electrolytic solutions in the canal.

  14. Efficacies of anterior wall plication for giant inguinal canal inguinal hernia in children%腹股沟管前壁折叠术治疗小儿巨大腹股沟斜疝的效果评价

    Institute of Scientific and Technical Information of China (English)

    张合成; 陈金兰; 靳三丁

    2016-01-01

    目的:探讨腹股沟管前壁折叠术在小儿巨大腹股沟斜疝中的应用效果。方法2012年1月至2015年1月我们共对301例334侧巨大腹股沟疝患儿实施手术。将患儿随机分成两组,实验组159例177侧,对照组142例157侧。对照组仅行腹股沟皮纹横切口疝囊高位结扎术,实验组予腹股沟皮纹横切口疝囊高位结扎并腹股沟管前壁折叠术。结果两组在年龄、性别、术后住院时间及并发症的发生情况上比较均无统计学意义。手术时间:实验组(21.4±4.6)min,对照组(17.2±3.5)min;术后复发情况:实验组复发1例,复发率0.56%;对照组复发7例,复发率4.46%。结论腹股沟管前壁折叠并疝囊高位结扎术特别适用于巨大腹股沟斜疝患儿,能明显降低术后复发率。%Objetive To explore the clinical efficacies of anterior wall plication of inguinal canal plica-tion in giant inguinal hernia of children. Methods A total of 301 patients of giant inguinal hernia with 334 sides from January 2012 to January 2015 were randomly divided into two groups.The control group underwent merely high ligation of hernia sac of inguinal skin.And high ligation of hernia sac and anterior wall plication of inguinal canal were performed in the experimental group.Results No significant inter-group differences exis-ted in gender,age,hospitalization duration and postoperative complications.Operative duration was slightly longer in experimental group than that in control group (21.4 ±4.6 vs 17.2 ±3.5 min).The postoperative re-currence rate was significantly lower in experimental group than that in control group (n =1,0.56% vs n =7, 4.46%). Conclusions Anterior wall plication of inguinal canal plus high ligation of hernial sac is particularly suitable for giant inguinal hernia in children.And it may significantly reduce the postoperative recurrence rate.

  15. Irrigant Flow beyond the Insertion Depth of an Ultrasonically Oscillating File in Straight and Curved Root Canals : Visualization and Cleaning Efficacy

    NARCIS (Netherlands)

    Malki, Maher; Verhaagen, Bram; Jiang, Lei-Meng; Nehme, Walid; Naaman, Alfred; Versluis, Michel; Wesselink, Paul; van der Sluis, Lucas

    2012-01-01

    Introduction: The purpose of this study was to evaluate the influence of the insertion depth of an ultrasonically oscillating file on the ability to remove dentin debris from simulated canal irregularities in an extracted tooth model of a straight root canal and its influence on the flow of irrigant

  16. The effects of current dentinal adhesives on the dentinal surface.

    Science.gov (United States)

    Chappell, R P; Spencer, P; Eick, J D

    1994-12-01

    The effects of the dentinal surface treatments from six currently available commercial dentinal adhesives are presented. The adhesives are All-Bond 2, etched and unetched, Syntac, Prisma Universal Bond 3, Scotchbond Multipurpose, Tenure Solution, and Adhesive By Choice. Unerupted third molar human teeth were sectioned and treated with the appropriate adhesive according to the manufacturer's directions. After the teeth were treated, they were processed for observation by scanning electron microscopy. Scanning-electron microscopic photomicrographs were made of each step in the process to show the effects of the constituents, including the adhesives, on the dentinal surface. For All-Bond 2, unetched, the smear layer was not removed before the primer and the adhesive were applied. The primer for Prisma Universal Bond 3 altered the smear layer by reacting with it but did not produce a large demineralized zone in the dentin. All the other adhesives did remove the smear layer before the tooth was treated with the primer and adhesive.

  17. Clinical application of pedicle retroauricular flap in canal wall-down tympanoplasty%耳后带蒂皮瓣在开放式鼓室成形术中的应用

    Institute of Scientific and Technical Information of China (English)

    黄永久; 鲍学礼

    2011-01-01

    Objective To explore the practical restorative procedure for tissue defect in canal wall-down (CWD) tympanoplasty based on a clinical trial. Methods Included in this study were 26 cases, among them 22 cases with cholesteatoma in the middle ear cleft and 4 with chronic suppurative otitis media, all treated by CWD type of tympanoplasty with pedicle retroauricular flap transplanting to repair the tissue defect in the operative cavity. Then, all these cases were followed up for 1 to 15 years to observe the therapeutic outcomes for evaluating the restorative effect on these cases. Results All the flaps were survived among these cases, with their operative cavities all clearing and dried in a period of one month and no granulation growing. During the following up period, it was found that the operated mastoid cavity were almost vanished in all of them, with a slightly wider external auditory meatus present when compared with that of the opposite side, covered with smooth and clear skin on the reconstructed posterior canal wall, and improved postoperative hearing level at different degrees. Conclusions The tissue defect in the operative cavity, met during CWD type of tympanoplasty, can be repaired with a pedicle retroauricular flap in a simple and convenient way to improve the survival rate of the flap to a higher level and to shorten the period of ear drying for avoiding granulation growing in the operative cavity.%目的 探讨开放式鼓室成形术中上皮缺损的有效修复方法.方法 26例开放式鼓室成形术患者,应用耳后带蒂皮瓣一期修复术腔上皮缺损,系统观察修复效果.结果 所有患者皮瓣全部成活,均在1月内干耳,术腔无肉芽生长.术后随访1~16年,全部患者乳突术腔基本消失,外耳道略宽,后壁皮肤光滑、洁净,术后听力均有不同程度提高.结论 对于开放式鼓室成形术中出现的上皮缺损,耳后带蒂皮瓣修复法简单方便,成活率高,有利于缩短干耳时间.

  18. The effects of various irrigating solutions on intra-radicular dentinal surface: An SEM analysis

    Directory of Open Access Journals (Sweden)

    J V Karunakaran

    2012-01-01

    Full Text Available Aim: The action of irrigant solutions on intra- radicular dentinal surface were evaluated in an in vitro setting using a scanning electron microscope (SEM and it was observed that sodium hypochlorite and MTAD produced the cleanest surface and that none of the irrigants were able to produce an ideal preparation of the dentinal surface when used individually. The primary objective of endodontic therapy is to achieve a clean, optimal environment in root canals to avoid unsuccessful treatment outcomes. The complexities of the root canal system necessitate the use of irrigating solutions which act on radicular dentin surface, modifying it. The action of irrigants can be beneficial, and yet at the same time, as they modify the surface structure of dentin, they can have an adverse impact on the properties of dentin. The present study was undertaken to assess the effect of various irrigants on the dentinal surface using an SEM. Materials and Methods: Forty-five roots were randomly divided into nine groups (n=5 and prepared by sectioning at the level of cemento-enamel junction (CEJ and 10 mm from the CEJ and split longitudinally. The dentin surface was prepared and the cemental surfaces were coated with double layer of varnish. The irrigants tested were normal saline, de-ionized water, 17% ethylenediaminetetraacetic acid (EDTA, 5% sodium hypochlorite (NaOCl, 5% NaOCl with ultrasonic agitation, 3% hydrogen peroxide, 2% chlorhexidine (CHX, MTAD, and MTAD with ultrasonic agitation. The prepared samples were placed in the irrigant solution for 3 min, subsequently dehydrated, sputter coated, and observed under SEM. The images were subsequently analyzed for dentinal surface changes. Results: 17% EDTA and MTAD produced the cleanest dentinal surface. Ultrasonic agitation enhanced the effect of irrigants. 5% NaOCl and 3% hydrogen peroxide were efficient at removal of organic debris, but were unable to remove the smear layer. De-ionized water, normal saline, and 2

  19. Antibacterial effect of bioactive glass in combination with powdered enamel and dentin

    Directory of Open Access Journals (Sweden)

    Prabhakar A

    2010-01-01

    Full Text Available Background and Objectives: In endodontics, various intracanal medications have been advocated to eliminate bacteria after root canal instrumentation. A recent study has revealed that addition of powdered dentin to bioactive glass (BAG led to increased glass dissolution, and an increased antibacterial efficacy. Therefore, the present study was undertaken to compare the effect of enamel and dentin powder on the antibacterial efficacy of a commercially available BAG. Materials and Methods: Dentin blocks (dbs were prepared from single rooted human teeth. These dbs were infected with Enterococcus faecalis for two weeks in Tryptic Soy Broth (TSB, while negative controls were kept in sterile TSB. In group I, the infected dbs were filled with BAG, in group II with BAG + Enamel powder and group III with BAG + Dentin powder. Dentin samples were harvested from the dbs and cultured. Statistical Analysis: Kruskal-Wallis ANOVA was used for multiple group comparison followed by Scheffe′s post hoc test for pair-wise comparisons. Results: All the combinations of BAG evaluated significantly reduced the bacterial counts compared to the control group. However, at the end of 24 hours, three days, and five days BAG + Dentin powder showed significant reduction ( P < 0.01 in bacterial counts compared to the other experimental groups. Conclusion: Among the various materials evaluated, it appeared that though BAG exhibits antimicrobial efficacy, the addition of powdered enamel and dentin in aqueous suspension definitely enhanced this property. However, the addition of enamel powder BAG did not significantly alter its antimicrobial efficacy compared to BAG + dentin powder.

  20. Carious dentine removal: current approach

    Directory of Open Access Journals (Sweden)

    Germana Coeli de Farias Sales

    2008-01-01

    Full Text Available Dentistry is renewed day after day through the results of qualified researches. The approach as regards carious dentin removal is goingthrough questioning and innovation. The scope of this study was to perform a literature review in the sense of elucidating questions pertaining to the problem of whether or not it is necessary to completely remove carious dentin, and the possibility of performing restoration in a single session, in addition to a discussion about which type of material should be applied in this type of substrate. After analyzing the referenced articles, it was concluded that the stepwise treatment controls caries progression; there is a trend in the literature to partially remove the carious dentin in deep lesions and perform definitive restoration; Calcium hydroxide cement is a classical liner in these situations, while glass ionomer cement and resinous materials are other possibilities of materials that can be in close contact with the remaining dentin.

  1. Functional remineralization of carious dentin

    Science.gov (United States)

    Pugach, Megan Kardon

    A primary goal of dental tissue engineering is the biological reconstruction of tooth substrate destroyed by caries or other diseases affecting tooth mineralization. Traditionally, dentists treat caries by using invasive techniques to remove the diseased dental tissue and restore the lesion, ideally preventing further progression of decay. Success in strategies associated with remineralization of enamel and root caries have contributed to the less invasive prospect of remineralization of dentinal carious lesions. The central hypothesis of this dissertation is that carious dentin lesions can be remineralized if the lesions contain residual mineral. Caries Detector (CD) stained zones (pink, light pink, transparent and normal) of arrested carious dentin lesions were characterized according to microstructure by atomic force microscopy (AFM) imaging, mineral content by digital transverse microradiography, and nanomechanical properties by AFM-based nanoindentation. CD-stained and unstained zones had significantly different microstructure, mineral content and nanomechanical properties. Furthermore, the most demineralized carious zone contained residual mineral. To obtain reproducible, standardized dentin caries lesions, we characterized the lesions from an artificial carious dentin lesion model using a 0.05M acetate demineralization buffer. The artificial caries-like lesions produced by the buffer had similar mineral content and nanomechanical properties in the stained and unstained zones as natural dentin lesions. Both natural and artificial lesions had significant correlations between mineral content and nanomechanical properties. Mineral crystallite size and shape was examined by small angle x-ray scattering. Both natural and artificial carious dentin had different mineral sizes than normal dentin. Collagen in natural and artificial carious dentin lesions was examined by trichrome stain, AFM high-resolution imaging, and UV resonance Raman spectroscopy, to determine if

  2. Laser-activated irrigation within root canals: cleaning efficacy and flow visualization

    NARCIS (Netherlands)

    Groot, de S.D.; Verhaagen, B.; Versluis, M.; Wu, M.-K.; Wesselink, P.R.; Sluis, van der L.W.M.

    2009-01-01

    Aim: To test ex vivo the efficiency of laser-activated irrigation in removing dentine debris from the apical part of the root canal and to visualize in vitro the fluid dynamics during the activation of the irrigant by laser, using high-speed imaging at a relevant timescale. - Methodology: Root cana

  3. Biodentine-a novel dentinal substitute for single visit apexification.

    Science.gov (United States)

    Nayak, Gurudutt; Hasan, Mohammad Faiz

    2014-05-01

    Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

  4. Hard tissue deposition in dental pulp canal by {alpha}-tricalcium phosphate cement

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.; Toda, T. [Osaka Dental Univ. (Japan). Dept. of Endodontics; Mandai, Y. [Bio-Chemical Lab. of Nitta Gelatin Inc., Yao (Japan); Oonishi, H. [Osaka Minami National Hospital, Kawachi (Japan). Dept. of Orthopaedic Surgery

    2001-07-01

    Canal closure by hard tissue proliferation in the pulp canal and/or apical foramen is the most ideal healing after pulp removal. Generally, Ca(OH){sub 2} may induce secondary dentine or dentine-bridge on the amputated pulp surface. However, Ca(OH){sub 2} shows strong alkalinity and may cause severe inflammatory responses in the residual pulp. Moreover, completely formed dentine-bridge at the orifice will disturb further treatment of residual pulp because of the difficulty in localizing the pathway. The purpose of this study was to see hard tissue induction using newly developed {alpha}-tricalcium phosphate cement and to recognize the morphological difference of hard tissue from that of Ca(OH){sub 2}. (orig.)

  5. Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin

    Directory of Open Access Journals (Sweden)

    Janaina Corazza Montero

    2012-08-01

    Full Text Available This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin.

  6. Epitympanoplasty with Cartilage Obliteration in the Canal Wall Up Technique to the Middle Ear Cholesteatoma%保留外耳道后壁上鼓室切开软骨重建术治疗中耳胆脂瘤

    Institute of Scientific and Technical Information of China (English)

    赵丹珩; 刘阳; 孙建军; 林勇生

    2013-01-01

    Objective To report the curative effect of the epitympanoplasty with cartilage obliteration in the treatment of middle ear cholesteatoma .Methods This study retrospectively analysed 123 cases ,with middle ear cholesteatoma treated in our department from November 2009 to July 2012 .The operation included mastoidectomy with posterior canal wall preserved ,lateral wall of attic resected ,facial recess opened to the epitympanum ,epitym-panum obliterated with cartilage and mastoid cavity blocked with bone dust .All cases were followed up on complica-tions and hearing improvement .Results All cases were followed up 6~38 months .In 123 cases ,there were 2 ca-ses had cholesteatoma recurrence in the middle ear cavity ,6 cases had infection of post auricular incision after opera-tion ,3 cases had residual marginal tympanic membrane perforation ,2 cases had ossicular replacement prosthesis ex-clusion ,and 6 cases had canal wall skin swelling or defect .The rest cases acquired full -recovery after 2 or 3 wound dressing changes .Out of 123 cases ,83 cases had the whole hearing document ,the average AB gap at 0 .5 ,1 ,2 kHz reduced from 32 .2 ± 11 .2 dB pre-operation to 20 .7 ± 12 .4 dB post -operation .The AB gap of pre - and post -operation had significant difference (P<0 .001) .Conclusion The mastoidectomy with posterior canal wall preserved greatly shortened the healing time .The resection of lateral wall of epitympanum can exposed operating field more completely and remove lesions thoroughly .The cartilage obliteration in the attic can prevent the retraction pocket formation effectively .This technique provides alternative in treating middle ear cholesteatoma .%目的探讨在保持外耳道后壁完整的情况下,切除上鼓室外侧壁并软骨封闭治疗中耳胆脂瘤的疗效。方法2009年11月~2012年7月对123例(123耳)中耳胆脂瘤患者行保留外耳道后壁的乳突切开、上鼓室盾板切除及面神经隐窝向上鼓室开放,清除病

  7. Quantitative assessment of root canal roughness with calcium-based hypochlorite irrigants by 3D CLSM.

    Science.gov (United States)

    Oliveira, Juliana Santos; Raucci Neto, Walter; Faria, Natália Spadine de; Fernandes, Fernanda Silva; Miranda, Carlos Eduardo Saraiva; Abi Rached-Junior, Fuad Jacob

    2014-01-01

    Chemical solutions play important roles in endodontic treatment and promote ultrastructural changes in dentin surface. The aim of this study was to quantify root canal roughness at different concentrations of calcium hypochlorite (Ca(OCl)2) and sodium hypochlorite (NaOCl) by confocal laser scanning microscopy (CLSM). Fifty-two human mandibular premolars were sectioned and randomly organized into thirteen groups (n=8): saline (control); 1%, 2.5% and 5% NaOCl; 1%, 2.5% and 5% Ca(OCl)2; the hypochlorite groups were further divided into with or without EDTA. The chlorine concentrations of the different solutions were measured by iodine titration (%). The superficial roughness (Sa) was quantified by CLSM. Ca(OCl)2 presented substantial decrease in chlorine concentration that differed from the package indication, but without compromising the dentin ultrastructure changes. There were no significant differences in dentin roughness between Ca(OCl)2 or NaOCl at all studied concentrations. The combination with EDTA provided similar roughness values among the solutions (p>0.05). The 5% Ca(OCl)2 and NaOCl solutions significantly increased dentin roughness and did not differ from the EDTA association (p>0.05). Ca(OCl)2 promoted similar dentin roughness as the NaOCl at the same concentrations and combined with EDTA. It may be concluded that Ca(OCl)2 modified the root canal dentin roughness similarly to NaOCl, at the same concentrations and EDTA combinations used in this study. Ca(OCl)2 and NaOCl, both at 5%, significantly altered dentin roughness, overcoming EDTA association, thus Ca(OCl)2 concentrations ranging from 1% to 2.5% may be suitable solutions for root canal irrigation protocols.

  8. 前壁外耳道-鼓膜瓣应用于开放式鼓室成形术31例%Application of anterior wall of external auditory canal ardrum flap for open tympanoplasty in 31 patients

    Institute of Scientific and Technical Information of China (English)

    陈泽; 钟兆棠; 梁敏志

    2014-01-01

    目的:探讨前壁外耳道-鼓膜瓣应用于开放式鼓室成形术中,能否提高鼓膜修补成功率和手术疗效。方法对慢性化脓性中耳炎及中耳胆脂瘤伴中、下鼓室自行封闭患者66例(66耳),予开放式鼓室成形术治疗,其中31例术中应用前壁外耳道-鼓膜瓣内植法鼓室成形(前瓣组),35例应用软骨和筋膜内植法鼓室成形(软骨组),测定术前及术后6个月气导(AC)、气骨导差(ABG),比较两组的临床疗效。结果前瓣组成功率为96.8%(30/31),软骨组88.6%(31/35),两组比较差异无统计学意义(P >0.05);前瓣组有效率为88.46%,软骨组为65.52%,两组比较差异有统计学意义(P <0.05),即前瓣组优于软骨组。结论伴有中、下鼓室封闭的慢性中耳炎患者,行开放式鼓室成形术中应用前壁外耳道-鼓膜瓣鼓室成形能提高筋膜成活率,术后鼓膜穿孔率低,较好成形鼓室,并能同期听力重建,提高听力。%Objective To investigate the application of anterior wall of external auditory canal-eardrum flap in open tympanoplasty to improve tympanic molding.Methods 66 patients (66 ears)with chronic suppurative otitis media or middle ear cholesteatoma accompanied with self sealing of mesotympanum and hypotympanum underwent open tympan-oplasty.31 cases were applied with anterior wall of external auditory meatus-eardrum flap (Anterior flap group)and 35 cases were treated with cartilage and fascia inner-transplanted method (Cartilage group).Air conduction (AC)and air bone gap (ABG)were performed six months before and after surgery.The clinical effect of the two groups were Com-pared.Results The success rates were 96.8%(30 /31)and 88.6%(31 /35)in anterior flap group and cartilage group respectively (P >0.05 ),while the effective rates were 88.46% and 65.52% correspondingly in the two groups (P <0.05).Conclusion For the patients

  9. The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

    OpenAIRE

    Zhang, Shan-chuan; Kern, Matthias

    2009-01-01

    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which migh...

  10. Effect of chloroform, eucalyptol and orange oil solvents on the microhardness of human root dentin.

    Directory of Open Access Journals (Sweden)

    Sedigheh Khedmat

    2015-02-01

    Full Text Available This study aimed to assess the effect of chloroform, eucalyptol and orange oil solvents on the microhardness of human root dentin.Sixty-eight single-rooted single-canal extracted human premolar teeth were used. Tooth crowns were separated from the roots at the cementoenamel junction (CEJ. Roots were buccolingually sectioned into mesial and distal halves. Specimens were randomly divided into 5 groups, with 20 teeth in each solvent group and 4 teeth in each control group. Primary microhardness of specimens was measured using Vickers microhardness tester. Specimens were exposed to solvents for 15 minutes and were subjected to microhardness testing again. Data were recorded and analyzed using repeated measure ANOVA.No significant difference was found in dentin microhardness before and after exposure to solvents in any of the orange oil, eucalyptol, chloroform or saline groups (P=0.727. None of the experimental groups showed any significant difference in terms of dentin microhardness reduction (P=0.99 and had no significant difference with the negative control group.This study showed that chloroform, eucalyptol and orange oil as gutta percha solvents did not decrease the microhardness of root dentin. Thus, none of the mentioned solvents has any superiority over the others in terms of affecting dentin properties.

  11. Morphological aspects and physical properties of enamel and dentine of Sus domesticus: A tooth model in laboratory research.

    Science.gov (United States)

    Fagundes, Nathalia Carolina Fernandes; Cardoso, Miquéias André Gomes; Miranda, Mayara Sabrina Luz; Silva, Raira de Brito; Teixeira, Francisco Bruno; Nogueira, Bárbara Catarina Lima; Nogueira, Brenna Magdalena Lima; de Melo, Sara Elisama Silva; da Costa, Natacha Malu Miranda; Lima, Rafael Rodrigues

    2015-11-01

    This study aims to describe and analyze morphological and physical properties of deciduous teeth of Sus domesticus. Ultrastructural analysis, mineral composition and microhardness of enamel and dentine tissues were performed on 10 skulls of S. domesticus. External anatomic characteristics and the internal anatomy of the teeth were also described. Data regarding microhardness and ultrastructural analysis were subjected to statistical tests. For ultrastructural analysis, we used the analysis of variance (ANOVA) with Tukey's post hoc (p≤0.05) test. In the analysis of microhardness, the difference between the enamel and dentine tissues was analyzed by a Student's t test. Values were expressed as mean with standard error. The results of ultrastructural analysis showed the presence of an enamel prism pattern. A dentinal tubule pattern was also observed, with a larger diameter in the pulp chamber and the cervical third, in comparison to middle and apical thirds. We observed an average microhardness of 259.2kgf/mm(2) for enamel and 55.17kgf/mm(2) for dentine. In porcine enamel and dentine, the chemical elements Ca and P showed the highest concentration. The analysis of internal anatomy revealed the presence of a simple root canal system and the occurrence of main canals in the roots. The observed features are compatible with the functional demand of these animals, following a pattern very similar to that seen in other groups of mammals, which can encourage the development of research using dental elements from the pig as a substitute for human teeth in laboratory research.

  12. 开放式鼓室成形听力重建术不同频率效果分析%Frequency-specific hearing assessment after canal wall-down tympanoplasty for chronic ear diseases

    Institute of Scientific and Technical Information of China (English)

    陶朵朵; 陈兵

    2012-01-01

    Objectives To analyze frequency-specific hearing results after canal wall-down tympanoplasty for chronic ear diseases, in relation to various surgical factors. Methods Patients who underwent canal wall-down tympanoplasty for chronic ear diseases from June 2008 to January 2011 in the Department of Otolaryngology, Eye Ear Nose & Throat Hospital, Fudan University were reviewed retrospectively (n=87). Using pure tone audiometry, air-conductive threshold (AC), bone-conductive threshold (BC) ,and air-bone gap (ABG), and pre- and post-operative changes were analyzed for each of the following frequencies: 0.25 kHz, 0.5 kHz, 1 kHz, 2 kHz, 3 kHz, 4 kHz (AC and BC) and 6 kHz (AC). Frequency-specific results were investigated in relation to various surgical factors. Results Both AC and ABC results showed improvements at each frequency, primarily in the low and mid frequencies. The improvement decreased gradually from low to high frequencies. BC results showed significant improvement at every frequency except 4 kHz. In patients without ossiculoplasty, BC results improved significantly only at 1 kHz. Conclusion Canal wall-down tympanoplasty for chronic ear diseases can improve hearing primarily in low and mid frequencies.%目的 探讨慢性中耳炎患者开放式鼓室成形术后听力重建效果,并对不同频率听力重建效果进行对比分析.方法 回顾2008年6月至2011年1月在复旦大学附属眼耳鼻喉科医院耳鼻喉科行开放式鼓室成形术的920例患者,从中筛选具有完整随访资料患者87名,利用纯音测听对患者手术前后0.25 kHz、0.5 kHz、1 kHz、2kHz、3 kHz、4kHz、6 kHz频率处的纯音气导听阈、骨导听阈和气骨导差进行评估,比较各项指标手术前后差异,探讨各频率重建效果的可能影响因素.结果 术后气导听阈总体平均值在各个频率均有显著改善,听觉重建效果从低频到高频呈下降趋势,其中1 kHz以下频率明显优于2 kHz以上频率;术后气骨导

  13. Effect of irrigation technique for removal of triple antibiotic paste on bond strength of MTA to root dentin.

    Science.gov (United States)

    Dumani, Aysin; Yilmaz, Sehnaz; Yoldas, Oguz; Bek, Zeliha Gonca

    2016-01-01

    This study evaluated the bond strength of mineral trioxide aggregate (MTA) to root canal dentin after the performance of various irrigation procedures to remove triple antibiotic paste (TAP). A total of 56 single-rooted human mandibular premolars were instrumented using a rotary system to size 40 and divided randomly into a control group (no intracanal dressing) and three experimental groups (TAP application for 28 days). TAP was then removed by rinsing with 10 mL 2.5% NaOCl using three irrigation systems (Vibringe sonic irrigation, CanalBrush, and syringe irrigation). The coronal and middle parts of root canals were then obturated with MTA. After storage for 1 week, each specimen was embedded in an acrylic block and sectioned horizontally (2-mm-thick slices) at two levels (coronal and middle). Bond strength of MTA to root canal dentin was assessed in 28 samples per group via push-out test using a universal testing machine. Data from the four groups were compared using one-way analysis of variance. Tukey's test was used for multiple comparisons. Push-out bond strength values were significantly higher in the control and Vibringe groups than in the CanalBrush and syringe irrigation groups (p irrigation system may increase the push-out bond strength of MTA compared with the use of the CanalBrush or syringe irrigation.

  14. Adhesion to bovine dentin--surface characterization.

    Science.gov (United States)

    Ruse, N D; Smith, D C

    1991-06-01

    X-ray photo-electron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were used to characterize the dentin surface, to determine the effects of different pre-conditioning procedures on the elemental composition of the dentin surface, and to investigate the interaction between dentin and a dentin bonding agent (ScotchBond) by studying the changes in the elemental composition of dentin as a result of the interaction. Scanning electron microscopy (SEM) was used to characterize sample surface morphology, which was then correlated with surface elemental composition. The results showed that: (a) the elemental composition of the smear layer was similar to that of the underlying dentin; (b) cleaning with hydrogen-peroxide did not produce any modification in the elemental composition of the dentin surface; and (c) acid-etching led to an almost complete demineralization of the dentin, leaving behind an organic-rich surface. The results suggest that bonding systems that use acid-etching as a pre-conditioning procedure should be based on agents able to interact with the organic components of dentin, since bonding agents that rely on a chelation-to-calcium reaction are unlikely to be successful. The investigation of the interaction between the bonding agent and dentin led to a postulated adhesive-bonding reaction mechanism and suggested a partially cohesive failure in the bonding agent during fracturing of a dentin-bonding-agent-bonded assembly.

  15. Assessment of the bacteria reduction in the infected root canal irradiated with diode laser; Avaliacao da reducao bacteriana em conduto radicular infectado e irradiado com laser de diodo. Estudo in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Radaelli, Claudia Amaral Rabello de Mello

    2002-07-01

    the periapical point which width measured 1 mm, approximately. The maximum temperature variation was 7.45 deg C. Under electron microscope scanning, the control groups showed areas with smear layer covering the dentinal walls. The laser irradiated groups showed a smooth, uniform, clean appearance, with small areas of closed dentinal tubules without cracking alternately with areas of exposed open dentinal tubules. Some parts showed fusion of the dentinal mass (groups irradiated with 3 W). In groups where calcium hydroxide was associated with laser irradiation remains were found over the irradiated surface and, in many parts, the dentinal tubules could not be observed. The use of high intensity diode laser at 830 nm proved to be efficient and able to promote reduction in the Enterococcus faecalis population in the infected root canals. (author)

  16. A radiographic study of mandibular canal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Chul; Lee, Sang Rae [Dept. of Oral Radiology, Division of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    1987-11-15

    The author invested the gonial angle, the angle of mandibular and mental canal to the lower border of the mandible, and a relationship of the position of the mandibular canal to the root apex of the posterior teeth and the cortical plate of the lower of the mandible. The materials consisted of 458 pantomograms in male and female aged 11-40 and divided into 5 groups at year intervals and subdivided into 3 groups by gonial angle. The results were as follows: 1. The gonial angle decreased with age, but slight increase occurred over 26-30 years. 2. The average angle of the mandibular canal to the lower border of the mandible was 151.6 degree and did not correlate with age. 3. The average angle of the mental canal to the lower border of the mandible was 36.9 degree and didn't correlate with age. 4. The angles of mandibular and mental canal to the lower border of mandible correlated with gonial angle. 5. The distance from the root apex of the posterior teeth to the upper wall mandibular canal was most short at the region of the distal root of the mandibular second and increased with age at the region of the mandibular second molar. 6. The distance from the lower wall of the mandibular canal to the cortical plate of the lower border of the mandibule was most short at the region of the mesial root of the mandibular first molar and didn't correlate with age.

  17. Substantivity of Ag-Ca-Si mesoporous nanoparticles on dentin and its ability to inhibit Enterococcus faecalis.

    Science.gov (United States)

    Fan, Wei; Wu, Yujie; Ma, Tengjiao; Li, Yanyun; Fan, Bing

    2016-01-01

    The main purpose of this study was to investigate the substantivity of Ag-Ca-Si mesoporous nanoparticles (Ag-MCSNs) on dentin and its residual antibacterial effects against Enterococcus faecalis. Ag-MCSNs were fabricated and characterized, ion release profile and pH were tested, and the ability to inhibit planktonic E. faecalis as well as the cytotoxicity was evaluated. Dentin slices were medicated with Ca(OH)2 paste, 2 % chlorhexidine gel and Ag-MCSNs paste for 7 days and then irrigated. Dentin slices were then immersed in E. faecalis suspension for 6 days and then transferred to fresh brain heart infusion solution. The optical density value within 10 h after immersing and transferring were measured and compared among groups. Results indicated that Ag-MCSNs showed high pH, sustained Ag(+)-Ca(2+)-SiO3 (2-) ion release, and high substantivity on dentin. The Ag-MCSNs exhibited strong antibacterial effects against planktonic E. faecalis and much better residual inhibition effects against E. faecalis growth on dentin than Ca(OH)2 paste (P faecalis and high substantivity on dentin, which might be developed to a new effective intra-canal medicament for human teeth.

  18. The permeability of dentine from bovine incisors in vitro.

    Science.gov (United States)

    Tagami, J; Tao, L; Pashley, D H; Horner, J A

    1989-01-01

    The permeability of coronal dentine was investigated by measuring the hydraulic conductance of dentine discs. Reductions in dentine thickness from the enamel side of disc resulted in a greater increase in permeability than reductions from the pulpal side. Scanning electron microscopy revealed fewer dentinal tubules with smaller diameters in superficial dentine than in deep dentine. The permeability of coronal incisor bovine dentine is six to eight times less than that of unerupted coronal human third molar dentine but similar to that of human root dentine.

  19. 完壁式鼓室成形术治疗慢性化脓性中耳炎%Intact Canal Wall Tympanoplasty in Treating Patients with Chronic Suppurative Otitis Media

    Institute of Scientific and Technical Information of China (English)

    王凯; 俞杰; 李幼珍; 张建

    2013-01-01

    目的:介绍完壁式鼓室成形术治疗慢性化脓性中耳炎的的手术体会。方法回顾性分析96完壁式鼓室成形术治疗慢性化脓性中耳炎的临床资料,术中注意上鼓室外侧壁盾板的完整,清除病灶保护粘膜,建立咽鼓管、鼓室、鼓窦、乳突的通气引流系统。结果术前纯音听力测试0.5、1.0、2.0、4.0kHz语言频率区听阈气骨导差的平均值0-10dB为0耳(0%),11-20 dB为4耳(4.17%),21-30 dB为29耳(30.2%),31-40 dB为46耳(47.9%),大于40 dB为17耳(17.7%),平均气导为(54.1±6.5)dB,平均骨导为(13.6±7.6)dB;术后3月纯音听力测试,0.5、1.0、2.0、4.0kHz语言频率区听阈气骨导差的平均值0-10dB为25耳(26.0%),11-20 dB为46耳(47.9%),21-30 dB为19耳(19.8%),31-40 dB为6耳(6.3%),大于40 dB为0耳0%),平均气导为(38.1.±7.9)dB,平均骨导为(12.5±6.3)dB。术后8月以上(平均间隔时间为11个月)纯音听力测试的情况是0-10dB为22耳(22.9%),11-20 dB为41耳(42.7%),21-30 dB为24耳(25%),31-40 dB为9耳(9.3%),大于40 dB为0耳0%),平均气导为(41.2±8.4)dB,平均骨导为(12.6±7.6)dB。术后8个月~3年随访中行颞骨CT扫描(平均间隔时间为11个月),96耳中75耳乳突鼓窦保持气化(78.1%),21耳乳突鼓窦软组织影充填(21.9%)。结论完壁式鼓室成形术治疗慢性化脓性中耳炎可取得满意疗效,遵循个体化原则建立合理的中耳通气引流系统是手术的关键。%Objective To introduce the experience of the intact canal wall tympanoplasty in chronic suppurative otitis media. Methods Clinical data of 96 cases of the intact canal wall tympanoplasty for treating chronic suppurative otitis media was retrospectively reviewed. During the operation, the outside wall of attic should be keeped intact, lesions should be re-moved, mucosa

  20. The fluid mechanics of root canal irrigation.

    Science.gov (United States)

    Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

    2010-12-01

    Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid

  1. Monoblocks in root canals: a hypothetical or a tangible goal.

    Science.gov (United States)

    Tay, Franklin R; Pashley, David H

    2007-04-01

    The term monoblock has become familiar in the endodontic literature with recent interest in the application of dentin adhesive technology to endodontics. Endodontic monoblocks have generated controversial discussions among academicians and clinicians as to whether they are able to improve the quality of seal in root fillings and to strengthen roots. This review attempts to provide a broader meaning to the term monoblock and to see how this definition may be applied to the materials that have been used in the past and present for rehabilitation of the root canal space. The potential of currently available bondable materials to achieve mechanically homogeneous units with root dentin is then discussed in relation to the classical concept in which the term monoblock was first employed in restorative dentistry and subsequently in endodontics.

  2. Contraction stress in dentin adhesives bonded to dentin.

    Science.gov (United States)

    Hashimoto, M; de Gee, A J; Kaga, M; Feilzer, A J

    2006-08-01

    Adhesives cured under constrained conditions develop contraction stresses. We hypothesized that, with dentin as a bonding substrate, the stress would reach a maximum, followed by a continuous decline. Stress development was determined with a tensilometer for two total-etch systems and two systems with self-etching primers. The adhesives were placed in a thin layer between a glass plate and a flat dentin surface pretreated with phosphoric acid or self-etching primer. After an initial maximum shortly after light-curing, the stress decreased dramatically for the total-etch systems (70%) and, to a lesser extent, for the adhesives with self-etching primers (30%). The greater stress decrease for the total-etch systems was ascribed to water and/or solvents released into the adhesives from the fully opened dentinal tubules by the pulling/sucking action of the contraction stress. This happened less with the adhesives with self-etching primers, where the tubules remained mainly closed.

  3. Effect of pressure upon wall-to-wall polymerization contraction of a chemically-cured resin.

    Science.gov (United States)

    Hansen, E K

    1983-02-01

    The marginal gaps of 105 Silar fillings were measured after application of a load between zero and 100 N on the matrix during the initial polymerization. The fillings were placed in non-etched dentin cavities in extracted human teeth. The dentin surrounding the cavities was either roughened with carborundum paper No. 220 or polished with Alfa Micropolish 1 micron before the cavities were filled. When load was applied to the matrix, no effect was found of the roughness surrounding the cavities, but without load the wall-to-wall contraction was significantly greater in cavities where the surrounding dentin surfaces had been polished with Alfa Micropolish. Apparently the effect of load was related to friction during the polymerization between filling surplus and the dentin surrounding the cavities and not to load per se.

  4. Experiment for Development of Simple Escape Countermeasures for Frogs Falling into Concrete Canals

    Science.gov (United States)

    Watabe, Keiji; Mori, Atsushi; Koizumi, Noriyuki; Takemura, Takeshi; Park, Myeong Soo

    Three prototype escape countermeasures for frogs that can be easily installed in U-shaped canals with widths of 30-50 cm and depths of 30-50 cm were experimentally produced because frogs cannot escape from agricultural canals with deep concrete walls after falling into the canal. The differences of effectiveness of the 3 prototypes in places for the countermeasures (1 and 2) and flow conditions (dry and water running) were investigated for 2 frog species (Tokyo Daruma Pond Frog and Japanese Brown Frog). The brown frogs escaped from the canals more easily than the pond frogs. The brown frogs escaped regardless of their body size, but the small pond frogs escaped more easily than the large pond frogs. The prototype with slopes beside both canal walls and a net spread across the center line of the canal enabled frogs to escape from the canal more easily than the prototypes with only slopes or nets beside both canal walls. Increasing the number of places for the countermeasures enhanced frog escape. The differences in frog escape between dry canals and canals with water running were not significant. Therefore, the prototypes were confirmed sufficient as escape countermeasures that is inexpensive and can be easily placed in and removed from agricultural canals.

  5. Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location

    NARCIS (Netherlands)

    P. Nieminen; L. Papagiannoulis-Lascarides; J. Waltimo-Siren; P. Ollila; S. Karjalainen; S. Arte; J. Veerkamp; V. Tallon Walton; E. Chimenos Küstner; T. Siltanen; H. Holappa; P.L. Lukinmaa; S. Alaluusua

    2011-01-01

    We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic fea

  6. Multi-factoriality of dentine hypersensitivity

    OpenAIRE

    Stojšin Ivana; Petrović Ljubomir; Stojanac Igor; Drobac Milan

    2008-01-01

    Introduction. Dentine hypersensitivity has been defined as a sharp, short pain arising from exposed dentin in response to stimuli typically thermal, evaporative tactile, osmoticor, chemical and which cannot be ascribed to any other form of dental defect or pathology. Prevalence. The most affected patients range in age from 20 to 40. The following teeth tend to be most sensitive: cuspids, premolars and incisors, location-concentrated on the facial surface. Morphological bases of dentine hypers...

  7. A quantitative analysis of rotary, ultrasonic and manual techniques to treat proximally flattened root canals

    Directory of Open Access Journals (Sweden)

    Fabiana Soares Grecca

    2007-04-01

    Full Text Available OBJECTIVE: The efficiency of rotary, manual and ultrasonic root canal instrumentation techniques was investigated in proximally flattened root canals. MATERIAL AND METHODS: Forty human mandibular left and right central incisors, lateral incisors and premolars were used. The pulp tissue was removed and the root canals were filled with red die. Teeth were instrumented using three techniques: (i K3 and ProTaper rotary systems; (ii ultrasonic crown-down technique; and (iii progressive manual technique. Roots were bisected longitudinally in a buccolingual direction. The instrumented canal walls were digitally captured and the images obtained were analyzed using the Sigma Scan software. Canal walls were evaluated for total canal wall area versus non-instrumented area on which dye remained. RESULTS: No statistically significant difference was found between the instrumentation techniques studied (p<0.05. CONCLUSION: The findings of this study showed that no instrumentation technique was 100% efficient to remove the dye.

  8. Application of a proanthocyanidin agent to improve the bond strength of root dentin treated with sodium hypochlorite

    Directory of Open Access Journals (Sweden)

    V Sujatha Manimaran

    2011-01-01

    Full Text Available Aim: The objective of this study was to analyze the application of PA agent that improves the bond strength of root dentin treated with NaOCl. Materials and Methods: Group 1: root canals were irrigated using 0.9% isotonic saline as an irrigant (negative control; Group 2: root canals were irrigated using 5.25% NaOCl (positive control; Group 3: root canals were irrigated with 5.25% NaOCl followed by 10% sodium ascorbate for 10 minutes; Group 4: root canals were irrigated with 5.25% NaOCl followed by 5% PA for 10 minutes. All the canals were then coated with self-etch dentin bonding agent, filled with resin cement, stored for one day in water, and then cross sectioned into three slabs of 2-mm thickness that were prepared and tested for microtensile bond strength. Results: The results demonstrated that 5.25% NaOCl caused significant reduction (P<0.05 in the bond strength, but this can be reversed by 5% PA significantly more than the 10% sodium ascorbate.

  9. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia.

    Science.gov (United States)

    Barron, Martin J; McDonnell, Sinead T; Mackie, Iain; Dixon, Michael J

    2008-11-20

    The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP), suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome), permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a number of options including

  10. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia

    Directory of Open Access Journals (Sweden)

    MacKie Iain

    2008-11-01

    Full Text Available Abstract The hereditary dentine disorders, dentinogenesis imperfecta (DGI and dentine dysplasia (DD, comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP, suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome, permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a

  11. Evaluation of the dentin changes in teeth subjected to endodontic treatment and photodynamic therapy

    Directory of Open Access Journals (Sweden)

    Mariane Floriano Lopes Santos LACERDA

    Full Text Available Abstract Introduction Antimicrobial photodynamic therapy (PDT is an efficient adjuvant technique to promote disinfection of the root canal system. Therefore, it is important to investigate changes to dentin morphology and permeability induced by the use of diode laser on the root dentin. Objective The purpose of this study was to investigate morphological changes and the percentage of apical leakage after the use of laser. Material and method Forty single-rooted teeth were instrumented using rotary system and irrigated. Teeth were randomly divided in two groups: G1 - not exposed to PDT (control, and G2 - pretreated with toluidine blue photosensitizer and irradiated with AsGaAl laser diode. Ten teeth in each group were evaluated by SEM for morphological changes. The other ten teeth were filled and stained with Rhodamine B to evaluate the apical leakage. Result The results showed significant difference between G1 and G2 (p 0.001. The apical leakage was significantly higher in G2 than in G1 (p <0.001 - Student's t-test. Conclusion It was concluded that the use of low-level laser reduced the smear layer and opened the dentinal tubules. Use of laser increased the permeability of the apical dentin.

  12. Fundamental Experiment to Determine Escape Countermeasures for Frogs Falling into Agricultural Canals

    Science.gov (United States)

    Watabe, Keiji; Mori, Atsushi; Koizumi, Noriyuki; Takemura, Takeshi

    Frogs often drown in agricultural canals with deep concrete walls, which are installed commonly in paddy fields after land improvement projects in Japan, because they cannot escape after falling into the canal. Therefore, countermeasures that enable frogs to escape from canals are required in some rural areas. An experimental canal with partially sloped walls was used as an escape countermeasure to investigate the preferable angle of slope for the walls, water depth and flow velocity that enables Tokyo Daruma Pond Frogs (Rana porosa porosa), which have no adhesive discs, to easily escape. Walls with slopes of 30-45 degrees allowed 50-60% of frogs to escape from the experimental canals, frogs especially easily climbed the 30 degree sloped walls. When the water depth was 5 cm or flow velocity was greater than 20 cm/s, approximately 80% of the frogs moved downstream and reached the sloped walls because the frogs' toes did not reach the bottom of the canal. However, if the depth was 2 cm and the flow velocity was 5 cm/s, only 4% of the frogs climbed the sloped walls because they could move freely. The frogs appeared to not be good at long-distance swimming and could not remain a long-time under running water. Therefore, walls sloped less than 30 degrees and control of both water depth and flow velocity appears important for enabling frogs to easily escape from canals.

  13. Ex vivo evaluation of three instrumentation techniques on E. faecalis biofilm within oval shaped root canals

    Directory of Open Access Journals (Sweden)

    Vitor Cesar NAKAMURA

    2015-01-01

    Full Text Available The objective of the present study was to assess the effectiveness of reciprocating instrumentation in disinfecting oval-shaped root canals infected with Enterococcus faecalis. Forty-five human lower premolars were infected with a culture of E. faecalis (ATCC 29212 for 28 days. Five other teeth that were neither contaminated nor instrumented were used as controls. The 45 specimens were divided into three experimental groups (n = 15 based on the root canal preparation technique used: manual (K-type, Dentsply Maillefer, Ballaigues, Switzerland; rotary (MTwo, VDW GmbH, Munich, Germany; and reciprocating (Reciproc R50, VDW GmbH, Munich, Germany instruments. During chemomechanical preparation, 21 mL of 2.5% NaOCl was used as the irrigating solution. Microbiological sampling was performed before (S1 and immediately after (S2 the chemomechanical preparation using sterilized paper points. Specimens were then cleaved, and 0.02 g of dentine chips was collected from the root thirds to verify the presence of microorganisms in dentinal tubules. All three preparation techniques reduced the number of microorganisms in the root canal lumen and dentine chips from the root thirds, but no significant differences were observed between the three groups (p > 0.05. Reciprocating instrumentation with Reciproc R50 was effective in reducing the number of microorganisms within the root canal system. Although this technique involves the use of only one file to perform the root canal therapy, it is as effective as conventional rotary instrumentation in reducing theE. faecalis biofilm from the root canal system. However, further clinical investigations are warranted in order to ratify these results.

  14. The treatment of cholesteatoma otitis media by intact-bridge tympanomastoidectomy and soft-wall reconstruction of ear canal%保留骨桥的乳突鼓室成形术及软壁外耳道重建治疗胆脂瘤中耳炎

    Institute of Scientific and Technical Information of China (English)

    阮奕劲; 曾薇; 朱怀文; 薛远琼; 肖富新; 蔡卓; 刘芊; 石雄州

    2012-01-01

    Objective To investigate and estimate the clinical effect of the treatment of cholesteatoma otitis media by intact-bridge tympanomastoidectomy (IBM) and soft-wall reconstruction of ear canal. Methods 67 otitis media patients (69 ears) with cholesteatoma who underwent modified IBM and soft-wall reconstruction of ear canal were enrolled in this study. The operation process included opening the tympanic sinus, the mastoid and the attic, also excising the ostesl posterior wall of the external acoustic meatus, and then opening the back tympanum through the facial recess, clearing the inconvertible pathology completely. In order to maintain the volume of the middle ear canals, the infraversion bridge should be retained. Meanwhile, filling up the operative lacuna with combined flaps of postauricular musculo-periosteal and canal skin flap, and reconstructing external acoustic meatus were conducted. A tympanoplasty was performed at the same or different period. Results The patients were followed up for more than 24 months, and the dry ear time was 16-35 days (23.1+3.4d on average). The air-bone conduction gap was reduced by (25.3+6.7) dB HL on average. The anatomic form and physiologic function of the external acoustic meatus were recovered basically. Conclusions: The IBM and soft-wall reconstruction of ear canal could remain or improve the hearing and recover the basis morphology and function of ear canal. This method could be a better choice for treating the cholesteatoma otitis media.%目的 探讨并评价保留骨桥的乳突鼓室成形术及软壁外耳道重建治疗胆脂瘤中耳炎的临床效果.方法 对67例(69耳)胆脂瘤中耳炎患者施行保留骨桥的乳突鼓室成形术(IBM)及软壁外耳道重建,手术开放鼓窦、乳突及上鼓室,切除骨性外耳道后壁,经面隐窝开放后鼓室,完全清理不可逆病变,为保持中耳腔容积,保留低位骨桥;同时应用带蒂耳后肌骨膜瓣-外耳道皮瓣复合瓣填充乳突术腔并重

  15. CT findings of the osteoma of the external auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ha Young; Song, Chang Joon; Yoon, Chung Dae; Park, Mi Hyun; Shin, Byung Seok [Chungnam National University, School of Medicine, Daejeon (Korea, Republic of)

    2006-07-15

    We wanted to report the CT image findings of the osteoma of the external auditory canal. Temporal bone CT scanning was performed on eight patients (4 males and 4 females aged between 8 and 41 years) with pathologically proven osteoma of the external auditory canal after operation, and the findings of the CT scanning were retrospectively reviewed. Not only did we analyze the size, shape, distribution and location of the osteomas, we also analyzed the relationship between the lesion and the tympanosqumaous or tympanomastoid suture line, and the changes seen on the CT scan images for the patients who were able to undergo follow-up. All the lesions of the osteoma of the external auditory canal were unilateral, solitary, pedunculated bony masses. In five patients, the osteomas occurred on the left side and for the other three patients, the osteomas occurred on the right side. The average size of the osteoma was 0.6 cm with the smallest being 0.5 cm and the largest being 1.2 cm. Each of the lesions was located at the osteochondral junction in the terminal part of the osseous external ear canal. The stalk of the osteoma of the external auditory canal was found to have occurred in the anteroinferior wall in five cases (63%), in the anterosuperior wall (the tympanosqumaous suture line) in two cases (25%), and in the anterior wall in one case. The osteoma of the external auditory canal was a compact form in five cases and it was a cancellous form in three cases. One case of the cancellous form was changed into a compact form 35 months later due to the advanced ossification. Osteoma of the external auditory canal developed in a unilateral and solitary fashion. The characteristic image findings show that it is attached to the external auditory canal by its stalk. Unlike our common knowledge about its occurrence, osteoma mostly occurred in the tympanic wall, and this is regardless of the tympanosquamous or tympanomastoid suture line.

  16. An investigation on the antibacterial and antibiofilm efficacy of cationic nanoparticulates for root canal disinfection.

    Science.gov (United States)

    Kishen, Anil; Shi, Zhilong; Shrestha, Annie; Neoh, Koon Gee

    2008-12-01

    This study aimed to investigate the antibacterial and antibiofilm efficacy of cationic nanoparticulates for root canal disinfection. Experiments were performed in two stages. In stage 1, experiments were conducted to examine the physical properties of three types of nanoparticulates. The antibacterial properties of nanoparticulates alone and nanoparticulates mixed with zinc oxide-eugenol-based sealer were studied. In stage 2, the ability of nanoparticulates-treated dentin to prevent bacterial adherence was examined. Zinc oxide nanoparticulates, chitosan nanoparticulates, a mixture of zinc oxide and chitosan nanoparticulates, and zinc oxide nanoparticulates with multilayered coating of chitosan were tested. This study showed that the incorporation of nanoparticulates did not alter the flow characteristics of sealer but improved the direct antibacterial property and the ability to leach out antibacterial components. There was a significant reduction in the adherence of Enterococcus faecalis to nanoparticulates-treated dentin (p < 0.05). These experiments highlighted the potential advantage of nanoparticulates in root canal disinfection.

  17. Design of canals

    CERN Document Server

    Swamee, P K

    2015-01-01

    The book presents firsthand material from the authors on design of hydraulic canals. The book discusses elements of design based on principles of hydraulic flow through canals. It covers optimization of design based on usage requirements and economic constraints. The book includes explicit design equations and design procedures along with design examples for varied cases. With its comprehensive coverage of the principles of hydraulic canal design, this book will prove useful to students, researchers, and practicing engineers. End-of-chapter pedagogical elements make it ideal for use in graduate courses on hydraulic structures offered by most civil engineering departments across the world.

  18. Clinical application of titanium ossicular prostheses in intact canal wall tympanoplasty with mastoidectomy%钛质听骨在完壁式鼓室成形中的应用

    Institute of Scientific and Technical Information of China (English)

    仇弋戈; 何蓉; 陈永国; 麻宁; 郭欣

    2012-01-01

    目的:评价钛质听小骨假体在完壁式乳突根治鼓室成形术(ICWT)后的疗效.方法:对31例使用钛质听小骨假体进行ICWT的患者进行评估,按听骨类型分为部分听骨赝复物(PORP)组和全听骨赝复物(TORP)组,对2组患者术后1年的听力情况和并发症发生率进行分析.结果:手术总有效率为(气骨导差≤20 dB)87.1%,术后平均增益PROP组为(19.38±10.08)dB,TORP组为(15.15±10.15)dB;术后气骨导差PROP组为(12.29±4.40)dB,TORP组为(15.48±6.26)dB;2组术后气骨导差及气导增益表现均差异无统计学意义,但在低频区(0.5 kHz)气骨导差存在统计学差异;未见听骨排出发生.结论:钛质听小骨在ICWT能够取得满意的听力结果,成功率高于其他综合文献的报告.但2种类型听骨比较差异无统计学意义,术后并发症发生率低,有待长期的随访.%To evaluate the effects of intact canal wall tympanoplasty with mastoidectomy(ICWT) with titanium ossicular prostheses. Method: A retrospective review was performed on 31 patients who underwent ICWT from 2008 to 201L Patients' postoperative hearing results and complication rates were evaluated based on different types of ossicular prosthesis: partial ossicular replacement prosthesis(PORP) , total ossicular replacement prosthesis(TORP). Result:The total effectiveness was 87. 1%. No prosthesis was extruded. There was no significant difference in postoperative hearing results (average postoperative gain and ABG) between the two prostheses. In the low frequency(0. 5 kHz), singnificant difference in ABG was found. Conclusion: No significant difference in postoperative hearing results was found between PORP and TORP, which could be useful materials for tympanoplasty and obviously improve the hearing of otitis media patients after operation. As for the low incidence of postoperative complications in our short-term study Jong-term follow-up visit is necessary.

  19. Unicystic ameloblastoma with the presence of dentin

    Directory of Open Access Journals (Sweden)

    Sivapathasundharam B

    2007-01-01

    Full Text Available We present a case of unicystic ameloblastoma of the posterior mandible in a 28 year-old female, histologically showing luminal and intramural plexiform epithelial proliferation with typical dentin in the connective tissue capsule. The characteristics of hard tissue formation in ameloblastomas reported in existing literature and the possible origin of the dentin mass seen in our case are discussed.

  20. Dentinal innervation of impacted human third molars.

    Science.gov (United States)

    Lilja, J; Fagerberg-Mohlin, B

    1984-12-01

    Five totally impacted third molars were studied in the transmission electron microscope for the presence of nervous structures in the dentin before eruption. In contradiction to earlier studies available, nervous structures were found in the predentin and the dentin of the impacted third molars in different parts of the crown and also in the predentin of the root.

  1. Raman spectra of human dentin mineral

    NARCIS (Netherlands)

    Tsuda, H; Ruben, J; Arends, J

    1996-01-01

    Human dentin mineral has been investigated by using micro-Raman spectroscopy. Fluorescence and thermal problems were largely avoided by preparing dentin samples by grinding and ultrasonic agitation in acetone. The Raman spectral features were consistent with those of impure hydroxyapatite containing

  2. Clinical effect of photodynamic therapy on primary carious dentin after partial caries removal

    Directory of Open Access Journals (Sweden)

    Pierre Adriano Moreno NEVES

    2016-01-01

    Full Text Available Abstract This study was conducted to assess the clinical effect of photodynamic therapy (PDT in the decontamination of the deep dentin of deciduous molars submitted to partial removal of carious tissue. After cavity preparation, dentin samples were taken from the pulp wall of nineteen deciduous molars before and after PDT application. Remaining dentin was treated with 0.01% methylene blue dye followed by irradiation with an InGaAlP diode laser (λ – 660 nm; 40 mW; 120 J/cm2; 120 s. Dentin samples were microbiologically assessed for the enumeration of total microorganisms, Lactobacillus spp. and mutans streptococci. There was no significant difference in the number of colony-forming units (CFU for any of the microorganisms assessed (p > 0.05. Photodynamic therapy, using 0.01% methylene blue dye at a dosimetry of 120 J/cm2 would not be a viable clinical alternative to reduce bacterial contamination in deep dentin.

  3. ON THE STIFFNESS OF DEMINERALIZED DENTIN MATRICES

    Science.gov (United States)

    Ryou, Heonjune; Turco, Gianluca; Breschi, Lorenzo; Tay, Franklin R.; Pashley, David H.; Arola, Dwayne

    2015-01-01

    Resin bonding to dentin requires the use of self-etching primers or acid etching to decalcify the surface and expose a layer of collagen fibrils of the dentin matrix. Acid-etching reduces the stiffness of demineralized dentin from approximately 19 GPa to 1 MPa, requiring that it floats in water to prevent it from collapsing during bonding procedures. Several publications show that crosslinking agents like gluteraladehyde, carbodiimide or grape seed extract can stiffen collagen and improve resin-dentin bond strength. Objective The objective was to assess a new approach for evaluating the changes in stiffness of decalcified dentin by polar solvents and a collagen cross-linker. Methods Fully demineralized dentin beams and sections of etched coronal dentin were subjected to indentation loading using a cylindrical flat indenter in water, and after treatment with ethanol or ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The stiffness was measured as a function of strain and as a function of loading rate from 1 to 50 µm/sec. Results At a strain of 0.25% the elastic modulus of the fully demineralized dentin was approximately 0.20 MPa. It increased to over 0.90 MPa at strains of 1%. Exposure to ethanol caused an increase in elastic modulus of up to four times. Increasing the loading rate from 1 to 50 µm/sec caused an increase in the apparent modulus of up to three times in both water and ethanol. EDC treatment caused increases in the stiffness in fully demineralized samples and in acid-etched demineralized dentin surfaces in situ. Significance Changes in the mechanical behavior of demineralized collagen matrices can be measured effectively under hydration via indentation with cylindrical flat indenters. This approach can be used for quantifying the effects of bonding treatments on the properties of decalcified dentin after acid etching, as well as to follow the loss of stiffness over time due to enzymatic degradation. PMID:26747822

  4. Tissue dissolution and modifications in dentin composition by different sodium hypochlorite concentrations

    Science.gov (United States)

    TARTARI, Talita; BACHMANN, Luciano; MALIZA, Amanda Garcia Alves; ANDRADE, Flaviana Bombarda; DUARTE, Marco Antonio Hungaro; BRAMANTE, Clovis Monteiro

    2016-01-01

    ABSTRACT Sodium hypochlorite (NaOCl) remains the most used irrigation solution during root canal preparation because of characteristics such as wide-spectrum antimicrobial activity and organic tissue dissolution capacity. However, these solutions can alter dentin composition and there is no consensus on the optimal concentration of NaOCl to be used. Objectives To determine the organic matter dissolution and changes in dentin chemical composition promoted by different concentrations of NaOCl over time. Material and Methods: Fragments of bovine muscle tissue were weighed before and after 5, 10, and 15 min of immersion in the groups (n=10): G1- 0.9% saline solution; G2- 1% NaOCl; G3- 2.5% NaOCl; and G4- 5% NaOCl. Bovine dentin fragments were subjected to the same irrigants and absorption spectra were collected by Attenuated Total Reflectance of Fourier Transform Infrared Spectroscopy (ATR-FTIR) before and after 0,5, 1, 2, 3, 5, 8, and 10 min of immersion in the solutions. The ratios of the amide III/phosphate and carbonate/phosphate absorption bands were determined. The tissue dissolution and carbonate/phosphate ratios were submitted to the two-way analysis of variance (ANOVA) with Tukey’s multiple-comparison test (α0.05). Intergroup differences were not observed in this ratio (p>0.05). Conclusions The increase in the exposure time and in the concentration of NaOCl solution lead to an increase in the tissue dissolution and dentin collagen deproteination. Furthermore, some carbonate ions are removed from the dentin inorganic phase by the NaOCl. PMID:27383711

  5. Scanning Electron Microscopic Evaluation of the Sealer-Dentine Interface of Three Sealers

    Science.gov (United States)

    Mohammadian, Fatemeh; Farahanimastary, Farzad; Dibaji, Fatemeh; Kharazifard, Mohammad Javad

    2017-01-01

    Introduction: This study aimed to evaluate the dentine-sealer interface in three different sealers using scanning electron microscopy (SEM). Methods and Materials: Thirty extracted human single-rooted teeth were prepared using ProTaper rotary files and were randomly divided into three groups (n=10) including BC Sealer, AH-Plus and Dorifill. The root canals were filled with cold lateral condensation technique and stored for 7 days in 100% humidity at 37°C. Cross sections were prepared from the coronal, middle, and apical sections of the roots. Then SEM images were taken and the width of gaps was measured by software. Sectional images were evaluated by two endodontists. Data were analyzed using two- and one-way ANOVA and Kruskal-Wallis tests. Results: The mean gap width was significantly lower in coronal area in BC Sealer group compared to Dorifill (P=0.043) and likewise in AH-Plus group compared to Dorifill (P=0.018). There was no significant difference between BC Sealer and AH-Plus group in this area (P=0.923). No significant difference was detected in apical and middle zones among three sealers (P=0.367 and 0.643, respectively). Dentine-sealer interface showed no significant difference in three sealers in the apical area (P=0.051), but dentine-BC Sealer interface was better than AH-Plus in middle and coronal areas, and both outperformed Dorifill (P=0.001). Conclusion: BC Sealer and AH-Plus had less gaps than Dorifill in coronal area. In addition, BC Sealer had better dentine interface in middle and coronal area compared to AH-Plus, and both performed better than Dorifill. Reverse relationship was observed between the mean gap width and dentine-sealer interface quality. PMID:28179922

  6. Estudio de la variación de la permeabilidad de la dentina radicular usando isótopos 99mTc, después de la aplicación de láser de alta intensidad Study of the dentin root permeability variation using 99mTc isotopes, after the application of high intensity laser

    Directory of Open Access Journals (Sweden)

    R. Cabrales Salgado

    2012-02-01

    containing 1 ml of saline. After 1 hour, the account of the radioactive isotope (99mTc was performed. Results: After statistical analysis (ANOVA found that the best results in terms of decreased permeability were found in Group 3, followed by Group 2 and Group 1. Conclusion: We conclude that irradiation with Nd: YAG caused a significant decrease in the permeability of root canal dentin. Laser Er: YAG and control in relation to the dentin permeability of root canal walls showed no statistically significant differences at 5%.

  7. Tensile bond strength and SEM evaluation of caries-affected dentin using dentin adhesives.

    Science.gov (United States)

    Nakajima, M; Sano, H; Burrow, M F; Tagami, J; Yoshiyama, M; Ebisu, S; Ciucchi, B; Russell, C M; Pashley, D H

    1995-10-01

    Tensile bond strength measurements are commonly used for the evaluation of dentin adhesive systems. Most tests are performed using extracted non-carious human or bovine dentin. However, the adhesion of resins to caries-affected dentin is still unclear. The objectives of this study were to test the hypothesis that bonding to caries-affected dentin is inferior to bonding to normal dentin, and that the quality of the hybrid layer plays a major role in creating good adhesion. We used a micro-tensile bond strength test to compare test bond strengths made to either caries-affected dentin or normal dentin, using three commercial adhesive systems (All Bond 2, Scotchbond Multi-Purpose, and Clearfil Liner Bond II). For scanning electron microscopy, the polished interfaces between the adhesive bond and dentin were subjected to brief exposure to 10% phosphoric acid solution and 5% sodium hypochlorite, so that the quality of the hybrid layers could be observed. Bonding to normal dentin with either All Bond 2 (26.9 +/- 8.8 MPa) or Clearfil Liner Bond II (29.5 +/- 10.9 MPa) showed tensile bond strengths higher than those to caries-affected dentin (13.0 +/- 3.6 MPa and 14.0 +/- 4.3 MPa, respectively). The tensile bond strengths obtained with Scotchbond Multi-Purpose were similar in normal and caries-affected dentin (20.3 +/- 5.5 MPa and 18.5 +/- 4.0 MPa, respectively). The hybrid layers created by All Bond 2 in normal dentin and by Clearfil Liner Bond II in normal or caries-affected dentin showed phosphoric acid and sodium hypochlorite resistance, whereas the hybrid layers created by All Bond 2 in caries-affected dentin and those created by Scotchbond Multi-Purpose to normal and caries-affected dentin showed partial susceptibility to the acid and sodium hypochlorite treatment. The results indicate that the strength of adhesion to dentin depends upon both the adhesive system used and the type of dentin. Moreover, the quality of the hybrid layer may not always contribute

  8. The role of perilymph in the response of the semicircular canals to angular acceleration.

    Science.gov (United States)

    Anliker, M.; Van Buskirk, W.

    1971-01-01

    A new model for the response of the semicircular canals to angular motion is postulated. This model is based on evidence that the bony canal is not compartmentalized and assumes that the ampulla wall is highly flexible. It is shown that the perilymph induces a cupula displacement far greater than that produced by the endolymph alone. The predicted dynamic behavior of the canals on the basis of this model is found to be consistent with experimental observations.

  9. First Branchial Cleft Fistula Associated with External Auditory Canal Stenosis and Middle Ear Cholesteatoma

    Directory of Open Access Journals (Sweden)

    shahin abdollahi fakhim

    2014-10-01

    Full Text Available Introduction: First branchial cleft anomalies manifest with duplication of the external auditory canal.   Case Report: This report features a rare case of microtia and congenital middle ear and canal cholesteatoma with first branchial fistula. External auditory canal stenosis was complicated by middle ear and external canal cholesteatoma, but branchial fistula, opening in the zygomatic root and a sinus in the helical root, may explain this feature. A canal wall down mastoidectomy with canaloplasty and wide meatoplasty was performed. The branchial cleft was excised through parotidectomy and facial nerve dissection.   Conclusion:  It should be considered that canal stenosis in such cases can induce cholesteatoma formation in the auditory canal and middle ear.

  10. Management of foreign object in the root canal of central incisor tooth

    Directory of Open Access Journals (Sweden)

    Mothanna Alrahabi

    2014-01-01

    Full Text Available There are several reports describing the impaction of foreign objects into the exposed pulp chambers and canals by patients, especially children as they often have the habit of inserting foreign objects in the oral cavity. These objects will become a potent source of infection.This case report describes the retrieval of a foreign object impacted into the root canal of a 12-year-old male patient who was referred to the endodontic specialty clinic at Taibah University College of Dentistry. The patient′s chief complaint was a pain in the upper left central tooth. Clinical examination revealed a complicated enamel-dentin fracture with a large caries cavity. A periapical radiographic image showed a radiopaque object in the root canal system. Stainless steel Hedstrom files were used to retrieve the object from the canal. Following a proper cleaning and shaping of the root canal system, an intra-canal calcium hydroxide dressing was placed for 1 week. The root canal system was then filled with sealer and gutta-percha using the lateral compaction technique and the tooth received an aesthetic restoration.

  11. Evaluation of Osteoconductive and Osteogenic Potential of a Dentin-Based Bone Substitute Using a Calvarial Defect Model

    Directory of Open Access Journals (Sweden)

    Ibrahim Hussain

    2012-01-01

    Full Text Available The aim of this study was to assess the osteoconductive and osteogenic properties of processed bovine dentin using a robust rabbit calvarial defect model. In total, 16 New Zealand White rabbits were operated to create three circular defects in the calvaria. One defect was left unfilled, one filled with collected autogenous bone, and the third defect was filled with the dentin-based bone substitute. Following surgery and after a healing period of either 1 or 6 weeks, a CT scan was obtained. Following sacrificing, the tissues were processed for histological examination. The CT data showed the density in the area grafted with the dentin-based material was higher than the surrounding bone and the areas grafted with autologous bone after 1 week and 6 weeks of healing. The area left unfilled remained an empty defect after 1 week and 6 weeks. Histological examination of the defects filled with the dentin product after 6 weeks showed soft tissue encapsulation around the dentin particles. It can be concluded that the rabbit calvarial model used in this study is a robust model for the assessment of bone materials. Bovine dentin is a biostable material; however, it may not be suitable for repairing large 4-wall defects.

  12. Effect of super-oxidized water, sodium hypochlorite and EDTA on dentin microhardness.

    Science.gov (United States)

    Ghisi, Alexandre Corrêa; Kopper, Patrícia Maria Poli; Baldasso, Flávia E R; Stürmer, Caroline P; Rossi-Fedele, Giampiero; Steier, Liviu; Figueiredo, José Antonio Poli de; Morgental, Renata Dornelles; Vier-Pelisser, Fabiana Vieira

    2014-01-01

    The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.

  13. Canals, Bypass Canal, Published in 2002, Duchesne County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Canals dataset, was produced all or in part from Other information as of 2002. It is described as 'Bypass Canal'. Data by this publisher are often provided in...

  14. Evaluation of bond strength of D.T.Light- post to root canal using dual-cure and self-cure resin cements after irrigation with various solutions

    Directory of Open Access Journals (Sweden)

    Atai M.

    2008-11-01

    Full Text Available "nBackground and Aim: Nonmetallic tooth- colored posts adhere to canal walls by dentin bonding agents and resin cements. Better retention and proper distribution of stress result from enough and proper bonding. The purpose of this study was to evaluate bond strength of D.T. Light - post with two different resin cements (self-cure & dual-cure and to investigate the effect of irrigating solutions applied in root canal on bond strength of the resin cements and D.T.Light- post to root canal wall. "nMaterials and Methods: In this experimental study 40 single root teeth (maxillary canine & central were selected and stored in 0.1% thymol solution for one week and transferred to distilled water. The teeth were decoronated 2mm above CEJ. The canal space was mechanically enlarged using k-files (up to # 70. The teeth were randomly divided into two groups. The first group was irrigated with 2.6% NaOCl, and the second was irrigated with normal saline. After drying, the teeth were filled with gutta percha cones using lateral condensing method. After two weeks the post space was prepared and D.T.Light- post was inserted in each subgroup using self or dual-cure cements according to manufacturer's instructions. After thermocycling, the apical part was cut 1cm below CEJ. The remained length was divided into 9 equal sequential sections. Each section was submitted to shear push-out test in universal testing machine. Statistical analysis of the bond strength data was performed using ANOVA and post hoc tests with p<0.05 as the level of significance. All failed specimens were examined under stereomicroscope. Degrees of conversion of the cements were determined by FTIR. "nResults: Significant difference in bond strength values were found among sites (P=0.001 and cements (P=0.03. With increasing in depth, bond strength decreased. The mean bond strength value in dual-cure resin cement was higher than self-cure cement. The irrigating solutions caused no significant

  15. Multistate nested canalizing functions

    CERN Document Server

    Adeyeye, J O; Laubenbacher, R; Li, Y

    2013-01-01

    The concept of a nested canalizing Boolean function has been studied over the course of the last decade in the context of understanding the regulatory logic of molecular interaction networks, such as gene regulatory networks. Such functions appear preferentially in published models of such networks. Recently, this concept has been generalized to include multi-state functions, and a recursive formula has been derived for their number, as a function of the number of variables. This paper carries out a detailed analysis of the class of nested canalizing functions over an arbitrary finite field. Furthermore, the paper generalizes the concept further, and derives a closed formula for the number of such generalized functions. The paper also derives a closed formula for the number of equivalence classes under permutation of variables. This is motivated by the fact that two nested canalizing functions that differ by a permutation of the variables share many important properties with each other. The paper contributes ...

  16. Isolated dentinogenesis imperfecta and dentin dysplasia: revision of the classification.

    Science.gov (United States)

    de La Dure-Molla, Muriel; Philippe Fournier, Benjamin; Berdal, Ariane

    2015-04-01

    Dentinogenesis imperfecta is an autosomal dominant disease characterized by severe hypomineralization of dentin and altered dentin structure. Dentin extra cellular matrix is composed of 90% of collagen type I and 10% of non-collagenous proteins among which dentin sialoprotein (DSP), dentin glycoprotein (DGP) and dentin phosphoprotein (DPP) are crucial in dentinogenesis. These proteins are encoded by a single gene: dentin sialophosphoprotein (DSPP) and undergo several post-translational modifications such as glycosylation and phosphorylation to contribute and to control mineralization. Human mutations of this DSPP gene are responsible for three isolated dentinal diseases classified by Shield in 1973: type II and III dentinogenesis imperfecta and type II dentin dysplasia. Shield classification was based on clinical phenotypes observed in patient. Genetics results show now that these three diseases are a severity variation of the same pathology. So this review aims to revise and to propose a new classification of the isolated forms of DI to simplify diagnosis for practitioners.

  17. Leeuwenhoek and the structure of dentine.

    Science.gov (United States)

    O'Sullivan, R; Flannelly, M

    1990-01-01

    This short paper includes extracts from the original translations of Leeuwenhoek's descriptions of the histology of teeth, investigates his findings and demonstrates that in addition to describing dentinal tubules, he may have identified the presence of calcospherites within that tissue.

  18. Love canal questions

    Science.gov (United States)

    Bell, Peter M.

    The Environmental Protection Agency (EPA) conducted a 3-month monitoring study of the Love Canal area near Niagara Falls, N.Y., after the federal government pronounced that a potential health risk existed due to chemical waste dumps. In 1982 the Department of Health and Human Services (HHS) decided that the area was habitable, subject to implementation of effective safeguards against leakage from the canal and to cleaning up of the contaminants. Now, the Congressional Office of Technology Assessment (OTA) has announced that, with the information available, it is not possible to demonstrate with certainty that unsafe levels do not exist within the so-called “emergency declaration area” (EDA).

  19. Multi-factoriality of dentine hypersensitivity

    Directory of Open Access Journals (Sweden)

    Stojšin Ivana

    2008-01-01

    Full Text Available Introduction. Dentine hypersensitivity has been defined as a sharp, short pain arising from exposed dentin in response to stimuli typically thermal, evaporative tactile, osmoticor, chemical and which cannot be ascribed to any other form of dental defect or pathology. Prevalence. The most affected patients range in age from 20 to 40. The following teeth tend to be most sensitive: cuspids, premolars and incisors, location-concentrated on the facial surface. Morphological bases of dentine hypersensitivity Sensitive teeth have much greater numbers of open tubules per unit area and the average diameter of tubules is almost 2 times greater than tubules in nonsensitive teeth. Mechanisms of dentine hypersensitivity. The most widely accepted theory of how the pain occurs is Brannstroms theory. Etiology Dentine hypersensitivity represents a condition of presumable multifactorial pathology. Two processes are essential for its development: (1 dentin must be exposed through either genetic disturbance, enamel defect (lamellae, tufts and spindles, loss of enamel (erosion, abrasion, attrition, abfraction, gingival recession with rapid loss of cementum and (2 the dentin tubules must be open to both the oral cavity and the pulp. Diagnosis. Diagnostic protocol for this condition consisted of Medical, Dental Dietary, Oral Hygiene History and Intra-oral examinations with air indexing method. Differential Diagnosis: We must take into consideration a number of variables such as: dental caries, cracked tooth, restorative sensitivity, medication sensitivity, bleaching sensitivity and abscessed or non-vital tooth. Conclusion. Dentin hypersensitivity is a problem that bothes many patients. Many conditions share the symptoms of tooth sensitivity so differential diagnosis is essential for suitable treatment or preventive measures.

  20. Effectiveness of bonding fiber posts to root canals and composite core build-ups.

    Science.gov (United States)

    Rathke, Andreas; Haj-Omer, Dima; Muche, Rainer; Haller, Bernd

    2009-10-01

    This study investigated the effects of fiber posts, silanization, and luting agents on the interfacial strength to root dentin and composite cores. Root canals of 120 crownless human teeth were instrumented. Three different posts (opaque and translucent), with and without silane treatment, were bonded using etch-and-rinse, self-etch, and self-adhesive luting agents. The restored roots were built up with dual-curing composite. After storage in water for 24 h at 37 degrees C, 2-mm-thick slices were cut from each sample: one from the composite core and one from the restored root. Interfacial push-out bond strengths of the posts were determined in a universal testing machine. Failure modes were analyzed using scanning electron microscopy. The post type and the luting agent had significant effects on both the post-to-dentin and post-to-core strengths. Silanization did not significantly influence post-to-dentin strengths, but enhanced post-to-core strengths. With etch-and-rinse luting agents, debonding occurred predominantly between the post and the cement, while the self-etch and self-adhesive luting agents showed more failures on root dentin. No failures occurred between the composite core and the cement. The combination of translucent posts and etch-and-rinse dual-curing luting agents can positively influence the retention of fiber posts in root canals. Silanization seems to be less relevant for intra-root canal bonding, but may have beneficial effects on post-to-core strengths.

  1. Regeneration of the dentine-pulp complex with revitalization/revascularization therapy: challenges and hopes.

    Science.gov (United States)

    Lin, L M; Ricucci, D; Huang, G T-J

    2014-08-01

    The concept of regenerative endodontics has gained much attention in clinical endodontics in the past decade. One aspect of this discipline is the application of revitalization/revascularization therapies for infected and/or necrotic immature pulps in permanent teeth. Following the publication of a case report (Iwaya et al. ), investigators have been rigorously examining the types of tissues formed in the canals as well as exploring strategies to regenerate the pulp-dentine complex in revitalized teeth. This review will provide an update on the types of tissues generated in the canals after revitalization/revascularization therapy in both animal and human studies. The understanding of the role of stem cells and microenvironment in the process of wound healing resulting in either regeneration or repair will be thoroughly discussed. Stem cells and microenvironmental cues introduced into the canal during revitalization/revascularization procedures will be examined. In addition, requirement of a sterile microenvironment in the canal and vital tissue generation in revitalization/revascularization therapy will be emphasized. The challenges that we face and the hopes that we have in revitalization/revascularization therapy for regenerative endodontics will be presented.

  2. Root dentin strain and temperature rise during endodontic treatment and post rehabilitation.

    Science.gov (United States)

    Amade, Euridsse Sulemane; Novais, Veridiana Resende; Roscoe, Marina Guimarães; Azevedo, Fabiane Maria Ferreira; Bicalho, Aline Aredes; Soares, Carlos José

    2013-01-01

    This study investigated the effects of endodontic treatment procedures and different post systems rehabilitation steps on the strain and temperature rise on apical and cervical root dentin regions. Twenty-one extracted human canine teeth had two strain gages attached to the distal root surface and two thermocouples attached to the mesial root surface (cervical and apical). The strain and temperature rise were recorded during the following procedures: root canal preparation, final rinse and drying, root canal filling and canal relief. Then the teeth were divided into three groups (n=7), according to the type of post system: CPC, cast post and core; FGP, fiberglass post; and PSP, prefabricated steel post. Data continued to be recorded during the post space preparation, post modeling (only for CPC), post trying and post cementation. Data were subjected to a two-way ANOVA followed by Tukey's test (α=0.05). The post-space preparation caused the highest temperature rise (4.0-14.9 °C) and the highest strain in the apical region during irrespective of post type. The resin cement light-activation resulted in significant temperature increases in the cervical region for all of the groups. The canal relief and the post-space preparation produced highest temperature rises. The CPC post modeling resulted in higher root strain level similarly the level of post preparation. The PSP resulted in highest strain during post trying and post cementation.

  3. Remineralization of caries lesions extending into dentin.

    Science.gov (United States)

    ten Cate, J M

    2001-05-01

    Remineralization is one aspect of the overall process of tooth decay. However, it is primarily studied in shallow lesions. The aim of this study was to explore whether caries lesions in enamel and extending into the dentin can be remineralized. A single-section model was developed for the longitudinal and non-destructive monitoring of changes in enamel and dentin. Lesions at least 200 microm into dentin were formed in undersaturated acetate buffers. Next, the lesions were divided into groups (three treatment and one control) and remineralized. The treatments were: weekly immersion in 1,000 ppm fluoride, single treatment with methanehydroxybisphosphonate, and a constant level of 1 ppm fluoride. De- and remineralization was assessed by transverse microradiography. Remineralization was observed in enamel, but also in dentin, indicating that, deep into dentin, the pores become supersaturated to apatite formation. Treatments affected remineralization only in the outer part of enamel. Both findings are explained by a relatively fast diffusion of mineral ions, with precipitation being rate-limiting. The results suggest that dentin remineralization, underneath enamel, can be achieved and could possibly be used in clinical treatment strategies.

  4. Current status of dentin adhesive systems.

    Science.gov (United States)

    Leinfelder, K F

    1998-12-01

    Undoubtedly, dentin bonding agents have undergone a major evolution during the last several years. The shear bond strength of composite resin to the surface of dentin is actually greater than the inherent strength of the dentin itself under well-controlled conditions. No longer must the clinician depend only upon the bonding to enamel as the sole bonding mechanism. Bonding to both types of dental structure permits even better reinforcement of the tooth itself. Perhaps even more important than the high level of bonding exhibited by the current dentin adhesives is their ability to seal the dentin. So effective is this sealing capability that it is now possible to protect the pulpal tissue from microbial invasion through the dentinal tubules. Further, by enclosing the odontoblastic processes and preventing fluid flow, the potential for postoperative sensitivity is diminished considerably. In fact, so evolutionary is the concept of bonding that the procedures associated with the restoration of teeth has changed dramatically. Undoubtedly, far greater improvements can be anticipated in the future.

  5. Trans-dentinal stimulation of tertiary dentinogenesis.

    Science.gov (United States)

    Smith, A J; Murray, P E; Sloan, A J; Matthews, J B; Zhao, S

    2001-08-01

    Trans-dentinal stimulation of tertiary dentinogenesis has long been recognized, and has traditionally been ascribed to diffusion of irritant substances arising during injury and restorative treatment. Identification of bio-active components, especially growth factors including TGF-beta s, sequestered within dentin matrix provides a new explanation for cellular signaling during tertiary dentinogenesis. Both isolated dentin matrix components and pure growth factors (TGF-beta s) have been shown to signal cellular events leading to reactionary and reparative tertiary dentinogenesis. Release of these bio-active components from dentin matrix may arise during carious attack and other injury to the tissue, and also during subsequent surgical intervention and restoration of the tooth. Both cavity-conditioning agents and leaching from restorative materials may contribute to release of these components. Distance of diffusion, as determined by cavity residual dentin thickness, and other restorative parameters may influence the signaling process after release of these components. Careful consideration of the interplay between tissue injury and surgical and restorative material factors is required for optimum exploitation of the exquisite regenerative capacity of dentin-pulp for more biological approaches to clinical treatment of dental disease.

  6. Permeability of normal versus carious dentin.

    Science.gov (United States)

    Pashley, E L; Talman, R; Horner, J A; Pashley, D H

    1991-10-01

    Although a number of reports have been published demonstrating that carious dentin is less permeable than normal dentin, these reports have been qualitative rather than quantitative. The purpose of this in vitro study was to apply a quantitative technique to the study of the permeability of carious human teeth before and after excavation, before and after removal of the smear layer and before and after preparation of a control cavity of similar size and depth in normal dentin subjected to the same measurements, for comparative purposes. Dentin permeability was measured as a hydraulic conductance. The permeability values measured at each step in the protocol were expressed as a percent of the maximum permeability of both cavities, permitting each tooth the serve as its own control. Carious lesions exhibited a slight degree of permeability (2.3 +/- 0.6% of controls) which remained unchanged after excavation of the lesions. Removal of the smear layer in the excavated carious lesions increased the permeability significantly to 6.9 +/- 3.2%. Preparation of a control cavity of the same area and depth increased the permeability slightly. Removal of its smear layer increased the permeability of the dentin 91%. These results confirm previous qualitative studies that carious dentin, even after excavation and removal of the smear layer has a very low permeability.

  7. Nutrient canal of the fibula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo-Hyuk; Ehara, Shigeru; Tamakawa, Yoshiharu [Departments of Radiology, Iwate Medical University School of Medicine, Morioka (Japan); Horiguchi, Masahura [Department of Anatomy I, Iwate Medical University School of Medicine, Morioka (Japan)

    2000-01-01

    Objective. To investigate the radiological features of the nutrient canal in the fibula.Design and patients. One hundred and seventy-nine dried fibulae were studied regarding the type, number, location, and direction of the nutrient canal. They were classified into a usual type (type I: a radiolucent line confined to the cortex) and an atypical type (type II: a radiolucent line extending beyond the cortex).Results. Among the total of 230 nutrient canals seen on radiography, 197 (86%) were type I and 33 (14%) were type II. On CT scans, the ossified rim of the canal extended into the medullary cavity in type II canals. The most common site was the posteromedial aspect in both type I and type II canals. Type II canals were significantly more common in fibulae with two or three nutrient canals. The frequency of the upward direction was more common in type II canals.Conclusion. Nutrient canals with extension of the ossified rim into the medullary canal are the cause of linear lucency that may simulate a fracture. Their features are slightly different from those of usual canals. (orig.)

  8. Tensile bond strength of hydroxyethyl methacrylate dentin bonding agent on dentin surface at various drying techniques

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    Kun Ismiyatin

    2010-06-01

    Full Text Available Background: There are several dentin surface drying techniques to provide a perfect resin penetration on dentin. There are two techniques which will be compared in this study. The first technique was by rubbing dentin surface gently using cotton pellet twice, this technique is called blot dry technique. The second technique is by air blowing dentin surface for one second and continued by rubbing dentin surface gently using moist cotton. Purpose: This experiment was aimed to examine the best dentin surface drying techniques after 37% phosphoric acid etching to obtain the optimum tensile bond strength between hydroxyethyl methacrylate (HEMA and dentin surface. Method: Bovine teeth was prepared flat to obtain the dentin surface and than was etched using 37% phosphoric acid for 15 seconds. After etching the dentin was cleaned using 20 cc plain water and dried with blot dry techniques (group I, or dried with air blow for one second (group II, or dried with air blow for one second, and continued with rubbing gently using moist cotton pellet (group III, and without any drying as control group (group IV. After these drying, the dentin surfaces were applied with resin dentin bonding agent and put into plunger facing the composite mould. The antagonist plunger was filled with composite resin. After 24 hours, therefore bond strength was measured using Autograph. Result: Data obtained was analyzed using One-Way ANOVA with 95% confidence level and continued with LSD test on p≤0.05. The result showed that the highest tensile bond strength was on group I, while the lowest on group IV. Group II and IV, III and IV, II and III did not show signigicant difference (p>0.05. Conclusion: Dentin surface drying techniques through gentle rubbing using cotton pellet twice (blot dry technique gave the greatest tensile bond strength.Latar belakang masalah: Tehnik pengeringan permukaan dentin agar resin dapat penetrasi dengan sempurna adalah dengan cara pengusapan secara

  9. Influence of flexion angle of files on the decentralization of oval canals during instrumentation

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    Maria Antonieta Veloso Carvalho de OLIVEIRA

    2015-01-01

    Full Text Available The aim of this study was to evaluate the influence of the flexion angle of files on the decentralization of root canals during instrumentation. Fifteen lower incisors were instrumented with Protaper Universal files and radiographed in two directions (mesiodistal and buccolingual before and after instrumentation with a #15 K-file in position for evaluating the flexion angle of files. The specimens were also scanned before and after instrumentation using micro-computed tomography to obtain the canal area and the distance from the center position of the file to the canal walls. Sections located 1.0 mm (end of the canal, 3.0 mm (apical third, 9.0 mm (middle third, and 15.0 mm (cervical third from the apex were verified. After instrumentation, the flexion angles of files decreased by an average of 0.76º in the buccolingual direction and 1.92º in the mesiodistal direction (p < 0.001; the canal area increased by an average of 0.58, 0.37, 0.23 and 0.13 mm2 from the cervical to the end of the root canal (p < 0.001. Non-instrumented areas were observed on the buccal and lingual walls, and effective action of files was determined on the mesial and distal walls. The sections from the end of the canal showed canal deviation toward the lingual wall, whereas the other sections showed deviation toward the buccal wall. The flexion angles of files influence the final shape of the root canal, resulting in file decentralization along the pathway of the canal.

  10. Induction of Reparative Dentin Formation on Exposed Dental Pulp by Dentin Phosphophoryn/Collagen Composite

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    Toshiyuki Koike

    2014-01-01

    Full Text Available The ultimate goal of vital pulp therapy is to regenerate rapidly dentin possessing an excellent quality using a biocompatible, bioactive agent. Dentin phosphophoryn (DPP, the most abundant noncollagenous polyanionic protein in dentin, cross-linked to atelocollagen fibrils was applied to direct pulp capping in rats. After 1, 2, and 3 weeks, the teeth applied were examined on the induction of reparative dentin formation and the response of pulp tissue, compared to calcium hydroxide-based agent conventionally used. The reparative dentin formation induced by DPP/collagen composite was more rapid than by calcium hydroxide. In the morphometrical analysis, the formation rate of reparative dentin by DPP/collagen composite was approximately the same as that by calcium hydroxide at 3 weeks. Nevertheless, the compactness of reparative dentin formed by DPP/collagen composite was much superior to what resulted from calcium hydroxide. Also, DPP/collagen composite showed high covering ability of exposed pulp. Moreover, DPP/collagen composite led only to slight pulp inflammation at the beginning whereas calcium hydroxide formed necrotic layer adjacent to the material and induced severe inflammation in pulp tissue at 1 week. The present study demonstrates a potential for DPP/collagen composite as a rapid biocompatible inducer for the formation of reparative dentin of excellent quality in rats.

  11. The role of host-derived dentinal matrix metalloproteinases in reducing dentin bonding of resin adhesives.

    Science.gov (United States)

    Zhang, Shan-chuan; Kern, Matthias

    2009-12-01

    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength. Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modem self-etch and etch-and-rinse adhesives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.

  12. Root Canal Morphology of Permanent Maxillary and Mandibular Canines in Indian Population Using Cone Beam Computed Tomography

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    Nikhita Somalinga Amardeep

    2014-01-01

    Full Text Available Aim. To investigate the root canal anatomy of single-rooted permanent maxillary and mandibular canines in an Indian population using cone beam computed tomography (CBCT. Methodology. A total of 250 permanent maxillary canines and 250 permanent mandibular canines were selected and scanned using CBCT. The root anatomy of each tooth was evaluated for the following parameters: the pattern of the root canals, anatomic length of the crown and the root, the presence of accessory canals, the shape of the access cavity, the position of the apical foramina, root diameter, and dentin thickness of the root. Results. Majority of the teeth had a Type I canal configuration in both maxillary canines (81.6% and mandibular canines (79.6%. In maxillary canine the other canal patterns found were Type III (11.6%, Type II (2.8%, Type V (2%, Type XIX (1.2%, and Type IV (0.8%. In mandibular canines the various other canal patterns found were Type III (13.6%, Type II (3.2%, Type V (2%, and Type XIX (1.6%. Apical foramina were laterally positioned in the majority of the teeth, 70.4% and 65.6% in maxillary and mandibular canines, respectively. 12% of the maxillary canines and 12.8% of the mandibular canines had accessory canals. Conclusion. The root canal anatomy of permanent maxillary and mandibular canines varied widely in an Indian population.

  13. Bacterial coronal leakage after obturation with three root canal sealers.

    Science.gov (United States)

    Timpawat, S; Amornchat, C; Trisuwan, W R

    2001-01-01

    The purpose of this study was to compare the bacterial leakage of root canals obturated with three root canal sealers, using Endodontalis faecalis as a microbial tracer to determine the length of time for bacteria to penetrate through the obturated root canal to the root apex. Seventy-five, single-rooted teeth with straight root canals had the crown cut off at the cementoenamel junction. Root canals were instrumented by a step-back technique. The prepared teeth were randomly divided into 3 groups of 19 teeth each and another 2 groups as positive and negative controls (9 teeth each). The experimental groups were dependent on the sealer used: AH-Plus, Apexit, and Ketac-Endo. The root canals were obturated using a lateral condensation technique. After 24 h the teeth were attached to microcentrifuge tubes with 2 mm of the root apex submerged in Brain Heart Infusion broth in glass test tubes. The coronal portions of the root canal filling materials were placed in contact with E. faecalis. The teeth were observed for bacterial leakage daily for 30 and 60 days. With the chi2 test for comparing pairs of groups at the 0.05 level (p 0.06), but Apexit had significantly higher leakage (p 0.05), but Apexit leaked more than AH-Plus. The conclusion drawn from this experiment was that epoxy resin root canal sealer was found to be more adaptable to the root canal wall and filling material than a calcium hydroxide sealer when bacterial coronal leakage was studied.

  14. EFFECT OF DENTIN TUBULES TO THE MECHANICAL PROPERTIES OF DENTIN.PART II:EXPERIMENTAL STUDY

    Institute of Scientific and Technical Information of China (English)

    Huo Bo; Zheng Quanshui; Zhang Qing; Wang Jiade

    2000-01-01

    To verify the theoretical models of varying transversely isotropic stress-strain relations of dentin established in the preceding work(Part I),we perform a set of experiments.Because of the very fine tooth size,it usually seems to be difficult to directly measure the inhomogeneons and anisotropic parameters of dentin.In this paper,by the digital speckle correlation method,tensile experiments are made on the small dentin samples either parallel or perpendicular to the dentin tubules.With the theoretically predicted elastic stress-strain relations,an optimization method is proposed to fit the strain curve adapted to the experimental data.The results show that the theoretical elastic stress-strain relations coincides very well with the experimental observations.The determined Young's modulus and Poisson's ratio of dentin matrix are 29.5GPa and 0.44,respectively,in the optimization sense.

  15. Evaluation of the Morphological Characteristics of Laser-Irradiated Dentin

    Science.gov (United States)

    Lilaj, Bledar; Franz, Alexander; Degendorfer, Daniela; Moritz, Andreas

    2015-01-01

    Abstract Objective: The aim of this study was to investigate the effect of different energy settings of Er:YAG laser irradiation on dentin surface morphology with respect to the number of opened dentinal tubules. Background data: An ideally prepared dentin surface with opened dentinal tubules is a prerequisite for adhesive fixation. No study, however, has yet compared the numbers of opened dentinal tubules with regard to statistical differences. Methods: Conventional preparations using a bur with or without additional acid etching acted as control groups. Dentin specimens were prepared from human third molars and randomly divided into eight groups according to the energy settings of the laser (1, 1.5, 4, 6, 7.5, and 8 W) and two controls (bur and bur plus acid etching). After surface preparation, dentin surfaces were analyzed with a scanning electron microscope, and the number of opened dentinal tubules in a defined area was counted. Results: The control groups showed smooth surfaces with (bur plus acid etching) and without opened dentinal tubules (bur), whereas all laser-irradiated surfaces showed rough surfaces. Using the energy setting of 4 W resulted in significantly more opened dentinal tubules than the conventional preparation technique using the bur with additional acid etching. In contrast, the energy setting of 8 W showed significantly fewer opened dentinal tubules, and also exhibited signs of thermal damage. Conclusions: The Er:YAG laser with an energy setting of 4 W generates a dentin surface with opened dentinal tubules, a prerequisite for adhesive fixation. PMID:26389986

  16. Adhesive dentistry and endodontics. Part 2: bonding in the root canal system-the promise and the problems: a review.

    Science.gov (United States)

    Schwartz, Richard S

    2006-12-01

    One of the recent trends in endodontics has been the development of bonded obturating materials, in an effort to provide a more effective seal coronally and apically. Materials utilizing dentin adhesive technology have been borrowed from restorative dentistry and adapted to obturating materials. This review discusses the obstacles to effective bonding in the root canal system, the progress that has been made, and possible strategies for improved materials in the future. Much of the literature reviewed and many of the principles discussed are taken from the restorative dentistry literature and applied to the unique environment of the root canal system.

  17. Curved canals: Ancestral files revisited

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    Jain Nidhi

    2008-01-01

    Full Text Available The aim of this article is to provide an insight into different techniques of cleaning and shaping of curved root canals with hand instruments. Although a plethora of root canal instruments like ProFile, ProTaper, LightSpeed ® etc dominate the current scenario, the inexpensive conventional root canal hand files such as K-files and flexible files can be used to get optimum results when handled meticulously. Special emphasis has been put on the modifications in biomechanical canal preparation in a variety of curved canal cases. This article compiles a series of clinical cases of root canals with curvatures in the middle and apical third and with S-shaped curvatures that were successfully completed by employing only conventional root canal hand instruments.

  18. Exopolysaccharide dispelled by calcium hydroxide with volatile vehicles related to bactericidal effect for root canal medication

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    Lei Lei

    Full Text Available ABSTRACT Objective: Enterococcus faecalis is the dominant microbial species responsible for persistent apical periodontitis with ability to deeply penetrate into the dentin. Exopolysaccharides (EPS contribute to the pathogenicity and antibiotic resistance of E. faecalis. Our aim was to investigate the antimicrobial activity of calcium hydroxide (CH, camphorated parachlorophenol (CMCP, and chlorhexidine (CHX against E. faecalis in dentinal tubules. Material and Methods: Decoronated single-canal human teeth and semicylindrical dentin blocks were incubated with E. faecalis for 3 weeks. Samples were randomly assigned to six medication groups for 1 week (n=10 per group: CH + 40% glycerin-water solution (1:1, wt/vol; CMCP; 2% CHX; CH + CMCP (1:1, wt/vol; CH + CMCP (2:3, wt/vol; and saline. Bacterial samples were collected and assayed for colony-forming units. After dentin blocks were split longitudinally, confocal laser scanning microscopy was used to assess the proportion of viable bacteria and EPS production in dentin. Results: CMCP exhibited the best antimicrobial activity, while CH was the least sensitive against E. faecalis (p0.05. CH combined with CMCP inhibited EPS synthesis by E. faecalis, which sensitized biofilms to antibacterial substances. Moreover, increasing concentrations of CMCP decreased EPS matrix formation, which effectively sensitized biofilms to disinfection agents. Conclusion: The EPS matrix dispelled by CH paste with CMCP may be related to its bactericidal effect; the visualization and analysis of EPS formation and microbial colonization in dentin may be a useful approach to verify medicaments for antimicrobial therapy.

  19. Pengaruh Konsentrasi dan Lama Aplikasi Sodium Hipoklorit (NaOCL sebagai Bahan Irigasi Saluran Akar terhadap Kekuatan Geser Perlekatan Siler Berbahan Dasar Resin Pada Dentin Saluran Akar

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    Tunjung Nugraheni

    2012-07-01

    menit dengan kelompok yang diirigasi NaOCI 5% selama 10 menit. Kesimpulan. Kekuatan geser perlekatan siler berbahan dasar resin pada dentin saluran akar berbeda setelah diirigasi NaOCI dengan konsentrasi dan waktu irigasi yang berbeda.   Background. Biomechanichal preparationin of root canal treatment used 0,5-5,25% sodium Hypochlorite as root canal irrigation, that may effect to physical properties of dentin. The purpose of this study was to find out the effect of concentration and duration application of sodium hypochlorite to shear bond strength of sealer resin based to root canal dentin. Methods. Thirthy premolar were splitted buccolingual then pulp tissue were cleaned out, smoothed and fixed into acrylic resin cast. They were devided into 2 group, group I were soaking into NaOCI 2,5% group II were soaking into NaOCI 5%. Group I and II were devided into 3 subgroup, group a were soaking 5 minutes, group b were soaking 10 minutes. Group c were soaking 15 minutes. Then sealer cast were fixed and filled with sealer resin-based, and incubated for 74 hours. They were tested for shear bond strength with Universal Testing Machine. The data were analyzed with two way Anava and LSD. Result. Two way Avana show that shear bond strength of sealer resin-based to root canal after irrigation with different concentration and duration application of sodium hypochlorite are significant. Conclusion. Shear bond strength of sealer resin-based to root canal dentin after irrigation with different concentration and duration application of sodium hypochlorite are different.

  20. Role of Dentin MMPs in Caries Progression and Bond Stability

    OpenAIRE

    A. Mazzoni; Tjäderhane, L.; Checchi, V.; Di Lenarda, R.; Salo, T.; Tay, F.R.; Pashley, D.H.; Breschi, L

    2015-01-01

    Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collag...

  1. Effect of irradiation mode and filling technique on resin/dentin bonding strength in Class I cavities.

    Science.gov (United States)

    dos Santos, Alex José Souza; Giannini, Marcelo; Paulillo, Luis Alexandre Maffei Sartini; Lovadino, José Roberto; de Carvalho, Ricardo Marins

    2004-01-01

    Factors such as light-curing mode, filling technique and cavity configuration may affect the bonding strength to dentin. This study evaluated the effect of irradiation mode and filling technique on resin/dentin bonding strength on the buccal wall of Class I cavities in human teeth. Occlusal enamel was removed to expose a flat dentin surface. Occlusal cavities (4 x 3 x 3 mm) were prepared in dentin. The adhesive Single Bond was applied according to the manufacturer's instructions and TPH Spectrum composite resin was placed using the following: oblique incremental, horizontal incremental or bulk filling techniques. The composite resin was light-cured either by continuous (600 mW/cm2 for 40 s) or Soft-Start (250 mW/cm2 for 10 s + 600 mW/cm2 for 30 s) modes. Specimens of the control group were obtained by bonding the material to the flat exposed buccal wall of the cavity (C-factor = 1). The teeth were stored in water at 37 degrees C for 24 h and prepared for microtensile testing. Bonded beams of approximately 0.8 mm2 were obtained from the buccal wall and tested with a tension of 0.5 mm/min. Results were analyzed by two-way ANOVA, Tukey's test and Dunnett's test (alpha = 0.05). Incremental placement techniques with both irradiation modes produced higher bonding strength values than the bulk technique (p < 0.05). Bonding strength tested in the cavities had lower values than those obtained in flat dentin surfaces (control group) (p < 0.05), except for incremental fillings using stepped irradiation. Bonding strength to the cavity walls depends on the filling technique and on the irradiation mode of composite resins.

  2. Managing curved canals

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    Iram Ansari

    2012-01-01

    Full Text Available Dilaceration is the result of a developmental anomaly in which there has been an abrupt change in the axial inclination between the crown and the root of a tooth. Dilaceration can be seen in both the permanent and deciduous dentitions, and is more commonly found in posterior teeth and in maxilla. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations. The controlled regularly tapered preparation of the curved canals is the ultimate challenge in endodontics. Careful and meticulous technique will yield a safe and sufficient enlargement of the curved canals. This article gives a review of the literature and three interesting case reports of root dilacerations.

  3. Influence of the glide path on various parameters of root canal prepared with WaveOne reciprocating file using cone beam computed tomography

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    Anil Dhingra

    2015-01-01

    Full Text Available Background: Nickel-titanium (NiTi rotary instrumentation carries a risk of fracture, mainly as a result of flexural (fatigue fracture and torsional (shear failure stresses. This risk might be reduced by creating a glide path before NiTi rotary instrumentation. The aim of this study was to compare various root canal parameters with the new WaveOne single-file reciprocating system in mesial canals of mandibular molars with and without glide path using cone beam computed tomography (CBCT. Materials and Methods: One hundred mandibular molar teeth with canal curvature between 20° and 30° were divided into two groups of 50 teeth each. In Group 1, no glide path was created, whereas in Group 2, a glide path was created with PathFiles at working length (WL. In both groups, canals were shaped with WaveOne primary reciprocating files to the WL. Canals were scanned in a CBCT unit before and after instrumentation. Postinstrumentation changes in canal curvature, cross-sectional area, centric ability, residual dentin thickness, and the extent of canal transportation were calculated using image analysis software and subjected to statistical analysis. Data were analyzed using Student′s t-test and Mann-Whitney U-test (P < 0.05. Results: The mean difference of root canal curvature, cross-sectional area, centric ability, and residual dentin thickness increased, whereas it reduced significantly for canal transportation in Group 2. Conclusion: WaveOne NiTi files appeared to maintain the original canal anatomy and the presence of a glide path further improves their performance and was found to be beneficial for all the parameters tested in this study.

  4. Effect of chitosan-ethylenediamine tetraacetic acid on Enterococcus faecalis dentinal biofilm and smear layer removal

    Science.gov (United States)

    Geethapriya, Nagarajan; Subbiya, Arunajatesan; Padmavathy, Kesavaram; Mahalakshmi, Krishnan; Vivekanandan, Paramasivam; Sukumaran, Virudhachalam Ganapathy

    2016-01-01

    Objective: The objective of the study was to evaluate the effectiveness of chitosan and chitosan-ethylenediamine tetraacetic acid (EDTA) (3:1,1:1,1:3) in comparison with 5.2% sodium hypochlorite (NaOCl) in disinfecting Enterococcus faecalis biofilm on root canal dentin and in the removal of smear layer with minimal erosion. Materials and Methods: Seventy single-rooted extracted human mandibular premolars (n = 70) were selected for the study. Forty tooth samples were biomechanically prepared, vertically sectioned, and sterilized by autoclaving. The tooth sections were artificially infected with E. faecalis (ATCC 29212 [n = 35] and clinical isolate [SBEF2, n = 35]) to form mature dentinal biofilm in vitro. The tooth samples were treated with the test solutions: chitosan and chitosan-EDTA (3:1, 1:1, 1:3), and the killing time was determined. The smear layer removal ability of the test solutions (Group A: chitosan-EDTA [1:1], Group B: EDTA, Group C: control) (n = 10 tooth/group) was assessed. Results: Chitosan and chitosan-EDTA (3:1, 1:1, 1:3) exhibited antibacterial activity against both the strains of E. faecalis. Chitosan and chitosan-EDTA caused 3 log reduction in the viable count of the sessile cells of E. faecalis at 15 min while 5.2% NaOCl exhibited 99.98% inhibition at 15 min. Chitosan-EDTA (1:1) was found to be effective in removing the smear layer and showed lesser erosion than EDTA at the coronal and middle portions. Conclusion: Chitosan-EDTA (1:1) is a potential root canal irrigant that performs a dual role – root canal disinfection and smear layer removal. PMID:27656070

  5. Scanning electron microscopy and dentinal permeability analysis of smear layer.

    Science.gov (United States)

    Prati, C; Mongiorgi, R; Pashley, D H; Riva di Sanseverino, L

    1991-05-01

    The aim of the present study was to evaluate the surface morphology and the permeability of dentine after different acid treatments: polyacrylic acid, maleic acid, phosphoric acid and saline solution as control. Dentine permeability was expressed as hydraulic conductance. All the acid treatments removed the smear layer and increased the dentine permeability.

  6. Plasma treatment of dentin surfaces for improving self-etching adhesive/dentin interface bonding

    Science.gov (United States)

    Dong, Xiaoqing; Li, Hao; Chen, Meng; Wang, Yong; Yu, Qingsong

    2015-01-01

    This study is to evaluate plasma treatment effects on dentin surfaces for improving self-etching adhesive and dentin interface bonding. Extracted unerupted human third molars were used after crown removal to expose dentin. One half of each dentin surface was treated with atmospheric non-thermal argon plasmas, while another half was untreated and used as the same tooth control. Self-etching adhesive and universal resin composite was applied to the dentin surfaces as directed. After restoration, the adhesive-dentin bonding strength was evaluated by micro-tensile bonding strength (μTBS) test. Bonding strength data was analyzed using histograms and Welch’s t-test based on unequal variances. μTBS test results showed that, with plasma treatment, the average μTBS value increased to 69.7±11.5 MPa as compared with the 57.1±17.5 MPa obtained from the untreated controls. After 2 months immersion of the restored teeth in 37 °C phosphate buffered saline (PBS), the adhesive-dentin bonding strengths of the plasma-treated specimens slightly decreased from 69.7±11.5 MPa to 63.9±14.4 MPa, while the strengths of the untreated specimens reduced from 57.1±17.5 MPa to 48.9±14.6 MPa. Water contact angle measurement and scanning electron microscopy (SEM) examination verified that plasma treatment followed by water rewetting could partially open dentin tubules, which could enhance adhesive penetration to form thicker hybrid layer and longer resin tags and consequently improve the adhesive/dentin interface quality. PMID:26273561

  7. Dentine microhardness after different methods for detection and removal of carious dentine tissue

    Science.gov (United States)

    MOLLICA, Fernanda Brandão; TORRES, Carlos Rocha Gomes; GONÇALVES, Sergio Eduardo de Paiva; MANCINI, †Maria Nadir Gasparoto

    2012-01-01

    There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. Objectives The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. Material and methods The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10), according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. Results ANOVA and Tukey's test (α=0.05) were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7±105.0; a), Caries-detector dye (370.5±78.3; ab), Tactile method (322.8±51.5; bc). Results for the remaining dentin microhardness were: "Papacárie" (42.2±10.5; bc), Caries-detector dye (44.6±11.8; abc), Tactile method (24.3±9.0; d). Conclusions DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values. PMID:23032207

  8. Dentine microhardness after different methods for detection and removal of carious dentine tissue

    Directory of Open Access Journals (Sweden)

    Fernanda Brandão Mollica

    2012-08-01

    Full Text Available There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. OBJECTIVES: The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. MATERIAL AND METHODS: The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10, according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. RESULTS: ANOVA and Tukey's test (α=0.05 were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7±105.0; a, Caries-detector dye (370.5±78.3; ab, Tactile method (322.8±51.5; bc. Results for the remaining dentin microhardness were: "Papacárie" (42.2±10.5; bc, Caries-detector dye (44.6±11.8; abc, Tactile method (24.3±9.0; d. CONCLUSIONS: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values.

  9. Comparative evaluation of microleakage of newer generation dentin bonding agents: An in vitro study

    Directory of Open Access Journals (Sweden)

    Rani Somani

    2016-01-01

    Full Text Available Context: Adhesive dentistry has been progressing with rapid pace over the past decade. Composite resin is the most esthetic restorative material currently available for restoring teeth. In spite of it being in use since a decade, still failure cases are seen which are mainly due to polymerization shrinkage and subsequent inadequate adhesion to cavity walls, leading to microleakage. Various generations of dentin bonding agents have been introduced to overcome the shortcoming of composite resin. Aims: To determine the microleakage of the 6 th , 7 th , and 8 th generation dentin bonding agents. Materials and Methods: Forty-five extracted human premolars were taken for the study. Standardized Class V cavities were prepared on all the teeth. The samples were divided into three groups according to the generation of bonding agent used. Group I was bonded with the 6 th generation, Group II with the 7 th generation, and Group III with the 8 th generation dentin bonding agent. All the Class V preparations were restored with a nano-ceramic composite restorative (Ceram X. The samples were then thermocycled between 5 and 55 ± 2°C for 100 cycles and immersed in 2% methylene blue for 48 h for evaluation of microleakage under a stereomicroscope. Statistical Analysis Used: The data was statistically analyzed using Kruskal-Wallis nonparametric analysis, and Mann-Whitney U-test was applied to compare the various groups. Results: The microleakage value was the highest in Group II (7 th generation bonding agent followed by Group I (6 th generation bonding agent and least in Group III (8 th generation bonding agent. Conclusions: The 8 th generation dentin bonding showed statistically significant results in terms of lesser microleakage as compared to the 6 th and 7 th generation dentin bonding agents.

  10. Effect of root canal treatment procedures with a novel rotary nickel titanium instrument (TRUShape) on stress in mandibular molars: a comparative finite element analysis.

    Science.gov (United States)

    Bonessio, Noemi; Arias, Ana; Lomiento, Guiseppe; Peters, Ove A

    2017-01-01

    The aim of this study was to investigate and compare, via finite element analysis (FEA), the effects of endodontic access and canal preparation on stress distribution under functional loading of a mandibular molar treated with novel (TRUShape) and conventional (Vortex) rotary root canal preparation instruments. Identical plastic mandibular molars with natural anatomy had all 4 canals shaped with either TRUShape or a conventional rotary, Vortex (#20 and #30, both by Dentsply Tulsa Dental). Finite element analysis was used to evaluate stress distribution in untreated and treated models. Micro-computed tomography (MCT) of the extracted teeth shaped in vitro was used to inform the FEA model regarding the geometry of root canals and external surfaces. Modeling the intact periodontal support and cancellous/cortical bone was based on anatomical data. Profiles of average and maximum von Mises stresses in dentin of the four treated conditions under functional loading were compared to the untreated model. This comparison was performed for each tooth model with and without root canal obturation and composite restoration. On average, the dentin sections with the most changes after preparation were located in the access cavity, with average stress increase up to +5.7, +8.5, +8.9, and +10.2 % for the TRUShape #20, Vortex #20, TRUShape #30 and Vortex #30, respectively, relative to the untreated model. Within the root canal system, the average stress differences were smaller than finite element analysis, preparation of the access cavity resulted in increased von Mises stresses under functional occlusal load. The limited (up to 0.7 %) retained radicular dentin in the TRUShape versus the Vortex cavity proved effective in reducing masticatory stresses. The bonded restoration modeled in this study only partially counterbalance the combined effects of access cavity and root canal preparation.

  11. Dentine in a capsule: Clinical case reports

    Directory of Open Access Journals (Sweden)

    Mallikarjuna Kenchappa

    2015-01-01

    Full Text Available Biodentine TM , a calcium silicate based material has been popular now and can be used as an alternative to mineral trioxide aggregate (MTA due to superior physical and biologic properties. It has been known by several terms as Biodentine, dentin substitute, and RD 94. It has varied clinical applications such as apexification, apexogenesis, pulpotomy, internal resorption, root perforation repair, retrograde filling, pulp capping procedure, and dentin replacement. This article describes the clinical case reports using Biodentine in apexification, apexogenesis, pulpotomy, and root perforation repair.

  12. Analysis of sedimentation of canals

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    Agunwamba, J.C.,

    2013-03-01

    Full Text Available The dredged canals in the Niger Delta coastal flood plain are being threatened by siltation. This study is limited to those canals in Rivers State of Nigeria, which are under the influence of tidal waves. A total of eight canals were considered with four each from Ekulama and Cawthorne Channel. Different approaches were used to carry out this study, which includes field reconnaissance survey, hydrographic survey, soil sample analysis and collection of all available data and information. The typical bed materials size (D50 is approximately 0.01mm; which gives a settling velocity of 0.09mm/sec using stroke’s law. Hydrographic survey of the canals from 1992 to 1996 revealed an average siltation rate of 2.35m/yr. A regression equation was also derived which relates the cost of dredging to canal area, rate of siltation and average aggregation. A plot of canal centre profile; entrance, middle and end cross sections showing sediment distribution along the canal profile, shows that majority of the particles that form the sediment enter the canal from the rivers. The sedimentation is caused by the reduction in water current, which has average value of 0.0145m/sec. The bathyorographical check on the canals revealed that the sum of the two exterior angles of the canal with the river at the point of connection has to lie within 1800 + 50 for an effective flow that will minimize settlement of particles. In addition, the canals should be constructed to start and terminate on a moving water body, to avoid dead ends. A regression equation was determined which relates the cost of dredging to canal area, rate of siltation and average aggradations.

  13. Risk-Based Disposal Plan for PCB Paint in the TRA Fluorinel Dissolution Process Mockup and Gamma Facilities Canal

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Montgomery

    2008-05-01

    This Toxic Substances Control Act Risk-Based Polychlorinated Biphenyl Disposal plan was developed for the Test Reactor Area Fluorinel Dissolution Process Mockup and Gamma Facilities Waste System, located in Building TRA-641 at the Reactor Technology Complex, Idaho National Laboratory Site, to address painted surfaces in the empty canal under 40 CFR 761.62(c) for paint, and under 40 CFR 761.61(c) for PCBs that may have penetrated into the concrete. The canal walls and floor will be painted with two coats of contrasting non-PCB paint and labeled as PCB. The canal is covered with open decking; the access grate is locked shut and signed to indicate PCB contamination in the canal. Access to the canal will require facility manager permission. Protective equipment for personnel and equipment entering the canal will be required. Waste from the canal, generated during ultimate Decontamination and Decommissioning, shall be managed and disposed as PCB Bulk Product Waste.

  14. Curative effect of cholesteatoma by canal wall-down mastoidectomy and type Ⅲa tympanoplasty%开放式乳突根治术并Ⅲa型鼓室成形术治疗胆脂瘤中耳炎的临床研究

    Institute of Scientific and Technical Information of China (English)

    翟锦明; 马钊恩; 陈观贵; 张建国

    2013-01-01

    Objective:To explore the curative effect and auditory outcomes in canal wall -down mastoidectomy and type Ⅲa tympanoplasty. Methods; Retrospective review of 62 patients with cholesteatoma , who underwent canal wall-down mastoidectomy and type Ⅲa tympanoplasty with titanium partial ossicular replacement prosthesis in a single stage. The postoperative complication , operation and aural rehabilitation were analyzed during 2-4 years follow-up. Results: In all 62 cases, 3 patients remained tympanic perforation , 6 patients with postoperative retraction pocket, 1 reurrence of cholesteatoma and 3 (3/62, 4.8%) extrusion of ossicular replacement prosthesis. The rate of total curative effectiveness was 58. 1% , dry ear was 91. 9% , postoperative infection rate was 8. 1%. Auditory outcomes showed that preoperative average air threshold (500, 1k, 2k, 4 k Hz) was (51. 0 ±13. 5) dB, postoperative (32. 6 ±8. 8 ) dB, and average air threshold reduction was statistically significant (t =16. 549, P <0. 01). Preoperative average air-bone gap was (35.2 ±10.0) dB, postoperative was (24.4 ±7.7) dB, with statistical significance (t = 11.276, P <0. 01). Conclusion: Canal wall-down mastoidectomy and type Ⅲa tympanoplasty with titanium partial ossicular replacement prosthesis in single stage is safe and effective surgery for chol -esteatoma, with less complication and relatively satisfactory hearing improvement . Application of tragal cartilage -perichondria autograft is of unique advantages .%目的:探讨开放式乳突根治术并Ⅲa型鼓室成形术治疗胆脂瘤中耳炎的临床效果.方法:62例胆脂瘤中耳炎患者均行开放式乳突根治术并Ⅲa型鼓室成形术(钛质部分听骨植入),随访2~4年,观察手术、术后并发症及听力恢复情况.结果:62例中3例鼓膜遗留穿孔,6例鼓膜内陷,1例胆脂瘤复发,3例(3/62,4.8%)听骨赝复物脱出,手术总有效率为58.1%,术后干耳率达91.9%,术后感染率为8.1%.

  15. An ex vivo comparison of detection ability of three methods in discovering of MB2 canal in maxillary molars

    Directory of Open Access Journals (Sweden)

    Ghorbanzadeh A.

    2009-11-01

    Full Text Available "nBackground and Aim: A considerable percentage of failure in Endodontic treatments in maxillary molars is attributed to undiscovered second mesiobuccal canal (MB2.There are different methods for discovering and accessing to this canal. The purpose of this ex vivo study was to compare the detection ability of three methods (direct look, fiberoptic loup and surgical microscope to find MB2 after troughing with ultrasonic. "nMaterials and Methods: In this experimental study, we selected 90 extracted maxillary molars (45 first and 45 second molars in which after access cavity preparation MB2 canal was not discovered by direct vision and endodontic explorer. They were divided into 3 groups (n=30. The dentinal shelf between mesiobuccal and palatal canals was eliminated by an endodontic ultrasonic tip (troughing. After that, first group was searched by direct vision, second group by a loup and fiberoptic light and third group by dental operating microscope. Data were analyzed, specificity and sensitivity were calculated. "nResults: The results showed that 21%, 61%, and 92% of MB2 canals after troughing was found by direct vision, fiberoptic loup, and surgical microscope, respectively. "nConclusion: Based on the results of this study, surgical microscope and loup with fiberoptic are preferred methods for discovering MB2 canal. Troughing with ultrasonic can help find MB2 canal in all methods.

  16. Effect of Nanofiller Addition to an Experimental Dentin Adhesive on Microtensile Bond Strength to Human Dentin

    Directory of Open Access Journals (Sweden)

    SH. Kasraei

    2009-06-01

    Full Text Available Objective: The purpose of the study was to evaluate the influence of adding nanofiller particles to a dentin bonding agent on resin-dentin bond strength.Materials and Methods: Fifty-four human intact premolar teeth were divided in to 6 groups of nine. The teeth were ground on occlusal surfaces and polished with 320 and then 600 grit silicon carbide papers. An experimental bonding system based on acetone/alcoholsolvent was provided with filler contents of 0.0, 0.5, 1.0, 2.5, 5.0, and 10.0 weight percent fumed silica nanofiller. After dentin surface etching, rinsing and blot drying, the experimentalbonding agents were applied to dentin surface. A composite resin was, then,bonded to the dentin on the bonding agent. The specimens were thermocycled for 500 cycles and sectioned in stick form. After two week of storage in distilled water, resin-dentin microtensile bond strength of the specimens was measured. Data were analyzed by one way ANOVA and DunnettT3 tests.Results: Bond strength to dentin was significantly affected by the filler level. Minimum and maximum resin-microtensile bond strength was in the experimental bonding agent with no filler (5.88 MPa and with filler level of 1.0 weight percent (15.15 MPa, respectively,and decreased with the increase of filler content down to 8.95 MPa for the filler level of 10.0 weight percent.Conclusion: Filler content seems to be one of the important factors influencing the bond strength of dental adhesives. Maximum dentin bond strength was obtained with 1% silanized nanofiller silica added to experimental adhesive system.

  17. Controversy at Love Canal.

    Science.gov (United States)

    Paigen, B

    1982-06-01

    A cancer researcher reviews the events surrounding the toxic waste contamination at Love Canal with emphasis on the political nature of the controversy about its health impact. Antagonism between the community and the New York State Department of Health was fueled by several factors: the state's awareness that it gained from delay in investigation, disagreement on health problems to be studied, control over the information gathering process, silencing of opposition opinion, and the violation of norms of scientific behavior. The author calls for the establishment of standards of ethical behavior for scientists in such situations, standards for conflict resolution, and means of appeal for those injured.

  18. Growth Factor Liberation and DPSC Response Following Dentine Conditioning.

    Science.gov (United States)

    Sadaghiani, L; Gleeson, H B; Youde, S; Waddington, R J; Lynch, C D; Sloan, A J

    2016-10-01

    Liberation of the sequestrated bioactive molecules from dentine by the action of applied dental materials has been proposed as an important mechanism in inducing a dentinogenic response in teeth with viable pulps. Although adhesive restorations and dentine-bonding procedures are routinely practiced, clinical protocols to improve pulp protection and dentine regeneration are not currently driven by biological knowledge. This study investigated the effect of dentine (powder and slice) conditioning by etchants/conditioners relevant to adhesive restorative systems on growth factor solubilization and odontoblast-like cell differentiation of human dental pulp progenitor cells (DPSCs). The agents included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH EDTA, phosphoric acid, and citric acid from powdered dentine. The dentine matrix extracts were shown to be bioactive, capable of stimulating odontogenic/osteogenic differentiation as observed by gene expression and phenotypic changes in DPSCs cultured in monolayer on plastic. Polyacrylic acid failed to solubilize proteins from powdered dentine and was therefore considered ineffective in triggering a growth factor-mediated response in cells. The study went on to investigate the effect of conditioning dentine slices on growth factor liberation and DPSC behavior. Conditioning by EDTA, phosphoric acid, and citric acid exposed growth factors on dentine and triggered an upregulation in genes associated with mineralized differentiation, osteopontin, and alkaline phosphatase in DPSCs cultured on dentine. The cells demonstrated odontoblast-like appearances with elongated bodies and long extracellular processes extending on dentine surface. However, phosphoric acid-treated dentine appeared strikingly less populated with cells, suggesting a detrimental impact on cell attachment and growth when conditioning by this agent. These findings take crucial steps in informing clinical practice on dentine

  19. Comparison of Endodontic Medicaments on Bond Strength of Fiber Post to Root Dentin Using Resin Cement

    Directory of Open Access Journals (Sweden)

    Maryam Zare Jahromi

    2017-03-01

    Full Text Available Statement of the Problem: Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin. Purpose: The aim of this study was to compare the effect of calcium hydroxide (Ca(OH2 and 2% chlorhexidine gel (CHX on bond strength of fiber post cemented with resin cement to root dentin. Materials and Method: This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca(OH2 paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group (control group. Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold. Results: The mean bond strength was 4.45 MPa in the Ca(OH2, 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups (p= 0.04. The Ca(OH2 group had significant differences with the CHX and control groups (p= 0.03 and p= 0.02, respectively. The difference between the CHX and control groups was not significant (p= 0.974. Conclusion: Based on the results, Ca(OH2 increased the bond strength of fiber post to root dentin but 2% CHX had no effect on

  20. Comparison of Endodontic Medicaments on Bond Strength of Fiber Post to Root Dentin Using Resin Cement

    Science.gov (United States)

    Zare Jahromi, Maryam; Barekatain, Mehrdad; Ravanbod, Shirin; Ranjbarian, Parisa; Kousehlar, Sara

    2017-01-01

    Statement of the Problem: Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin. Purpose: The aim of this study was to compare the effect of calcium hydroxide (Ca(OH)2) and 2% chlorhexidine gel (CHX) on bond strength of fiber post cemented with resin cement to root dentin. Materials and Method: This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca(OH)2 paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group (control group). Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold. Results: The mean bond strength was 4.45 MPa in the Ca(OH)2, 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups (p= 0.04). The Ca(OH)2 group had significant differences with the CHX and control groups (p= 0.03 and p= 0.02, respectively). The difference between the CHX and control groups was not significant (p= 0.974). Conclusion: Based on the results, Ca(OH)2 increased the bond strength of fiber post to root dentin but 2% CHX had no effect on bond

  1. Classification, mechanism and surgical treatments for spinal canal cysts

    Institute of Scientific and Technical Information of China (English)

    Jianjun Sun

    2016-01-01

    A variety of cystic lesions may develop in spinal canal. These cysts can be divided into intramedullary, intradural, extradural, cervical, thoracic, lumbar, and sacral cysts according to anatomical presentation, as well as arachnoid, meningeal, perineural, juxtafacet, discal, neurenteric cysts, and cyst-like lesions according to different etiologies. Mechanisms of initiation and growth vary for different cysts, such as congenital, trauma, bleeding, inflammatory, instability, hydrostatic pressure, osmosis of water, secretion of cyst wall, and one-way-valve effect, etc. Up to now, many treatment methods are available for these different spinal canal cysts. One operation method can be applied in cysts with different types. On the other hand, several operation methods may be utilized in one type of cyst according to the difference of location or style. However, same principle should be obeyed in surgical treatment despite of difference among spinal canal cysts, given open surgery is melely for symptomatic cyst. The surgical approach should be tailored to the individual patient.

  2. Penetration of amalgam constituents into dentine

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; Ozcan, Mutlu; Huysmans, Marie-Charlotte D. N. J. M.

    2009-01-01

    Objectives: Amalgam restorations are replaced by adhesively placed composite resin restorations at an increasing rate. After the removal of amalgam dentine often shows marked dark discoloration that is attributed to the penetration of corrosion products from overlying amalgams. it is questioned whet

  3. Penetration of amalgam constituents into dentine.

    NARCIS (Netherlands)

    Scholtanus, J.D.; Ozcan, M.; Huysmans, M.C.D.N.J.M.

    2009-01-01

    OBJECTIVES: Amalgam restorations are replaced by adhesively placed composite resin restorations at an increasing rate. After the removal of amalgam dentine often shows marked dark discoloration that is attributed to the penetration of corrosion products from overlying amalgams. It is questioned whet

  4. Resin diffusion through demineralized dentin matrix

    Directory of Open Access Journals (Sweden)

    CARVALHO Ricardo M.

    1999-01-01

    Full Text Available This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.

  5. Hydrofluoric acid on dentin should be avoided.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Mine, A.; Roeters, F.J.M.; Opdam, N.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2010-01-01

    Hydrofluoric acid can be used for intra-oral repair of restorations. Contamination of tooth substrate with hydrofluoric acid cannot always be avoided. OBJECTIVES: To investigate the bonding effectiveness to hydrofluoric acid contaminated dentin by, micro-tensile bond strength testing, SEM and TEM. M

  6. “Comparative evaluation of dentinal penetration of three different endodontic sealers with and without smear layer removal” - Scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    K R Sonu

    2016-01-01

    Full Text Available Aim and Objectives: The aim of this study was to test the dentinal tubule penetration of mineral trioxide aggregate (MTA Fillapex (Angelus, Londria, PR, Brazil, GuttaFlow® 2 sealer (Coltene/Whaledent with standard sealer AH Plus (Dentsply Detrey, Konstanz, Germany in instrumented root canals obturated by using cold lateral compaction techniques in either the presence or absence of the smear layer. Materials and Methods: Sixty extracted human mandibular premolars with a single root canal were used for this study. All teeth were prepared using F2 Pro Taper nickel–titanium rotary system. Teeth were randomly divided into three groups of 20 teeth each. GuttaFlow 2, MTA Fillapex and AH Plus were used as sealers in Group I, Group II, and Group III, respectively. Groups were divided into two subgroups in which either the smear layer was removed or retained. Removal of smear layer was achieved by continuous irrigation with 5.25% sodium hypochlorite and 2 ml of 17% ethylenediaminetetraacetic acid. The canals were dried and obturated using respective sealers by cold lateral compaction techniques. After storage at 37°C and 100% humidity for 14 days, the roots were then split into two halves using chisel and mallet. On each section, sealer penetration in the dentinal tubules at cervical, middle, and apical levels was examined by using scanning electron microscope. Results: Sealer penetration into the dentinal tubules was noticed in all groups. AH plus showed deeper penetration, followed by MTA Fillapex and GuttaFlow® 2. The penetration depth of the sealers at the cervical and middle third of root was significantly more than those at apical third. Conclusions: Within the parameters of the present study it was concluded, with the removal of smear layer AH plus sealer showed deeper penetration into the dentinal tubules at cervical and middle third of root compared with apical third.

  7. The Possible Role of Dentin as a Piezoelectric Signal Generator by Determining the Elec-tromechanical Coupling Factor of Dentin

    Directory of Open Access Journals (Sweden)

    Atabak Shahidi

    2011-08-01

    Full Text Available Introduction: This article aimed at calculation of the electromechanical coupling factor of dentin which is an indicator of the effectiveness with which a piezoelectric material converts electrical en-ergy into mechanical energy, or vice versa. The hypothesis: The electro-mechanical coupling factor of dentin was determined in mode 11 and 33 by calculating the ratio of the produced electrical energy to the stored elastic energy in dentin under applied pressure. This study showed that the electromechanical coupling factor of dentin was affected by the direction of the applied force and the moisture content of dentin. Also dentin was a weak electromechanical energy converter which might be categorized as a piezoelectric pressure sensor.Evaluation of the hypothesis: Determination of the electrome-chanical coupling factor of dentin and its other piezoelectric constants is essential to investigate the biologic role of piezoelectricity in tooth.

  8. Spinal canal stenosis; Spinalkanalstenose

    Energy Technology Data Exchange (ETDEWEB)

    Papanagiotou, P.; Boutchakova, M. [Klinikum Bremen-Mitte/Bremen-Ost, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Bremen (Germany)

    2014-11-15

    Spinal stenosis is a narrowing of the spinal canal by a combination of bone and soft tissues, which can lead to mechanical compression of spinal nerve roots or the dural sac. The lumbal spinal compression of these nerve roots can be symptomatic, resulting in weakness, reflex alterations, gait disturbances, bowel or bladder dysfunction, motor and sensory changes, radicular pain or atypical leg pain and neurogenic claudication. The anatomical presence of spinal canal stenosis is confirmed radiologically with computerized tomography, myelography or magnetic resonance imaging and play a decisive role in optimal patient-oriented therapy decision-making. (orig.) [German] Die Spinalkanalstenose ist eine umschriebene, knoechern-ligamentaer bedingte Einengung des Spinalkanals, die zur Kompression der Nervenwurzeln oder des Duralsacks fuehren kann. Die lumbale Spinalkanalstenose manifestiert sich klinisch als Komplex aus Rueckenschmerzen sowie sensiblen und motorischen neurologischen Ausfaellen, die in der Regel belastungsabhaengig sind (Claudicatio spinalis). Die bildgebende Diagnostik mittels Magnetresonanztomographie, Computertomographie und Myelographie spielt eine entscheidende Rolle bei der optimalen patientenbezogenen Therapieentscheidung. (orig.)

  9. Characterization of Genipin-Modified Dentin Collagen

    Directory of Open Access Journals (Sweden)

    Hiroko Nagaoka

    2014-01-01

    Full Text Available Application of biomodification techniques to dentin can improve its biochemical and biomechanical properties. Several collagen cross-linking agents have been reported to strengthen the mechanical properties of dentin. However, the characteristics of collagen that has undergone agent-induced biomodification are not well understood. The objective of this study was to analyze the effects of a natural cross-linking agent, genipin (GE, on dentin discoloration, collagen stability, and changes in amino acid composition and lysyl oxidase mediated natural collagen cross-links. Dentin collagen obtained from extracted bovine teeth was treated with three different concentrations of GE (0.01%, 0.1%, and 0.5% for several treatment times (0–24 h. Changes in biochemical properties of NaB3H4-reduced collagen were characterized by amino acid and cross-link analyses. The treatment of dentin collagen with GE resulted in a concentration- and time-dependent pigmentation and stability against bacterial collagenase. The lysyl oxidase-mediated trivalent mature cross-link, pyridinoline, showed no difference among all groups while the major divalent immature cross-link, dehydro-dihydroxylysinonorleucine/its ketoamine in collagen treated with 0.5% GE for 24 h, significantly decreased compared to control (P< 0.05. The newly formed GE-induced cross-links most likely involve lysine and hydroxylysine residues of collagen in a concentration-dependent manner. Some of these cross-links appear to be reducible and stabilized with NaB3H4.

  10. Extracellular matrix proteins and the dynamics of dentin formation.

    Science.gov (United States)

    Butler, William T; Brunn, Jan C; Qin, Chunlin; McKee, Marc D

    2002-01-01

    Dentinogenesis involves controlled reactions that result in conversion of unmineralized predentin to dentin when apatite crystals are formed. This process is dynamic: Maturation events occur within predentin beginning at the proximal layer and progressing to the predentin-dentin (PD) border. One type of controlled reaction is the proteolytic processing of dentin sialophosphoprotein (DSPP) to dentin sialoprotein (DSP) and dentin phosphoprotein (DPP), by cleavage of at least three highly conserved peptide bonds. We postulate that this processing event represents an activation step, resulting in release of DPP, which is active in its effects on formation and growth of apatite crystals. Dentin matrix protein 1 (DPM1), present as a processed fragment (57-kD protein) in bone, is seen in dentin on sodium dodecyl sulfate polyacrylamide gel electrophoresis as one intact protein of 150-200 kD. Anti-57-kD antibodies elicit immunoreactivity in bone, dentin, and cellular cementum. In bone, the reactivity is associated with osteocytes and their cell processes. Similarly, dentin shows reactivity in odontoblasts, predentin, and the odontoblast processes. In summary, the processing of large sialic acid-rich proteins into smaller fragments may be an important part of the controlled conversion of predentin to dentin and osteoid to bone.

  11. New perspectives about molecular arrangement of primary and permanent dentin

    Energy Technology Data Exchange (ETDEWEB)

    Sanches Borges, Ana Flavia [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Andrade Bitar, Renata [Biomedical Engineering, Valley of Paraiba University (UNIVAP) (Brazil); Kantovitz, Kamila Rosamilia [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Bortollazo Correr, Americo [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Martin, Airton Abrahao [Biomedical Engineering Post Graduation, Valley of Paraiba University (UNIVAP) (Brazil); Puppin-Rontani, Regina Maria [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil)], E-mail: rmpuppin@fop.unicamp.br

    2007-12-30

    The dentin quality of primary and permanent teeth was inspected by Fourier transformed Raman spectroscopy (FT-Raman); scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and hardness test. Middle dentin of crowns were reached by carbide bur abrading providing a uniform smear layer. Phosphoric acid was applied in order to simulate the etching of total etching adhesive systems. The groups were (n = 10): G1 (primary dentin smear layer); G2 (35% phosphoric acid etched primary dentin); G3 (permanent dentin smear layer); G4 (35% phosphoric acid etched permanent dentin). FT-Raman results were subjected to cluster analysis. SEM/EDS were made in order to add the data obtained by FT-Raman. The hardness data were subjected to ANOVA and Tukey test. FT-Raman showed differences among groups, either to organic or inorganic content. For the organic content, primary and permanent dentin became similar after the etching; conversely, the inorganic content showed differences for the two substrates. Hardness test showed no significant differences between primary and permanent dentin, before or after etching, but the etching decreased these values. The mineral content arrangement of primary dentin is different from permanent dentin, independently of the etching. The substrate type did no influence the hardness, but the etching decreased it.

  12. Effects of CO2 laser energy on dentin permeability.

    Science.gov (United States)

    Pashley, E L; Horner, J A; Liu, M; Kim, S; Pashley, D H

    1992-06-01

    The effect of a CO2 laser on the structure and permeability of smear layer-covered human dentin was evaluated in vitro. Three different energy levels were used (11, 113, and 566 J/cm2). The lowest exposure to the laser energy increased dentin permeability, measured as a hydraulic conductance, due to partial measured as a hydraulic conductance, due to partial loss of the superficial smear layer and smear plugs. The intermediate energy level also increased dentin permeability by crater formation, making the dentin thinner. The lack of uniform glazing of the surface of the crater, leaving its surface porous and in communication with the underlying dentinal tubules also contributed to the increase in dentin permeability seen with the intermediate laser energy. The highest laser energy produced complete glazing of the crater surfaces and sealed the dentinal tubules beneath the crater. However, it also completely removed the smear layer in a halo zone about 100-microns wide around each crater which increased the permeability of the pericrater dentin at the same time it decreased the permeability of the dentin within the crater. The combined use of scanning electron microscopy and permeability measurements provides important complementary information that is essential in evaluating the effects of lasers on dentin.

  13. Origin and evolution of the canal raphe system in diatoms.

    Science.gov (United States)

    Ruck, Elizabeth C; Theriot, Edward C

    2011-11-01

    One lineage of pennate diatoms has a slit through the siliceous cell wall, called a "raphe," that functions in motility. Raphid pennate diatoms number in the perhaps tens of thousands of species, with the diversity of raphe forms potentially matching this number. Three lineages-the Bacillariales, Rhopalodiales, and Surirellales-possess a complex and presumably highly derived raphe that is physically separated from the cell interior, most often by a set of siliceous braces. Because the relationship among these three lineages is unclear, the number of origins of the canal raphe system and the homology of it and its constitutive parts among these lineages, is equally unclear. We reconstructed the phylogeny of raphid pennate diatoms and included, for the first time, members of all three canal raphid diatom lineages, and used the phylogeny to test specific hypotheses about the origin of the canal raphe. The canal raphe appears to have evolved twice, once in the common ancestor of Bacillariales and once in the common ancestor of Rhopalodiales and Surirellales, which form a monophyletic group in our analyses. These results recommend careful follow-up morphogenesis studies of the canal raphe in these two lineages to determine the underlying developmental basis for this remarkable case of parallel evolution.

  14. Cytotoxicity of 5% Tamarindus indica extract and 3% hydrogen peroxide as root canal irrigation

    Directory of Open Access Journals (Sweden)

    Erawati Wulandari

    2008-09-01

    Full Text Available Background: Preparation of root canal is an important stage in endodontic treatment. During conducting preparation, it is always be followed with root canal irrigation that has aim to clean root canal from necrotic tissue remains, grind down dentin powder, micro organism, wet the root canal to make preparation process of root canal easier, and solute root canal content at area that can not be reached by equipment. Flesh of Tamarindus indica (pulpa tamarindorum is used as traditional medicine and it contains vitamin C (antioxidant, protein, fat, glucose, etc. Previous research shows that 5% tamarindus indica extract can clean smear layer but it is more cytotoxicity to cell line BHK–21 than sterilized aquabides. Purpose: This research is to compare cytotoxicity between 5% Tamarindus indica extract with 3% H2O2 as root canal irrigation material. Method: Four teen culture cell line BHK 21 divides into 2 groups. Group 1 is treated with 3% H2O2 and Group 2 is treated with 5% Tamarindus indica extract, for about 2.5 minutes in every group. Then, living and death cell percentage is measured. Data is analyzed with independent t test with significant level of 0.05%. Result: The research showed that death cell in group 1 was 29.3% and in group 2 was 21.1%. There was a significant different (p < 0.05 between group 1 and group 2. Conclusion: Cytotoxicity of 5% Tamarindus indica extract to the cell line BHK–21 is lower than 3% H2O2.

  15. Shear bond strength of amalgam to dentin using different dentin adhesive systems

    Directory of Open Access Journals (Sweden)

    Farimah Sardari

    2012-01-01

    Full Text Available Background and Aims: The aim of this in vitro study was to assess the shear bond strength of amalgam to dentin using four dentin adhesive systems.Materials and Methods: One hundred human molars were selected. After enamel removal, a dentin cylinder with 3 mm thickness was prepared. Eighty specimens were resorted with amalgam and four dentin adhesive systems as follows (n=20: group 1, Scotch Bond Multi-Purpose; group 2, One Coat Bond; group 3, PQ1; and group 4, Panavia-F. In group 5, 20 specimens were resorted with amalgam and varnish as control group. The specimens were incubated at 37°C for 24 h. The shear bond strengths were then measured by using push out method. The data were analyzed by one-way ANOVA and post hoc Duncan's tests.Results: Mean values for bond strengths of test groups were as follows: group 1=21.03±8.9, group 2=23.47±9, group 3=13.16±8.8, group 4=20.07±8.9 and group 5=14.15±8.7 MPa±SD. One-way ANOVA showed the statistically significant difference between the bond strengths of five groups (P=0.001. Post hoc Duncan's test showed significant difference between groups 1and 3 (P=0.008, groups 1 and 5 (P=0.019, groups 2 and 5 (P=0.0008, groups 4 and 5 (P=0.042, and groups 3 and 4 (P=0.018.Conclusion: Results of this study showed that the bond strength of amalgam to dentin using One Coat Bond as dentin adhesive system was higher than that observed in other dentin adhesive systems.

  16. Porcine dentin sialoprotein glycosylation and glycosaminoglycan attachments

    Directory of Open Access Journals (Sweden)

    Yamakoshi Fumiko

    2011-02-01

    Full Text Available Abstract Background Dentin sialophosphoprotein (Dspp is a multidomain, secreted protein that is critical for the formation of tooth dentin. Mutations in DSPP cause inherited dentin defects categorized as dentin dysplasia type II and dentinogenesis imperfecta type II and type III. Dentin sialoprotein (Dsp, the N-terminal domain of dentin sialophosphoprotein (Dspp, is a highly glycosylated proteoglycan, but little is known about the number, character, and attachment sites of its carbohydrate moieties. Results To identify its carbohydrate attachment sites we isolated Dsp from developing porcine molars and digested it with endoproteinase Glu-C or pronase, fractionated the digestion products, identified fractions containing glycosylated peptides using a phenol sulfuric acid assay, and characterized the glycopeptides by N-terminal sequencing, amino acid analyses, or LC/MSMS. To determine the average number of sialic acid attachments per N-glycosylation, we digested Dsp with glycopeptidase A, labeled the released N-glycosylations with 2-aminobenzoic acid, and quantified the moles of released glycosylations by comparison to labeled standards of known concentration. Sialic acid was released by sialidase digestion and quantified by measuring β-NADH reduction of pyruvic acid, which was generated stoichiometrically from sialic acid by aldolase. To determine its forms, sialic acid released by sialidase digestion was labeled with 1,2-diamino-4,5-methyleneoxybenzene (DMB and compared to a DMB-labeled sialic acid reference panel by RP-HPLC. To determine the composition of Dsp glycosaminoglycan (GAG attachments, we digested Dsp with chondroitinase ABC and compared the chromotagraphic profiles of the released disaccharides to commercial standards. N-glycosylations were identified at Asn37, Asn77, Asn136, Asn155, Asn161, and Asn176. Dsp averages one sialic acid per N-glycosylation, which is always in the form of N-acetylneuraminic acid. O-glycosylations were

  17. Regeneratieve capaciteit van de pulpa: adulte humane stamcellen uit de pulpa: meer dan reparatie van dentine

    NARCIS (Netherlands)

    Bronckers, A.L.J.J.

    2010-01-01

    Vorming van tertiair dentine is de natuurlijke reactie van de pulpa om zich te beschermen na verwonding. Reactief dentine wordt geproduceerd door de oorspronkelijke (primaire) odontoblasten die tijdelijk geactiveerd worden. Reparatief dentine wordt gevormd vanuit secundaire odontoblasten, ontstaan u

  18. Evaluation of Calcium Phosphate Cement As a Root Canal Sealer Filling Material

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Calcium phosphate cement for root end sealing was obtained by mixing α-tricalcium phosphate and additives with an aqueous solution of citric. Powder and liquid were mixed at a ratio of 1.25g/mL. The biocompatibility of this material was investigated primarily by subcutaneous implantation tests. Then calcium phosphate cement was used to fill three adult dogs' root canal, both calcium hydroxide paste and hydroxyapatite paste as control. The animals were killed at 4,12,20 weeks postoperatively respectively. The effects of different materials on the apical closure, restoration of periapical tissues and adaptability to the dentinal surface were examined by optical and electronic microscope. The observation at 20 weeks shows that the calcium phosphate cement has the potentialities of being a root canal sealer filling material available for pulpless teeth with open-apex and destructive periapical tissue.

  19. Dentin tubule invasion by Enterococcus faecalis under stress conditions ex vivo.

    Science.gov (United States)

    Ran, Shujun; Gu, Shensheng; Wang, Jia; Zhu, Cailian; Liang, Jingping

    2015-08-21

    Enterococcus faecalis is the species most frequently isolated from failed endodontic treatments because it can survive under stress conditions imposed by root canal treatment. The objective of this study was to determine the ability of E. faecalis to invade dentine tubules under alkaline and energy-starvation stress and to explore the potential mechanisms. Roots from single-rooted human teeth were infected with E. faecalis under alkaline and energy-starvation stress conditions. After 4 wk of culture, samples were processed to establish the tubule-penetration distance. In addition, the hydrophobicity of E. faecalis cells under these conditions was analysed and the expression of genes involved in adhesion was quantified by real-time quantitative PCR. Culture of E. faecalis under alkaline and energy-starvation stress conditions resulted in a marked reduction of tubule-penetration distance, a significant increase in hydrophobicity of the bacterial surface, and marked down-regulation of most adhesin genes compared with E. faecalis cultured in tryptic soy broth. The results indicate that the dentine tubule invasion ability of E. faecalis was markedly decreased under alkaline and glucose-starvation stress conditions, possibly because of the increase of hydrophobicity and down-regulation of some adhesion genes.

  20. Effect of dentin location and long-term water storage on bonding effectiveness of dentin adhesives.

    Science.gov (United States)

    De Munck, Jan; Mine, Atsushi; Vivan Cardoso, Marcio; De Almeida Neves, Aline; Van Landuyt, Kirsten L; Poitevin, André; Van Meerbeek, Bart

    2011-01-01

    Dentin is a variable substrate with properties that change considerable in a single surface. The purpose of this study was to evaluate the bonding effectiveness to these different dentin locations and evaluate these differences over time. After bonding procedures with five different adhesives, small micro-tensile bond strength (µTBS) beams were prepared and dichotomously divided in 'center' and 'periphery' dentin specimens. After 1 week, 3, 6 and 12 months of water storage the µTBS of specimens of each group was determined, enabling a paired study design. The bond strengths of both etch&rinse adhesives were insensitive to regional variability. For the two-step self-etch adhesives, a marked increase in bond strengths was observed with increasing amount of intertubular dentin. Regional variability did not affect the long-term bonding effectiveness for any of the adhesives tested. In conclusion, only for the mild self-etch adhesives, µTBS to 'periphery' dentin was higher than for the 'center' specimens.

  1. Dentin phosphoprotein compound mutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III.

    Science.gov (United States)

    Dong, Juan; Gu, TingTing; Jeffords, Leticia; MacDougall, Mary

    2005-01-30

    A rare compound mutation involving a 36 bp deletion and 18 bp insertion within exon 5 of the dentin sialophosphoprotein (DSPP) gene has been identified in a family with dentinogenesis imperfecta type III (DGI-III). The DSPP gene encodes two major tooth matrix proteins dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). DSPP mutations associated with DGI-III results in an in frame truncation of the serine aspartic acid triplet repeat found in DPP near the highly conserved carboxyl terminal region shortening the protein by six amino acids. Clinically this family presents with discolored amber opalescent teeth and severe attrition of the tooth structure. This study is the first report of a mutation within DPP associated with a genetic dentin disease. Our study indicates that DGI-III is allelic with some forms of DGI-II with and without progressive hearing loss and dentin dysplasia type II that have been shown to be caused by mutations within the DSP coding or signal peptide regions.

  2. Antibacterial efficacy of Mangifera indica L. kernel and Ocimum sanctum L. leaves against Enterococcus faecalis dentinal biofilm

    Directory of Open Access Journals (Sweden)

    Arunajatesan Subbiya

    2013-01-01

    Full Text Available Introduction: The Enterococcus faecalis biofilm in the root canal makes it difficult to be eradicated by the conventional irrigants with no toxicity to the tissues. Hence, plant products with least side effects are explored for their use as irrigants in the root canal therapy. Aim: To evaluate and compare the antibacterial efficacy of Mangifera indica L. kernel (mango kernel and Ocimum sanctum L. leaves (tulsi extracts with conventional irrigants (5% sodium hypochlorite (NaOCl and 2% chlorhexidine against E. faecalis dentinal biofilm. Materials and Methods: Agar diffusion and broth microdilution assay was performed with the herbal extracts and conventional irrigants (2% chlorhexidine and 5% NaOCl against E. faecalis planktonic cells. The assay was extended onto 3 week E. faecalis dentinal biofilm. Results: Significant reduction of colony forming units (CFU/mL was observed for the herbal groups and the antibacterial activity of the herbal groups was at par with 5% NaOCl. Conclusions: The antibacterial activity of these herbal extracts is found to be comparable with that of conventional irrigants both on the biofilm and planktonic counterparts.

  3. Hood Canal Steelhead - Hood Canal Steelhead Supplementation Experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Hood Canal Steelhead Project is a 17-year before-after-control-impact experiment that tests the effects of supplementation on natural steelhead populations in...

  4. [External auditory canal osteoma resulting in cholesteatoma which is complicated with meningitis].

    Science.gov (United States)

    Yorgancılar, Ediz; Kınış, Vefa; Gün, Ramazan; Bakır, Salih; Ozbay, Musa; Topçu, Ismail

    2013-01-01

    Osteoma of external auditory canal is a unilateral benign tumor which usually presents with no symptoms. They only cause symptoms when cerumen collection or conduction type hearing loss occurs. They are the most common osseous lesions of the temporal bone. It very rarely presents with cholesteatoma. So far, no osteoma case concomitant with, cholesteatoma and meningitis has not been reported. In this article, we report an interesting case presenting with external auditory canal osteoma, cholestatoma and meningitis concomitantly who was treated successfully using the canal Wall-down mastoidectomy technique.

  5. Morphological effects of MMPs inhibitors on the dentin bonding

    OpenAIRE

    Li, He; Li, Tianbo; LI, XIUYING; Zhang, Zhimin; Li, Penglian; Li, Zhenling

    2015-01-01

    Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength. However, morphologic characteristics of the collagen network after etching and of the post-adhesive dentin hybrid layers (DHL) after MMP inhibitors pretreatment have not been evaluated. Thus, we investigated demineralized dentin pretreated with chlorhexidine (CHX) and...

  6. Shear bond strength of partial coverage restorations to dentin

    OpenAIRE

    Román Rodríguez, Juan Luis; Agustín Panadero, Rubén; Alonso Pérez Barquero, Jorge; Fons Font, Antonio; Solá Ruiz, María Fernanda

    2015-01-01

    Background When partial coverage restorations (veneers, inlays, onlays…) must be cemented to dentin, bond strength may not reach the same predictable values as to enamel. The purpose of this study was: 1. To compare, with a shear bond test, the bond strength to dentin of a total-etch and a self-etching bonding agent. 2. To determine whether creating microretention improves the bond strength to dentin. Material and Methods Two bonding agents were assayed, Optibond FL® (Kerr), two-bottle adhesi...

  7. A Stereomicroscopic Evaluation of Dentinal Cracks at Different Instrumentation Lengths by Using Different Rotary Files (ProTaper Universal, ProTaper Next, and HyFlex CM): An Ex Vivo Study

    OpenAIRE

    Fauzia Ashraf; Pushpa Shankarappa; Abhinav Misra; Asheesh Sawhney; Nandamuri Sridevi; Anu Singh

    2016-01-01

    Introduction. The aim of the present study was to evaluate the dentinal cracks after root canal preparation with rotary files: Gates Glidden, ProTaper Universal, ProTaper Next, and HyFlex CM at different instrumentation lengths. Methodology. Sixty-five mandibular premolars were mounted in the acrylic tube with simulated periodontal ligaments and the apex was exposed. The root canals were instrumented with different rotary files, namely, ProTaper Universal, ProTaper Next, and HyFlex CM, to the...

  8. Tubular occlusion optimizes bonding of hydrophobic resins to dentin.

    Science.gov (United States)

    Sadek, F T; Pashley, D H; Ferrari, M; Tay, F R

    2007-06-01

    Although hydrophobic resins may be bonded to acid-etched dentin with an ethanol wet-bonding technique, the protocol is sensitive to moisture contamination when bonding is performed in deep dentin. This study tested the hypothesis that the use of oxalate or poly(glutamic) acid-modified, diluted ceramicrete (PADC) for dentinal tubule occlusion prevents fluid contamination and improves the bonding of an experimental hydrophobic adhesive to acid-etched, ethanol-dehydrated dentin. Mid-coronal and deep acid-etched moist dentin pre-treated with oxalate or PADC was dehydrated by ethanol wet-bonding and infiltrated with the experimental three-step etch-and-rinse hydrophobic adhesive under simulated pulpal pressure. Tensile bond strengths to deep dentin without pre-treatment were severely compromised. Conversely, oxalate and PADC pre-treatments reduced dentin permeability, prevented water contamination, and improved bond strengths. Minimal nanoleakage was identified within hybrid layers created in the oxalate- and PADC-pre-treated deep dentin. The use of tubular occluding agents optimized bonding of hydrophobic resins to dentin.

  9. The Crystal Characteristics of Enamel and Dentin by XRD Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Crystal characteristics of tooth enamel and dentin were investigated using XRD, SEM, and EPMA methods.The results show that the mineral phase in enamel is HA and in dentin is HA and minor whitlock ites.The dentin HA and the enamel HA have different crystallinity, the crystallinity of enamel HA is much higher than that of dentin HA.The average particle size of the enamel HA and dentin HA are 897A and 309A, respectively.The HA in enamel is regularly arranged, and in dentin the arrangement of HA is diifferent from the enamel HA in the same section.Both the enamel and the dentin are mainly consisted of Ca, P, O, and C, and the trace elements Mg , Sr, Al, Na , and K.The dentin contains more trace elements than the enamel.However,the incorporation of trace elements in both dentin and enamel are very limited.Other impurities such as F and Cl are less than their detection limit.The a and c values of enamel HA are 9.433A and 6.8A, and those of thedentin HA are 9.498A and 6.896A, respectively.The expansion in a value results from those the larger size of [CO3 ]2 group substituing for the smaller [ OH]- group in the channel, and replacement of [ OH ]- by[ CO3 ]2- dominates the change in cell parameter, taking into account of other trace elements.

  10. Dentin permeability: effects of endodontic procedures on root slabs.

    Science.gov (United States)

    Fogel, H M; Pashley, D H

    1990-09-01

    The permeability of human radicular dentin was measured as a hydraulic conductance before and after treatment with K files and before and after subsequent treatment of the endodontic smear layer with NaOCl, 50% citric acid, or 3% monopotassium-monohydrogen oxalate. Filing reduced dentin permeability 25 to 49%, respectively, depending upon whether outer or inner root dentin was filed. The permeability of these smear layers was unaffected by 5% NaOCl but increased many times after treatment with 50% citric acid for 2 min. Oxalate treatment lowered root dentin permeability to levels below that produced by creation of smear layers due to the production of a crystalline precipitate.

  11. Effect of ethylene diamine tetra-acetic acid, MTAD TM , and HEBP as a final rinse on the microhardness of root dentin

    Directory of Open Access Journals (Sweden)

    Mukura Kulasekaran Dineshkumar

    2012-01-01

    Aims: This study evaluated the effect of 17% EDTA, MTAD, and 18% HEBP solutions on the microhardness of human root canal dentin using the Vickers microhardness test. Materials and Methods: Forty human single-rooted teeth were decoronated at the cementoenamel junction and sectioned longitudinally into buccal and lingual segments. Eighty specimens were divided into four groups (n=20. Group I was treated with distilled water (control, groups II, III, and IV were treated with 1.3% NaOCl as a working solution for 20 minutes followed by 17% EDTA, MTAD, and 18% HEBP respectively. The surface hardness of the root dentin was determined in each specimen with a Vicker′s hardness tester. The values were statistically analyzed using the one-way ANOVA and post hoc Tukey multiple comparison tests. Results: There was a statistical significant difference among all the groups (one-way ANOVA; P<0.001. Among the experimental groups, HEBP showed the highest dentin microhardness (53.74 MPa, P<0.001. Least microhardness was found with MTAD (42.85 MPa, P<0.001. Conclusions: HEBP as a final rinse appears to be a promising irrigation protocol with less impact on the mineral content of root dentin.

  12. Caries-resistant bonding layer in dentin.

    Science.gov (United States)

    Zhou, Wei; Niu, Li-Na; Hu, Lin; Jiao, Kai; Chang, Gang; Shen, Li-Juan; Tay, Franklin R; Chen, Ji-Hua

    2016-09-07

    The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibacterial adhesive and augmented-pressure adhesive displacement (N-H), antibacterial adhesive and gentle adhesive displacement (A-G), antibacterial adhesive and augmented-pressure adhesive displacement (A-H). The depth of demineralization induced by biological or chemical demineralization models was measured using confocal laser scanning microscopy and analyzed with two-way ANOVA. Pulp responses of vital dog's teeth to the augmented-pressure adhesive displacement technique were evaluated using light microscopy. Depth of demineralization was significantly affected by "adhesive type" and "intensity of adhesive displacement" for biological demineralization. For chemical demineralization, only "intensity of adhesive displacement" showed significant influence on lesion depth. Pulp response of 0.1, 0.2 and 0.3 MPa groups showed only moderate disorganization of the odontoblast layer at 24 hours that completely re-organized after 3 weeks. Augmented-pressure adhesive displacement improves the caries resistance property of bonded dentin and does not cause irreversible pulpal damage to vital teeth when the air pressure employed is equal or smaller than 0.3 MPa.

  13. Chlorhexidine preserves dentin bond in vitro.

    Science.gov (United States)

    Carrilho, M R O; Carvalho, R M; de Goes, M F; di Hipólito, V; Geraldeli, S; Tay, F R; Pashley, D H; Tjäderhane, L

    2007-01-01

    Loss of hybrid layer integrity compromises resin-dentin bond stability. Matrix metalloproteinases (MMPs) may be partially responsible for hybrid layer degradation. Since chlorhexidine inhibits MMPs, we hypothesized that chlorhexidine would decelerate the loss of resin-dentin bonds. Class I preparations in extracted third molars were sectioned into two halves. One half was customarily restored (etch-and-rinse adhesive/resin composite), and the other was treated with 2% chlorhexidine after being acid-etched before restoration. Specimens were stored in artificial saliva with/without protease inhibitors. Microtensile bond strengths and failure mode distribution under SEM were analyzed immediately after specimens' preparation and 6 months later. With chlorhexidine, significantly better preservation of bond strength was observed after 6 months; protease inhibitors in the storage medium had no effect. Failure analysis showed significantly less failure in the hybrid layer with chlorhexidine, compared with controls after 6 months. In conclusion, this in vitro study suggests that chlorhexidine might be useful for the preservation of dentin bond strength.

  14. Cigarette smoke affects bonding to dentin.

    Science.gov (United States)

    Almeida e Silva, Junio S; de Araujo, Edson Medeiro; Araujo, Elito

    2010-01-01

    This in vitro study evaluated the microtensile bond strength (muTBS) of composite resin bonded to dentin that had been contaminated by cigarette smoke. Ten extracted unerupted human third molars were used: Six molars were prepared for muTBS testing, while the other four molars were assigned to pre- and post-etching scanning electronic microscopy (SEM) analysis. The 20 specimens obtained from the 10 coronal portions were distributed into two experimental groups so that each tooth served as its own control. Group 1 underwent a daily toothbrushing simulation and exposure to a smoking simulation chamber, while Group 2 received only a daily simulated toothbrushing. Student's t-test demonstrated that Group 1 samples demonstrated significantly lower bond strength (49.58 MPa) than Group 2 samples (58.48 MPa). Pre and postetching SEM analysis revealed the presence of contaminants on the dentinal surfaces of the Group 1 specimens. It was concluded that contamination by cigarette smoke decreases the bond strength between dentin and composite resin.

  15. Depolarization canals and interstellar turbulence

    CERN Document Server

    Fletcher, A; Fletcher, Andrew; Shukurov, Anvar

    2006-01-01

    Recent radio polarization observations have revealed a plethora of unexpected features in the polarized Galactic radio background that arise from propagation effects in the random (turbulent) interstellar medium. The canals are especially striking among them, a random network of very dark, narrow regions clearly visible in many directions against a bright polarized Galactic synchrotron background. There are no obvious physical structures in the ISM that may have caused the canals, and so they have been called Faraday ghosts. They evidently carry information about interstellar turbulence but only now is it becoming clear how this information can be extracted. Two theories for the origin of the canals have been proposed; both attribute the canals to Faraday rotation, but one invokes strong gradients in Faraday rotation in the sky plane (specifically, in a foreground Faraday screen) and the other only relies on line-of-sight effects (differential Faraday rotation). In this review we discuss the physical nature o...

  16. The Love Canal: Beyond science?

    Science.gov (United States)

    Bell, Peter M.

    When in 1978, the New York State Department of Health issued the report, ‘Love Canal—Public Health Time Bomb,’ the serious effects of chemical waste contamination in the Love Canal area became an issue of national concern. A few ‘studies’ since then have produced results in concert with those of initial reports that described ‘conditions of acute health effects’ as being linked to hazardous wastes incorporated in landfill in the Love Canal site near Niagara Falls, New York. Now that a ‘blue ribbon’ panel of experts from the medical sciences has reviewed the problems of Love Canal, however, a different view has emerged. The ‘Report of the Governors' Panel to Review Scientific Studies and the Development of Public Policy on Problems Resulting from Hazardous Wastes,’ transmitted in October of this year, identifies the following factors about the health effects at Love Canal:

  17. A Stereomicroscopic Evaluation of Dentinal Cracks at Different Instrumentation Lengths by Using Different Rotary Files (ProTaper Universal, ProTaper Next, and HyFlex CM): An Ex Vivo Study.

    Science.gov (United States)

    Ashraf, Fauzia; Shankarappa, Pushpa; Misra, Abhinav; Sawhney, Asheesh; Sridevi, Nandamuri; Singh, Anu

    2016-01-01

    Introduction. The aim of the present study was to evaluate the dentinal cracks after root canal preparation with rotary files: Gates Glidden, ProTaper Universal, ProTaper Next, and HyFlex CM at different instrumentation lengths. Methodology. Sixty-five mandibular premolars were mounted in the acrylic tube with simulated periodontal ligaments and the apex was exposed. The root canals were instrumented with different rotary files, namely, ProTaper Universal, ProTaper Next, and HyFlex CM, to the major apical foramen (AF), short AF, and beyond AF. The root apex was stained with 1% methylene blue dye and digital images of apical surface of every tooth were taken and development of dentinal defects was determined by using stereomicroscope. Multinomial logistic regression test was performed to identify influencing factors. Results. Instrumentation with rotary files terminated 2 mm short AF and did not cause any cracks. Significantly less cracks were seen when instrumentation with rotary files terminated 1 mm short apical foramen when compared with the instrumentation terminated at or beyond apical foramen (p ProTaper Universal rotary files caused more dentinal cracks than ProTaper Next and HyFlex CM. Instrumentation short AF reduced the risk of dentinal defects.

  18. A Stereomicroscopic Evaluation of Dentinal Cracks at Different Instrumentation Lengths by Using Different Rotary Files (ProTaper Universal, ProTaper Next, and HyFlex CM: An Ex Vivo Study

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    Fauzia Ashraf

    2016-01-01

    Full Text Available Introduction. The aim of the present study was to evaluate the dentinal cracks after root canal preparation with rotary files: Gates Glidden, ProTaper Universal, ProTaper Next, and HyFlex CM at different instrumentation lengths. Methodology. Sixty-five mandibular premolars were mounted in the acrylic tube with simulated periodontal ligaments and the apex was exposed. The root canals were instrumented with different rotary files, namely, ProTaper Universal, ProTaper Next, and HyFlex CM, to the major apical foramen (AF, short AF, and beyond AF. The root apex was stained with 1% methylene blue dye and digital images of apical surface of every tooth were taken and development of dentinal defects was determined by using stereomicroscope. Multinomial logistic regression test was performed to identify influencing factors. Results. Instrumentation with rotary files terminated 2 mm short AF and did not cause any cracks. Significantly less cracks were seen when instrumentation with rotary files terminated 1 mm short apical foramen when compared with the instrumentation terminated at or beyond apical foramen (p<0.05. Conclusion. ProTaper Universal rotary files caused more dentinal cracks than ProTaper Next and HyFlex CM. Instrumentation short AF reduced the risk of dentinal defects.

  19. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding

    Science.gov (United States)

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-01-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm−1 and amide II at 1550 cm−1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding. PMID:25267936

  20. Comparative scanning electron microscopy evaluation of Canal Brushing technique, sonic activation, and master apical file for the removal of triple antibiotic paste from root canal (in vitro study

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    Deepa Ashoksingh Thakur

    2015-01-01

    Full Text Available Aims: To compare and evaluate the effectiveness of Canal Brushing technique, sonic activation, and master apical file (MAF for the removal of triple antibiotic paste (TAP from root canal using scanning electron microscopy (SEM. Materials and Methods: Twenty-two single rooted teeth were instrumented with ProTaper up to the size number F2 and dressed with TAP. TAP was removed with Canal Brush technique (Group I, n: 6, sonic (EndoActivator (Group II, n: 6, and MAF (Group III, n: 6. Four teeth served as positive (n: 2 and negative (n: 2 controls. The roots were split in the buccolingual direction and prepared for SEM examination (×1000 at coronal, middle, and apical third. Three examiners evaluated the wall cleanliness. Statistical Analysis: Statistical analysis was performed by Kruskal–Wallis test and Wilcoxon rank sum test. Results: Difference in cleanliness between three groups is statistically significant in cervical region only. Pairwise comparison in cervical region Canal Brush and sonic activation showed more removal of TAP than MAF. Conclusions: Canal Brush and sonic activation system showed better result than MAF in the cervical and middle third of canal. In the apical third, none of the techniques showed a better result. None of the techniques showed complete removal of TAP from the canal.

  1. Horizontal Canal Benign Positional Vertigo

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    Mohtaram Najafi

    1998-03-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV is a syndrome characterized by transient episodes of vertigo in association with rapid changes in head position in Dix-Halpike Maneuver. This kind of vertigo is thought to be caused by migration of otoconial debris into canals other than the posterior canal, such as the anterior or lateral canals. It is also theoretically possible for many aberrant patterns of BPPV to occur from an interaction of debris in several canals, location of debris within the canal, and central adaptation patterns to lesions. The symptoms of BPPV are much more consistent with free-moving densities (canaliths in the posterior SCC rather than fixed densities attached to the cupula. While the head is upright, the particles sit in the PSC at the most gravity-dependent position. The best method to induce and see vertigo and nystagmus in BPPV of the lateral semicircular canal is to rotate head 90°while patient is in the supine position, nystagmus would appear in the unaffected side weaker but longer than the affected side. canal paresis has been described in one third of the patients with BPPV. Adaptation which is one of the remarkable features of BPPV in PSC is rarely seen in LSC. Rotations of 270° or 360° around the yaw axis (the so-called barbecue maneuver toward the unaffected ear are popular methods for the treatment of geotropic HC-BPPV. These maneuvers consist of sequential head turning of 90° toward the healthy side while supine. With these maneuvers, the free-floating otoconial debris migrates in the ampullofugal direction, finally entering the utricle through the nonampullated end of the horizontal canal. This kind of vertigo recovers spontaneously more rapidly and suddenly.

  2. The effect of dentine location and tubule orientation on the bond strengths between resin and dentine.

    Science.gov (United States)

    Phrukkanon, S; Burrow, M F; Tyas, M J

    1999-05-01

    This study determined the influence of dentine structure on the micro-tensile bond strengths between resin and dentine of two different dentine adhesive systems (Single Bond, 3M Dental Products, St Paul, MN; MF-102 (experimental self-etching primer), GC Corporation, Tokyo, Japan). The study was separated into two main parts: bond strength measurement and investigation of the bonding interface. Twenty-two human premolars were used for the bond strength measurement. Each tooth was cut vertically, separating the tooth into mesio-distal halves. One half of the tooth was used to bond to a surface perpendicular to the dentinal tubules and other half to bond to a surface parallel to the tubules. For each half, six locations of dentine were bonded. Each material was used in accordance to the manufacturer's directions. Cylindrical hourglass-shaped specimens of 1.2 mm diameter at the bonded interface were manufactured. The bonds were stressed in tension at a crosshead speed of 1 mm/min. Mean bond strengths were compared using LSD, one-way ANOVA, and Student's t-test. The fractured surfaces were examined under a scanning electron microscope, and the frequency of fracture modes was compared using the Kruskal-Wallis and Mann-Whitney U tests. For the investigation of the bonded interface, four teeth were prepared by the same procedure used for the bond test specimens. The bonded interfaces were observed after an acid-base treatment or fracturing across the bonded interface, prior to investigation with a field-emission scanning electron microscope. For Single Bond, the bond strengths for mid-root dentine were significantly lower than for other locations (p 0.05). MF-102 bonded well to all locations of dentine while Single Bond showed a porous zone at the base of the hybrid layer. The bonds were not influenced by tubule orientation. The results indicate that the bond for Single Bond may be affected by its ability to penetrate demineralised dentine in different locations of a tooth

  3. Dentin matrix protein 1 and dentin sialophosphoprotein in human sound and carious teeth: an immunohistochemical and colorimetric assay

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    D. Martini

    2013-10-01

    Full Text Available Dentin matrix protein 1 (DMP1 and dentin sialophosphoprotein (DSPP are extracellular matrix proteins produced by odontoblasts involved in the dentin mineralization. The aim this study was to compare the distribution of DMP1 and DSPP in human sound dentin vs human sclerotic dentin. Sixteen sound and sixteen carious human molars were selected, fixed in paraformaldehyde and processed for immunohistochemical detection of DMP1 and DSPP by means of light microscopy, transmission electron microscopy (TEM and high-resolution field emission in-lens scanning electron microscopy (FEI-SEM. Specimens were submitted to a pre-embedding or a post-embedding immunolabeling technique using primary antibodies anti DMP1 and anti-DSPP and gold-conjugated secondary antibodies. Other samples were processed for the detection of DMP1 and DSPP levels. Dentin from these samples was mechanically fractured to powder, then a protein extraction and a protein level detection assay were performed. DMP1 and DSPP were more abundant in carious than in sound samples. Immunohistochemical analyses in sclerotic dentin disclosed a high expression of DMP1 and DSPP inside the tubules, suggesting an active biomineralization of dentin by odontoblasts. Furthermore, the detection of small amounts of these proteins inside the tubules far from the carious lesion, as shown in the present study, is consistent with the hypothesis of a preventive defense of all dentin after a noxious stimulus has undermined the tooth.

  4. Dentin matrix protein 1 and dentin sialophosphoprotein in human sound and carious teeth: an immunohistochemical and colorimetric assay.

    Science.gov (United States)

    Martini, D; Trirè, A; Breschi, L; Mazzoni, A; Teti, G; Falconi, M; Ruggeri, A

    2013-10-29

    Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) are extracellular matrix proteins produced by odontoblasts involved in the dentin mineralization. The aim this study was to compare the distribution of DMP1 and DSPP in human sound dentin vs human sclerotic dentin. Sixteen sound and sixteen carious human molars were selected, fixed in paraformaldehyde and processed for immunohistochemical detection of DMP1 and DSPP by means of light microscopy, transmission electron microscopy (TEM) and high-resolution field emission in-lens scanning electron microscopy (FEI-SEM). Specimens were submitted to a pre-embedding or a post-embedding immunolabeling technique using primary antibodies anti DMP1 and anti-DSPP and gold-conjugated secondary antibodies. Other samples were processed for the detection of DMP1 and DSPP levels. Dentin from these samples was mechanically fractured to powder, then a protein extraction and a protein level detection assay were performed. DMP1 and DSPP were more abundant in carious than in sound samples. Immunohistochemical analyses in sclerotic dentin disclosed a high expression of DMP1 and DSPP inside the tubules, suggesting an active biomineralization of dentin by odontoblasts. Furthermore, the detection of small amounts of these proteins inside the tubules far from the carious lesion, as shown in the present study, is consistent with the hypothesis of a preventive defense of all dentin after a noxious stimulus has undermined the tooth.

  5. Bactericidal effect of the 908 nm diode laser on Enterococcus faecalis in infected root canals

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    Thomas Preethee

    2012-01-01

    Full Text Available Aim: The aim of this study is to evaluate the bactericidal effect of 908 nm diode laser in conjunction with various irrigation regimes in disinfection of apical third of root dentin. Materials and Methods: Sixty prepared teeth with single canals were contaminated with Enterococcus faecalis. The specimens were divided into 6 groups (n = 10: Group 1 and 3 and 5 were subjected to chemo-mechanical preparation using 5.25% sodium hypochlorite (NaOCl, 17% Ethylenediaminetetraacetic acid (EDTA; 1.3% NaOCl, MTAD (mixture of doxycycline, citric acid and a detergent (Tween 80; and, 8.5% saline, respectively followed by 908 nm diode laser irradiation; Group 2 and 4, followed the same procedure as Group1 and 3, however without laser irradiation; and, Group 6, rinsed with saline solution (control. Dentin shavings from apical third were analyzed for the presence of E. faecalis using culture method and Polymerase Chain reaction (PCR. Results: One-way Analysis of variance showed statistically significant differences between the laser irradiated groups, non irradiated groups and the control group. Conclusion: 908 nm diode used in conjunction with conventional chemomechanical techniques demonstrated a significant elimination of E. faecalis in the apical third of root dentin.

  6. The antimicrobial effect of iodine-potassium iodide after cleaning and shaping procedures in mesial root canals of mandibular molars.

    Science.gov (United States)

    Tello-Barbaran, Javier; Nakata, Hilda Moromi; Salcedo-Moncada, Doris; Bramante, Clovis M; Ordinola-Zapata, Ronald

    2010-01-01

    The aim of this study was to evaluate the antibacterial activity of 2% iodine potassium iodide (IKI) used as a final rinse after the cleaning and shaping procedures in mesial root canals of mandibular molars infected with Enterococcus faecalis. Seventy two mandibular first molars were used. The root canals were infected with Enterococcus faecalisfor 30 days. After the infection procedures, the root canals were cleaned and shaped by using the Pro Taper rotary system and manual files. The teeth were randomly assigned to four experimental groups (N = 18). In group 1, the root canals were irrigated with sterile distilled water (control). In group 2, the root canals were irrigated with 1% Sodium hypochlorite (NaOCl) during instrumentation. In group 3, root canals were irrigated with 1% NaOCl during instrumentation and a five minute final irrigation using 2% IKI. In group 4, the root canals were irrigated with 1% NaOCl during instrumentation and a 15 minutes final irrigation with 2% IKI. Bacteria colony-forming units (CFU) from root canals were semi-quantified and the presence of negative cultures among the groups was compared using Fisher's test (p < 0.05). The order of effectiveness was: 1% NaOCI plus 2% IKl for 15 minutes (95%), 1% NaOCl plus 2% IKl for 5 minutes (44%), 1% NaOCl (17%) and sterile distilled water (0%). Fisher's exact test showed a significant difference among the groups (p < 0.05). It was concluded that under in vitro conditions, IKI was able to eliminate the Enterococcus faecalis from infected dentin significantly in a 15-minute time frame after the cleaning and shaping procedures.

  7. The role of perilymph in the response of the semicircular canals to angular acceleration. [dynamic model for perilymph induced displacement of cupula

    Science.gov (United States)

    Anliker, M.; Vanbuskirk, W.

    1973-01-01

    A new model for the response of the semicircular canals to angular motion is postulated. This model is based on evidence that the bony canal is not compartmentalized and assumes that the ampulla wall is highly flexible. It is shown that the perilymph induces a cupula displacement far greater than that produced by the endolymph alone. The predicted dynamic behavior of the canals on the basis of this model is found to be consistent with experimental observations.

  8. Limitations of navigation through Nubaria canal, Egypt.

    Science.gov (United States)

    Samuel, Magdy G

    2014-03-01

    Alexandria port is the main Egyptian port at the Mediterranean Sea. It is connected to the Nile River through Nubaria canal, which is a main irrigation canal. The canal was designed to irrigate eight hundred thousand acres of agricultural lands, along its course which extends 100 km. The canal has three barrages and four locks to control the flow and allow light navigation by some small barges. Recently, it was decided to improve the locks located on the canal. More than 40 million US$ was invested in these projects. This decision was taken to allow larger barges and increase the transported capacity through the canal. On the other hand, navigation through canals and restricted shallow waterways is affected by several parameters related to both the channel and the vessel. Navigation lane width as well as vessel speed and maneuverability are affected by both the channel and vessel dimensions. Moreover, vessel dimensions and speed will affect the canal stability. In Egypt, there are no guide rules for navigation through narrow and shallow canals such Nubaria. This situation threatens the canal stability and safety of navigation through it. This paper discussed the characteristics of Nubaria canal and the guide rules for navigation in shallow restricted water ways. Dimensions limitation for barges navigating through Nubaria canal is presented. New safe operation rules for navigation in Nubaria canal are also presented. Moreover, the implication of navigation through locks on canal discharge is estimated.

  9. Limitations of navigation through Nubaria canal, Egypt

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    Magdy G. Samuel

    2014-03-01

    Full Text Available Alexandria port is the main Egyptian port at the Mediterranean Sea. It is connected to the Nile River through Nubaria canal, which is a main irrigation canal. The canal was designed to irrigate eight hundred thousand acres of agricultural lands, along its course which extends 100 km. The canal has three barrages and four locks to control the flow and allow light navigation by some small barges. Recently, it was decided to improve the locks located on the canal. More than 40 million US$ was invested in these projects. This decision was taken to allow larger barges and increase the transported capacity through the canal. On the other hand, navigation through canals and restricted shallow waterways is affected by several parameters related to both the channel and the vessel. Navigation lane width as well as vessel speed and maneuverability are affected by both the channel and vessel dimensions. Moreover, vessel dimensions and speed will affect the canal stability. In Egypt, there are no guide rules for navigation through narrow and shallow canals such Nubaria. This situation threatens the canal stability and safety of navigation through it. This paper discussed the characteristics of Nubaria canal and the guide rules for navigation in shallow restricted water ways. Dimensions limitation for barges navigating through Nubaria canal is presented. New safe operation rules for navigation in Nubaria canal are also presented. Moreover, the implication of navigation through locks on canal discharge is estimated.

  10. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; van der Hoorn, Wietske; Huysmans, Marie-Charlotte D. N. J. M.; Roeters, Joost F. M.; Kleverlaan, Cornelis J.; Feilzer, Albert J.; Ozcan, Mutlu

    2013-01-01

    Purpose: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. Methods: Sound human molars (n= 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n=

  11. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    Scholtanus, J.D.; van der Hoorn, W.; Özcan, M.; Huysmans, M.C.D.N.J.M.; Roeters, J.F.M.; Kleverlaan, C.J.; Feilzer, A.J.

    2013-01-01

    PURPOSE: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. METHODS: Sound human molars (n = 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n

  12. External Dentin Stimulation Induces ATP Release in Human Teeth.

    Science.gov (United States)

    Liu, X; Wang, C; Fujita, T; Malmstrom, H S; Nedergaard, M; Ren, Y F; Dirksen, R T

    2015-09-01

    ATP is involved in neurosensory processing, including nociceptive transduction. Thus, ATP signaling may participate in dentin hypersensitivity and dental pain. In this study, we investigated whether pannexins, which can form mechanosensitive ATP-permeable channels, are present in human dental pulp. We also assessed the existence and functional activity of ecto-ATPase for extracellular ATP degradation. We further tested if ATP is released from dental pulp upon dentin mechanical or thermal stimulation that induces dentin hypersensitivity and dental pain and if pannexin or pannexin/gap junction channel blockers reduce stimulation-dependent ATP release. Using immunofluorescence staining, we demonstrated immunoreactivity of pannexin 1 and 2 in odontoblasts and their processes extending into the dentin tubules. Using enzymatic histochemistry staining, we also demonstrated functional ecto-ATPase activity within the odontoblast layer, subodontoblast layer, dental pulp nerve bundles, and blood vessels. Using an ATP bioluminescence assay, we found that mechanical or cold stimulation to the exposed dentin induced ATP release in an in vitro human tooth perfusion model. We further demonstrated that blocking pannexin/gap junction channels with probenecid or carbenoxolone significantly reduced external dentin stimulation-induced ATP release. Our results provide evidence for the existence of functional machinery required for ATP release and degradation in human dental pulp and that pannexin channels are involved in external dentin stimulation-induced ATP release. These findings support a plausible role for ATP signaling in dentin hypersensitivity and dental pain.

  13. RETRATAMENTO ENDODÔNTICO: ESTUDO COMPARATIVO ENTRE TÉCNICA MANUAL, ULTRA-SOM E CANAL FINDER ENDODONTIC RETREATMENT: COMPARATIVE STUDY BETWEEN MANUAL TECHNIQUE, ULTRASONIC SCALER, AND CANAL FINDER

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    Clovis Monteiro BRAMANTE

    1998-01-01

    Full Text Available Instrumentações manual, ultra-sônica e com Canal Finder foram utilizadas para retratamento de 30 dentes com canais obturados com guta-percha e óxido de zinco e eugenol. Avaliaram-se: 1. tempo gasto para a penetração inicial até o ápice; 2. tempo para completar a limpeza; 3. extrusão de material e 4. limpeza dos canais. O Canal Finder foi a técnica que propiciou melhor limpeza, seguida da manual e da ultra-sônica. A parede palatina do canal foi constantemente mais limpa do que a vestibular. Quanto à extrusão, a técnica de ultra-som foi a que propiciou mais extravasamento de material obturador.Endodontic retreatment of 30 teeth filled with guta percha and zinc oxide-eugenol was carried out using manual instrumentation, ultrasonic scaler, and the Canal Finder System. The following variables were evaluated: time spent to reach the apex; time spent to complete cleaning of the canal; apical extrusion of material; and cleanliness of the canals. Results showed the Canal Finder System as providing the highest level of cleanliness of the canal system; lingual walls were constantly cleaner than buccal walls; ultrasonic technique presented a greater degree of apical extrusion of filling material.

  14. Polymerization contraction stress in dentin adhesives bonded to dentin and enamel

    NARCIS (Netherlands)

    M. Hashimoto; A.J. de Gee; A.J. Feilzer

    2008-01-01

    Objective In a previous study on of polymerization contraction stress determinations of adhesives bonded to dentin a continuous decline of stress was observed after the adhesives had been light-cured. The decline was ascribed to stress relief caused by diffusion into the adhesive layer of water and/

  15. A COMPARATIVE EVALUATION OF BOND - STRENGTH BETWEEN NORMAL DENTIN AND CARIES AFFECTED DENTIN: AN INVITRO STUDY

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    Arun

    2015-03-01

    Full Text Available INTRODUCTION: The concept of adhesive dentistry has taken leaps forward and has resulted in a concept of more conservation of tooth structure which in turn enhance the life of teeth. The bonding agent forms a hybrid layer with dentin and its other side co - polymerize with the matrix p hase of dental composite, producing strong micro - mechanical bonding. AIMS AND OBJECTIVE: To evaluate the bond strength of adhesive agent to normal dentin and caries affected dentin and also to compare the bond strength between different bonding agents. METHOD: 20 mandibular molar were collected, washed and stored in normal saline. Each tooth was cut longitudinally. Healthy tooth structure of each half of the tooth represents the control group and the carious portion of the same tooth represents as experi mental group. Thus, 80 samples were prepared. The groups were then further subdivided into 4 sub - groups of 4 different bonding agents. The dentin surface of all the sub groups were etched by 37% of phosphoric acid gel for 10 - 15 secs and respective bonding agent were used and cured for 20 secs. Cylindrical composite resin was prepared using a plastic module of internal diameter of 3mm and length 5mm. Statistical analysis was done using mean standard deviation (S.D, student ‘t’ test and level of significance ‘P’. RESULTS: For both the control and experimental group, 3M single bond has showed the strongest bond strength followed by Prime and Bond NT, Excite and PQ1.

  16. Penetração intratubular de cimentos endodônticos Intratubular penetration of root canal sealers

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    Gustavo de Deus

    2002-12-01

    Full Text Available Este estudo foi desenvolvido para avaliar a capacidade de penetração de diferentes cimentos endodônticos (Endo Fill, Sealapex, AH Plus e Pulp Canal Sealer nos túbulos dentinários em dentes devidamente modelados e obturados. Foram utilizados 72 incisivos centrais superiores, os quais foram instrumentados no sentido coroa-ápice pela técnica de forças balanceadas. O comprimento de trabalho foi estabelecido a 1 mm do ápice radicular. Durante a limpeza e modelagem, todos os dentes foram irrigados com 10 ml de hipoclorito de sódio a 5,25%. Os dentes foram divididos em 4 grupos, sendo 1 para cada tipo de cimento. Estes grupos foram então subdivididos em função do uso ou não de EDTA a 17% previamente à obturação dos canais radiculares, para a remoção da lama dentinária. Todos os dentes foram obturados pela técnica da onda de condensação com cone médio calibrado. Após obturação, as raízes foram seccionadas no sentido mésio-distal e foi escolhida a secção de melhor qualidade visual. Estas foram então analisadas em microscopia eletrônica de varredura (MEV, sendo o foco de observação sempre a interface dentina/material obturador. Após obtenção das imagens, mensurou-se os prolongamentos dos cimentos para o interior dos túbulos dentinários. O cimento de Rickert (Pulp Canal Sealer apresentou a maior capacidade de penetração nos túbulos dentinários, sendo os piores resultados apresentados pelo grupo em que se utilizou o Sealapex. Os resultados foram avaliados estatisticamente pelo teste de Spearman, o qual mostrou diferença estatisticamente significante (p The purpose of this study was to evaluate the capacity of penetration of four endodontic sealers (Endo Fill, Sealapex, AH Plus and Pulp Canal Sealer into dentinal tubules. Seventy-two extracted human maxillary anterior teeth were utilized in this study. The teeth were cleaned and shaped by means of the balanced-forces technique. The work length was established at 1

  17. Bacterial penetration of the root canal of intact incisor teeth after a simulated traumatic injury.

    Science.gov (United States)

    Love, R M

    1996-12-01

    One of the aims in treating traumatised teeth is to maintain the vitality of the pulp or allow conditions favourable for pulp revascularisation. However, infection of the pulp and root canal system may prevent this. A number of pathways have been proposed that allow bacteria to invade the root canal system, however most of these pathways cannot account for pulp infection in teeth that did not sustain injury to the periodontal attachment. Enamel/dentine cracks have been proposed as a portal for bacterial invasion of seemingly intact teeth and the aim of this study was to determine if bacteria could invade the root canal system after a simulated traumatic episode. Twenty intact and sound upper central incisors were chosen and prepared. One tooth was selected as a sterility control and the external crown surface of the remaining 19 teeth was subjected to infection with Streptococcus gordonii in a bacterial microleakage model. Over 7 days samples of growth media from the root canal system were taken and tested for bacteria. Sixteen of the teeth did not demonstrate bacterial invasion over the time frame. These teeth were then prepared for testing in a pendulum impact device and were subjected to a blow which did not fracture the crowns or dislodge the tooth from its simulated alveolus. The teeth were then prepared and tested in the bacterial microleakage model. After impact seven of the teeth demonstrated bacterial invasion of the root canal system (P = 0.002). These teeth were then reprepared for testing in the bacterial microleakage model. The crowns of five teeth, selected at random, were coated with two layers of light cured unfilled resin, the remaining two were used as positive controls. All the teeth coated with resin did not demonstrate bacterial invasion (P = 0.00), while the positive controls demonstrated invasion. The results suggested that enamel/dentine infractions were pathways for bacterial invasion of the root canal system of traumatised teeth. The

  18. Cryopreserved dentin matrix as a scaffold material for dentin-pulp tissue regeneration.

    Science.gov (United States)

    Jiao, Liang; Xie, Li; Yang, Bo; Yu, Mei; Jiang, Zongting; Feng, Lian; Guo, Weihua; Tian, Weidong

    2014-06-01

    Cryopreservation has been identified as an efficient approach to preserve tissue engineered products for a long term. Our prior studies have suggested that the treated dentin matrix (TDM) could be an ideal bioactive scaffold for dental tissue regeneration. In this study, we hypothesize that the cryopreservation could effectively maintain the survival and viability of dentinogenesis-related proteins of TDM and the cryopreserved dentin matrix (CDM) would provide the suitable biological scaffold and inductive microenvironment for the regeneration of dentin-pulp like tissue. CDM-3 and CDM-6 were prepared by cryopreserving TDM in liquid nitrogen (-196 °C) with cryoprotectant for 3 months and 6 months, respectively. Various biological characteristics of CDM, including mechanical properties, cell proliferation, and odontogenesis ability, were investigated. To further evaluate the inductive capacity of CDM, human dental follicle cells were encapsulated within CDM, and implanted the scaffold into a mouse model for 8 weeks, and the grafts were harvested and assessed histologically. The CDM showed superior mechanical properties than TDM. Compared to TDM, CDM can release more dentinogenesis-related proteins due to the larger pore diameter. Cell proliferation with the addition of CDM extract liquid was similar to that of TDM in the first five days. Human dental follicle cells, under the effect of CDM extract liquid, highly expressed bone sialoprotein, collagen-1, alkaline phosphatase, indicating that CDM, regarded as the inductive microenvironment, plays an important role in odontogenesis. Most importantly, in vivo, CDM could induce dental follicle cells to regenerate new dentin-pulp like tissues, such as dentinal tubules, predentin, collagen fibers, nerves, and blood vessels which were positive for dentin sialophosphoprotein, dental matrix protein-1, Tubulin, and collagen-1. In conclusion, CDM is an ideal biological scaffold material for human dentin-pulp like tissue

  19. Quality improvement of photopolimerizable-cement root canal obturation

    Science.gov (United States)

    Lupato Conrado, Luis A.; Frois, Iris M.; Amaro Zangaro, Renato; Munin, Egberto; Kuranaga, Carlos; Dias da Silva, Marcos; do Carmo de Andrade Nono, Maria; Cerquiera Rezende, Mirabel

    2003-06-01

    The sealing cements commonly used for endodontic applications are of the type cured through chemical reactions. During the polymerization process, mechanical contractions are not uncommon, leading to a non-perfect sealing. Photopolymerizable cements usually presents superior performance as compared to those chemically activated. However, difficulties in carrying the light to difficult-to-reach regions like the dental apex preclude those material of being accepted in the dental office routine. This work reports on a novel technique which allow the light curing of photopolymerizable cements in endodontic applications. A special light guide had been developed to allow the curing light to reach and polymerize the sealing cement in the apex region. The technique was tested by using single-root human teeth with normal canal morphology. The Ultradent EndoREZ root canal sealer and a resin-based photopolymerizable filler specially developed for the current application had been used. The cone-shaped light guide was introduced into treated canals filled with the photopolymerizable material, up to the apical region. Light from an argon laser was launched onto the light guide for polymerization. All test samples were immersed in methylene-blue solution for microleakage testing. All samples treated with the self-polymerizable material presented dye penetration to some extent. No sample within the group which had the filling material polymerized by using the light guide presented dye penetration through the canal wall.

  20. Exposure and direct stimulation of the semicircular canal cupula.

    Science.gov (United States)

    Suzuki, M; Harada, Y

    1985-01-01

    The ampullary wall of the posterior semicircular canal was isolated from the frog, cut and the cupula exposed in frog Ringer's solution. The cupula was stimulated by depression with a fine glass micropipette. Three points on the cupula were selected for depression: point A, the lowest point on the midline of the cupula surface on the utricular side; point B, the uppermost on the midline of the same surface; and point C, in the middle of the lateral surface of the cupula. Depression at points A and B was toward the canal, whereas depression at point C was toward the centre of the cupula. The amount of depression was controlled by a micromanipulator. At point A, the minimum depression facilitating the posterior canal action potential was 1 micron; at point B, a greater amount of depression was needed to produce the action potential. Even a large amount of depression at point C resulted in only a small action potential, possibly because the direction of the sensory cell polarity is along the long axis of the canal.

  1. Alternative adhesive strategies to optimize bonding to radicular dentin.

    Science.gov (United States)

    Bouillaguet, Serge; Bertossa, Bruno; Krejci, Ivo; Wataha, John C; Tay, Franklin R; Pashley, David H

    2007-10-01

    This study tested the hypothesis that bond strengths of filling materials to radicular dentin might be optimized by using an indirect dentin bonding procedure with an acrylic core material. Roots of human teeth were endodontically prepared and obturated with EndoREZ, Epiphany, or the bonding of an acrylic point with SE Bond by using a direct or an indirect bonding technique. Bond strengths of endodontic sealers to radicular dentin were measured with a thin slice push-out test. Push-out strengths of EndoREZ and Epiphany to radicular dentin were less than 5 megapascals (MPa). The direct bonding technique with acrylic points and the self-etching adhesive had push-out strengths of 10 MPa, increasing to 18 MPa with the indirect technique. The use of the indirect bonding protocol with an acrylic point to compensate for polymerization stresses appears to be a viable means for optimizing bond strengths of endodontic filling materials to radicular dentin.

  2. Dentin permeability. Effects of desensitizing dentifrices in vitro.

    Science.gov (United States)

    Pashley, D H; O'Meara, J A; Kepler, E E; Galloway, S E; Thompson, S M; Stewart, F P

    1984-09-01

    Patients using placebo dentifrices in clinical trials usually show a significant decrease in dentin sensitivity over a 2- to 4-week period. If their sensitivity were due to hydrodynamic fluid movement, then the results suggest that there was a decrease in their dentin permeability. This hypothesis was tested in vitro by measuring the ease with which fluid could flow (i.e., hydraulic conductance) across dentin discs before and after brushing the discs with a variety of dentifrices, including most of the marketed densensitizing dentifrices. All dentifrices decreased the hydraulic conductance of dentin. An experimental dentifrice containing oxalate as the active ingredient was far more effective than any of the marketed dentifrices. The results tend to support the hypothesis that, at least part of the reduction in clinical sensitivity in patients with hypersensitive dentin is due to the abrasive action of the dentifrice.

  3. Effect of periodontal root planing on dentin permeability.

    Science.gov (United States)

    Fogel, H M; Pashley, D H

    1993-10-01

    The purpose of this study was to quantitate the effects of root planing on the permeability of human root dentin in vitro. Unerupted 3rd molars were used. The crowns were removed and longitudinal slices made of the root. The hydraulic conductance of the root dentin was measured before and after root planing, acid etching and potassium oxalate application using a fluid filtration method. The results showed that root planing creates a smear layer that reduces the permeability of the underlying dentin. However, this smear layer is acid labile. Thus, root planing may ultimately cause increased dentin permeability and the associated sequelae of sensitive dentin, bacterial invasion of tubules, reduced periodontal reattachment and pulpal irritation.

  4. El Canal del Atazar I

    Directory of Open Access Journals (Sweden)

    López de Berges y de los Santos, Emilio

    1967-03-01

    Full Text Available The Atazar Canal helps to supply Madrid with water, from the rivers Lozoya, Jarama and Sorbe. The section which operates at present starts at the Torrelaguna dam and finishes at the El Goloso reservoir. Later a further section will be added, from the Atazar dam, on the Lozoya river, to link up with the control dam at Torrelaguna. The canal capacity is 16 m3/sec, and it is 43.47 km long. It has a slope of 4/10.000. The cross section is similar to that of the Jarama canal, already built. There are interconnections between this canal and the Canal Alto, which previously supplied the high and medium part of Madrid. To overcome the ground unevenness 5 syphons have been built, the most important of which is the Colmenar Goloso syphon, which is 10.88 km in length. Construction commenced on December 10, 1962, and water reached Madrid on June 15th, 1966. The initial budget for this project was 1,500 million pesetas.El canal del Atazar refuerza considerablemente el abastecimiento de aguas a Madrid, procedentes de los ríos Lozoya, Jarama y, en un próximo futuro, del Sorbe. El tramo, actualmente en funcionamiento, empieza en el salto de Torrelaguna y finaliza en los depósitos de El Goloso. Más adelante se completará su trazado mediante un nuevo tramo que partirá del embalse de Atazar, en el Lozoya, para unirse al actual en el depósito regulador de Torrelaguna. Su capacidad es de 16 m3/s; su longitud, 43,471 km, y su pendiente, 4 diezmilésimas. La sección tipo es análoga a la del canal del Jarama, de construcción anterior. Mediante la oportuna obra de transvase se realizan intercambios entre este Canal y el Canal Alto que abastecía anteriormente la parte media y alta de la capital. Para salvar los desniveles del terreno se han construido 5 sifones, siendo el más importante el de Colmenar-Goloso, con una longitud de 10,8S4 km. El comienzo de las obras tuvo lugar el 10 de diciembre de 1962, y el agua llegó a Madrid el 15 de junio de 1966. Su

  5. Diagnosis of Dentin Caries – Ultraviolet Fluorescence

    Directory of Open Access Journals (Sweden)

    Uzunov Ts.

    2014-12-01

    Full Text Available The technology advance in recent years determines the need of construction of modern appliances for early diagnosis of dental caries, which are categorized by great precision, non-invasiveness, easy usage and wide availability. Such non-invasive and accurate tool for diagnostics of caries is Caries Detector (LED, Bulgarian product by “Optica Laser”. The detector emits a specific wavelength of near ultraviolet light, which causes fluorescence to porphyrins - metabolic products of the life cycle of caries-inducing bacteria. The purpose of the study is piloting a new diagnostic tool for detection and monitoring of caries excavation based on fluorescence - LED UV caries detector of company “Optica laser”. Subjected to examination by caries indicator dye and UV caries detector were sixty permanent teeth with deep dentine caries. Two methods were used to assess the dentin caries - UV fluorescence detector of “Optica Laser” and staining with caries indicator - dye (Sable ™ Seek®. It was found that among all sixty teeth, the fields, closed by margins of carious process overlap. Fifty-four of tested teeth has shown bigger field of images with staining method and six - smaller in comparison to the fluorescent method. Ultraviolet fLuorescence caries detector of “Optica Laser” company is affordable and easy applicable method for controlled excavation of dentine caries. The detector can be used in daily dental practice equally with other methods. The unit has a number of advantages - non-invasiveness, lack of interaction with tooth structures, speed, reliability, efficiency, predictability and repeatability of results.

  6. Canals - CANALS_HISTORIC_STRUCTURES_IN: Historic Canal Structures in Indiana (Bernardin-Lochmueller & Associates, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Data depicts the locations of historic structures associated with the Wabash-Erie, Central, and Whitewater Canals constructed in Indiana in from 1830-1870. Canal...

  7. Analysis of ground vibrations produced by an 80 in3 water gun in the Chicago Sanitary and Ship Canal, Lemont, Illinois

    Science.gov (United States)

    Koebel, Carolyn Michelle

    Since its completion in 1910, the Chicago Sanitary and Ship Canal (CSSC) has become a pathway for invasive species (and potentially Asian carp) to reach the Great Lakes. Currently, an electric barrier is used to prevent Asian carp migration through the canal, but the need for a secondary method is necessary, especially when the electric barrier undergoes maintenance. The underwater Asian carp "cannon" (water gun) provides such a method. Analysis of the ground movement produced by an 80 in3 water gun in the CSSC was performed in order to establish any potential for damage to the either the canal or structures built along the canal. Ground movement was collected using 3-component geophones on both the land surface and in boreholes. The peak particle velocities (PPVs) were analyzed to determine if damage would be caused to structures located along the canal. Vector sum velocity ground movement along the canal wall was as high as 0.28 in/s (7.11 mm/s), which is much lower than the United States Bureau of Mines (USBM) ground vibration damage threshold of 0.75 in/s (19.1 mm/s), causing no potential for damage to structures along the canal wall. The dominant frequency of ground motion produced by the water gun is primarily above 40 Hz, so the wave energy should attenuate fairly quickly away from the canal wall, with little disturbance to structures further from the wall.

  8. Corinth Canal, Greece

    Science.gov (United States)

    2006-01-01

    The Isthmus of Corinth has played a very important role in the history of Greece. It is the only land bridge between the country's north (Attica) and south (Peloponnese). It is a 6 km wide tongue of land separating the Gulf of Corinth from the Saronic Sea. Populations, armies and commodities have got to move through it. In the 6th century BCE, the Greeks built the Diolkos, a 10 meter-wide stone roadway to pull ships across the Isthmus on wooden cylinders and wheeled vehicles. In 1882, a canal was started and completed 11 years later. It is 6343 meters long, 25 meters wide, and 8 meters deep. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. Size: 25.3 by 37.7 kilometers (15.7 by 23.4 miles) Location: 37.9 degrees North latitude, 23 degrees East longitude Orientation: North at top Image

  9. Fluidmechanics of semicircular canals revisited

    Science.gov (United States)

    Obrist, Dominik

    2008-05-01

    In this work we find the exact solution for the flow field in a semicircular canal which is the main sensor for angular motion in the human body. When the head is rotated the inertia of the fluid in the semicircular canal leads to a deflection of sensory hair cells which are part of a gelatinous structure called cupula. A modal expansion of the governing equation shows that the semicircular organ can be understood as a dynamic system governed by duct modes and a single cupular mode. We use this result to derive an explicit expression for the displacement of the cupula as a function of the angular motion of the head. This result shows in a mathematically and physically clean way that the semicircular canal is a transducer for angular velocity.

  10. Retention of Root Canal Posts

    DEFF Research Database (Denmark)

    Sahafi, A; Benetti, Ana Raquel; Flury, S;

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc......] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half...... received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement...

  11. Comparison of Resilon and Gutta-Percha Filling Materials on Root Canal Fracture Resistance Following Restoring with Quartz Fiber Posts

    OpenAIRE

    Mehrvarzfar, P.; Rezvani, Y.; Jalalian, E.

    2012-01-01

    Objective: Bacterial leakage and root fractures are the most important reasons of root canal treatment failure. Due to the lack of adhesion of gutta percha to the canal walls, Resilon has been introduced as a root-filling material able to bond to the root walls. Metal posts may predispose the tooth walls to oblique and vertical fracture which usually leads to tooth loss; whereas, fiber posts may reinforce the remaining tooth structure. The purpose of this study was to compare the effect of Re...

  12. Influence of flexion angle of files on the decentralization of oval canals during instrumentation.

    Science.gov (United States)

    Oliveira, Maria Antonieta Veloso Carvalho de; Alves, Letícia Duarte; Pereira, Analice Giovani; Raposo, Luís Henrique Araújo; Biffi, João Carlos Gabrielli

    2015-01-01

    The aim of this study was to evaluate the influence of the flexion angle of files on the decentralization of root canals during instrumentation. Fifteen lower incisors were instrumented with Protaper Universal files and radiographed in two directions (mesiodistal and buccolingual) before and after instrumentation with a #15 K-file in position for evaluating the flexion angle of files. The specimens were also scanned before and after instrumentation using micro-computed tomography to obtain the canal area and the distance from the center position of the file to the canal walls. Sections located 1.0 mm (end of the canal), 3.0 mm (apical third), 9.0 mm (middle third), and 15.0 mm (cervical third) from the apex were verified. After instrumentation, the flexion angles of files decreased by an average of 0.76º in the buccolingual direction and 1.92º in the mesiodistal direction (p cervical to the end of the root canal (p flexion angles of files influence the final shape of the root canal, resulting in file decentralization along the pathway of the canal.

  13. The cartilage bone junction and its implications for deep canal hearing instrument fittings

    DEFF Research Database (Denmark)

    Nielsen, Claus; Darkner, Sune

    2011-01-01

    The popularity of hearing instruments deeply placed in the ear canal has been driven by their superior cosmetic characteristics. However, people fitted with these hearing instruments often complain about the sound quality of their voice, which is typically described as being hollow, echoing......, or like talking in a barrel. This problem is caused by the occlusion effect. The effect is primarily due to vibrations of the walls in the soft part of the ear canal, which generate a sound pressure that is trapped in the cavity between the tip of the occluding hearing aid and the tympanic membrane....... If the hearing aid is fitted with a seal in the bony portion of the ear canal, preventing vibration in the soft part of the ear canal from reaching the tympanic membrane, then occlusion problems can be solved or at least reduced in most cases....

  14. INSTRUMENTATION OF CURVED CANALS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Senthil Kumar

    2013-02-01

    Full Text Available INTRODUCTION: Nature seldom draws a straight line. Nowhere is thi s more apparent than in the anatomy of teeth roots and root canal systems o f human teeth. Even teeth with straight roots can harbor severely curved canals. Canal shapi ng is a critical aspect of endodontic treatment because it influences the outcome of the subsequent phases of canal irrigation and filling and the success of the treatment itself. In fact, curved canals are the most common endodontic complexity 1 . The need for some manner of root canal preparation pri or to root canal filling has long been recognized as an essential step in endodontic t reatment. Concepts concerning the role and purpose of this canal preparation, however, have differ ed remarkably at different times in the development of endodontics and in the hands of diffe rent practitioners 2

  15. Spectroscopic and morphologic characterization of the dentin/adhesive interface

    Science.gov (United States)

    Lemor, R. M.; Kruger, Michael B.; Wieliczka, David M.; Swafford, Jim R.; Spencer, Paulette

    1999-01-01

    The potential environmental risks associated with mercury release have forced many European countries to ban the use of dental amalgam. Alternative materials such as composite resins do not provide the clinical function for the length of time characteristically associated with dental amalgam. The weak link in the composite restoration is the dentin/adhesive bond. The purpose of this study was to correlate morphologic characterization of the dentin/adhesive bond with chemical analyses using micro- Fourier transform infrared and micro-Raman spectroscopy. A commercial dental adhesive was placed on dentin substrates cut from extracted, unerupted human third molars. Sections of the dentin/adhesive interface were investigated using infrared radiation produced at the Aladdin synchrotron source; visible radiation from a Kr+ laser was used for the micro-Raman spectroscopy. Sections of the dentin/adhesive interface, differentially stained to identify protein, mineral, and adhesive, were examined using light microscopy. Due to its limited spatial resolution and the unknown sample thickness the infrared results cannot be used quantitatively in determining the extent of diffusion. The results from the micro-Raman spectroscopy and light microscopy indicate exposed protein at the dentin/adhesive interface. Using a laser that reduces background fluorescence, the micro-Raman spectroscopy provides quantitative chemical and morphologic information on the dentin/adhesive interface. The staining procedure is sensitive to sites of pure protein and thus, complements the Raman results.

  16. Characterization of Dentine to Assess Bond Strength of Dental Composites

    Directory of Open Access Journals (Sweden)

    Saad Liaqat

    2015-04-01

    Full Text Available This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.

  17. Carbodiimide inactivation of MMPs and effect on dentin bonding.

    Science.gov (United States)

    Mazzoni, A; Apolonio, F M; Saboia, V P A; Santi, S; Angeloni, V; Checchi, V; Curci, R; Di Lenarda, R; Tay, F R; Pashley, D H; Breschi, L

    2014-03-01

    The use of protein cross-linking agents during bonding procedures has been recently proposed to improve bond durability. This study aimed to use zymography and in situ zymography techniques to evaluate the ability of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linker to inhibit matrix metalloproteinase (MMP) activity. The hypotheses tested were that: (1) bonding procedures increase dentin gelatinolytic activity and (2) EDC pre-treatment prevents this enzymatic activity. The zymographic assay was performed on protein extracts obtained from dentin powder treated with Optibond FL or Scotchbond 1XT with or without 0.3M EDC pre-treatment. For in situ zymography, adhesive/dentin interfaces were created with the same adhesives applied to acid-etched dentin slabs pre-treated or not with EDC conditioner. Zymograms revealed increased expression of dentin endogenous MMP-2 and -9 after adhesive application, while the use of EDC as a primer inactivated dentin gelatinases. Results of in situ zymograpy showed that hybrid layers of tested adhesives exhibited intense collagenolytic activity, while almost no fluorescence signal was detected when specimens were pre-treated with EDC. The correlative analysis used in this study demonstrated that EDC could contribute to inactivate endogenous dentin MMPs within the hybrid layer created by etch-and-rinse adhesives.

  18. 33 CFR 117.444 - Falgout Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Falgout Canal. 117.444 Section 117.444 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.444 Falgout Canal. The draw of the LA 315 bridge across Falgout Canal, mile 3.1,...

  19. Developmental spinal canal stenosis and somatotype.

    OpenAIRE

    Nightingale, S.

    1989-01-01

    The hypothesis that somatotype and cervical spine developmental canal stenosis may be associated has been investigated by anthropometry and measurement of lateral projection cervical spine radiographs. A significant association of canal size with somatotype has been found such that those with developmentally narrow canals are more likely to have relatively shorter long-bones, particularly in the upper arm, and longer trunks.

  20. 三种器械预备弯曲根管成形效果的比较%Shaping efficacy of three instruments in curved root canal preparation

    Institute of Scientific and Technical Information of China (English)

    庄沛林; 叶剑涛; 黄卓珊; 余艳崧; 伍虹

    2014-01-01

    Objective To evaluate the shaping efficacy of K files , Safesiders files and HERO Shaper files in curved root canal preparation of human teeth in vitro. Methods Sixty mandibular premolars with curved root canal were divided into three groups randomly, and prepared by K files, Safesiders files and HERO Shaper files respectively. Compound meglumine diatrizoate was injected into root canals and X-ray graphs of teeth were taken before and after instrumentation . The amount of dentin removed from inner and outer walls , centering ability and degree of straightening of root canal after preparation were analyzed. Results Safesiders files and HERO Shaper files removed less dentin from inner and outer walls than K files at all measuring points (P 0.05). The use of K files resulted in more straightening of root canal after instrumentation compared to other instruments (P 0.05). Conclusions K files, Safesiders files and HERO Shaper files caused transportation when preparing curved root canals . Safesiders files and HERO Shaper files showed less transportation and better shaping efficacy .%目的:评价K锉、Safesiders锉和HERO Shaper锉预备离体牙弯曲根管的成形效果。方法60颗根管弯曲的离体下颌前磨牙随机分为3组,分别用K锉、Safesiders锉和HERO Shaper锉进行根管预备,根管预备前后分别往根管内注入复方泛影葡胺并拍摄X线片,分析根管预备后根管弯曲内外侧壁牙本质去除量、中心定位能力及根管直化角度。结果在根管弯曲内外侧壁所有观测点,Safesiders锉组和HERO Shaper锉组牙本质去除量均少于K锉组(P均>0.05)。 Safesiders锉组牙本质去除量多于HERO Shaper锉组,但仅在根管弯曲内侧壁3和4 mm观测点处差异有统计学意义(3 mm:t=3.72,P<0.05;4 mm:t=7.62,P<0.05)。在距根尖孔5 mm以下观测点,Safesiders锉组和HERO Shaper锉组中心定位能力优于K锉组(1 mm:F=7.45,P<0.05;2 mm

  1. Role of dentin MMPs in caries progression and bond stability.

    Science.gov (United States)

    Mazzoni, A; Tjäderhane, L; Checchi, V; Di Lenarda, R; Salo, T; Tay, F R; Pashley, D H; Breschi, L

    2015-02-01

    Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This

  2. Role of Dentin MMPs in Caries Progression and Bond Stability

    Science.gov (United States)

    Mazzoni, A.; Tjäderhane, L.; Checchi, V.; Di Lenarda, R.; Salo, T.; Tay, F.R.; Pashley, D.H.

    2015-01-01

    Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This

  3. Nanolayering of phosphoric acid ester monomer on enamel and dentin.

    Science.gov (United States)

    Yoshihara, Kumiko; Yoshida, Yasuhiro; Hayakawa, Satoshi; Nagaoka, Noriyuki; Irie, Masao; Ogawa, Tatsuyuki; Van Landuyt, Kirsten L; Osaka, Akiyoshi; Suzuki, Kazuomi; Minagi, Shogo; Van Meerbeek, Bart

    2011-08-01

    Following the "adhesion-decalcification" concept, specific functional monomers possess the capacity to primary chemically interact with hydroxyapatite (HAp). Such ionic bonding with synthetic HAp has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), manifest as self-assembled "nanolayering". In continuation of that basic research this study aimed to explore whether nanolayering also occurs on enamel and dentin when a 10-MDP primer is applied following a common clinical application protocol. Therefore, the interaction of an experimental 10-MDP primer and a control, commercially available, 10-MDP-based primer (Clearfil SE Bond primer (C-SE), Kuraray) with enamel and dentin was characterized by X-ray diffraction (XRD), complemented with transmission electron microscopy interfacial ultrastructural data upon their reaction with enamel and dentin. In addition, XRD was used to study the effect of the concentration of 10-MDP on nanolayering on dentin. Finally, the stability of the nanolayers was determined by measuring the bond strength to enamel and dentin when a photoinitiator was added to the experimental primer or when interfacial polymerization depended solely on the photoinitiator supplied with the subsequently applied adhesive resin. XRD confirmed nanolayering on enamel and dentin, which was significantly greater on dentin than on enamel, and also when the surface was actively rubbed with the primer. Nanolayering was also proportional to the concentration of 10-MDP in the primer. Finally, the experimental primer needed the photoinitiator to obtain a tensile bond strength to dentin comparable with that of the control C-SE primer (which also contains a photoinitiator), but not when bonded to enamel. It is concluded that self-assembled nanolayering occurs on enamel and dentin, even when following a clinically used application protocol. The lower bonding effectiveness of mild self-etch adhesives to enamel should be ascribed in part to a lower

  4. Endodontic Treatment of a Mandibular Second Premolar with Type IV Wiene’s Root Canal: A Case Report

    Directory of Open Access Journals (Sweden)

    Noushad Matavan Chalil

    2014-01-01

    Full Text Available This case report describes an endodontic treatment of a mandibular second premolar with type IV root canal. A 26-year-old male patient reported pain in right mandibular second premolar. Clinical examination showed a large carious lesion with pulp exposure. Radiographs showed minimal periapical changes and slight widening of periodontal ligament space. Mandibular second premolars usually have one canal. The mandibular second premolar may present large number of anatomic variations. The clinician should be aware of the configuration of the pulp system. This case presents the diagnosis and clinical management of a mandibular second premolar with two distinct canals in the apical third of root (Type IV Wiene’s canal configuration, drawing particular attention to tactile examination of all the canal walls and obturating it with calamus 3D obturation system.

  5. Canal Water Scarcity Hits Farmers

    Institute of Scientific and Technical Information of China (English)

    张忠潮

    2007-01-01

    Acute shortage of canal water for irrigation in this district has caused resentment among the farmers.The water is being released in the various channels for just one week in a month,which is not enough to meet the irrigation needs of the farmers who are preparing their fields for paddy

  6. The Dehiscent Facial Nerve Canal

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    Sertac Yetiser

    2012-01-01

    Full Text Available Accidental injury to the facial nerve where the bony canal defects are present may result with facial nerve dysfunction during otological surgery. Therefore, it is critical to know the incidence and the type of facial nerve dehiscences in the presence of normal development of the facial canal. The aim of this study is to review the site and the type of such bony defects in 144 patients operated for facial paralysis, myringoplasty, stapedotomy, middle ear exploration for sudden hearing loss, and so forth, other than chronic suppurative otitis media with or without cholesteatoma, middle ear tumors, and anomaly. Correlation of intraoperative findings with preoperative computerized tomography was also analyzed in 35 patients. Conclusively, one out of every 10 surgical cases may have dehiscence of the facial canal which has to be always borne in mind during surgical manipulation of the middle ear. Computerized tomography has some limitations to evaluate the dehiscent facial canal due to high false negative and positive rates.

  7. [Endodontic microbiology: antimicrobial canal medications].

    Science.gov (United States)

    Seltzer, S; Farber, P A

    1989-06-01

    Medicaments used for reducing or eliminating microorganisms from infected root canals include: irrigating solutions, such as sodium hypochlorite, urea peroxide and hydrogen peroxide, chloramine, iodine-potassium-iodide solution, and chlorhexidine solution. In addition, various intracanal drugs, such as calcium hydroxide and antibiotics, are in use. The characteristics of these drugs are discussed.

  8. Effect of relining on fiber post retention to root canal

    Directory of Open Access Journals (Sweden)

    André Luís Faria-e-Silva

    2009-12-01

    Full Text Available One of the clinically relevant problems dentists face when restoring endodontically treated teeth is the mismatch between fiber post and post space diameters, which results in an excessively thick resin cement layer. Fiber post relining appears as a solution for this problem. OBJECTIVES: The aim of this study was to evaluate the effect of fiber post relining with composite resin on push-out bond strength. MATERIAL AND METHODS: Twenty bovine incisors were selected to assess post retention. The crowns were removed below the cementoenamel junction and the root canals were treated endodontically and flared with diamond burs. The roots were allocated into two groups (n=10: G1: fiber posts without relining and G2: fiber posts relined with composite resin. The posts were cemented with a dual-cured resin cement and the specimens were sectioned transversally. Three 1.5-mm thick slabs were obtained per root and identified as cervical, medium and apical thirds. The push-out test was performed at a crosshead speed of 0.5 mm/min until post dislodgement occurred. The failure mode of fractured specimens was analyzed under scanning electron microscopy. Data were analyzed by split-plot ANOVA and post-hoc Tukey's test at a pre-set alpha of 0.05. RESULTS: Relined fiber posts presented higher retention values than non-relined post in all thirds. No statistically significant differences (p>0.05 were found among thirds for relined posts. All failures occurred at the interface between resin cement and root dentin. CONCLUSIONS: Relining with composite resin seems to be an effective method to improve the retention of fiber posts to flared root canals.

  9. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    NARCIS (Netherlands)

    Pisano, Dominic V.; Niesten, Marlien E. F.; Merchant, Saumil N.; Nakajima, Hideko Heidi

    2012-01-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal i

  10. Shear bond strength of two resin cements to human root dentin using three dentin bonding agents.

    Science.gov (United States)

    Gogos, C; Stavrianos, C; Kolokouris, I; Economides, N; Papadoyannis, I

    2007-01-01

    This study compared the bond strength of two resin cements to human root dentin when used with three bonding agents. The materials used were Rely X ARC and Perma Cem, two one-bottle bonding agents (Single Bond, Bond-1) and one self-etching bonding agent (Clearfil SE Bond). The dentin was obtained from single rooted human teeth, and the specimens were treated with either 15% EDTA or 37% phosphoric acid to remove the smear layer, except in groups where the self-etching bonding agent was used. The resin cements were placed on dentin surfaces with the use of bonding agents. Shear bond strength (SBS) was tested using a single plane shear test assembly. The dentin specimens were divided into 10 groups. Eight groups were pre-treated with EDTA or phosphoric acid to remove the smear layer, followed by a bonding agent (Bond-1 or Single Bond) and resin cement (Rely X or Perma Cem). In the two remaining groups, the smear layer was left intact, and the two resins cements were used in combination with the self-etching bonding agent (Clearfil SE Bond). No statistically significant differences were observed among the eight groups treated with one-bottle bonding agents. The mean bond strengths of the two groups treated with the self-etching bonding agent did not differ significantly from each other but were both significantly greater than the bond strengths of all the other groups. The results of this study also showed that EDTA can be used as an alternative to phosphoric acid in bonding procedures for resin cements. However, the bond strengths of resin cements, in combination with a self-etching bonding agent, were significantly greater than those of the same cements when used with one-bottle bonding agents.

  11. Mandibular Second Premolar with Four Canals

    Directory of Open Access Journals (Sweden)

    Javad Ghiasi

    2015-09-01

    Full Text Available A mandibular second premolar with four canals is an interesting example of anatomic variations. This report describes a case of a mandibular second premolar with three roots and four canals (one mesiobuccal, two distobuccal and one lingual. The canals were prepared using K-files and irrigated with NaOCl (5.25% and normal saline as the final irrigant. The canals were filled laterally with gutta percha and AH26 sealer (De Trey, Dentsply, Switzerland. This case shows a rare anatomic configuration and points out the importance of looking for additional canals.

  12. Effects of different intra canal medicaments on the push out bond strength of endodontic sealers

    Science.gov (United States)

    Shakouie, Sahar; Shahi, Shahriar; Samiei, Mohammad; Milani, Amin-Salem; Reyhani, Mohammad-Frough; Paksefat, Sara; Eskandarinekhad, Mahsa

    2017-01-01

    Background One of the essential properties of the root canal sealers is the adhesion to root canal dentin and their higher bond strength decreases the microleakage. The aim of the present study was to compare the effect of Different Intracanal medicaments on the push out bond strength of AH26 and MTA Fillapex sealers. Material and Methods A total of 104 one-rooted extracted human teeth were divided into 4 (n=26) experimental groups. After the cleaning and shaping, the root canals were filled with Ca(OH)2, triantibiotic paste (TAP), Metapex or 2% chlorhexidine gel for two weeks. Then, intracanal medicaments were rinsed away and the samples in the sub-groups were obturated with gutta-percha and AH26 or MTA Fillapex sealers. After two weeks incubation, 2-mm-thick middle section of each root was then subjected to push-out testing. Data were analyzed with two-way ANOVA and LSD test. Results With all the intracanal medicaments, the overall mean of bond strength values were significantly higher with AH26 compared to MTA Fillapex (pendodontic sealers was not negative. Key words:AH26, medicament, MTA Fillapex, push-out bond. PMID:28298989

  13. Synthesis and Characterization of New Chlorhexidine-Containing Nanoparticles for Root Canal Disinfection

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    Ridwan Haseeb

    2016-06-01

    Full Text Available Root canal system disinfection is limited due to anatomical complexities. Better delivery systems of antimicrobial agents are needed to ensure efficient bacteria eradication. The purpose of this study was to design chlorhexidine-containing nanoparticles that could steadily release the drug. The drug chlorhexidine was encapsulated in poly(ethylene glycol–block–poly(l-lactide (PEG–b–PLA to synthesize bilayer nanoparticles. The encapsulation efficiency was determined through thermogravimetric analysis (TGA, and particle characterization was performed through microscopy studies of particle morphology and size. Their antimicrobial effect was assessed over the endodontic pathogen Enterococcus faecalis. The nanoparticles ranged in size from 300–500 nm, which is considered small enough for penetration inside small dentin tubules. The nanoparticles were dispersed in a hydrogel matrix carrier system composed of 1% hydroxyethyl cellulose, and this hydrogel system was observed to have enhanced bacterial inhibition over longer periods of time. Chlorhexidine-containing nanoparticles demonstrate potential as a drug carrier for root canal procedures. Their size and rate of release may allow for sustained inhibition of bacteria in the root canal system.

  14. Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

    Directory of Open Access Journals (Sweden)

    Robert Dalby

    2012-01-01

    Full Text Available Objectives. To examine the effect of immediate dentin sealing (IDS, with dentin bonding agents (DBAs applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go! that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic luted to the sealed dentin surface using RXU. Group E (control had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent using RXU following the manufacturer’s instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (0.05 in the SBS between the test groups (A–D or the control (group E. Conclusion. IDS using the dentin bonding agents tested does not statistically (>0.05 affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control.

  15. Effect of depth and tubule direction on ultimate tensile strength of human coronal dentin.

    Science.gov (United States)

    Inoue, Satoshi; Pereira, Patricia N R; Kawamoto, Chiharu; Nakajima, Masatoshi; Koshiro, Kenichi; Tagami, Junji; Carvalho, Ricardo M; Pashley, David H; Sano, Hidehiko

    2003-03-01

    The purpose of this study was to evaluate the effect of dentin depth and tubule direction on the ultimate tensile strength (UTS) of human dentin. Dentin slabs of 0.5-mm thickness were trimmed either from the mesial and distal (for specimens with the tubules parallel to the tensile force; parallel group) or from the occlusal and pulpal surfaces (perpendicular group) to reduce the cross-sectional area of the superficial, middle, and deep regions to 0.25 mm2, and subjected to microtensile testing. From SEM photomicrographs of the fractured specimens of the parallel group, the tubule density was investigated. For both parallel and perpendicular groups, superficial dentin showed a significantly higher UTS than deep dentin. The tubule density of superficial dentin was significantly lower than that of middle and deep dentin. When performing the microtensile bond test to deep dentin, it is possible that cohesive failure of dentin can occur at relatively low tensile stresses.

  16. Morphology of the dentin structure of sloths Bradypus tridactylus: a light and scanning electron microscopy investigation.

    Science.gov (United States)

    Santana, L N S; Barbosa, L V M; Teixeira, F B; Costa, A M P; Fernandes, L M P; Lima, R R

    2013-12-01

    The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species.

  17. Effects of distance from the pulp and thickness on the hydraulic conductance of human radicular dentin.

    Science.gov (United States)

    Fogel, H M; Marshall, F J; Pashley, D H

    1988-11-01

    The purposes of this study were: (1) to measure the effect of distance from the pulp on the hydraulic conductance of human radicular dentin; (2) to determine the influence of dentin thickness on the rates of fluid flow; and (3) to attempt to correlate dentinal tubule densities and diameters with root dentin hydraulic conductance. Dentin slabs prepared from extracted, unerupted, human third molar teeth were placed in a split-chamber device to permit quantitation of fluid filtration rate (hydraulic conductance). In the SEM portion of the study, dentinal tubule numbers and diameters were recorded. The results indicated that radicular dentin hydraulic conductance decreased with distance from the pulp and with increasing dentin thickness. Tubule density and diameter correlated well with the measured hydraulic conductances. The relatively low hydraulic conductance of outer root dentin makes it a significant barrier to fluid movement across root structure.

  18. Role of Alcohol on the Fracture Resistance of Dentin

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, Ravi K.; Kinney, John H.; Tomsia, Antoni P.; Ritchie,Robert O.

    2006-05-01

    Healthy dentin, the mineralized tissue that makes up the bulk of the tooth, is naturally hydrated in vivo; however, it is known that various chemical reagents including acetone and ethanol can induce dehydration and thereby affect its properties. Here, we seek to investigate this in light of the effect alcohol can have on the mechanical properties of dentin, specifically by measuring the stiffness, strength and toughness of dentin in simulated body fluid and scotch whisky. Results indicate that chemical dehydration induced by the whisky has a significant beneficial effect on the elastic modulus, strength and fracture toughness of dentin. Although this makes teeth more resistant to fracture, the change in properties is fully reversible upon rehydration. This effect is considered to be associated with increased cross-linking of the collagen molecules from intermolecular hydrogen-bonding where water is replaced with weaker hydrogen-bond forming solvents such as alcohol.

  19. Dentinal fluid dynamics in human teeth, in vivo.

    Science.gov (United States)

    Ciucchi, B; Bouillaguet, S; Holz, J; Pashley, D

    1995-04-01

    Cavities were prepared in human premolars scheduled for extraction for orthodontic reasons. The smear layer was removed from the dentin surface by acid etching, and the cavity was sealed using a hollow chamber. The chamber was filled with sterile saline solution and connected via tubing to a hydraulic circuit featuring an adjustable pressure reservoir and a device that measures fluid movement across dentin. In the absence of any exogenous pressure, all cavities exhibited an outward fluid flow rate of 0.36 microliters min-1 cm-2. As exogenous pressure was applied to the cavity, the outward flow slowed. The exogenous pressure that stopped outward fluid flow was taken to be equal to normal pulpal tissue pressure. The mean value was 14.1 cm H2O in five teeth. This simple method permits measurement of dentinal fluid flux, the hydraulic conductance of dentin, and estimates pulpal tissue pressure.

  20. Dentin permeability: effects of temperature on hydraulic conductance.

    Science.gov (United States)

    Pashley, D H; Thompson, S M; Stewart, F P

    1983-09-01

    The rates of fluid movement across dentin discs, in vitro, were measured at 10, 20, 30, 40, and 50 degrees C in unetched and acid-etched dentin. Increasing the temperature 40 degrees (i.e., from 10 to 50 degrees C) resulted in a 1.8-fold increase in fluid flow in unetched dentin, which was of a magnitude similar to the decrease in viscosity that occurred over the same temperature range. In acid-etched dentin, the 40 degrees C temperature change produced more than a four-fold increase in fluid conductance, more than double that which could be accounted for by changes in viscosity. Analysis of the data suggests that this additional increment in hydraulic conductance is due to thermal expansion-induced increases in tubular diameter.

  1. 75 FR 39632 - Regulated Navigation Area; Gulf Intracoastal Waterway, Inner Harbor Navigation Canal, Harvey...

    Science.gov (United States)

    2010-07-12

    ..., Inner Harbor Navigation Canal, Harvey Canal, Algiers Canal, New Orleans, LA; Correction ACTION: Interim... Navigation Canal, Harvey Canal, Algiers Canal, New Orleans, LA into the Code of Federal Regulations....

  2. Morphological effects of MMPs inhibitors on the dentin bonding.

    Science.gov (United States)

    Li, He; Li, Tianbo; Li, Xiuying; Zhang, Zhimin; Li, Penglian; Li, Zhenling

    2015-01-01

    Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength. However, morphologic characteristics of the collagen network after etching and of the post-adhesive dentin hybrid layers (DHL) after MMP inhibitors pretreatment have not been evaluated. Thus, we investigated demineralized dentin pretreated with chlorhexidine (CHX) and minocycline (MI) in an etch- and -rinse adhesive system with field emission scanning electron microscopy (FESEM) and immuno-gold labeling markers to observe the collagen network and DHL. FESEM revealed after CHX and MI, a demineralized dentin surface and improved collagen network formation, reduced collagen degradation, and distinct gold-labeling signals. Applying adhesive after either MMP inhibitor created a better dentin interface as evidenced by immuno-gold staining, better adhesive penetration, and higher DHL quality. With microtensile bond strength tests (µTBS) we estimated bonding strength using µTBS data. Immediate µTBS was enhanced with MMP inhibitor application to the bonding surface, and the CHX group was significantly different than non-treated etched surfaces, but no significant change was detected in the MI group. Surface micromorphology of the fractured dentin resin restoration showed that the CHX group had a better resin and dentin tube combination. Both MMP inhibitors created uniform resin coverage. Thus, morphologic results and µTBS data suggest that CHX and MI can inhibit MMP activity, improve immediate bonding strength, and enhance dentin bonding stability with an etch- and -rinse adhesive system.

  3. Bonding stability of adhesive systems to eroded dentin

    Directory of Open Access Journals (Sweden)

    Janaina Barros CRUZ

    2015-01-01

    Full Text Available This in vitro study evaluated the immediate and 6 months microshear bond strength (µSBS of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days. Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond, two-step self-etch system (Clearfil SE Bond, or one-step self-etch adhesive (Adper Easy One. Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250. Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37°C. Failure mode was evaluated using a stereomicroscope (400×. Data were analyzed by three-way repeated measures analysis of variance and Tukey’s post hoc tests (α = 0.05. After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

  4. Bonding stability of adhesive systems to eroded dentin.

    Science.gov (United States)

    Cruz, Janaina Barros; Bonini, Gabriela; Lenzi, Tathiane Larissa; Imparato, José Carlos Pettorossi; Raggio, Daniela Prócida

    2015-01-01

    This in vitro study evaluated the immediate and 6 months microshear bond strength (µSBS) of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva) and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days). Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond), two-step self-etch system (Clearfil SE Bond), or one-step self-etch adhesive (Adper Easy One). Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250). Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37 °C. Failure mode was evaluated using a stereomicroscope (400 ×). Data were analyzed by three-way repeated measures analysis of variance and Tukey's post hoc tests (α = 0.05). After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

  5. Regional variability in the permeability of human dentine.

    Science.gov (United States)

    Pashley, D H; Andringa, H J; Derkson, G D; Derkson, M E; Kalathoor, S R

    1987-01-01

    This was measured qualitatively by using dyes and quantitatively by hydraulic conductance in dentine discs and crown segments in vitro. Both types of preparation demonstrated large regional differences in permeability, with the highest values at the periphery and the lowest in the centre of the disc or crown. As dentine permeability may vary 3-10-fold across a few millimetres, investigators should use as large a surface area as possible to compensate for these regional differences.

  6. Strain Distribution in Root Surface Dentin of Maxillary Central Incisors during Lateral Compaction.

    Directory of Open Access Journals (Sweden)

    Raphael Pilo

    Full Text Available To precisely quantify the circumferential strains created along the radicular dentin of maxillary incisors during a simulated clinical procedure of lateral compaction.Six miniature strain gauges were bonded on the roots of fourteen recently extracted maxillary central incisors that were subjected to root canal instrumentation. The strain gauges were bonded at three levels (apical, middle, and coronal and four aspects (buccal, lingual, mesial, and distal of the roots. Each tooth was embedded in a PVC cylinder containing polyvinyl-siloxane impression material. Root filling was then performed by simulating the clinical procedure of lateral compaction using nickel-titanium finger spreaders. The force applied to the spreader and the strains developing in the surface root dentin were continuously recorded at a frequency of 10 Hz.The highest strains that developed during lateral compaction were in the mesial and distal aspects at the apical level of the root. The magnitudes of the maximal mesial/distal strains at the apical as well as the mid-root levels were approximately 2.5-3 times higher than those at the buccal/lingual aspects (p = 0.041. The strains decreased significantly (p<0.04 from the apical through the mid-root levels to the coronal level, yielding gradients of 2.5- and 6-fold, respectively. The mesial and distal strains were consistently tensile and did not differ significantly; however, the buccal strains were generally 35-65% higher than the lingual strains (p = 0.078. Lateral compaction resulted in the gradual build-up of residual strains, resulting in generation of a 'stair-step' curve. These strains declined gradually and almost completely disappeared after 1000 sec.With proper mounting of several miniature strain gauges at various levels and aspects of the root, significant circumferential strains can be monitored under clinically relevant compaction forces. The residual strains at the end of lateral compaction are not stored in the

  7. Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

    Directory of Open Access Journals (Sweden)

    Jefferson Ricardo PEREIRA

    2014-10-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs and resinmodified glass ionomer cements (RMGICs. MATERIAL AND METHODS: Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. RESULTS: Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05. The post level did not influence the bond strength of fiber posts to root dentin (P=0.148. The major cause of failure was cohesive at the cement for all GICs and RMGICs. CONCLUSIONS: Except for Ionoseal, all cements provided satisfactory bond strength values.

  8. Resin-infiltrated-dentine--a FE-ESEM microscopy investigation.

    Science.gov (United States)

    Eick, J D; Dusevich, V M; de Wet, F A; van der Vyver, P J

    2004-09-01

    The formation of a hybrid layer is essential for bonding of dental composites to dentine. The objective of this study was to examine the effects of various etchants/conditioners and dentine bonding systems on dentine surfaces utilising a Field Emission Environmental SEM (FE-ESEM). Twenty one, freshly extracted human molar teeth were utilised. Dentine without resin application was initially observed both wet and dried in the following conditions: (1) fractured surface, (2) smear layer, and (3) smear layer removed with 37% phosphoric acid. Resin infiltration into dentine was then studied after applying Scotchbond 1, Optibond Solo, Prime & Bond NT, or Prompt L-Pop systems. Scotchbond 1, Optibond Solo, and Prime & Bond NT resins penetrated the dentine tubules and created hybrid layers; although, in some cases Prime & Bond NT only created a partially filled hybrid layer. No polymerised resin or hybrid layer was observed for Prompt L-Pop. The FE-ESEM permitted observation of specimens at near in-vivo wet conditions.

  9. Human pulp response to acid pretreatment of dentin and to composite restoration.

    Science.gov (United States)

    Stanley, H R; Going, R E; Chauncey, H H

    1975-10-01

    The newer composites, although free of methacrylic acid and of a neutral pH, were still found to be toxic to the pulp. The intensity of response was increased after acid pretreatment procedures; this indicates an increase in dentin permeability. When the remaining dentin thickness was 1.0 mm or less, regardless of whether the dentin was primary dentin or primary and reparative dentin, the percentage of teeth with abscess formations increased. Use of calcium hydroxide bases or liners to coat the dentin before acid pretreatment of enamel is therefore highly recommended.

  10. Effect of multi-step and single- step dentin bonding agents on the bond strength of composite to dentin

    Directory of Open Access Journals (Sweden)

    Maleknejad F

    2002-07-01

    Full Text Available Composite resin restorative materials, that nowadays are used as tooth-colour materials, have both benefits and weaknesses. One of these weaknesses is the contraction resulted from resin polymerization which influences on the composite dentin bond strength and it has been tried to be eliminated by different bonding systems. The aim of this in-vitro study was to compare the dentin bond strength of two dentine adhesive systems: multi-step Scoth Bond Multipurpose (SBMP and single- step Excite, by two composites of Ideal Makoo and Tetric. One hundred sixty (160 sound human molars were selected. At first they were debrided and mounted with acrylic resin in molds. The enamel of the buccal surface was eliminated by diamond burs. To provide a flat dentin surface, it was removed about lmm. Then, based on the type of dentin adhesive, they were divided into two groups of 30 teeth and were applied on the exposed dentine surface according to the manufacturer's instructions. Then, each group was divided into two subgroups of 15, based on the type of composite resin. Cylinders of the desired composite resin, attached to the dentin surface, were used for 80 seconds. The samples were stored in 100% humidity (37°c for 24 hours. The bond strengths was measured by a cross head blade with the speed of 2mm/min. Variance analysis and Duncan test, with 95% confidence level, showed that statistically, two factors of adhesive and composite, interact on each other, in bond strength. There was no significant difference in bond strength, between two composites with similar adhesives, however, comparing two different adhesives with the same composite, showed that the bond strength of Tetric with Excite (28.39 was more than that of SBMP (17.98 Mpa. Finally, it was recognized that among four experimental groups, there was only a significant difference in bond strengths, between Tetric-Excite with Tetric- SBMP. This study shows that dentin bond strength is influenced by

  11. Effect of ultrasonic streaming on intra-dentinal disinfection and penetration of calcium hydroxide paste in endodontic treatment

    Directory of Open Access Journals (Sweden)

    Marcela Paola Castro ARIAS

    Full Text Available ABSTRACT Objective The antimicrobial effect of ultrasonic agitation of calcium hydroxide (CH pastes in infected bovine dentin and their penetrability were evaluated using confocal laser scanning microscopy (CLSM and microbiological culture. Material and Methods Fifty-two bovine teeth were infected with Enterococcus faecalis using a new contamination protocol; then they received CH paste and were divided into groups with or without ultrasound. Ultrasonic agitation was conducted for 1 min with a plain point insert. After 15 d, the CLSM analyzed the viable and dead bacteria with Live and Dead assay. The dentinal wall debris was collected by burs, and the colony forming units (CFU/mL were counted. The penetrability of the paste inside dentinal tubules was tested using the B-rodamine dye. Results The calcium hydroxide paste showed better results with the use of ultrasonic agitation (p<0.05. Conclusion The ultrasonic agitation of CH paste increased its antimicrobial action and was responsible for intradentinal penetration with the fulfilment of the tubules.

  12. Effect of ultrasonic streaming on intra-dentinal disinfection and penetration of calcium hydroxide paste in endodontic treatment

    Science.gov (United States)

    ARIAS, Marcela Paola Castro; MALIZA, Amanda Garcia Alves; MIDENA, Raquel Zanin; GRAEFF, Márcia Sirlene Zardin; DUARTE, Marco Antonio Húngaro; de ANDRADE, Flaviana Bombarda

    2016-01-01

    ABSTRACT Objective The antimicrobial effect of ultrasonic agitation of calcium hydroxide (CH) pastes in infected bovine dentin and their penetrability were evaluated using confocal laser scanning microscopy (CLSM) and microbiological culture. Material and Methods Fifty-two bovine teeth were infected with Enterococcus faecalis using a new contamination protocol; then they received CH paste and were divided into groups with or without ultrasound. Ultrasonic agitation was conducted for 1 min with a plain point insert. After 15 d, the CLSM analyzed the viable and dead bacteria with Live and Dead assay. The dentinal wall debris was collected by burs, and the colony forming units (CFU/mL) were counted. The penetrability of the paste inside dentinal tubules was tested using the B-rodamine dye. Results The calcium hydroxide paste showed better results with the use of ultrasonic agitation (p<0.05). Conclusion The ultrasonic agitation of CH paste increased its antimicrobial action and was responsible for intradentinal penetration with the fulfilment of the tubules. PMID:28076462

  13. Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

    Directory of Open Access Journals (Sweden)

    Rebeca Di Nicoló

    2007-10-01

    Full Text Available The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS of a resin modified glass ionomer cement (RM-GIC to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12. In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37ºC for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5% and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

  14. Antimicrobial efficacy of different root canal sealers by using real-time polymerase chain reaction: An ex vivo study

    Directory of Open Access Journals (Sweden)

    R Gnana Seelan

    2015-01-01

    Full Text Available Background: Root canal sealers help to minimize leakage, provides antimicrobial activity to reduce the possibility of residual bacteria, and to resolve periapical lesion. Aim: To compare five different root canal sealers against Enterococcus faecalis in an infected root canal model by using real-time polymerase chain reaction (RT-PCR. Settings and Design: Sixty human mandibular premolars were sectioned to standardize a uniform length of 14 mm. Fifty microliters of the inoculum containing E. faecalis were transferred into each microcentrifuge tube (n = 60. The samples were divided into six groups Tubli-Seal, Apexit Plus, Fillapex, AH Plus, RoekoSeal, and Positive control, respectively. Materials and Methods: Five groups after the incubation with the microorganism E. faecalis were coated with different root canal sealers and obturated using F3 ProTaper Gutta-percha point. The dentinal shavings were collected and analyzed for RT-PCR. Statistical Analysis: The mean difference between six groups was calculated using analysis of variance and post-hoc test. Results: The highest antibacterial activity was achieved with Tubli-Seal (1938.13 DNA in pictogram [pg] and least by RoekoSeal (3034.54 DNA in pg. Conclusion: The maximum antimicrobial activity was achieved AH Plus and Tubli-Seal. RT-PCR can be used as a valuable and accurate tool for testing antimicrobial activity.

  15. Temperature changes across CO2-lased dentin during multiple exposures

    Science.gov (United States)

    Zakariasen, Kenneth L.; Barron, Joseph R.; Boran, Thomas L.

    1990-06-01

    The literature increasingly indicates that lasers will have a multitude of applications for dental hard tissue procedures, e.g. preventive therapy, caries removal, laser etching and endodontic therapy. However, it is critical that such laser therapies avoid the production of heat levels which will be damaging to the surrounding vital tissues, such as the dental pulp and periodontal tissues. Our preliminary research on temperature changes across C02 lased dentin indicated that for single preventive therapeutic exposures (1.2 W., 0. 1 sec., 1.0 mm focal spot) the mean temperature rise across 350 j.tm of dentin was 0.57 0C while across 1000 .tm of dentin the mean rise was only 0.18 °C. Further research utilizing multiple preventive therapeutic exposures (1.2 W., 0. 1 sec., 1.0 mm focal spot, 3 x 1.0 sec. intervals) showed mean temperature elevations of 1.56 0C across 350 m of dentin and 0.66 O across 1000 xm of dentin. While these temperature elevations, which would be associated with preventive therapy, are very low and would be biologically acceptable, it must be noted that exposures of higher intensities are required to fuse enamel and porcelain, or remove decay. This current research investigates temperature elevations which occuT during C02 lasing utilizing the following exposure parameters: 8.0 W., 1.0 mm focal spot, 0.1 sec. exposures, 2 or 4 exposures per site pulsed 1.0 sec. apart. Three dentin thicknesses were utilized, i.e. 1000 jim, 1500 p.tm and 2000 .tm. Four sections of each thickness were utilized with four exposure sites per specimen (2 with 2 exposures, 2 with 4 exposures). All dentin sections were prepared from non-carious third molars using a hard tissue microtome. A thermistor was placed on the dentin surface opposite each lased site and temperature changes were recorded for approximately 50 sec. following lasing. Mean temperature elevations ranged from a high of 3.07 C for the 1000 xm section utilizing four exposures to a low of 0.37 0C for the

  16. Nested Canalizing Functions and Their Networks

    CERN Document Server

    Kadelka, Claus; Adeyeye, John O; Laubenbacher, Reinhard

    2014-01-01

    The concept of a nested canalizing Boolean function has been studied over the last decade in the context of understanding the regulatory logic of molecular interaction networks, such as gene regulatory networks. Such networks are predominantly governed by nested canalizing functions. Derrida values are frequently used to analyze the robustness of a Boolean network to perturbations. This paper introduces closed formulas for the calculation of Derrida values of networks governed by Boolean nested canalizing functions, which previously required extensive simulations. Recently, the concept of nested canalizing functions has been generalized to include multistate functions, and a recursive formula has been derived for their number, as a function of the number of variables. This paper contains a detailed analysis of the class of nested canalizing functions over an arbitrary finite field. In addition, the concept of nested canalization is further generalized and closed formulas for the number of such generalized fun...

  17. The effect of IDS (immediate dentin sealing) on dentin bond strength under various thermocycling periods

    Science.gov (United States)

    Leesungbok, Richard; Lee, Sang-Min; Park, Su-Jung; Lee, Suk-Won; Lee, Do Yun; Im, Byung-Jin

    2015-01-01

    PURPOSE The purpose of this study was to find out the effect of immediate dentin sealing (IDS) on bond strength of ceramic restoration under various thermocycling periods with DBA (dentin bonding agent system). MATERIALS AND METHODS Fifty freshly extracted human mandibular third molars were divided into 5 groups (1 control and 4 experimental groups) of 10 teeth. We removed enamel layer of sound teeth and embedded them which will proceed to be IDS, using All Bond II. A thermocycling was applied to experimental groups for 1, 2, 7, 14 days respectively and was not applied to control group. IPS Empress II for ceramic was acid-etched with ceramic etchant (9.5% HF) and silane was applied. Each ceramic disc was bonded to specimens with Duo-link, dual curable resin cement by means of light curing for 100 seconds. After the cementation procedures, shear bond strength measurement and SEM analysis of the fractured surface were done. The data were analyzed with a one-way ANOVA and Tukey multiple comparison test (α=.05). RESULTS There were no statistically significant differences between 4 experimental groups and control group, however the mean value started to decrease in group 7d, and group 14d showed the lowest mean bond strength in all groups. Also, group 7d and 14d showed distinct exposed dentin and collapsed hybrid layer was observed in SEM analysis. CONCLUSION In the present study, it can be concluded that ceramic restorations like a laminate veneer restoration should be bonded using resin cement within one week after IDS procedure. PMID:26140174

  18. Stability of guest molecules in urea canal complexes by canal polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Yoshii, Fumio; Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1995-03-01

    It was found that various organic materials are attracted into urea canal by hexanediol diacrylate (HDDA) and long chain compounds. This means that materials which does not form complex by itself are induced in canal by HDDA and long chain compounds. To include with stability perfumes, insecticides, attractants and repellents in urea canal, leaf alcohol was used as a model compound for guest molecules in the canal. The leaf alcohol from the canal released gradually over many days and the release was inhibited for 15 days by long chain compounds and for 30 days by polymerized HDDA after irradiation. After releasing, the leaf alcohol in the canal remained 25 % stable for long chain compounds and 40 % for polymerized HDDA. The dose required for stabilization of leaf alcohol in the urea canal by canal polymerization of HDDA was 30 kGy. (author).

  19. Canals, DMADCanals-Irrigation canals in Millard Co., Published in 2007, Millard County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Canals dataset, was produced all or in part from Other information as of 2007. It is described as 'DMADCanals-Irrigation canals in Millard Co.'. Data by this...

  20. Inhibition of dentin demineralization by fluoride in vitro.

    Science.gov (United States)

    ten Cate, J M; Damen, J J; Buijs, M J

    1998-01-01

    Compared with the knowledge accumulated on enamel-fluoride interactions, relatively little data is available regarding fluoride effects on dentin. This applies to both laboratory and clinical studies into the efficacy of fluoride schemes for the prevention of root surface caries. This study aimed to determine the effects of fluoride and pH on the demineralization of dentin, such as to provide information necessary to develop preventive programmes. Bovine dentin blocks were subjected to undersaturated calcium- and phosphate-containing solutions in the pH range 4.0-6.0 with fluoride added at concentrations between 0.5 and 10 ppm. Non-fluoride solutions served as controls. Mineral loss was assessed chemically and by transversal microradiography. Comparisons were made with similar studies on enamel demineralization. The results showed that demineralization of dentin depends on both pH and fluoride concentration in the demineralizing solution. Inhibition of demineralization that could be relevant from a clinical point of view was found at fluoride values 5-10 times the corresponding values for enamel. Also rapid depletion of fluoride from the solutions was observed, indicating the high uptake capacity of dentin for fluoride. Lesion depth depended on pH of the solution while the fluoride levels were associated with the surface layer, both in mineral content and depth. For dentin we propose a demineralization mechanism where acid penetrates rapidly into the tissue, presumably through the tubules, after which the released calcium and phosphate is partly trapped by the inward diffusing fluoride. This leads to the formation of a surface layer, which may even be hypermineralized compared to sound dentin.

  1. Shear bond strength of partial coverage restorations to dentin

    Science.gov (United States)

    Agustín-Panadero, Rubén; Alonso-Pérez-Barquero, Jorge; Fons-Font, Antonio; Solá-Ruíz, María-Fernanda

    2015-01-01

    Background When partial coverage restorations (veneers, inlays, onlays…) must be cemented to dentin, bond strength may not reach the same predictable values as to enamel. The purpose of this study was: 1. To compare, with a shear bond test, the bond strength to dentin of a total-etch and a self-etching bonding agent. 2. To determine whether creating microretention improves the bond strength to dentin. Material and Methods Two bonding agents were assayed, Optibond FL® (Kerr), two-bottle adhesive requiring acid etching, and Clearfil SE Bond® (Kuraray), two-bottle self-etching adhesive. The vestibular, lingual, distal and mesial surfaces of ten molars (n=10) were ground to remove all enamel and 40 ceramic samples were cemented with Variolink II® (Ivoclar Vivadent). Half the molar surfaces were treated to create round microretention (pits) to determine whether these could influence bond strength to dentin. The 40 molar surfaces were divided into four groups (n=10): Optibond FL (O); Clearfil SE (C); Optibond FL + microretention (OM); Clearfil SE + micro retention (CM). A shear bond test was performed and the bond failures provoked examined under an optical microscope. Results O=35.27±8.02 MPa; C=36.23±11.23 MPa; OM=28.61±6.27 MPa; CM=27.01±7.57 MPa. No statistically significant differences were found between the adhesives. Optibond FL showed less statistical dispersion than Clearfil SE. The presence of microretentions reduced bond strength values regardless of the adhesive used. Conclusions 1. Clearfil SE self-etching adhesive and Optibond FL acid-etch showed adequate bond strengths and can be recommended for bonding ceramic restorations to dentin. 2. The creation of round microretention pits compromises these adhesives’ bond strength to dentin. Key words:Adhesion to dentin, bonding agent, Optibond FL, Clearfil SE, microretention, shear bond test. PMID:26330937

  2. MRI Findings in Spinal Canal Stenosis

    OpenAIRE

    Maryam Barzin

    2010-01-01

    Spinal canal stenosis results from progressive narrowing of the central spinal canal and the lateral recesses. Primary (congenital) lumbar spinal stenosis is associated with achondroplastic dwarfism. The spinal canal may become narrowed by bulging or protrusion of the intervertebral disc annulus, herniation of the nucleus pulposus posteriorly, thickening of the posterior longitudinal ligament, hypertrophy of the facet joints, hypertrophy of the ligamentum flavum, epidural fat deposition, spon...

  3. Modelling of Buckingham Canal water quality.

    Science.gov (United States)

    Abbasi, S A; Khan, F I; Sentilvelan, K; Shabudeen, A

    2002-10-01

    The paper presents a case study of the modelling of the water quality of a canal situated in a petrochemical industrial complex, which receives wastewaters from Madras Refineries Limited (MRL), and Madras Fertilizers Limited (MFL). The canal well known Buckingham Canal which passes through Chennai (Madras), India has been modelled using the software QUAL2E-UNCAS. After testing and validation of the model, simulations have been carried out. The exercise enables forecasting the impacts of different seasons, base flows, and waste water inputs on the water quality of the Buckingham Canal. It also enables development of water management strategies.

  4. Effects of air-drying in vitro on human dentine permeability.

    Science.gov (United States)

    Pashley, D H; Stewart, F P; Galloway, S E

    1984-01-01

    The effects of evaporation produced by air blasts of 0, 0.5, 2 or 5 min to dentine in vitro were evaluated by measuring dentine hydraulic conductance before and after each trial. When the tubules were filled with water, even prolonged evaporation had no effect on dentine permeability. Tubules filled with physiological salt solution produced a time-dependent decrease in dentine permeability. Tubules filled with 1.5 per cent albumin in water gave the largest reductions in dentine permeability. These effects were more marked in unetched as opposed to acid-etched dentine. The results suggest that part of the reduction in dentine sensitivity produced clinically by prolonged air blasts may be due to precipitation of organic and inorganic constituents of dentinal fluid at the surface.

  5. Effects of a Dicalcium and Tetracalcium Phosphate-Based Desensitizer on In Vitro Dentin Permeability

    OpenAIRE

    Jianfeng Zhou; Ayaka Chiba; Debora L S Scheffel; Josimeri Hebling; Kelli Agee; Li-Na Niu; Franklin R. Tay; David H Pashley

    2016-01-01

    The present study evaluated the effectiveness of a dicalcium and tetracalcium phosphate-based desensitizer in reducing dentin permeability in vitro. Dentin fluid flow was measured before and after treatment of dentin with patent dentinal tubules using 1 or 3 applications of the dicalcium and tetracalcium phosphate containing agent TeethmateTM (TM) and comparing the results with two sodium fluoride varnishes VellaTM (VLA) and VanishTM (VAN), after storage in artificial saliva for 24 h, 48 h an...

  6. Effects of acidic primer/adhesives on primary and permanent dentin

    OpenAIRE

    2009-01-01

    Purpose: To evaluate the quality of primary and permanent dentin by Fourier transformed Raman spectroscopy (FT-Raman), and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS). Methods: The middle dentin of crowns was reached by carbide bur abrading providing a uniform smear layer. Self-etching primers were applied in order to simulate the etching of self-etching adhesive systems. The groups were (n = 6): G1 (primary dentin smear layer); G2 (primary dentin etched by primer of...

  7. [The effect of Kaviner and the smear layer on dentin permeability of permanent teeth in children].

    Science.gov (United States)

    Tadmiscija, H; Kobaslija, S; Ganibegović, M; Jusufagić, H; Huseinbegović, A

    1996-01-01

    The dentin permeability is defined as a moving of fluid, of chemical substances and microbial products as well through the dentin. The clinical protection of children permanent teeth in other words the protection of pulp-dentin complex after their preparation makes a big problem into the restorative stomatology. Caviner is one of the newer means which is used in the protection of pulp-dentin complex which represents the components of powder dispersing within the ethyl-acetate mixture of polystirol. The important variable in this study is the presence or absence of smearing layer which has the important influence onto the dentin permeability. In order to confirm the Caviner and smearing layer working onto the dentin permeability of the children permanent teeth in vitro experiment was designed. We used for it the dentin disks made of the intact first premolar, extracted because of orthodontic reasons at the ten years old children. They were put into the split chamber which represents a part of apparatus made at our Faculty, which is, in fact, a modified apparatus which was formed by prof. D.H. Pashley (Georgia, USA), and it is used for measuring of dentin permeability with the help of hydraulic conductance (Lp) of dentin. The dentin permeability is expressed by the hydraulic conductance term, but the measures are still expressed as the Lp percentage maximum because of better survey of results. Comparing the obtained results with the other authors results we have come to the similar conclusions, and that is in fact, that the smearing layer significantly reduces the dentin permeability, and that the Caviner, as the other layners, reduces the dentin permeability. If we compare the reduction of dentin permeability at the dentin covered with the smearing layer and with the Caviner, it has been noticed that the smearing layer reduces more significantly. It should be accented that the Caviner reduces the dentin permeability less than the most earlier researched means for

  8. Adhesion to enamel, dentin, metal, and porcelain.

    Science.gov (United States)

    Kanca, J

    1994-01-01

    Adhesion has an inseparable association with cosmetic dentistry. The ability to bond well to tooth structure has allowed the placement of countless porcelain veneers and many ceramic inlays and onlays. Improved materials and techniques have offered clinicians the ability to place these restorations with skill and reliability. The past year has seen many developments and additions to the armamentarium of the cosmetic dentist. The compiled data have been placed in different sections to facilitate the learning process. Review of the following material will familiarize the clinician with the current state of the art in the adhesive aspect of cosmetic dentistry. The ability to employ adhesive techniques has revolutionized the practice of dentistry. Clinicians have at their command materials that allow the placement of thin pieces of ceramic onto tooth structure without shattering, the routine placement of composite materials into posterior teeth, the diminishing reliance on liners and bases, and lessened postoperative discomfort with the use of dentin bonding systems. It is, as previously noted, useful to separate the analyses of adhesion to each of the substrates. Advances continue to be made in each of these areas that although not necessarily facilitating treatment ease, improve the reliability of the procedure. This review attempts to highlight the significant literature of the previous year.

  9. Innovative Approaches to Regenerate Enamel and Dentin

    Directory of Open Access Journals (Sweden)

    Xanthippi Chatzistavrou

    2012-01-01

    Full Text Available The process of tooth mineralization and the role of molecular control of cellular behavior during embryonic tooth development have attracted much attention the last few years. The knowledge gained from the research in these fields has improved the general understanding about the formation of dental tissues and the entire tooth and set the basis for teeth regeneration. Tissue engineering using scaffold and cell aggregate methods has been considered to produce bioengineered dental tissues, while dental stem/progenitor cells, which can differentiate into dental cell lineages, have been also introduced into the field of tooth mineralization and regeneration. Some of the main strategies for making enamel, dentin, and complex tooth-like structures are presented in this paper. However, there are still significant barriers that obstruct such strategies to move into the regular clinic practice, and these should be overcome in order to have the regenerative dentistry as the important mean that can treat the consequences of tooth-related diseases.

  10. Machining human dentin by abrasive water jet drilling.

    Science.gov (United States)

    Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

    2014-01-01

    The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin.

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

    Directory of Open Access Journals (Sweden)

    M MOUSAVINASAB

    2002-09-01

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

  12. Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II.

    Science.gov (United States)

    Lee, K-E; Kang, H-Y; Lee, S-K; Yoo, S-H; Lee, J-C; Hwang, Y-H; Nam, K H; Kim, J-S; Park, J-C; Kim, J-W

    2011-04-01

    The dentin sialophosphoprotein (DSPP) gene encodes the most abundant non-collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the DSPP gene have been solely related to non-syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon-intron boundaries of the DSPP gene based on the candidate gene approach. Direct sequencing of PCR products and allele-specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.

  13. Protective effect of green tea on dentin erosion and abrasion

    Directory of Open Access Journals (Sweden)

    Melissa Thiemi Kato

    2009-12-01

    Full Text Available OBJECTIVE: This in situ study evaluated the protective effect of green tea on dentin erosion (ERO and erosion-abrasion (ABR. MATERIAL AND METHODS: Ten volunteers wore intraoral palatal appliances with bovine dentin specimens subjected to ERO or ERO + toothbrushing abrasion performed immediately (ERO+I-ABR or 30 min after erosion (ERO+30-min-ABR. During 2 experimental 5-day crossover phases, the volunteers rinsed with green tea or water (control, 1 min between each erosive (5 min, cola drink and abrasive challenge (30 s, toothbrushing, 4x/day. Dentin wear was measured by profilometry. RESULTS: The green tea reduced the dentin wear significantly for all conditions compared to control. ERO+I-ABR led to significantly higher wear than ERO, but it was not significantly different from ERO+30-min-ABR. ERO+30-min-ABR provoked significant higher wear than ERO, only for the placebo treatment. CONCLUSIONS: From the results of the present study, it may be concluded that green tea reduces the dentin wear under erosive/abrasive conditions.

  14. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  15. Effect of Dentin Bonding Agent on the Prevention of Tooth Discoloration Produced by Mineral Trioxide Aggregate

    Directory of Open Access Journals (Sweden)

    Majid Akbari

    2012-01-01

    Full Text Available Objective. Determination of the effect of dentin bonding agent (DBA on the prevention of tooth discoloration produced by mineral trioxide aggregate (MTA. Methods. 50 teeth were endodontically treated and after removal of 3 mm of obturating materials were divided into five groups. In white MTA (WMTA and grey MTA (GMTA groups, these materials were placed in root canal below the orifice. In DBA + WMTA and DBA + GMTA groups, DBAs were applied in the access cavity. Then, 3 mm of WMTA and GMTA was placed. The last 10 teeth served as control. All of teeth were restored and color measurement was recorded for each specimen at this time and 6 months later. Results. The mean tooth discoloration in WMTA and GMTA groups was significantly more than DBA + WMTA and DBA + GMTA groups, respectively. There was no significant difference between DBA + WMTA and DBA + GMTA groups and control group. Conclusion. Application of DBA before MTA may prevent tooth discoloration.

  16. The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

    Directory of Open Access Journals (Sweden)

    Sheila Leite PINTO

    Full Text Available Abstract Introduction Cervical preflaring is an important step of the canal system instrumentation, but can lead to excessive enlargement or root perforation. Objective Evaluate the remaining dentin thickness in the mandibular molars of mesial roots using cone beam computed tomography: Gates-Glidden (crown-down; Gates-Glidden (step-back; LA Axxess and Easy Pro-Design. Material and method Were selected 40 lower molars mesial roots, which were scanned in a cone beam CT scanner before and after preparation. Were obtained five sections of the CT images with an interval of 1 mm from the furcation, and measured the thickness variation between the root canal to the root external portion in analysis software. Result The evaluation of the different levels showed no significance within the same group for the Gates-Glidden group. On the other hand, were observed difference for LA Axxess (p=0.002 and Easy Pro-Design (p=0.005. In the intergroup analysis, were observed difference in all levels, especially for Gates-Glidden in the ascendant order (ANOVA and Tukey. Conclusion Within the limitations of these study, is possible to conclude that the protocol with greater wear in the cervical risk area was the Gates-Glidden in step-back sequence, as the other groups were equivalent (p>0.05.

  17. Viable bacteria in root dentinal tubules of teeth with apical periodontitis

    NARCIS (Netherlands)

    Peters, LB; Wesselink, P.R.; Buijs, JF; van Winkelhoff, AJ

    2001-01-01

    Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight

  18. Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix

    Institute of Scientific and Technical Information of China (English)

    Rui-Rui Liu; Ming Fang; Ling Zhang; Cheng-Fang Tang; Qi Dou; Ji-Hua Chen

    2014-01-01

    Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2%chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.

  19. 牙本质唾液酸焦磷酸蛋白和牙本质%Dentin sialophosphoprotein and dentin

    Institute of Scientific and Technical Information of China (English)

    胡鑫瑜; 王浩洋

    2010-01-01

    在牙本质,两个编码Ⅰ型胶原蛋白基因的突变会导致成骨发育不全.除了胶原蛋白,在牙本质还有一定数量的非胶原蛋白.在牙本质非胶原蛋白编码的基因中,只有牙本质唾液酸焦磷酸蛋白(dentin sialophosphoprotein,DSPP)的突变引起遗传性牙齿畸形.DSPP的突变会引起牙本质发育不全(dentinogenesis imperfecta,DGI)Ⅰ型、Ⅱ型和牙本质发育异常(dentin dysplasia,DD)Ⅱ型.DSPP由成牙质细胞表达并分泌.分泌之后,DSPP由多个细胞外蛋白酶酶切成小片.DSPP被蛋白酶酶切为三个主要部分:牙本质涎蛋白(dentin sialoprotein,DSP),牙本质糖蛋白(dentin glycoprotein,DGP)和牙本质磷蛋白(dentin phosphoprotein,DPP).本文就这三种蛋白的最新进展进行回顾.

  20. A technical report on repair of amalgam-dentin complex.

    Science.gov (United States)

    Ozcan, M; Salihoğlu-Yener, E

    2011-01-01

    This clinical report describes a repair protocol for cusp fracture of a failed amalgam-dentin complex. A maxillary right first premolar with an amalgam restoration presented a buccal cusp fracture. Chairside repair has been undertaken by conditioning the existing amalgam restoration with silica coating (30 μm CoJet®-Sand), phosphoric acid etching the beveled enamel surface, priming dentin, and application of a bonding agent on both enamel and dentin. Thereafter, the amalgam was silanized (ESPE®-Sil), and opaque resin was applied and polymerized to mask the amalgam. The fractured buccal cusp was modeled using resin composite (Clearfil Photo Posterior) and photo-polymerized. Finally, the amalgam was refinished and refurbished and the composite was finished and polished.

  1. Amalgam buildups: shear strength and dentin sealing properties.

    Science.gov (United States)

    Pashley, E L; Comer, R W; Parry, E E; Pashley, D H

    1991-01-01

    The retentive strength and sealing properties of amalgam buildups were compared in vitro in three groups of specimens. All teeth were prepared with flat, nonretentive surfaces. In the first group, the amalgam buildups were retained by four self-threading Minim pins. In the second group, retention was provided by a circumferential slot prepared in the dentin just inside the DEJ. The third group utilized an adhesive resin for retention. Dentin permeability was measured as a hydraulic conductance before and after placement of the amalgam buildups and before and after thermocycling. All methods of retention sealed dentin very well even in the absence of cavity varnish. The 90 degree retentive strength was: pins, 10.3 +/- 0.9 MPa; slots, 4.1 +/- 0.5 MPa; resin, 3.1 +/- 0.8 MPa (mean +/- SEM).

  2. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

  3. Wonderful Walls

    Science.gov (United States)

    Greenman, Jim

    2006-01-01

    In this article, the author emphasizes the importance of "working" walls in children's programs. Children's programs need "working" walls (and ceilings and floors) which can be put to use for communication, display, storage, and activity space. The furnishings also work, or don't work, for the program in another sense: in aggregate, they serve as…

  4. [Upper lateral incisor with 2 canals].

    Science.gov (United States)

    Fabra Campos, H

    1991-01-01

    Clinical case summary of the patient with an upper lateral incisor with two root canals. The suspicion that there might be an anatomic anomaly in the root that includes a complex root canal system was made when an advanced radicular groove was detected in the lingual surface or an excessively enlarged cingulum.

  5. Bilateral duplication of the internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Weon, Young Cheol; Kim, Jae Hyoung; Choi, Sung Kyu [Seoul National University College of Medicine, Department of Radiology, Seoul National University Bundang Hospital, Seongnam-si (Korea); Koo, Ja-Won [Seoul National University College of Medicine, Department of Otolaryngology, Seoul National University Bundang Hospital, Seongnam-si (Korea)

    2007-10-15

    Duplication of the internal auditory canal is an extremely rare temporal bone anomaly that is believed to result from aplasia or hypoplasia of the vestibulocochlear nerve. We report bilateral duplication of the internal auditory canal in a 28-month-old boy with developmental delay and sensorineural hearing loss. (orig.)

  6. 33 CFR 117.285 - Grand Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing Island bridge, mile 0.7, shall open on...

  7. 33 CFR 117.453 - Houma Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Houma Canal. 117.453 Section 117.453 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.453 Houma Canal. The draw of the S3197 bridge, mile 1.7 at Houma, shall open on signal...

  8. 33 CFR 117.438 - Company Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of the S1 bridge, mile 0.4 at Lockport, shall open...

  9. Neuronal hyperplasia in the anal canal

    DEFF Research Database (Denmark)

    Fenger, C; Schrøder, H D

    1990-01-01

    In a consecutive series of minor surgical specimens from the anal canal, neuronal hyperplasia was found in nine of 56 haemorrhoidectomy specimens and in four of 23 fibrous polyps. In an additional series of 14 resections of the anal canal, neuronal hyperplasia was present in six cases, of which...

  10. 33 CFR 117.787 - Gowanus Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Gowanus Canal. 117.787 Section 117.787 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.787 Gowanus Canal. The draws of the Ninth Street Bridge, mile 1.4, the Third...

  11. Blending Canal Surfaces Based on PH Curves

    Institute of Scientific and Technical Information of China (English)

    Chen-Dong Xu; Fa-Lai Chen

    2005-01-01

    In this paper, a new method for blending two canal surfaces is proposed. The blending surface is itself a generalized canal surface, the spine curve of which is a PH (Pythagorean-Hodograph) curve. The blending surface possesses an attractive property - its representation is rational. The method is extensible to blend general surfaces as long as the blending boundaries are well-defined.

  12. 33 CFR 117.445 - Franklin Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Franklin Canal. 117.445 Section 117.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.445 Franklin Canal. The draw of the Chatsworth Bridge, mile 4.8 at Franklin, shall...

  13. 33 CFR 117.1045 - Hood Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Hood Canal. 117.1045 Section 117.1045 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington State pontoon highway bridge near...

  14. DESIGN OF SEDIMENT TRANSPORTING CANAL SECTIONS

    Institute of Scientific and Technical Information of China (English)

    Prabhata K.SWAMEE; Nimisha SWAMEE

    2004-01-01

    Design equations for minimum area or maximum velocity canal-sections for transport of bulk sediment carried by water have been obtained. Such canals are economically feasible in the terrain where large slopes are available. The design procedure is illustrated by a practical example.

  15. Chlorhexidine as a root canal irrigant: Antimicrobial and scanning electron microscopic evaluation

    Directory of Open Access Journals (Sweden)

    Živković Slavoljub

    2010-01-01

    Full Text Available Introduction. Selection of irrigant is very important for longterm success of root canal therapy. Objective. This study was undertaken to evaluate the antimicrobial effects of 2% chlorhexidine digluconate solution (CHX against five selected microorganisms and to evaluate its efficacy in root canal cleaning. Methods. In this study, by agar diffusion test, were evaluated antimicrobial effects of three root canal irrigants: 5.25% NaOCl, 2.5% NaOCl and 2% CHX. The microorganisms tested in this study were Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, Escherichia coli and Candida albicans. A scanning electron microscope was used to evaluate root canal cleaning ability of 5.25% NaOCl, 2.5% NaOCl, 2% CHX and 15% EDTA. Twelve extracted single-root human teeth were divided into four groups depending on the irrigant used during instrumentation. Mechanical preparation was performed with Step back technique and K files. Data were analyzed statistically by Student’s t-test. Results 5.25% NaOCl was the most effective against all tested microorganisms. 2.5% NaOCl and 2% CHX showed antimicrobial effects against all tested microorganisms but zones of inhibition were smaller. The best results in root canal walls cleaning were obtained in the group where the irrigant was 15% EDTA (score 2.33. In 5.25% NaOCl, 2.5% NaOCl and 2% CHX groups, there was more smear layer (score 4 and 5. Conclusion. 2% chlorhexidine digluconate showed strong antimicrobial effect on the tested microorganisms, but was not effective in cleaning root canal walls.

  16. Bond strength of adhesives to dentin contaminated with smoker's saliva.

    Science.gov (United States)

    Pinzon, Lilliam M; Oguri, Makoto; O'Keefe, Kathy; Dusevish, Vladimir; Spencer, Paulette; Powers, John M; Marshall, Grayson W

    2010-02-01

    The purpose of this study was to determine the effects of contamination with smoker's and non-smoker's saliva on the bond strength of resin composite to superficial dentin using different adhesive systems. The interfacial structure between the resin and dentin was evaluated for each treatment using environmental scanning electron microscopy (ESEM). Freshly extracted human molars were ground with 600-grit SiC paper to expose the superficial dentin. Adhesives [One-Up-Bond-F-Plus (OUFP) and Adper-Prompt-L-Pop (APLP)] and resin composite (TPHSpectrum) were bonded to the dentin (n = 8/group, 180 total specimens) under five surface conditions: control (adhesive applied following manufacturers' instructions); saliva, then 5-s air dry, then adhesive; adhesive, saliva, 5-s air dry; adhesive, saliva, 5-s water rinse, 5-s air dry (ASW group); and adhesive, saliva, 5-s water rinse, 5-s air dry, reapply adhesive (ASWA group). After storage in water at 37 degrees C for 24 h, the specimens were debonded under tension at a speed of 0.5 mm/min. ESEM photomicrographs of the dentin/adhesive interfaces were taken. Mean bond strength ranged from 8.1 to 24.1 MPa. Fisher's protected least significant difference (P = 0.05) intervals for critical adhesive, saliva, and surface condition differences were 1.3, 1.3, and 2.1 MPa, respectively. There were no significant differences in bond strength to dentin between contamination by smoker's and nonsmoker's saliva, but bond strengths were significantly different between adhesive systems, with OUFP twice as strong as APLP under almost all conditions. After adhesive application and contamination with either smoker's or nonsmoker's saliva followed by washing and reapplication of the adhesive (ASWA group), the bond strength of both adhesive systems was the same as that of the control group.

  17. Quantitative microleakage of some dentinal bonding restorative systems.

    Science.gov (United States)

    Hasegawa, T; Retief, D H

    1993-03-01

    The quantitative microleakage of class V cementum (dentin) cavities restored with six dentinal bonding restorative systems was determined in vitro. Ninety extracted human permanent first and second mandibular and maxillary premolars were used in this study. Class V preparations were made in cementum (dentin) at the root facial surfaces. The preparations were restored with 1) a dentin bonding system containing 2% HEMA and BisGMA and a light-cured microfilled composite; 2) the same materials only substituting META/MMA base and TBB catalyst monomers for the BisGMA sealer; 3) a dentin bonding system containing 35% HEMA with META/MMA base and TBB catalyst, and a light-cured hybrid composite; 5) the same dentin bonding system only substituting the 35% glycerylmethacrylate for the 35% HEMA and using the microfilled composite; and 6) the previously described system with a substitution of 0.5 mol EDTA for the 10% citric acid -3% FeCl3. Fifteen teeth were restored with each procedure. The restorations were finished with 12-bladed carbide burs 15 min after placement, the teeth were stored in saline at 37 degrees C for 24 h, finished with Sof-Lex discs and then thermocycled in 2% methylene blue solution 500 times between 50 degrees C and 8 degrees C with a dwell time of 15 s. Quantitative microleakage was determined by a spectrophotometric dye-recovery method and expressed in microgram/dye/restoration. The data were analyzed by ANOVA, Student-Newman-Keuls and Kruskal-Wallis tests. The quantitative microleakage of the teeth restored with the adhesive systems containing 35% glyceryl methacrylate was significantly reduced. The bonding mechanism of glyceryl methacrylate is not known.

  18. Type III apical transportation of root canal

    Directory of Open Access Journals (Sweden)

    Shiv P Mantri

    2012-01-01

    Full Text Available Procedural accidents leading to complications such as canal transportation have been ascribed to inapt cleaning and shaping concepts. Canal transportation is an undesirable deviation from the natural canal path. Herewith a case of apical transportation of root canal resulting in endodontic retreatment failure and its management is presented. A healthy 21-year-old young male presented discomfort and swelling associated with painful endodontically retreated maxillary incisor. Radiograph revealed periradicular radiolucency involving underfilled 11 and overfilled 12. Insufficiently obturated 11 exhibited apical transportation of canal. This type III transportation was treated by periradicular surgery and repair using white mineral trioxide aggregate (MTA. Comfortable asymptomatic patient presented uneventful healing at third and fourth month recall visits. A decrease in the size of radiolucency in radiograph supported the clinical finding. In the present case, MTA is useful in repairing the transportation defect. The result of these procedures is predictable and successful.

  19. Effect of immediate and delayed dentin sealing on the fracture strength, failure type and Weilbull characteristics of lithiumdisilicate laminate veneers

    NARCIS (Netherlands)

    Gresnigt, Marco M.M.; Cune, Marco S.; de Roos, Joanne G.; Özcan, Mutlu

    2016-01-01

    OBJECTIVES: Adhesion on dentin is less reliable than on enamel, which could affect the durability of laminate veneers (LV). Immediate dentin sealing (IDS) is suggested instead of delayed dentin sealing (DDS) to overcome hypersensitivity and prevent debonding from dentin. This study evaluated the eff

  20. Evaluation of accessory furcation canals of permanent mandibular molars using radiography and clearing = Avaliação do canal cavo-interradicular em molares inferiores permanentes através de Rx e diafanização

    Directory of Open Access Journals (Sweden)

    Harb, Leandro José Corrêa

    2010-01-01

    Full Text Available Objetivo: Avaliar a presença do canal cavo-interradicular em molares inferiores permanentes através de radiografias e diafanização. Metodologia: A amostra foi constituída por 344 molares inferiores re-hidratados, preparados e armazenados individualmente em recipientes de vidro. A presença do canal cavo-interradicular foi investigada por um único operador treinado usando lupa (4x para as radiografias e microscópio óptico odontológico (30x para as amostras diafanizadas. Microscopia eletrônica de varredura (MEV foi usada para verificar diferenças morfológicas do assoalho pulpar. Resultados: A análise radiográfica mostrou que 9% das amostras tinham uma zona levemente radiolúcida, 2% mostravam uma imagem sugestiva, e 89% das amostras não tinham nenhuma evidência. Pela diafanização, o canal não foi encontrado nas amostras avaliadas. Pela MEV, as amostras recém extraídas mostraram com canalículos dentinários uniformes; as demais apresentaram pequenos sítios com canalículos uniformes. Conclusão: O exame radiográfico não foi o melhor método de diagnóstico; a diafanização é um excelente método avaliativo, pois permite a visualização tridimensional da anatomia interna dental em pesquisas in vitro

  1. Influence of handpiece maintenance sprays on resin bonding to dentin

    Directory of Open Access Journals (Sweden)

    Toyotarou Sugawara

    2010-03-01

    Full Text Available Toyotarou Sugawara1, Atsushi Kameyama2, Akiko Haruyama3, Takumi Oishi4, Nobuyuki Kukidome2, Yasuaki Takase2, Masatake Tsunoda21Undergraduate Student, Tokyo Dental College, Chiba, Japan; 2Division of General Dentistry, Tokyo Dental College Chiba Hospital, Chiba, Japan; 3Department of Dental Materials Science, Tokyo Dental College, Chiba, Japan; 4Department of Dentistry and Oral Surgery, Keio University School of Medicine, Tokyo, JapanObjective: To investigate the influence of maintenance spray on resin bonding to dentin.Materials and methods: The crown of extracted, caries-free human molars was transversally sectioned with a model trimmer to prepare the dentin surfaces from mid-coronal sound dentin, and then uniformly abraded with #600 silicon carbide paper. The dentin surfaces were randomly divided into three groups: oil-free spray group where maintenance cleaner for air bearing handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; oil-containing spray group where maintenance cleaner for micro motor handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; and control group where the surface was rinsed with water spray for 30 s and then air-dried. These surfaces were then bonded with Clearfil SE Bond (Kuraray Medical, and resin composite (Clearfil AP-X, Kuraray Medical build-up crowns were incrementally constructed on the bonded surfaces. After storage for 24 h in 37°C water, the bonded teeth were sectioned into hour-glass shaped slices (0.7-mm thick perpendicular to the bonded surfaces. The specimens were then subjected to microtensile bond strength (μTBS testing at a crosshead speed of 1.0 mm/min. Data were analyzed with one-way ANOVA and the Tukey-Kramer test.Results: Maintenance spray-contaminated specimens (oil-free and oil-containing spray groups showed significantly lower μTBS than control specimens (P < 0.05. However, there was no significant difference between

  2. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    Directory of Open Access Journals (Sweden)

    Flávio Fernando DEMARCO

    1997-07-01

    Full Text Available The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. They were embedded in acrylic resin and subjected to shear stress, in a Wolpert Machine, at a crosshead speed of 0.5 mm/min. The mean cohesive strength of dentin in shear mode was 33.95 (+-9.72 MPa. The fracture surfaces were observed under a X40 magnification. A finite element analysis was performed to observe the stress distribution as related to the shear test. The failure pattern was compatible with the shear test and also with the stress distribution in the finite element analysisA resistência de união dos adesivos dentinários tem sido aumentada com o desenvolvimento de cada nova geração. Pouca importância tem sido dada à resistência coesiva da dentina. A proposta deste estudo foi avaliar a resistência coesiva da dentina. Dezessete caninos humanos hígidos, os quais tinham sido extraídos há mais de um ano, foram usados. Os dentes foram desgastados até a obtenção de corpos-de-prova em dentina, de formato quadrangular, com tamanho aproximado de 2 X 2 mm. Os dentes foram incluídos em resina acrílica e, então, submetidos ao teste de cisalhamento em uma máquina de ensaios universais Wolpert, com uma velocidade de 0,5 mm/min. A resistência coesiva média da dentina no teste de cisalhamento foi de 33,95 (+- 9,72 MPa. O tipo de fratura foi analisado com um aumento de 40X. Foi realizada uma análise com elemento finito, para observar a distribuição do estresse relacionada com o teste de cisalhamento. O padrão de fratura encontrado foi compat

  3. MRI Findings in Spinal Canal Stenosis

    Directory of Open Access Journals (Sweden)

    Maryam Barzin

    2010-05-01

    Full Text Available Spinal canal stenosis results from progressive narrowing of the central spinal canal and the lateral recesses. Primary (congenital lumbar spinal stenosis is associated with achondroplastic dwarfism. The spinal canal may become narrowed by bulging or protrusion of the intervertebral disc annulus, herniation of the nucleus pulposus posteriorly, thickening of the posterior longitudinal ligament, hypertrophy of the facet joints, hypertrophy of the ligamentum flavum, epidural fat deposition, spondylosis of the intervertebral disc margins and uncovertebral joint hypertrophy in the neck. The central canal and the neurorecess may be compromised by tumor infiltration, such as metastatic disease, or by infectious spondylitis."nAP diameter of the normal adult cervical canal has a mean value of 17-18 mm at vertebral levels C3-5. The lower cervical canal measures 12-14 mm. Cervical stenosis is associated with an AP diameter of less than 10 mm. The thoracic spinal canal varies from 12 to 14 mm in diameter in the adult. The diameter of the normal lumbar spinal canal varies from 15 to 27 mm. Lumbar stenosis results from a spinal canal diameter of less than 12 mm in some patients; a diameter of 10 mm is definitely stenotic."nSpinal MRI is the most suitable technique for the diagnosis of spinal stenosis. The examination should be performed using thin sections (3 mm and high resolution, including the axial and sagittal planes using T1-weighted, proton-density, and T2-weighted techniques. The bony and osteophytic components are seen best using a T2-weighted gradient-echo technique."nOn MRI, findings of spinal stenosis have a variable presentation depending on the specific disease. The goal of spinal imaging is to localize the site and level of disease and to help differentiate between conditions in which patients require surgery or conservative treatment."nIn this presentation, different kinds of spinal canal stenosis and their MRI findings would be discussed.

  4. Debris and smear removal in flattened root canals after use of different irrigant agitation protocols.

    Science.gov (United States)

    Ribeiro, Eduardo Milani; Silva-Sousa, Yara T C; Souza-Gabriel, Aline Evangelista; Sousa-Neto, Manoel Damião; Lorencetti, Karina Torales; Silva, Silvio Rocha Correa

    2012-06-01

    Scanning electron microscopy (SEM) can be used to analyze the presence of debris and smear layer on the internal walls of root canal. This study evaluated the debris and smear removal in flattened root canals using SEM after use of different irrigant agitation protocols. Fifty mandibular incisors were distributed into five groups (n = 10) according to the irrigant agitation protocol used during chemomechanical preparation: conventional syringe irrigation with NaviTip needle (no activation), active scrubbing of irrigant with brush-covered NaviTip FX needle, manual dynamic irrigation, continuous passive ultrasonic irrigation, and apical negative pressure irrigation (EndoVac system). Canals were irrigated with 5 mL of 2.5% NaOCl at each change of instrument and received a final flush with 17% EDTA for 1 min. After instrumentation, the roots were split longitudinally and SEM micrographs at ×100 and ×1,000 were taken to evaluate the amount of debris and smear layer, respectively, in each third. Data were analyzed by Kruskal-Wallis and Dunn's post-hoc tests (α = 5%). Manual dynamic activation left significantly (p protocols, while ultrasonic irrigation and EndoVac were the most effective (p 0.05) either among the irrigant agitation protocols or between the protocol-canal third interactions. Although none of the irrigant agitation protocols completely removed debris and smear layer from flattened root canals, the machine-assisted agitation systems (ultrasound and EndoVac) removed more debris than the manual techniques.

  5. Developmentof the safety monitoring system of hydraulic structuresof the Moscow canal

    Directory of Open Access Journals (Sweden)

    Levachev Stanislav Nikolaevich

    2015-05-01

    Full Text Available The basis of the enterprise “Moscow Canal” in its present state is the canal Moscow - Volga constructed in 1937. Today “Moscow Canal” is the biggest water transport and water industry complex. It has 10 filiations and solves a substantial complex of tasks. One of the most important part of hydraulic structures operation is their observation or monitoring of their safety, which gives us timely and adequate picture of their work and helps to forecast and prevent emergency situations.The article is devoted to the development of the monitoring system of the waterworks of the Moscow canal beginning with the moment of its construction to the present time, the observation analysis of the condition of the walls of canal locks chambers, lock no. 2 where destructive processes in the operation of the walls were first discovered and different methods of liquidation of their development were made. The main problems in the field of monitoring of hydrotechnical structures of the Moscow canal are identified basing on the analysis of the observations.

  6. Influence of immediate dentin sealing on the shear bond strength of pressed ceramic luted to dentin with self-etch resin cement.

    Science.gov (United States)

    Dalby, Robert; Ellakwa, Ayman; Millar, Brian; Martin, F Elizabeth

    2012-01-01

    Objectives. To examine the effect of immediate dentin sealing (IDS), with dentin bonding agents (DBAs) applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU) cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E) of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go!) that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic) luted to the sealed dentin surface using RXU. Group E (control) had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent) using RXU following the manufacturer's instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (P Optibond FL (Group A) and Go! (Group D). There was no statistical difference (P > 0.05) in the SBS between the test groups (A-D) or the control (group E). Conclusion. IDS using the dentin bonding agents tested does not statistically (P > 0.05) affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control.

  7. Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals

    Science.gov (United States)

    HARAGUSHIKU, Gisele Aihara; BACK, Eduardo Donato Eing Engelke; TOMAZINHO, Paulo Henrique; BARATTO, Flares; FURUSE, Adilson Yoshio

    2015-01-01

    Objective This study evaluated the effect of root canal disinfectants on the elimination of bacteria from the root canals, as well as their effect on glass-fiber posts bond strength. Material and Methods Fifty-three endodontically treated root canals had post spaces of 11 mm in length prepared and contaminated with E. faecalis. For CFU/ml analysis, eight teeth were contaminated for 1 h or 30 days (n=4). Teeth were decontaminated with 5% NaOCl, 2% CHX, or distilled water. As control, no decontamination was conducted. After decontamination, sterile paper points were used to collect samples, and CFU/ml were counted. For push-out, three groups were evaluated (n=15): irrigation with 2.5% NaOCl, 2% CHX, or sterile distilled water. A bonding agent was applied to root canal dentin, and a glass-fiber post was cemented with a dual-cured cement. After 24 h, 1-mm-thick slices of the middle portion of root canals were obtained and submitted to the push-out evaluation. Three specimens of each group were evaluated in scanning electron microscopy (SEM). Data were analyzed with one-way ANOVA and Dunnett’s T3 test (α=0.05). Results The number of CFU/ml increased from 1 h to 30 days of contamination in control and sterile distilled water groups. Decontamination with NaOCl was effective only when teeth were contaminated for 1 h. CHX was effective at both contamination times. NaOCl did not influence the bond strength (p>0.05). Higher values were observed with CHX (ppost bonding. PMID:26398518

  8. A rapid non-destructive method for root dentin moisture measurements

    Science.gov (United States)

    Komabayashi, Takashi; Zhu, Qiang; Jiang, Jin; Safavi, Kamran E.; Spångberg, Larz S.W.

    2009-01-01

    Dentin moisture content is important in adhesive bonding and structural strength research. However, there is no rapid method available to assess dentin moisture without sample destruction. This study examined the use of a digital grain moisture meter to measure root dentin moisture in vitro. Extracted mandibular single rooted teeth were sectioned at the CEJ. The moisture of the root dentin was measured at six measuring modes for different grains and repeated five times. Dentin weight changes before and after drying were measured to obtain control values. The control values were compared with machine readings. In conclusion, (1) Each non-destructive measurement took less than 30 seconds. (2) 24 hours storage at 37°C and 100 % humidity did not restore dentin moisture. (3) Five grain modes had a high validity, and could be used for dentin moisture measurements. PMID:19157921

  9. Effect of Repeated Container Lid Opening on Dentin Shear Bond Strength of Two Dentin Adhesive Systems

    Directory of Open Access Journals (Sweden)

    H. Hassanzadeh

    2008-03-01

    Full Text Available Objective: Comparing the effect of repeated opening of the container lid of two dentin adhesive systems, Prime&Bond NT (P&B NT and iBond (iB, on shear bond strength.Materials and Methods: Intact bovine lower incisors (n=60, fixed in acrylic were ran-domly divided into six groups (n=10. Groups I and II were set as control groups. P&B NT and iB were applied on the samples after five days a week, three times a day for two weeks of use in groups III and VI; and after four weeks of use in groups V and VI. The samples were evaluated by a universal testing-machine (Instron, cross-head speed 1mm/min and stereomicroscope.Results: There was no significant difference between the bond strengths in any of the three P&B NT. The mean amount of the shear bond strength for iB after 60 times of use (15.31 MPa was significantly lowerthan that at the baseline (23.51 MPa. There was no significant difference between iB at the baseline and after 30 times of use (19.26 Mpa, and also between iB after 30 times of use and after 60 times of use. All P&B NT groups showed significantly highershear bond strengths when compared with their similar iB groups in iB.Conclusion: Repeated use (60 times of the all-in-one adhesive container seems to reduce dentin shear bond strength. Therefore, containers with a lower content of the same adhe-sive or a single-dose of the adhesive are preferred.

  10. Dentin sialophosphoprotein knockout mouse teeth display widened predentin zone and develop defective dentin mineralization similar to human dentinogenesis imperfecta type III.

    Science.gov (United States)

    Sreenath, Taduru; Thyagarajan, Tamizchelvi; Hall, Bradford; Longenecker, Glenn; D'Souza, Rena; Hong, Sung; Wright, J Tim; MacDougall, Mary; Sauk, John; Kulkarni, Ashok B

    2003-07-01

    Dentin sialophosphoprotein (Dspp) is mainly expressed in teeth by the odontoblasts and preameloblasts. The Dspp mRNA is translated into a single protein, Dspp, and cleaved into two peptides, dentin sialoprotein and dentin phosphoprotein, that are localized within the dentin matrix. Recently, mutations in this gene were identified in human dentinogenesis imperfecta II (Online Mendelian Inheritance in Man (OMIM) accession number 125490) and in dentin dysplasia II (OMIM accession number 125420) syndromes. Herein, we report the generation of Dspp-null mice that develop tooth defects similar to human dentinogenesis imperfecta III with enlarged pulp chambers, increased width of predentin zone, hypomineralization, and pulp exposure. Electron microscopy revealed an irregular mineralization front and a lack of calcospherites coalescence in the dentin. Interestingly, the levels of biglycan and decorin, small leucine-rich proteoglycans, were increased in the widened predentin zone and in void spaces among the calcospherites in the dentin of null teeth. These enhanced levels correlate well with the defective regions in mineralization and further indicate that these molecules may adversely affect the dentin mineralization process by interfering with coalescence of calcospherites. Overall, our results identify a crucial role for Dspp in orchestrating the events essential during dentin mineralization, including potential regulation of proteoglycan levels.

  11. In vitro evaluation of efficacy of different rotary instrument systems for gutta percha removal during root canal retreatment

    Science.gov (United States)

    Joseph, Mercy; Malhotra, Amit; Rao, Murali; Sharma, Abhimanyu; Talwar, Sangeeta

    2016-01-01

    Background Complete removal of old filling material during root canal retreatment is fundamental for predictable cleaning and shaping of canal anatomy. Most of the retreatment methods tested in earlier studies have shown inability to achieve complete removal of root canal filling. Therefore the aim of this investigation was to assess the efficacy of three different rotary nickel titanium retreatment systems and Hedstrom files in removing filling material from root canals. Material and Methods Sixty extracted mandibular premolars were decoronated to leave 15 mm root. Specimen were hand instrumented and obturated using gutta percha and AH plus root canal sealer. After storage period of two weeks, roots were retreated with three (Protaper retreatment files, Mtwo retreatment files, NRT GPR) rotary retreatment instrument systems and Hedstroem files. Subsequently, samples were sectioned longitudinally and examined under stereomicroscope. Digital images were recorded and evaluated using Digital Image Analysing Software. The retreatment time was recorded for each tooth using a stopwatch. The area of canal and the residual filling material was recorded in mm2 and the percentage of remaining filling material on canal walls was calculated. Data was analysed using ANOVA test. Results Significantly less amount of residual filling material was present in protaper and Mtwo instrumented teeth (p Protaper instruments also required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. Conclusions None of the instruments were able to remove the filling material completely from root canal. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files. Key words:Gutta-percha removal, nickel titanium, root canal retreatment, rotary instruments. PMID:27703601

  12. Fluorine analysis of human dentin surrounding resin composite after fluoride application by μ-PIGE/PIXE analysis

    OpenAIRE

    Okuyama, Katsushi; Komatsu, Hisanori; YAMAMOTO, Hiroko; Pereira, Patricia N. R.; Bedran-Russo, Ana K.; Nomachi, Masaharu; Sato, Takahiro; Sano, Hidehiko

    2011-01-01

    The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system; however, demineralization also introduce...

  13. Evaluation of smear layer removal and marginal adaptation of root canal sealer after final irrigation using ethylenediaminetetraacetic, peracetic, and etidronic acids with different concentrations.

    Science.gov (United States)

    Ulusoy, Özgür İlke; Zeyrek, Salev; Çelik, Bülent

    2017-02-12

    The purpose of this study was to investigate the effects of different irrigation solutions on the smear layer removal and marginal adaptation of a resin-based sealer to root canal dentine. A total of 152 instrumented roots were irrigated with the following irrigants: 9,18% etidronic acid (HEBP), 0.5, 1,2% peracetic acid (PAA), 17% ethylenediaminetetraacetic acid (EDTA), saline. The amount of smear layer was evaluated using scanning electron microscope (SEM) in seventy root samples. Eighty-two roots were filled with AH Plus and gutta-percha. Slices obtained from apical third of each specimen were viewed with SEM to assess marginal adaptation. Use of 9% and 18% HEBP resulted in more efficient smear layer removal in the apical third than the other chelators (p acid is a promising candidate for final irrigation of root canals.

  14. Wall Turbulence.

    Science.gov (United States)

    Hanratty, Thomas J.

    1980-01-01

    This paper gives an account of research on the structure of turbulence close to a solid boundary. Included is a method to study the flow close to the wall of a pipe without interferring with it. (Author/JN)

  15. Canals in Milky Way radio polarization maps

    CERN Document Server

    Fletcher, A; Fletcher, Andrew; Shukurov, Anvar

    2006-01-01

    Narrow depolarized canals are common in maps of the polarized synchrotron emission of the Milky Way. Two physical effects that can produce these canals have been identified: the presence of Faraday rotation measure ($\\RM$) gradients in a foreground screen and the cumulative cancellation of polarization known as differential Faraday rotation. We show that the behaviour of the Stokes parameters $Q$ and $U$ in the vicinity of a canal can be used to identify its origin. In the case of canals produced by a Faraday screen we demonstrate that, if the polarization angle changes by $90\\degr$ across the canal, as is observed in all fields to-date, the gradients in $\\RM$ must be discontinuous. Shocks are an obvious source of such discontinuities and we derive a relation of the expected mean separation of canals to the abundance and Mach number of supernova driven shocks, and compare this with recent observations by \\citet{Haverkorn03}. We also predict the existence of less common canals with polarization angle changes o...

  16. Panama Canal Watershed Experiment- Agua Salud Project

    Science.gov (United States)

    Stallard, Robert F.; Ogden, Fred L.; Elsenbeer, Helmut; Hall, Jefferson S.

    2010-01-01

    The Agua Salud Project utilizes the Panama Canal’s (Canal) central role in world commerce to focus global attention on the ecosystem services provided by tropical forests. The Canal was one of the great engineering projects in the world. Completed in 1914, after almost a decade of concerted effort, its 80 km length greatly shortened the voyage between the Atlantic and Pacific Oceans. An entire class of ships, the Panamax, has been constructed to maximize the amount of cargo that can be carried in a Canal passage. In today’s parlance, the Canal is a “green” operation, powered largely by water (Table 1). The locks, three pairs on each end with a net lift of 27 meters, are gravity fed. For each ton of cargo that is transferred from ocean to ocean, about 13 tons of water (m3) are used. Lake Gatún forms much of the waterway in the Canal transect. Hydroelectricity is generated at the Gatún dam, whenever there is surplus water, and at Madden Dam (completed in 1936) when water is transferred from Lake Alhajuela to Lake Gatún. The Canal watershed is the source of drinking water for Panama City and Colon City, at either end of the Canal, and numerous towns in between.

  17. Analysis of resin-dentin interface morphology and bond strength evaluation of core materials for one stage post-endodontic restorations.

    Directory of Open Access Journals (Sweden)

    Kerstin Bitter

    Full Text Available PURPOSE: Restoration of endodontically treated teeth using fiber posts in a one-stage procedure gains more popularity and aims to create a secondary monoblock. Data of detailed analyses of so called "post-and-core-systems" with respect to morphological characteristics of the resin-dentin interface in combination with bond strength measurements of fiber posts luted with these materials are scarce. The present study aimed to analyze four different post-and-core-systems with two different adhesive approaches (self-etch and etch-and-rinse. MATERIALS AND METHODS: Human anterior teeth (n = 80 were endodontically treated and post space preparations and post placement were performed using the following systems: Rebilda Post/Rebilda DC/Futurabond DC (Voco (RB, Luxapost/Luxacore Z/Luxabond Prebond and Luxabond A+B (DMG (LC, X Post/Core X Flow/XP Bond and Self Cure Activator (Dentsply DeTrey (CX, FRC Postec/MultiCore Flow/AdheSE DC (Ivoclar Vivadent (MC. Adhesive systems and core materials of 10 specimens per group were labeled using fluorescent dyes and resin-dentin interfaces were analyzed using Confocal Laser Scanning Microscopy (CLSM. Bond strengths were evaluated using a push-out test. Data were analyzed using repeated measurement ANOVA and following post-hoc test. RESULTS: CLSM analyses revealed significant differences between groups with respect to the factors hybrid layer thickness (p<0.0005 and number of resin tags (p = 0.02; ANOVA. Bond strength was significantly affected by core material (p = 0.001, location inside the root canal (p<0.0005 and incorporation of fluorescent dyes (p = 0.036; ANOVA. CX [7.7 (4.4 MPa] demonstrated significantly lower bond strength compared to LC [14.2 (8.7 MPa] and RB [13.3 (3.7 MPa] (p<0.05; Tukey HSD but did not differ significantly from MC [11.5 (3.5 MPa]. CONCLUSION: It can be concluded that bond strengths inside the root canal were not affected by the adhesive approach of the post-and-core-system. All systems

  18. Dentin hypersensitivity: from diagnosis to a breakthrough therapy for everyday sensitivity relief.

    Science.gov (United States)

    Cummins, Diane

    2009-01-01

    This paper provides an overview of the current knowledge of diagnosis, epidemiology, etiology, and clinical management of dentin hypersensitivity. It summarizes technical approaches to relieve sensitivity in professional and home-use products, with emphasis on the clinical evidence for the efficacy of desensitizing toothpaste, and introduces a new innovative dentifrice technology containing 8% arginine, calcium carbonate, and 1450 ppm fluoride. Dentin hypersensitivity is characterized by short, sharp pain arising from exposed dentin in response to external stimuli which cannot be ascribed to any other form of dental defect or disease. The hydrodynamic theory proposes that pain-producing stimuli cause a change in dentin fluid flow that activates intra-dental nerve fibers, via a mechanoreceptor response, to cause pain. To be hypersensitive, dentin must be exposed and dentin tubules must be open to external stimuli and patent at the pulp. Gingival recession is the primary cause of dentin exposure, and a major predisposing factor for dentin hypersensitivity. Dentin hypersensitivity is a prevalent condition. It has been reported to afflict 15-20% of the adult population, typically 20 to 50-year-olds, with peak incidence between 30 and 39 years. Some studies have reported higher prevalence levels of up to 57%. The incidence of dentin hypersensitivity is expected to rise with changing diets, and as caries and periodontal disease prevention result in improved oral health status, and retention and functionality of the dentition. Treatments to relieve dentin hypersensitivity are based on interruption of the neural response to pain stimuli or occlusion of open tubules to block the hydrodynamic mechanism. Effective and robust dentin occlusion offers the greatest prospect for instant and lasting relief of dentin hypersensitivity. In particular, materials which can coat exposed dentin surfaces, in addition to plugging and sealing open dentin tubules, offer the intriguing

  19. Dental pulp response to bacterial cell wall material.

    Science.gov (United States)

    Warfvinge, J; Dahlén, G; Bergenholtz, G

    1985-08-01

    Lipopolysaccharides (LPS) from Bacteroides oralis and Veillonella parvula and cell wall material from Lactobacillus casei were studied for their capacity to induce leukocyte migration in the dental pulp and in an implanted wound chamber. Three adult monkeys were challenged using lyophilized material sealed into buccal Class V cavities prepared in dentin. Pulp tissue responses were observed histologically eight and 72 hours after initiation of the experiment. Subjacent to cut dentinal tubules, bacterial materials induced polymorphonuclear leukocyte (PMN's) infiltration in the pulp tissue of the majority of test teeth examined. Responses were similar for the three bacterial test materials at both time periods. Topical applications of bovine serum albumin (BSA), used as a control, induced significantly less accumulation of PMN's. Assessments of induced exudate volumes and leukocyte densities in chambers implanted in rats showed comparable rankings with pulpal experiment between test (i.e., bacterial) and control (BSA) materials. Analysis of the data indicates that high-molecular-weight complexes of bacterial cell walls may adversely affect pulpal tissue across freshly exposed dentin.

  20. Study of the areas and thicknesses of mesiobucal root canals prepared by three endodontic techniques Estudo das áreas e espessuras de canais radiculares mésio-vestibulares preparados por três técnicas endodônticas

    Directory of Open Access Journals (Sweden)

    Isa Geralda Teixeira Constante

    2007-06-01

    Full Text Available The purpose of this study was to compare, in vitro, by means of computerized analysis of digital radiographic images, the anatomic alterations produced in the mandibular molar tooth dentinal walls of mesiobucal canals with severe curvature by three different endodontic techniques: Progressive Preparation, Staged and Serial Preparation. A selection was made of 45 extracted, human, mandibular molars, with root curvatures greater than 25°. They were divided into three groups for every technique studied, which were then sub-divided into three sub-groups in accordance with the position of the curvature along the root: cervical, median or apical. After access surgery and tooth length determination, the canals were filled with 100% Barium Sulphate radiological contrast and the teeth were then radiographed with a direct digital radiography system, using a special apparatus capable of keeping the samples in the same spatial position during the different radiographic takes. After the above-mentioned endodontic techniques had been performed, the teeth were again filled with Barium sulphate and were also radiographed under the same previously mentioned conditions. The pre- and post-operative digital images were then analyzed in two computerized programs, AutoCAD 2004 and CorelDraw 10, to assess, respectively, the areas and the horizontal alterations which occurred in the internal and external walls of the root canals. The results indicated that although no significant differences among the techniques were shown in the statistical analysis, in a descriptive analysis the Progressive Preparation technique was shown to be more regular, uniform and effective.Objetivou-se comparar, in vitro, através de análise computadorizada de imagens radiográficas digitais, as alterações anatômicas promovidas nas paredes dentinárias de canais mésio-vestibulares com curvatura severa de molares inferiores por três técnicas endodônticas diferentes: Preparo Progressivo

  1. APF and dentifrice effect on root dentin demineralization and biofilm

    NARCIS (Netherlands)

    G.C. Vale; C.P.M. Tabchoury; A.A. Del Bel Cury; L.M.A. Tenuta; J.M. ten Cate; J.A. Cury

    2011-01-01

    Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for denti

  2. Amalgam stained dentin: a proper substrate for bonding resin composite?

    NARCIS (Netherlands)

    Scholtanus, J.D.

    2016-01-01

    Nowadays the use of dental amalgam is mostly abandoned and substituted by tooth colored resin composites that can be bonded to teeth tissues by adhesive techniques. The aim of this thesis was to find out whether dark stained dentin, as often observed after removal of amalgam restorations and attribu

  3. Economic aspects of the detection of occlusal dentine caries

    DEFF Research Database (Denmark)

    Norlund, Anders; Axelsson, Susanna; Dahlen, Gunnar

    2009-01-01

    OBJECTIVE: To evaluate the cost of true-positive occlusal dentine caries detection in permanent molars assessed by: (I) visual-tactile examination, (II) visual-tactile examination combined with bitewing radiographs, and (III) selective radiographic examination of patients with lesions detected cl...

  4. Guided tissue remineralisation of partially demineralised human dentine.

    Science.gov (United States)

    Tay, Franklin R; Pashley, David H

    2008-03-01

    Biomineralisation is a well-regulated process mediated by extracellular matrix proteins. Biomimetic remineralisation strategies should reproduce the dimension and structural hierarchy of apatite deposits within a demineralised collagen matrix. Interfibrillar and intrafibrillar remineralisation of phosphoric acid-etched human dentine was demonstrated in this study using a Portland cement/phosphate-containing fluid system in the presence of polyacrylic acid and polyvinylphosphonic acid as respective calcium phosphate- and collagen-binding matrix protein analogues. Metastable amorphous calcium phosphate nanoprecursors were generated when polyacrylic acid was included in the phosphate-containing fluid. When both polyvinylphosphonic acid and polyacrylic acid were included, these nanoprecursors were attracted to the acid-demineralised collagen matrix and transformed into polyelectrolyte-stabilised apatite nanocrystals that assembled along the microfibrils (intrafibrillar remineralisation) and surface of the collagen fibrils (interfibrillar remineralisation). Transition from nanocrystals to larger apatite platelets probably occurred via the formation of mesocrystal intermediates. Guided tissue remineralisation is potentially useful in the remineralisation of acid-etched dentine that is incompletely infiltrated by dentine adhesives, as well as partially demineralised caries-affected dentine.

  5. Proteolytic processing of dentin sialophosphoprotein (DSPP) is essential to dentinogenesis.

    Science.gov (United States)

    Zhu, Qinglin; Gibson, Monica Prasad; Liu, Qilin; Liu, Ying; Lu, Yongbo; Wang, Xiaofang; Feng, Jian Q; Qin, Chunlin

    2012-08-31

    DSPP, which plays a crucial role in dentin formation, is processed into the NH(2)-terminal and COOH-terminal fragments. We believe that the proteolytic processing of DSPP is an essential activation step for its biological function in biomineralization. We tested this hypothesis by analyzing transgenic mice expressing the mutant D452A-DSPP in the Dspp-knock-out (Dspp-KO) background (referred to as "Dspp-KO/D452A-Tg" mice). We employed multipronged approaches to characterize the dentin of the Dspp-KO/D452A-Tg mice, in comparison with Dspp-KO mice and mice expressing the normal DSPP transgene in the Dspp-KO background (named Dspp-KO/normal-Tg mice). Our analyses showed that 90% of the D452A-DSPP in the dentin of Dspp-KO/D452A-Tg mice was not cleaved, indicating that D452A substitution effectively blocked the proteolytic processing of DSPP in vivo. While the expression of the normal DSPP fully rescued the dentin defects of the Dspp-KO mice, expressing the D452A-DSPP failed to do so. These results indicate that the proteolytic processing of DSPP is an activation step essential to its biological function in dentinogenesis.

  6. In vitro reparative dentin: a biochemical and morphological study

    Directory of Open Access Journals (Sweden)

    G. Teti

    2013-08-01

    Full Text Available In this study, starting from human dental pulp cells cultured in vitro, we simulated reparative dentinogenesis using a medium supplemented with different odontogenic inductors. The differentiation of dental pulp cells in odontoblast-like cells was evaluated by means of staining, and ultramorphological, biochemical and biomolecular methods. Alizarin red staining showed mineral deposition while transmission electron microscopy revealed a  synthesis of extracellular matrix fibers during the differentiation process. Biochemical assays demonstrated that the differentiated phenotype expressed odontoblast markers, such as Dentin Matrix Protein 1 (DMP1 and Dentin Sialoprotein (DSP, as well as type I collagen. Quantitative data regarding the mRNA expression of DMP1, DSP and type I  collagen were obtained by Real Time PCR. Immunofluorescence data demonstrated the various localizations of DSP and DMP1 during odontoblast differentiation. Based on our results, we obtained odontoblast-like cells which simulated the reparative dentin processes in order to better investigate the mechanism of odontoblast differentiation, and dentin extracellular matrix deposition and mineralization. 

  7. Characterization and Streptococcus mutans adhesion on air polishing dentin.

    Science.gov (United States)

    Tada, Kazuhiro; Oda, Hirotake; Inatomi, Michitomo; Sato, Soh

    2014-07-01

    Air polishing is known as an effective and time saving tooth cleaning method. However, this method increased surface roughness and bacterial adhesion on dentin surface. The aim of this study was to characterize and examine Streptococcus mutans adhesion on dentin surface after air polishing as compared to the conventional method. The dentin blocks (4 × 4 × 1 mm) were polished by a rubber cup with polishing material (Polishing) and air-polished by 25 μm glycine (G25), 65 μm glycine (G65), and 65 μm sodium bicarbonate (NHC65) microparticles. Surface roughness (Ra) was measured by a laser electron microscope. The amount of adhered S. mutans was quantified using a resazurin reduction assay (alamarBlue(®)). The Ra of G25 and G65 was significantly (p Polishing. However, there was no significant difference in S. mutans adhesion among Polishing, G25, and G65, while NHC65 showed significantly (p polishing using glycine microparticles conditioned S. mutans adhesion on dentin surface in a similar fashion than the conventional method, and less than air polishing using sodium bicarbonate microparticles.

  8. Bonding longevity of flowable GIC layer in artificially carious dentin

    NARCIS (Netherlands)

    Tedesco, T.K.; Bonifácio, C.C.; Hesse, D.; Kleverlaan, C.J.; Lenzi, T.L.; Raggio, D.P.

    2014-01-01

    Purpose To evaluate the bond longevity of glass ionomer cement (GIC) to sound and artificially carious dentin, using a high viscosity material with regular consistency and using a flowable GIC, after one year water storage. Material and methods Sixty bovine incisors were polished to obtain flat bucc

  9. Compounded PHOSPHO1/ALPL deficiencies reduce dentin mineralization.

    Science.gov (United States)

    McKee, M D; Yadav, M C; Foster, B L; Somerman, M J; Farquharson, C; Millán, J L

    2013-08-01

    Phosphatases are involved in bone and tooth mineralization, but their mechanisms of action are not completely understood. Tissue-nonspecific alkaline phosphatase (TNAP, ALPL) regulates inhibitory extracellular pyrophosphate through its pyrophosphatase activity to control mineral propagation in the matrix; mice without TNAP lack acellular cementum, and have mineralization defects in dentin, enamel, and bone. PHOSPHO1 is a phosphatase found within membrane-bounded matrix vesicles in mineralized tissues, and double ablation of Alpl and Phospho1 in mice leads to a complete absence of skeletal mineralization. Here, we describe mineralization abnormalities in the teeth of Phospho1(-/-) mice, and in compound knockout mice lacking Phospho1 and one allele of Alpl (Phospho1(-/-);Alpl(+/-) ). In wild-type mice, PHOSPHO1 and TNAP co-localized to odontoblasts at early stages of dentinogenesis, coincident with the early mineralization of mantle dentin. In Phospho1 knockout mice, radiography, micro-computed tomography, histology, and transmission electron microscopy all demonstrated mineralization abnormalities of incisor dentin, with the most remarkable findings being reduced overall mineralization coincident with decreased matrix vesicle mineralization in the Phospho1(-/-) mice, and the almost complete absence of matrix vesicles in the Phospho1(-/-);Alpl(+/-) mice, whose incisors showed a further reduction in mineralization. Results from this study support prominent non-redundant roles for both PHOSPHO1 and TNAP in dentin mineralization.

  10. Dentin dysplasia type I : Five cases within one family

    NARCIS (Netherlands)

    Kalk, WWI; Batenburg, RHK; Vissink, A

    1998-01-01

    Five cases of dentin dysplasia type I within one family are described. Clinically and radiologically, such patients are characterized by a delayed eruption pattern, opacity of the incisional margins, hypermobility of the teeth, short and defective roots, and obliterated pulp chambers. A conservative

  11. Anterior canal BPPV and apogeotropic posterior canal BPPV: two rare forms of vertical canalolithiasis.

    Science.gov (United States)

    Califano, L; Salafia, F; Mazzone, S; Melillo, M G; Califano, M

    2014-06-01

    Posterior canal benign paroxysmal positional vertigo (BPPV) is the most frequent form of BPPV. It is characterized by a paroxysmal positioning nystagmus evoked through Dix-Hallpike and Semont positioning tests. Anterior canal BPPV (AC) is more rare than posterior canal BPPV; it presents a prevalent down beating positioning nystagmus, with a torsional component clockwise for the left canal, counterclockwise for the right canal. Due to the possible lack of the torsional component, it is sometimes difficult to identify the affected ear. An apogeotropic variant of posterior BPPV (APC) has recently been described, characterised by a paroxysmal positional nystagmus in the opposite direction to the one evoked in posterior canal BPPV: the linear component is down-beating, the torsional component is clockwise for the right canal, counter-clockwise for the left canal, so that a contra-lateral anterior canal BPPV could be simulated. During a 16 month period, of 934 BPPV patients observed, the authors identified 23 (2.5%) cases of apogeotropic posterior canal BPPV and 11 (1.2%) cases of anterior canal BPPV, diagnosed using the specific oculomotor patterns described in the literature. Anterior canal BPPV was treated with the repositioning manoeuvre proposed by Yacovino, which does not require identification of the affected side, whereas apogeotropic posterior canal BPPV was treated with the Quick Liberatory Rotation manoeuvre for the typical posterior canal BPPV, since in the Dix-Hallpike position otoliths are in the same position if they come either from the ampullary arm or from the non-ampullary arm. The direct resolution of BPPV (one step therapy) was obtained in 12/34 patients, 8/23 patients with APC and 4/11 patients with AC; canalar conversion into typical posterior canal BPPV, later treated through Quick Liberatory Rotation (two-step therapy), was obtained in 19 patients,14/23 with APC and 5/11 with AC. Three patients were lost to follow-up. Considering the effects of

  12. Comparative Analysis of Crack Propagation in Roots with Hand and Rotary Instrumentation of the Root Canal -An Ex-vivo Study

    Science.gov (United States)

    Krishnaswamy, Manjunath Mysore

    2016-01-01

    Introduction Success of any endodontic treatment depends on strict adherence to ‘endodontic triad’. Preparation of root canal system is recognized as being one of the most important stages in root canal treatment. At times, we inevitably end up damaging root dentin which becomes a Gateway for infections like perforation, zipping, dentinal cracks and minute intricate fractures or even vertical root fractures, thereby resulting in failure of treatment. Several factors may be responsible for the formation of dentinal cracks like high concentration of sodium hypochlorite, compaction methods and various canal shaping methods. Aim To compare and evaluate the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Materials and Methods Seventy extracted premolars with straight roots were mounted on resin blocks with simulated periodontal ligaments, exposing 1-2 mm of the apex followed by sectioning of 1mm of root tip for better visualization under stereomicroscope. The teeth were divided into seven groups of 10 teeth each – a control group and six experimental groups. Subgroup A & B were instrumented with: Stainless Steel hand files (SS) up to Root Canal Length (RCL) & (RCL –1 mm) respectively; sub group C & D were instrumented using ProTaper Universal (PTU) up to RCL and (RCL -1mm) respectively; subgroup E & F were instrumented using ProTaper Next (PTN) up to RCL & (RCL -1 mm) respectively. Stereomicroscopic images of the instrumentation sequence were compared for each tooth. The data was analyzed statistically using descriptive analysis by ‘Phi’ and ‘Cramers’ test to find out statistical significance between the groups. The level of significance was set at pProTaper Universal & ProTaper Next though statistically not significant. Samples instrumented up to 1mm short of working length (RCL-1mm) showed lesser number of cracks. Conclusion All groups showed cracks formation, the stainless steel group

  13. Inner Harbor Navigation Canal Basin Velocity Analysis

    Science.gov (United States)

    2014-10-01

    ER D C/ CH L TR -1 4- 12 Inner Harbor Navigation Canal Basin Velocity Analysis Co as ta l a nd H yd ra ul ic s La bo ra to ry...library at http://acwc.sdp.sirsi.net/client/default. ERDC/CHL TR-14-12 October 2014 Inner Harbor Navigation Canal Basin Velocity Analysis...system of levees, gates, and drainage structures in the Inner Harbor Navigation Canal (IHNC) basin and the greater New Orleans, Louisiana, area. Two

  14. A scoping review of root canal revascularization: relevant aspects for clinical success and tissue formation.

    Science.gov (United States)

    Conde, M C M; Chisini, L A; Sarkis-Onofre, R; Schuch, H S; Nör, J E; Demarco, F F

    2016-10-22

    The aim of this scoping study was to evaluate the survival rate and nature of tissue formed inside root canals of human immature permanent teeth with necrotic pulps (NIPT) under root canal revascularization (RCR). The search was performed in SciVerse Scopus®, PubMed/MEDLINE, Web of Science®, BIREME and in the grey literature up to November 2015. The keywords were selected using MeSH terms and DECs. Two independent reviewers scrutinized the records obtained considering specific inclusion criteria. The included studies were evaluated in accordance with a modified Arksey and O' Malley's framework. From 375 studies that were evaluated, 75 were included. A total of 367 NIPT were submitted to RCR, from which only 21 needed further endodontic treatment. The weighted mean follow-up time was 17.6 months. The data were derived mainly from case reports (69%) or small case series (15%). NaOCl [0.5-6%] was applied as the disinfecting solution in almost all studies. Triple antibiotic paste was as effective as Ca(OH)2 as on intracanal medicament. De novo tissue was cementum and poorly mineralized bone positive to bone sialoprotein (BSP) but negative to dentine sialoprotein (DSP). Failures were associated mainly with reinfection of the root canal. The majority of included studies reported a significant increase in both root length and width. However, as most of these data came from case reports, they must be interpreted with care, as most were focused on treatment successes (not failures). Therefore, well-designed randomized controlled trials comparing RCR with available apexification treatments are needed to address this gap in the literature.

  15. Ablation of dentin by irradiation of violet diode laser

    Science.gov (United States)

    Hatayama, H.; Kato, J.; Akashi, G.; Hirai, Y.; Inoue, A.

    2006-02-01

    Several lasers have been used for clinical treatment in dentistry. Among them, diode lasers are attractive because of their compactness compared with other laser sources. Near-infrared diode lasers have been practically used for cutting soft tissues. Because they penetrate deep to soft tissues, they cause sufficiently thick coagulation layer. However, they aren't suitable for removal of carious dentin because absorption by components in dentin is low. Recently, a violet diode laser with a wavelength of 405nm has been developed. It will be effective for cavity preparation because dentin contains about 20% of collagen whose absorption coefficient at a violet wavelength is larger than that at a near-infrared wavelength. In this paper, we examined cutting performance of the violet diode laser for dentin. To our knowledge, there have been no previous reports on application of a violet laser to dentin ablation. Bovine teeth were irradiated by continuous wave violet diode laser with output powers in a range from 0.4W to 2.4W. The beam diameter on the sample was about 270μm and an irradiation time was one second. We obtained the crater ablated at more than an output power of 0.8W. The depth of crater ranged from 20μm at 0.8W to 90μm at 2.4W. Furthermore, the beam spot with an output power of 1.7W was scanned at a speed of 1mm/second corresponding to movement of a dentist's hand in clinical treatment. Grooves with the depth of more than 50μm were also obtained. From these findings, the violet diode laser has good potential for cavity preparation. Therefore, the violet diode laser may become an effective tool for cavity preparation.

  16. Dentin bonding--state of the art 1999.

    Science.gov (United States)

    Perdigão, J; Lopes, M

    1999-12-01

    The adhesion of restorative materials to the hard components of tooth structure has been a goal pursued by many researchers ever since Buonocore established the foundation for adhesive and preventive dentistry. Based on the industrial use of phosphoric acid to obtain better adhesion of paints and resin coatings to metal surfaces, Buonocore proposed that phosphoric acid could be used to transform the surface of enamel to "render it more receptive to adhesion." Subsequent research indicated that the formation of taglike resin prolongations into the enamel microporosities was the leading bonding mechanism of resin to phosphoric acid-etched enamel. The enamel bonding agents of the 1960s and 1970s progressively evolved into complex multibottle or universal adhesives in the early 1990s, which were designed to bond to enamel, dentin, composite, amalgam, porcelain, and non-precious metal. Although bonding to enamel has been a dependable technique, bonding to dentin still represents an overwhelming task because dentin is a naturally wet organic tissue penetrated by a tubular maze containing the odontoblastic process, which communicates with the pulp. This intrinsic moisture may actually benefit the chemistry of the newest adhesive systems, which must be applied on moist dentin to be effective. In fact, the collapse of the collagen that occurs on air-drying may prevent the adhesive monomers from penetrating the network of nano-channels formed by the dissolution of hydroxyapatite crystals between collagen fibrils. In view of the complexity of the mechanisms associated with these mechanisms, the objective of this review article is to summarize the most recent concepts in dentin bonding.

  17. Viability of imaging structures inside human dentin using dental transillumination

    Science.gov (United States)

    Grandisoli, C. L.; Alves-de-Souza, F. D.; Costa, M. M.; Castro, L.; Ana, P. A.; Zezell, D. M.; Lins, E. C.

    2014-02-01

    Dental Transillumination (DT) is a technique for imaging internal structures of teeth by detecting infrared radiation transmitted throughout the specimens. It was successfully used to detect caries even considering dental enamel and dentin scatter infrared radiation strongly. Literature reports enamel's scattering coefficient is 10 to 30 times lower than dentin; this explain why DT is useful for imaging pathologies in dental enamel, but does not disable its using for imaging dental structures or pathologies inside the dentin. There was no conclusive data in the literature about the limitations of using DT to access biomedical information of dentin. The goal in this study was to present an application of DT to imaging internal structures of dentin. Slices of tooth were confectioned varying the thickness of groups from 0.5 mm up to 2,5 mm. For imaging a FPA InGaAs camera Xeva 1.7- 320 (900-1700 nm; Xenics, Inc., Belgium) and a 3W lamp-based broadband light source (Ocean Optics, Inc., USA) was used; bandpass optical filters at 1000+/-10 nm, 1100+/-10 nm, 1200+/-10 nm and 1300+/-50 nm spectral region were also applied to spectral selection. Images were captured for different camera exposure times and finally a computational processing was applied. The best results revealed the viability to imaging dent in tissue with thickness up to 2,5 mm without a filter (900-1700nm spectral range). After these results a pilot experiment of using DT to detect the pulp chamber of an incisive human tooth was made. New data showed the viability to imaging the pulp chamber of specimen.

  18. Assessment of dysplastic dentin in osteogenesis imperfecta and dentinogenesis imperfecta.

    Science.gov (United States)

    Malmgren, Barbro; Lindskog, Sven

    2003-04-01

    Two semiquantitative scoring systems, Clinical Radiographic Score (CRS) and Dysplastic Dentin Score (DDS), were introduced for analyzing degree of dysplastic manifestations in dentin. The utility of both systems was demonstrated in a large material of teeth from patients with dentinogenesis imperfecta (DI) and osteogenesis imperfecta (OI). Twenty teeth from healthy controls, 81 teeth from 40 patients with OI, and 18 teeth with DI without OI (DI type II) were examined. The degree of dysplasia was correlated with type and form of OI and type of DI. The median DDS did not differ between DI associated with OI (DI type I) and DI type II. DDS in OI patients without clinical signs of DI was above that of control teeth. Both circumpulpal and mantle dentin showed increased DDS, although circumpulpal dentin was more severely affected. The median DDS was highest for the most severe type of non-lethal OI (type III). DDS increased significantly with form (severity) of OI. A significant association between DDS and CRS was found, although diagnosis of DI in less severe cases was not possible based on radiographic or clinical signs alone. Thus, the DDS system proved valuable when the CRS system based on radiographic/clinical manifestations failed, the most significant finding being subclinical histological manifestations of DI in patients with OI but without clinical or radiographic signs of DI. These subtle dysplastic changes are most likely an expression of genetic disturbances associated with OI and should not be diagnosed as DI, but rather be termed histologic manifestations of dysplastic dentin associated with OI.

  19. Shaping Ability of Reciproc, UnicOne, and Protaper Universal in Simulated Root Canals

    Directory of Open Access Journals (Sweden)

    Etevaldo Matos Maia Filho

    2015-01-01

    Full Text Available The study aimed to compare the shaping effects, preservation of the original curvature, and transportation of the apical foramen of Reciproc (VDW, Munich, Germany, UnicOne (Medin, Nové Město na Moravě, Czech Republic, and Protaper Universal (Dentsply Maillefer, Ballaigues, Switzerland in simulated root canals. Thirty resin blocks with simulated curved root canals were distributed into three groups (n=10, and prepared using Reciproc (RCp, UnicOne (UnO and the Protaper Universal (PTu. Standardized photographs were taken before and after the instrumentation, after which they were superimposed. Measurements were taken of the quantity of resin removed from the inner and outer walls of the curvature at 6 levels, the curvature angles before and after instrumentation, and the transportation of the apical foramen. RCp obtained the highest values for amount of resin removed from the inner wall while UnO demonstrated similar shaping on both the inner and outer walls. PTu produced the greatest transportation of foramen when compared to the reciprocating instruments. There was no significant difference between the groups in terms of the change in angle (P>0.05. All the instruments were capable of maintaining the original curvature of the root canal; however, the UnO, which used reciprocating movement, produced more conservative shapes with lower foramen transportation.

  20. Antimicrobial effect of different root canal irrigant combinations on infected root canals under passive ultrasonic irrigation%超声下不同根管冲洗剂组合对感染根管内粪肠球菌杀灭效果的研究

    Institute of Scientific and Technical Information of China (English)

    张敏; 仇臖; 侯晖; 李琳; 周洁; 范晓敏

    2014-01-01

    AIM:To compare the antimicrobial effect of different root canal irrigant combinations under pas-sive ultrasonic irrigation in root canals.METHODS:90 human root canals contaminated with Enterococcus faecalis were randomly divided into 4 experimental groups (group A:25 g/L NaClO/20 g/L CHX,group B:25 g/L NaClO 30 mL/L H2 O2 ,group C:10 g/L NaClO 20 g/L CHX,group D:10 g/L NaClO/30 mL/L H2 O2 )and 2 two control groups (group E:52.5 g/L NaClO,group F:0.9%normal saline,n=10,5 were used as base line control).Before and after treatment bacterial content on the surface of root canal walls and at 100,200,300 μm in depth inside the dentinal tubules was measured and analyzed by means of one-way analysis of variance.RESULTS:On the surface and at different depths of dentine,the bactericidal efficiency of groups of A,B,C,D and E were significantly greater than that of group F (P0.05 )except at depth of 200 ~300um,the bactericidal efficiency of group A was lower than that of group E (P0.05).CONCLUSION:The combination of 25 g/L NaClO and 20 g/L CHX can be considered to be the ideal irrigant of root canal disinfection.%目的:比较超声作用下不同根管冲洗剂组合对根管内粪肠球菌的杀灭效果。方法:取粪肠球菌感染根管模型样本90个,随机分为6组(n=15),其中5个样本用于基线对照,10个样本分别按相应分组处理,A组:25 g/L次氯酸钠液液+20 g/L洗必泰液;B组:25 g/L次氯酸钠液+30 mL/L过氧化氢液;C组:10 g/L次氯酸钠液+20 g/L洗必泰液;D组:10 g/L次氯酸钠液+30 mL/L过氧化氢液;E组:52.5 g/L次氯酸钠液阳性对照;F组:生理盐水阴性对照。处理前后从样本的根管壁表面采样,并钻取不同深度牙本质进行细菌培养和计数。结果:A、B、C、D、E组根管壁表面及不同深度牙本质的细菌清除率均显著高于F组(P<0.05);对各层牙本质的细菌清除率,A组高于B、C、D组(P<0.05

  1. Residual Antimicrobial Activity of MTAD(® in Human Dentin After Obturation with Gutta-Percha/AH26 and Resilon/RealSeal SE at Different Time Intervals; An Ex Vivo Study.

    Directory of Open Access Journals (Sweden)

    Behnam Bolhari

    2014-02-01

    Full Text Available To eliminate microorganisms that are responsible for pulpal and periapical infections and to prevent reinfection of the root canal system an effective chemomechanical preparation by irrigants with sustained antimicrobial activity is beneficial. Hereby, we evaluated the residual antibacterial activity of MTAD after canal obturation at different time intervals.A total of 120 human single-canalled anterior teeth were selected. The root canals were instrumented to a standardized apical size. Among all, 90 teeth received final irrigation with MTAD and were divided into three groups according to their obturation materials; i.e. gutta-percha/AH26, Resilon/RealSeal SE and positive controls. All these groups were divided into three 1-, 3- and 6-week time interval subgroups. Thirty teeth as negative control had no final irrigation with MTAD, but were obturated with gutta-percha/AH26 or Resilon/RealSealSE. Dentin powder was prepared after 1, 3 and 6 weeks. Dentin powder was exposed to Enterococcus faecalis for 24h and then cultured. Colony Forming Unit (CFU was counted.Residual antimicrobial activity of MTAD in the teeth obturated with guttapercha/AH26 was significantly higher than the teeth obturated with Resilon/RealSeal SE (p<0.001. It also showed a time dependent decrease in MTAD antimicrobial activity for all groups. The highest antimicrobial activity of MTAD was found in the 1-week positive control and 1-week gutta-percha/AH26 specimens. The lowest antimicrobial activity of MTAD was found in 6-week Resilon/RealSeal SE samples and then the negative controls.MTAD had antimicrobial activity even at the sixth week, although it had a time-dependent decrease. Resilon/Epiphany SE significantly decreased antimicrobial activity of MTAD at all time points.

  2. Hyperlipidemia induced by high-fat diet enhances dentin formation and delays dentin mineralization in mouse incisor.

    Science.gov (United States)

    Ye, Xin; Zhang, Jin; Yang, Pishan

    2016-10-01

    Dyslipidemia has become a serious health problem in children and adolescents worldwide for its high prevalence. Since hard tissues of permanent teeth form mainly during this period and lipids are actively involved in tooth development, the effects of hyperlipidemia on dental tissue formation and mineralization need to be illustrated. In this study, hyperlipidemia model was established in mice fed with high-fat diet (HFD). Micro-CT and histomorphological analyses were performed on the mandibular bones to assess the morphological changes of the mandibular incisor and first molar. After 4 weeks of HFD feeding, mice had significantly elevated serum lipid levels compared with mice fed with control diet. After 8 weeks, the mandibular incisor presented significantly increased dentin thickness and decreased diameter of pulp cavity in HFD-fed mice compared with control diet-fed mice, while its gross morphology and enamel thickness were not altered. In the mandibular first molar, dentin thickness of root did not show difference between the two groups. Histological section showed that mandibular incisor of HFD-fed mice manifested a wider predentin region and a lower mineral apposition rate compared with that of the control mice. In conclusion, hyperlipidemia induced by HFD feeding enhances dentin formation and delays dentin mineralization in the developing mouse incisor.

  3. Boolean nested canalizing functions: a comprehensive analysis

    CERN Document Server

    Li, Yuan; Murrugarra, David; Aguilar, Boris; Laubenbacher, Reinhard

    2012-01-01

    Boolean network models of molecular regulatory networks have been used successfully in computational systems biology. The Boolean functions that appear in published models tend to have special properties, in particular the property of being nested canalizing, a property inspired by the concept of canalization in evolutionary biology. It has been shown that networks comprised of nested canalizing functions have dynamic properties that make them suitable for modeling molecular regulatory networks, namely a small number of (large) attractors, as well as relatively short limit cycles. This paper contains a detailed analysis of this class of functions, based on a novel normal form as polynomial functions over the Boolean field. The concept of layer is introduced that stratifies variables into different classes depending on their level of dominance. Using this layer concept a closed form formula is derived for the number of nested canalizing functions with a given number of variables. Additional metrics analyzed in...

  4. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    Science.gov (United States)

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  5. In vivo remineralization of dentin using an agarose hydrogel biomimetic mineralization system

    Science.gov (United States)

    Han, Min; Li, Quan-Li; Cao, Ying; Fang, Hui; Xia, Rong; Zhang, Zhi-Hong

    2017-02-01

    A novel agarose hydrogel biomimetic mineralization system loaded with calcium and phosphate was used to remineralize dentin and induce the oriented densely parallel packed HA layer on defective dentin surface in vivo in a rabbit model. Firstly, the enamel of the labial surface of rabbits’ incisor was removed and the dentin was exposed to oral environment. Secondly, the hydrogel biomimetic mineralization system was applied to the exposed dentin surface by using a custom tray. Finally, the teeth were extracted and evaluated by scanning electron microscopy, X-ray diffraction, and nanoindentation test after a certain time of mineralization intervals. The regenerated tissue on the dentin surface was composed of highly organised HA crystals. Densely packed along the c axis, these newly precipitated HA crystals were perpendicular to the underlying dental surface with a tight bond. The demineralized dentin was remineralized and dentinal tubules were occluded by the grown HA crystals. The nanohardness and elastic modulus of the regenerated tissue were similar to natural dentin. The results indicated a potential clinical use for repairing dentin-exposed related diseases, such as erosion, wear, and dentin hypersensitivity.

  6. The effects of desensitizing agents on the hydraulic conductance of human dentin in vitro.

    Science.gov (United States)

    Greenhill, J D; Pashley, D H

    1981-03-01

    The hydrodynamic theory of dentin sensitivity states that a stimulus applied at the orifice of exposed dentinal tubules causes movement of tubular fluid which stimulates nerve receptors. The fluid should obey principles of fluid movement through capillary tubes. Any decrease in the functional radius of the dentinal tubules should greatly reduce the rate of fluid flow, thus reducing dentinal sensitivity. The purpose of this study was to evaluate the ability of agents that have been used previously for clinical dentin desensitization to reduce the rate of fluid flow through dentin in vitro. Dentin discs prepared from extracted human third molars were treated with 50% citric acid to remove debris from tubular orifices. After placing the discs in a split chamber device, the rate at which buffer solution could filter across the dentin under 240 cm of water pressure was measured. The occlusal side of the disc was then treated with an agent thought to desensitize dentin to determine if it reduced fluid flow rate. Discs that had more than a 50% reduction in flow rate were examined by scanning electron microscopy to determine if those agents that decreased fluid flow also partially occluded tubular orifices. This in vitro model provided a useful quantitative method for screening a host of preparations that have been used in the past to decrease dentin sensitivity.

  7. Effects of a Dicalcium and Tetracalcium Phosphate-Based Desensitizer on In Vitro Dentin Permeability.

    Directory of Open Access Journals (Sweden)

    Jianfeng Zhou

    Full Text Available The present study evaluated the effectiveness of a dicalcium and tetracalcium phosphate-based desensitizer in reducing dentin permeability in vitro. Dentin fluid flow was measured before and after treatment of dentin with patent dentinal tubules using 1 or 3 applications of the dicalcium and tetracalcium phosphate containing agent TeethmateTM (TM and comparing the results with two sodium fluoride varnishes VellaTM (VLA and VanishTM (VAN, after storage in artificial saliva for 24 h, 48 h and 7 days. Significant differences were observed among the 4 methods employed for reducing dentin permeability (p < 0.001 and the 3 post-treatment times (p < 0.001. VLA and VAN never achieved 50% permeability reductions consistently in any of the 3 time periods. Only the calcium phosphate-based desensitizer applied for 3 times consistently reduced dentin permeability by 50% after 24 h. When applied once, the permeability reduction of TM increased progressively over the 3 time periods. After 7 days, only one and three applications of the calcium phosphate-based desensitizer consistently reduced dentin permeability by more than 50%. Permeability reductions corresponded well with scanning electron microscopy examination of dentinal tubule orifice occlusion in dentin specimens treated with the agents. Overall, the dicalcium and tetracalcium phosphate-based desensitizer is effective in reducing dentin permeability via a tubule occlusion mechanism. The ability of the agent to reduce dentin permeability renders it to be potentially useful as a clinical dentin desensitizing agent, which has to be confirmed in future clinical studies. By contrast, the two sodium fluoride varnishes are not effective in dentin permeability reduction and should be considered as topical fluoride delivering agents rather than tubular orifice-blocking agents.

  8. Effects of a Dicalcium and Tetracalcium Phosphate-Based Desensitizer on In Vitro Dentin Permeability.

    Science.gov (United States)

    Zhou, Jianfeng; Chiba, Ayaka; Scheffel, Debora L S; Hebling, Josimeri; Agee, Kelli; Niu, Li-Na; Tay, Franklin R; Pashley, David H

    2016-01-01

    The present study evaluated the effectiveness of a dicalcium and tetracalcium phosphate-based desensitizer in reducing dentin permeability in vitro. Dentin fluid flow was measured before and after treatment of dentin with patent dentinal tubules using 1 or 3 applications of the dicalcium and tetracalcium phosphate containing agent TeethmateTM (TM) and comparing the results with two sodium fluoride varnishes VellaTM (VLA) and VanishTM (VAN), after storage in artificial saliva for 24 h, 48 h and 7 days. Significant differences were observed among the 4 methods employed for reducing dentin permeability (p < 0.001) and the 3 post-treatment times (p < 0.001). VLA and VAN never achieved 50% permeability reductions consistently in any of the 3 time periods. Only the calcium phosphate-based desensitizer applied for 3 times consistently reduced dentin permeability by 50% after 24 h. When applied once, the permeability reduction of TM increased progressively over the 3 time periods. After 7 days, only one and three applications of the calcium phosphate-based desensitizer consistently reduced dentin permeability by more than 50%. Permeability reductions corresponded well with scanning electron microscopy examination of dentinal tubule orifice occlusion in dentin specimens treated with the agents. Overall, the dicalcium and tetracalcium phosphate-based desensitizer is effective in reducing dentin permeability via a tubule occlusion mechanism. The ability of the agent to reduce dentin permeability renders it to be potentially useful as a clinical dentin desensitizing agent, which has to be confirmed in future clinical studies. By contrast, the two sodium fluoride varnishes are not effective in dentin permeability reduction and should be considered as topical fluoride delivering agents rather than tubular orifice-blocking agents.

  9. Two root canals in maxillary central incisor

    Directory of Open Access Journals (Sweden)

    Fábio de Almeida Gomes

    2011-07-01

    Full Text Available Introduction and objective: The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Case report: This clinical article reports an unusual root canal configuration that was detected in a maxillary central incisor with two root canals, demonstrated by radiographic and computerized tomography exams. Conclusion: Knowledge of endodontic anatomy as well as the obtainment of both preoperative radiographs and tomography is important to detect abnormal tooth morphology.

  10. Effect of endodontic sealer and resin luting strategies on pull-out bond strength of glass fiber posts to dentin.

    Science.gov (United States)

    Souza-Junior, Eduardo J; Bueno, Vanessa C P S; Dias, Carlos T S; Paulillo, Luís A M S

    2010-01-01

    The aim of this study was to evaluate the influence of eugenol-containing endodontic sealers and luting strategy on the pull-out bond strength of glass fiber posts to dentin. Sixty-four bovine incisors were randomly assigned into two groups of 32 specimens each for obturation procedure with gutta-percha only, or with Pulp Canal Sealer EWT Subsequently, the roots were prepared for the fiber post Reforpost and all specimens of each endodontic sealing procedure were allocated to four groups (n = 8), according to the strategies for post cementation: A) Single Bond 2 and RelyX ARC; B) All Bond 2 and C&B cement; C) All Bond 2 and RelyX ARC; D) Single Bond 2 and C&B Cement. The posts were cemented immediately after the endodontic treatment. The pull-out test was performed at a cross-head speed of 0.5 mm/min in a universal testing machine (EMIC). Data (Kgf) were submitted to a two-way ANOVA and Tukey test (p < or = 0.05). The eugenol-based sealer did not influence the pull-out bond strength of fiber posts regardless of the luting strategy. RelyX ARC showed higher bond strength than C&B Cement when used with Single Bond 2 adhesive system, when the eugenol-based sealer was present. All Bond 2, when associated to all cements studied, promoted similar bond strength, regardless of the eugenol-containing endodontic sealer In conclusion, eugenol-containing sealer did not influence the pull-out bond strength values of the resin luting systems for glass fiber post cementation. The bond system and resin cement association from the same manufacturer had similar bond strength values for dentin.

  11. Effect of Different Irrigating Solutions and Endodontic Sealers on Bond Strength of the Dentin - Post Interface with and without Defects

    Science.gov (United States)

    Grassi, Felice R.; Pappalettere, Carmine; Di Comite, Mariasevera; Corsalini, Massimo; Mori, Giorgio; Ballini, Andrea; Crincoli, Vito; Pettini, Francesco; Rapone, Biagio; Boccaccio, Antonio

    2012-01-01

    Aims. To investigate how the interfacial shear strength of the dentin - post interface with and without defects changes for different combinations irrigant/sealer. Methods. In forty human decoronated and instrumented teeth, fibreglass posts were inserted. The obtained root segments were randomly assigned to four different groups according to the irrigant adopted and the cement used to seal the root canal. The root segments were processed for metyl-methacrylate embedding. Serial sections were obtained and submitted to histomorphometric analyses in order to observe any defect of adhesion at the dentin - post interface and to measure the defects' dimension. The serial sections were also submitted to micro-push-out test. The measured shear strength values were subjected to statistical analysis by one-way ANOVA. The values of bond strength determined for the defective samples were correlated with the dimension of the defects. Finite element models were built to interpret and corroborate the experimental findings. Results. ANOVA showed that the generic combination irrigant/sealer does not affect the interfacial shear strength values. The bond strength of the samples without defects was averagely twice as large as that of the defective samples. The defects occupying more than 12 % of the total transverse section area of the endodontic cement layer led to a reduction of the bond strength of about 70 %. The predictions of the finite element models were in agreement with the experimental results. Conclusion. Defects occupying less than 2 % of the total transverse section area of the cement layer were shown to be acceptable as they have rather negligible effects on the shear strength values. Technologies/protocols should be developed to minimize the number and the size of the defects. PMID:23055816

  12. The comparison between two irrigation regimens on the dentine wettability for an epoxy resin based sealer by measuring its contact angle formed to the irrigated dentine

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    Rayapudi Phani Mohan

    2015-01-01

    Conclusion: An irrigation regimen consisting of NaOCl with either EDTA or EDTAC solution as a final irrigant influences the dentine wettability and contact angle of a sealer. EDTAC as a final irrigant facilitates better dentin wettability than EDTA for AH Plus to promote its better flow and adhesion.

  13. Evaluation of Bond Strength and Quality of Fiber Posts Cemented With Two Cements in Asymmetric Dental Root Canal

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    Atefeh Ramezani

    2016-09-01

    Full Text Available Background and Objective:Debonding is one of the most common causes of failures in post fibers used in the root canalat interface of dentin-fiberpost. The purpose of this study is to evaluate the interface of the fibers post in the root canal with appropriate and inappropriate compliance with CBCT and its push-out bond strength with two types of resin cement used in the mandibular premolars. Materials and Methods:Forty (40Mandibular Premolarteeth which were extracted were useddue to theorthodontic problems. After endodontic, the teeth were randomly classified into two groups including teeth with post space in compliance with the fiber post and a group of posts space wider than fiber post. Thereafter,each group wassub-divided into two groups according to the used cement: panaviaF2.0 (Kuraray Medical Inc., Osaka, Japan, Rebilda DC(Voco, and Germany and finally, four groups were created [P.a:canal with appropriate adaptation + panavia F2.0, P.in:canal with inappropriate adaptation + panavia F2.0, R.a:canal with appropriate adaptation + Rebilda DC, R.in:canal with inappropriate adaptation + Rebilda DC]. Data analysis was carried out using ANOVA, Post hoc Tukey test, Chisquare test (p <0.05. Results: The bond strength was significantly affected by the analyzed root area (p-value = 0.03 and there was a significant difference between two canals with appropriate and inappropriate compliance with the same type of cement (p-value = 0.05. In addition, the bond strength was not affected by cement type (p-value = 0.67 and the area of the voids was higher in P.in groups. Nevertheless, in R.a group, no void was observed. Conclusion: The bond strength was affected by the post space but it was not affected by cementation techniques. As a result of this, applicator of Rebilda cement reduces the voids in the root canal with appropriate compliance

  14. Matrix metalloproteinase 20-dentin sialophosphoprotein interaction in oral cancer.

    Science.gov (United States)

    Saxena, G; Koli, K; de la Garza, J; Ogbureke, K U E

    2015-04-01

    Matrix metalloproteinase 20 (MMP-20), widely regarded as tooth specific, participates with MMP-2 in processing dentin sialophosphoprotein (DSPP) into dentin sialoprotein, dentin phosphoprotein, and dentin glycoprotein. In biochemical system, MMP-2, MMP-3, and MMP-9 bind with high affinity to, and are activated by, specific small integrin-binding ligand N-linked glycoproteins (SIBLINGs): bone sialoprotein, osteopontin, and dentin matrix protein 1, respectively. Subsequent reports documented possible biological relevance of SIBLING-MMP interaction in vivo by showing that SIBLINGs are always coexpressed with their MMP partners. However, the cognate MMPs for 2 other SIBLINGs-DSPP and matrix extracellular phosphogylcoprotein-are yet to be identified. Our goal was to investigate MMP-20 expression and to explore preliminary evidence of its interaction with DSPP in oral squamous cell carcinomas (OSCCs). Immunohistochemistry analysis of sections from 21 cases of archived human OSCC tissues showed immunoreactivity for MMP-20 in 18 (86%) and coexpression with DSPP in all 15 cases (71%) positive for DSPP. Similarly, 28 (93%) of 30 cases of oral epithelial dysplasia were positive for MMP-20. Western blot and quantitative real-time polymerase chain reaction analysis on OSCC cell lines showed upregulation of MMP-20 protein and mRNA, respectively, while immunofluorescence showed coexpression of MMP-20 and DSPP. Colocalization and potential interaction of MMP-20 with dentin sialoprotein was confirmed by coimmunoprecipitation and mass spectrometry analysis of immunoprecipitation product from OSCC cell lysate, and in situ proximity ligation assays. Significantly, results of chromatin immunoprecipation revealed a 9-fold enrichment of DSPP at MMP-20 promoter-proximal elements. Our data provide evidence that MMP-20 has a wider tissue distribution than previously acknowledged. MMP-20-DSPP specific interaction, excluding other MMP-20-SIBLING pairings, identifies MMP-20 as DSPP cognate MMP

  15. Localized mechanics of dentin self-etching adhesive system

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    Rodolfo Bruniera Anchieta

    2007-08-01

    Full Text Available The bond strength of composite resins (CRs to dentin is influenced by the interfacial microstructure of the hybrid layer (HL and the resin tags (TAG. The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 µm, two TAG lengths (13 or 17 µm and two loading conditions (perpendicular and oblique-25º were investigated by the finite element (FE analysis. Five two-dimensional FE models (M of a dentin specimen restored with CR (38 x 64 µm were constructed: M1 - no HL and no TAG; M2 - 3 µm of HL and 13 µm of TAG; M3 - 3 µm of HL and 17 µm of TAG; M4 - 6 µm of HL and 13 µm of TAG; and M5 - 6 µm of HL and 17 µm of TAG. Two distributed loadings (L (20N were applied on CR surface: L1 - perpendicular, and L2 - oblique (25º. Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys®, Houston, PA, USA software was used to calculate the stress fields. The peak of von Mises (sigmavM and maximum principal stress (sigmamax was higher in L2 than in L1. Microstructures (HL and TAG had no effect on local stresses for L1. Decreasing HL decreased sigmavM and sigmamax in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigmavM and sigmamax than TAG length. The peritubular dentin and its adjacent structures showed the highest sigmavM and sigmamax, mainly in the oblique loading.

  16. Effect of intracoronal bleaching agents on ultrastructure and mineral content of dentin

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    Fatemeh Maleknejad

    2012-01-01

    Full Text Available Aim: The purpose of this in vitro study was to evaluate the ultrastructural changes of dentin induced after exposure to different intracoronal tooth bleaching agents. Materials and Methods: Dental discs of 1 mm thickness were prepared from coronal dentin of sixty-four human maxillary premolars. Experimental specimens were divided into four subgroups: 45% carbamide peroxide, 35% hydrogen peroxide, sodium perborate + 30% hydrogen peroxide, sodium perborate + water. The specimens were then evaluated under scanning electron microscope to determine diameter of dentinal tubules and chemical analysis. Results: There was significant difference between dentinal tubule diameter of all test and control groups with the exception of sodium perborate + water. Chemical analysis revealed that there was no significant difference between experimental subgroups regarding calcium and sulfur wt%. Conclusions: All bleaching agents increased dentinal tubule diameter and promote alterations in mineral content of dentin with the exception of Sodium perborate mixed with water.

  17. Splicing site mutations in dentin sialophosphoprotein causing dentinogenesis imperfecta type II.

    Science.gov (United States)

    Holappa, Heidi; Nieminen, Pekka; Tolva, Liisa; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu

    2006-10-01

    Dentinogenesis imperfecta (DGI) type II (OMIM # 125490) is an inherited disorder affecting dentin. Defective dentin formation results in discolored teeth that are prone to attrition and fracture. To date, several mutations have been described in the dentin sialophosphoprotein (DSPP) gene, causing DGI types II and III and dentin dysplasia type II. DSPP encodes two proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Here, we describe a mutational analysis of DSPP in seven Finnish families with DGI type II. We report two mutations and five single nucleotide polymorphisms. In one family we found a mutation that has been described earlier in families with different ethnicity, while in six families we found a novel g.1194C>A (IVS2-3) transversion. Bioinformatic analysis of known DSPP mutations suggests that DGI type II is usually caused by aberration of normal splicing.

  18. Comparison of Push-Out Bond Strength of Two Bulk-Fill and One Conventional Composite to Intracanal Dentin in Severely Damaged Primary Anterior Teeth

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    Shahram Mosharrafian

    2016-10-01

    Full Text Available Objectives: This study sought to compare the push-out bond strength of two bulk-fill and one conventional composite to intracanal dentin in primary anterior teeth.Materials and Methods: This in vitro, experimental study was conducted on 39 primary anterior teeth, which were randomly divided into three groups. After cleaning and shaping, the root canals were filled with Metapex in such a way that after the application of 1mm light-cure liner on top of it, the coronal 3mm of the canal remained empty for composite post space. Z250 conventional composite was used in group 1 and SonicFill and Filtek bulk-fill composites along with Single Bond 2 were used in groups 2 and 3, respectively. The samples were subjected to thermocycling. One-millimeter thick sections were made of the mid-root and subjected to push-out bond strength test. Mode of failure was determined under a stereomicroscope at ×25 magnification. The data were analyzed using one-way ANOVA.Results: The mean (±standard deviation push-out bond strength was 11.40±4.23MPa, 10.94±6.69MPa and 8.79±4.12MPa in the conventional, SonicFill and Filtek groups, respectively. The difference in this regard among the three groups was not statistically significant (P=0.397.Conclusions: Based on the results, bulk-fill composites, similar to conventional types, can be successfully used for the fabrication of composite intracanal posts in primary teeth to decrease the treatment time in children.Keywords: Composite Resins; Dentin; Tooth, Deciduous

  19. Effect of Different Obturation Materials on Residual Antimicrobial Activity of 2% Chlorhexidine in Dentin at Different Time Intervals: An Ex Vivo Study

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    Behnam Bolhari

    2016-03-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of gutta percha/AH26 and Resilon/RealSeal SE on residual antimicrobial activity of chlorhexidine (CHX in human root dentin and suggest the best filling material when CHX is used as final irrigant.Materials and Methods: One-hundred and forty-four single-rooted human teeth were selected for this study. Canals were instrumented to the apical size #35. Smear layer was removed using 5.25% NaOCl and 17% EDTA and then 108 teeth were irrigated with 2% CHX and randomly divided into three groups of gutta percha/AH26, Resilon/RealSeal SE and positive controls. Each group was divided into three subgroups for different time intervals (one, three and six weeks. Thirty-six teeth, as negative controls, were irrigated with saline and obturated with gutta percha/AH26 and Resilon/RealSeal SE. Dentin powder was prepared at the afore-mentioned intervals. After exposure to Enterococcus faecalis for 24 hours, colony forming units (CFUs were counted and residual antimicrobial activity was calculated. The data were analyzed using the Kruskal Wallis test and one-way ANOVA. The significance level was set at P<0.05.Results: The antimicrobial activity of CHX gradually decreased in a time-dependent manner but it maintained over 95% of its antimicrobial activity after six weeks. Moreover, Resilon/RealSeal SE significantly decreased the antimicrobial activity of CHX in comparison with gutta-percha/AH26 (P<0.05.Conclusion: After a final irrigation with CHX, gutta-percha/AH26 is a better choice for root canal obturation.Key words: Chlorhexidine; Gutta-Percha; Epoxy resin AH-26; Resilon sealer. 

  20. Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin

    OpenAIRE

    Ali, Abdelraheem Mohamed; Hamouda, Ibrahim Mohamed; Ghazy, Mohamed Hamed; Abo-Madina, Manal Mohamed

    2012-01-01

    We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm bel...

  1. Posterior semicircular canal dehiscence: a morphologic cause of vertigo similar to superior semicircular canal dehiscence

    Energy Technology Data Exchange (ETDEWEB)

    Krombach, G.A.; Schmitz-Rode, T.; Haage, P.; Guenther, R.W. [Department of Diagnostic Radiology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); DiMartino, E. [Department of Otorhinolaryngology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Prescher, A. [Department of Anatomy, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Kinzel, S. [Department of Experimental Veterinarian Medicine, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany)

    2003-06-01

    Heading Abstract.The aim of this study was to assess imaging findings of posterior semicircular dehiscence on computed tomography and to evaluate incidence of posterior and superior semicircular canal dehiscence in patients presenting with vertigo, sensorineuronal hearing loss or in a control group without symptoms related to the inner ear. Computed tomography was performed in 507 patients presenting either with vertigo (n=128; 23 of these patients suffered also from sensorineuronal hearing loss), other symptoms related to the inner ear, such as hearing loss or tinnitus (n=183) or symptoms unrelated to the labyrinth (n=196). All images were reviewed for presence of dehiscence of the bone, overlying the semicircular canals. Twenty-nine patients had superior semicircular canal dehiscence. Of these patients, 83% presented with vertigo, 10% with hearing loss or tinnitus and the remaining 7% with symptoms unrelated to the inner ear. In 23 patients dehiscence of the posterior semicircular canal was encountered. Of these patients, 86% presented with vertigo, 9% with hearing loss or tinnitus and 5% with symptoms unrelated to the inner ear. Defects of the bony overly are found at the posterior semicircular canal, in addition to the recently introduced superior canal dehiscence syndrome. Significant prevalence of vertigo in these patients suggests that posterior semicircular canal dehiscence can cause vertigo, similar to superior semicircular canal dehiscence. (orig.)

  2. Evaluation Value of Three Methods in the Diagnosis of Dentin Cracks Caused by Apical Resection

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    Abdollah Ghorbanzadeh

    2013-01-01

    Full Text Available Objective: To compare three various methods in the diagnosis of dentinal cracks formed in the apical third after root resection.Materials and Methods: One hundred extracted human maxillary central incisors were selected. The root canals were prepared with step-back technique. Then 3mm from the apical end of all roots was cut perpendicular to the long axis of the tooth. The apical end of each root was evaluated to make sure there were no cracks. Fifty specimens were randomly chosen and connected to an apparatus especially designed for application of force (50-60N by a universal testing machine for crack formation. The cracked (no=50 and non-cracked (no=50 specimens were examined by three methods of fiber optic transillumination, methylene blue staining and combination of the two. Sensitivity and specificity of the methods were evaluated. The most suitable method for detecting cracks was determined using Youden index. To compare agreement between studied methods with the gold standard, kappa statistics and odds ratio of McNemar were utilized.Results: The sensitivity of transillumination, staining and the combination method were 82.0, 50.0 and 90.0%, respectively. The staining technique had the lowest sensitivity and the highest specificity. Both transillumination and the combination method had Youden index of 0.56, but the combination method diagnosed truly cracked samples more than the other techniques.Conclusion: The efficacy of transillumination in identification of apical root-end cracks undetectable by unaided vision was similar to the combination method. However, the efficacy of 2% methylene blue without transillumination was significantly lower than the other two methodologies.

  3. An in vitro model to investigate filling of lateral canals.

    Science.gov (United States)

    Venturi, Mauro; Di Lenarda, Roberto; Prati, Carlo; Breschi, Lorenzo

    2005-12-01

    Aims of this work were to examine lateral canals in extracted teeth, to propose a new technique to produce artificial lateral canals, and to compare two obturation techniques. Cleared roots were examined to record measure and shape of lateral canals. Artificial lateral canals were prepared on human demineralized teeth before final clearing. Specimens were divided in two groups: canals of group 1 were filled with Schilder's technique, canals of group 2 were filled with vertical compaction with apical backfilling. Stereomicroscopic analysis of lateral canal filling revealed lower filling rates in apical canals compared to coronal ones and higher filling rates with "vertical compaction with apical backfilling" compared to Schilder's group. The tested procedure appears to be a reliable technique to obtain standardized lateral canals and to compare filling procedures.

  4. The effect of light-curing source and mode on microtensile bond strength to bovine dentin

    OpenAIRE

    Amaral, CM; Peris, AR; Ambrosano, GMB; Swift, EJ; Pimenta, LAF

    2006-01-01

    Purpose: The purpose of this study was to evaluate the effects of different light-curing techniques on the microtensile bond strength of hybrid and packable resin composite to dentin. The null hypotheses were that different light-curing techniques do not affect the adhesion of resin composites to tooth structure and that different resin composites do not have a similar bond to dentin. Materials and Methods: One hundred four box-shaped buccal preparations were made and dentin/enamel adhesive w...

  5. Inhibition of matrix metalloproteinase activity in human dentin via novel antibacterial monomer

    Science.gov (United States)

    Li, Fang; Majd, Hessam; Weir, Michael D.; Arola, Dwayne D.; Xu, Hockin H.K.

    2015-01-01

    Objectives Dentin-composite bond failure is caused by factors including hybrid layer degradation, which in turn can be caused by hydrolysis and enzymatic degradation of the exposed collagen in the dentin. The objectives of this study were to investigate a new antibacterial monomer (dimethylaminododecyl methacrylate, DMADDM) as an inhibitor for matrix metalloproteinases (MMPs), and to determine the effects of DMADDM on both soluble recombinant human MMPs (rhMMPs) and dentin matrix-bound endogenous MMPs. Methods Inhibitory effects of DMADDM at six mass% (0.1% to 10%) on soluble rhMMP-8 and rhMMP-9 were measured using a colorimetic assay. Matrix-bound endogenous MMP activity was evaluated in demineralized human dentin. Dentin beams were divided into four groups (n = 10) and incubated in calcium- and zinc-containing media (control medium); or control medium + 0.2% chlorhexidine (CHX); 5% 12-methacryloyloxydodecylpyridinium bromide (MDPB); or 5% DMADDM. Dissolution of dentin collagen peptides was evaluated by mechanical testing in three-point flexure, loss of dentin mass, and a hydroxyproline assay. Results Use of 0.1% to 10% DMADDM exhibited a strong concentration-dependent anti-MMP effect, reaching 90% of inhibition on rhMMP-8 and rhMMP-9 at 5% DMADDM concentration. Dentin beams in medium with 5% DMADDM showed 34% decrease in elastic modulus (vs. 73% decrease for control), 3% loss of dry dentin mass (vs. 28% loss for control), and significantly less solubilized hydroxyproline when compared with control (p dentin MMPs. These results, together with previous studies showing that adhesives containing DMADDM inhibited biofilms without compromising dentin bond strength, suggest that DMADDM is promising for use in adhesives to prevent collagen degradation in hybrid layer and protect the resin-dentin bond. PMID:25595564

  6. A Model System for Predicting Drug Penetration thru Decayed Dentin into Inflamed Pulps

    Science.gov (United States)

    1991-01-09

    FOGEL, H.; MARSHALL, F.; and PASHLEY , D.; (1988): Effects of Distance from the Pulp and Thickness on the Hydraulic Conductance of Human Radicular Dentin ...559. PASHLEY , D.; THOMPSON, S.; and STEWART, F. (19 8 3 b): Dentin Permeability: Effects of Temperature on Hydraulic Conductance , J Dent Res 62(9...WALTON, R.; LIVINGSTON, M.; and PASHLEY , D. (1978): Dentin Permeability: Determinants of Hydraulic Conductance , J Dent Res 57(2): 187-193. ROBBINS, S

  7. CBCT assisted diagnosis and treatment of mandibular canine with apical periodontitis and double root canals in a case%CBCT 辅助诊断、治疗左下颌尖牙双根管根尖周炎1例

    Institute of Scientific and Technical Information of China (English)

    田李静; 彭冬; 张贤华

    2015-01-01

    报道1例在 CBCT 辅助下诊断和治疗的左下颌尖牙双根管病例。CBCT 能够三维显示根管的形态和分布,在术前术中对根管变异作出明确的诊断,对防止根管遗漏、保存牙本质和保障根管治疗成功有一定的临床指导意义。%A case of mandibular canine with apical periodontitis and double root canals was treated by CBCT assisted diagnosis and root ca-nal therapy.CBCT distinctly demonstrated the morphology of the root canal system in three dimensions and provided the information of canal varieties,prevented missed canals and conserved dentin.CBCT can guarantee the success of root canal therapy for the tooth with canal vareties.

  8. Fracture resistance of teeth restored with dentin-bonded crowns.

    Science.gov (United States)

    Burke, F J; Watts, D C

    1994-05-01

    While dentin-bonded crowns may hold esthetic advantages over metal-ceramic restorations, and minimal tooth preparation may also be appropriate, resistance to fracture of the restored unit is an important consideration. Dentin-bonded crowns were placed on standardized preparations in two groups of 10 maxillary premolar teeth in vitro. The preparations differed only in degree of taper. The restored specimens were subjected to compressive loading at 1 mm/min from a steel bar placed along the midline fissure. Mean fracture loads of 0.77 kN (6-degree taper) and 0.71 kN (8-degree taper) were recorded for the groups of prepared teeth, and a mean fracture load of 0.97 kN was obtained for a group of unprepared controls. Statistical analysis indicated that there was no significant difference between the fracture load of the 6-degree taper group and that of the sound control teeth.

  9. A comparative analysis of root dentin transparency with known age

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    Anita Singhal

    2010-01-01

    Full Text Available Objective: To correlate dimensions of root transparency and age, and to assess whether transparency is reliable for age estimation of unknown. Materials and Methods: 50 freshly extracted single rooted permanent teeth from 50 different individuals (27 males and 23 females were collected and their ground sections of 400 ΅m were stained with 1% methylene blue. The area of the translucent zone was measured by superimposing a transparent graph paper on the ground section under stereomicroscope. The length of the translucency was measured by using digital vernier caliper. Results: A strong positive correlation between age and translucency of dentin was noted. The length rather than the area of the translucent zone correlated more with age. Conclusion: Translucency of the root dentin increases with age and it can be used as a reliable parameter for the age estimation.

  10. Traumatic facial nerve palsy: CT patterns of facial nerve canal fracture and correlation with clinical severity

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jae Cheol; Kim, Sang Joon; Park, Hyun Min; Lee, Young Suk; Lee, Jee Young [College of Medicine, Dankook Univ., Chonan (Korea, Republic of)

    2002-07-01

    To analyse the patterns of facial nerve canal injury seen at temporal bone computed tomography (CT) in patients with traumatic facial nerve palsy and to correlate these with clinical manifestations and outcome. Thirty cases of temporal bone CT in 29 patients with traumatic facial nerve palsy were analyzed with regard to the patterns of facial nerve canal involvement. The patterns were correlated with clinical grade, the electroneurographic (ENoG) findings, and clinical outcome. For clinical grading, the House-Brackmann scale was used, as follows:grade I-IV, partial palsy group; grade V-VI, complete palsy group. The electroneuronographic findings were categorized as mild to moderate (below 90%) or severe (90% and over) degeneration. In 25 cases, the bony wall of the facial nerve canals was involved directly (direct finding): discontinuity of the bony wall was onted in 22 cases, bony spicules in ten, and bony wall displacement in five. Indirect findings were canal widening in nine cases and adjacent bone fracture in two. In one case, there were no direct or indirect findings. All cases in which there was complete palsy (n=8) showed one or more direct findings including spicules in six, while in the incomplete palsy group (n=22), 17 cases showed direct findings. In the severe degeneration group (n=13), on ENog, 12 cases demonstrated direct findings, including spicules in nine cases. In 24 patients, symptoms of facial palsy showed improvement at follow up evaluation. Four of the five patients in whom symptoms did not improve had spicules. Among ten patients with spicules, five underwent surgery and symptoms improved in four of these; among the five patients not operated on , symptoms did not improve in three. In most patients with facial palsy after temporal bone injury, temporal bone CT revealed direct or indirect facial nerve canal involvement, and in complete palsy or severe degeneration groups, there were direct findings in most cases. We believe that meticulous

  11. Chemical characterization of the dentin/adhesive interface by Fourier transform infrared photoacoustic spectroscopy.

    Science.gov (United States)

    Spencer, P; Byerley, T J; Eick, J D; Witt, J D

    1992-01-01

    Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crowns of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6 mm x 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm-1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacturer's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.

  12. Dentine sealing provided by smear layer/smear plugs vs. adhesive resins/resin tags.

    Science.gov (United States)

    Carrilho, Marcela R; Tay, Franklin R; Sword, Jeremy; Donnelly, Adam M; Agee, Kelli A; Nishitani, Yoshihiro; Sadek, Fernanda T; Carvalho, Ricardo M; Pashley, David H

    2007-08-01

    The aim of this study was to evaluate the ability of five experimental resins, which ranged from hydrophobic to hydrophilic blends, to seal acid-etched dentine saturated with water or ethanol. The experimental resins (R1, R2, R3, R4, and R5) were evaluated as neat bonding agents (100% resin) or as solutions solvated with absolute ethanol (70% resin/30% ethanol). Fluid conductance was measured at 20 cm H(2)O hydrostatic pressure after sound dentine surfaces were: (i) covered with a smear layer; (ii) acid-etched; or (iii) bonded with neat or solvated resins, which were applied to acid-etched dentine saturated with water or ethanol. In general, the fluid conductance of resin-bonded dentine was significantly higher than that of smear layer-covered dentine. However, when the most hydrophobic neat resins (R1 and R2) were applied to acid-etched dentine saturated with ethanol, the fluid conductance was as low as that produced by smear layers. The fluid conductance of resin-bonded dentine saturated with ethanol was significantly lower than for resin bonded to water-saturated dentine, except for resin R4. Application of more hydrophobic resins may provide better sealing of acid-etched dentine if the substrate is saturated with ethanol instead of with water.

  13. [Dependence of the dentinal abrasion of human teeth on their microhardness].

    Science.gov (United States)

    Remizov, S M; Pruzhanskiĭ, L Iu

    1989-01-01

    The dentin resistance against abrasion was studied as related to its microhardness. Sections of 15 intact teeth were investigated (central upper incisors). Water suspensions (40% weight-to weight) of dicalcium phosphate (DCP, FRG; and DKF-1 and DKF-2, USSR) were used as abrasives. Dentin microhardness was measured with a PMT-3 device, and abrasion assessed with profilographic technique. Dentin abrasion was related to its microhardness and to the kind of abrasive used. Dentin abrasion increased as its microhardness decreased. DCF showed minimal abrasive effect, DKF-2 had maximal effect with DKF-1 keeping the intermediate position.

  14. Chitosan/Riboflavin-modified demineralized dentin as a potential substrate for bonding.

    Science.gov (United States)

    Fawzy, Amr S; Nitisusanta, Lorraine I; Iqbal, Kulsum; Daood, Umer; Beng, Lu Thong; Neo, Jennifer

    2013-01-01

    Previous studies have suggested different approaches to modify dentin collagen for potential improvement in bonding to dentin. Here, we are proposing a new approach to reinforce dentin collagen fibrils network by chitosan as a reinforcement phase and UVA-activated riboflavin as crosslinking agent within clinically acceptable time-frame as potential substrate for bonding. The effect of modifying demineralized dentin substrates with chitosan/riboflavin, with a gradual increase in chitosan content, was investigated by SEM, nano-indentation, conventional-mechanical testing and hydroxyproline (HYP) release at collagenolytic and/or hydrolytic challenges. The resin/dentin interface morphology, immediate bond strength and short-term bond durability were also investigated using etch-and-rinse dentin adhesive. Modification with chitosan/riboflavin increased the mechanical properties, enhanced the mechanical stability of demineralized dentin substrates against hydrolytic and/or collagenolytic degradation challenges and decreased HYP release with collagenase exposure. When chitosan was added to riboflavin at 20%v/v ratio, significant improvement in bond strength at 24 h and 6 months in distilled water was found indicating the positive dual effect on bonding to dentin. With the gradual increase in chitosan content, obliteration of interfibrillar-spaces that might adversely affect bonding to dentin was found. Although it has a synergetic effect, chitosan content is crucial for any subsequent application in adhesive dentistry.

  15. Effect of erbium:yttrium-aluminum-garnet laser energies on superficial and deep dentin microhardness.

    Science.gov (United States)

    Chinelatti, Michelle Alexandra; Raucci-Neto, Walter; Corona, Silmara Aparecida Milori; Palma-Dibb, Regina Guenka

    2010-05-01

    This study evaluated the microhardness of superficial and deep dentin irradiated with different erbium:yttrium-aluminum-garnet (Er:YAG) laser energies. Seventy-two molars were bisected and randomly assigned to two groups (superficial dentin or deep dentin) and into six subgroups (160 mJ, 200 mJ, 260 mJ, 300 mJ, 360 mJ, and control). After irradiation, the cavities were longitudinally bisected. Microhardness was measured at six points (20 microm, 40 microm, 60 microm, 80 microm, 100 microm, and 200 microm) under the cavity floor. Data were submitted to analysis of variance (ANOVA) and Fisher's tests (alpha = 0.05). Superficial dentin presented higher microhardness than deep dentin; energy of 160 mJ resulted in the highest microhardness and 360 mJ the lowest one. Values at all points were different, exhibiting increasing microhardness throughout; superficial dentin microhardness was the highest at 20 microm with 160 mJ energy; for deep dentin, microhardness after irradiation at 160 mJ and 200 mJ was similar to that of the control. The lowest energy increased superficial dentin microhardness at the closest extent under the cavity; deep dentin microhardness was not altered by energies of 160 mJ and 200 mJ.

  16. Morphology and chemical composition of dentin in permanent first molars with the diagnose MIH.

    Science.gov (United States)

    Heijs, Suzanne C B; Dietz, Wolfram; Norén, Jörgen G; Blanksma, Nynke G; Jälevik, Birgitta

    2007-01-01

    The purpose of this investigation was to study the morphology and distribution of some inorganic elements in dentin in first permanent molars from children with Molar-Incisor Hypomineralization (MIH). Sixty four tooth sections from thirty two children were examined in polarized light. Fifteen representative sections were selected for SEM/XRMA analysis; 5 were used for SEM analysis and 10 for XRMA analysis. No morphological changes in the dentin were revealed in polarized light microscopy (PLM). However, in all but two sections interglobular dentin was found. The SEM analyzes confirmed the findings of the PLM with no structural changes to be found in the dentin. The XRMA results showed a difference in the concentration of elements between dentin below normal and dentin below carious or hypomineralized enamel. Elements related to organic matter appeared with higher values in dentin below hypomineralized and carious enamel. The morphological and chemical findings in dentin below hypomineralized enamel imply that the odontoblasts are not affected in cases of MIH, but may be affected by hypocalcemia, reflected by the presence of interglobular dentin.

  17. Effects of fluoridated milk on root dentin remineralization.

    Directory of Open Access Journals (Sweden)

    Wolfgang H Arnold

    Full Text Available The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF application without milk.Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. The data were statistically evaluated using a one-way ANOVA for multiple comparisons.The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca.Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.

  18. Treatment of dentinal tubules by Nd:YAG laser

    Science.gov (United States)

    Chmelíčkova, Hana; Zapletalova, Zdeňka; Peřina, Jan, Jr.; Novotný, Radko; Kubínek, Roman; Stranyánek, Martin

    2005-08-01

    Symptom of cervical dentine hypersensitivity attacks from 10% to 15% of population and causes an uncomfortable pain during contact with any matter. Sealing of open dentinal tubules is one of the methods to reach insensibility. Laser as a source of coherent radiation is used to melt dentine surface layers. Melted dentine turns to hard mass with a smooth, non-porous surface. Simulation of this therapy was made in vitro by means of LASAG Nd:YAG pulsed laser system KLS 246-102. Eighty human extracted teeth were cut horizontally to obtain samples from 2 mm to 3 mm thick. First experiments were done on cross section surfaces to find an optimal range of laser parameters. A wide range of energies from 30 mJ to 210 mJ embedded in 0,3 ms long pulse was tested. Motion in X and Y axes was ensured by a CNC driven table and the pulse frequency 15 Hz was chosen to have a suitable overlap of laser spots. Some color agents were examined with the aim to improve surface absorption. Scanning Electron Microscopy was used to evaluate all samples and provided optimal values of energies around 50 J.cm-2. Next experiments were done with the beam oriented perpendicularly to a root surface, close to the real situation. Optical fibers with the diameter of 0,6 mm and 0,2 mm were used to guide a laser beam to teeth surfaces. Laser processing heads with lens F = 100 mm and F = 50 mm were used. The best samples were investigated by means of the Atomic Force Microscopy.

  19. Environmental scanning electron microscopy of hydrated conditioned/etched dentine.

    Science.gov (United States)

    de Wet, F A; van der Vyver, P J; Eick, J D; Dusevich, V M

    2000-11-01

    Various etchants/conditioners are used during dental treatment to affect or remove the smear layer. The purpose of this study was to evaluate the effect of different treatments on moist dentine, using a field emission environmental scanning electron microscope (FE-ESEM). Twenty freshly extracted, human molar teeth were utilised. The roots and pulps were removed, and the crowns horizontally sectioned with a low speed diamond saw (Isomet) (with cooling in a saline solution) in order to expose superficial dentine. A smear layer was created on these surfaces by using 600 grit silicone carbide paper. Test surfaces were then treated in one of the following ways: 1. 37% phosphoric acid liquid 2. 37% phosphoric acid gel 3. NRC (non-rinse conditioner) without rinsing 4. NRC with rinsing. Shallow grooves were cut on the untreated sides, using a thin diamond bur. This enabled the samples to be split in half when pressure was applied in the grooves. Samples were maintained moist throughout specimen preparation. Samples were examined in the FE-ESEM (Philips XL 30) in such a way that the effect of the treatment could be viewed occlusally, as well as perpendicular to the treated interface. Phosphoric acid liquid and gel removed the smear layer, and demineralised the dentine for approximately 5-10 micrometers. NRC penetrated the smear layer and modified it to a lesser degree. However, washing of the NRC treated surface removed part of the smear layer, and opened up some dentinal tubules. Excellent resolution was possible with the FE-ESEM in both the wet and dry modes.

  20. Dentin-cement Interfacial Interaction: Calcium Silicates and Polyalkenoates

    OpenAIRE

    Atmeh, A.R.; Chong, E.Z.; Richard, G; Festy, F.; Watson, T.F.

    2012-01-01

    The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline c...

  1. Application of Diode Laser in the Treatment of Dentine Hypersensitivity

    Science.gov (United States)

    Gojkov-Vukelic, Mirjana; Hadzic, Sanja; Zukanovic, Amila; Pasic, Enes; Pavlic, Veriva

    2016-01-01

    Introduction: Dentine hypersensitivity is characterized by acute, sharp pain arising from the exposed dentine, most commonly in response to thermal, tactile, or chemical stimuli, and which cannot be linked to any other pathological changes in the tooth or the environment. Therapy uses various impregnating agents in the form of solutions or gels and, in more recent times, laser. Aim: The aim of this research was to examine the effects of treatment of hypersensitive dental cervix with diode laser. Materials and Methods: The study included 18 patients with 82 sensitive teeth. The degree of dentine hypersensitivity was evaluated by visual analogue scale (VAS), and the treatment was carried out by application of low-power diode laser over the span of three visits, which depended on the initial sensitivity. Results: There is a significant difference in VAS values measured at the onset of treatment (baseline) and immediately after the first laser treatment (t=9.275; p=0.000), after 7 days, after the second laser treatment (14 days) (t=7.085, p=0.000), as well as after 14 days and the third laser treatment (t=5.517, p=0.000), which confirms the effectiveness of this therapeutic procedure. The results showed a reduction of hypersensitivity in response to tactile stimulus with a probe after the third treatment, even with teeth whose value on the VAS was very high at the beginning of treatment (baseline). Conclusion: Within the scope of the conducted study, laser therapy has provided extremely safe and effective results in the treatment of cervical dentine hypersensitivity.

  2. Effect of two desensitizing agents on dentin permeability in vitro

    Science.gov (United States)

    ISHIHATA, Hiroshi; KANEHIRA, Masafumi; FINGER, Werner J.; TAKAHASHI, Hidekazu; TOMITA, Makoto; SASAKI, Keiichi

    2017-01-01

    Abstract Objective The aim of this in vitro study was to investigate the effect of two desensitizing agents and water on hydraulic conductance in human dentin. Material and Methods GLUMA Desensitizer PowerGel (GLU) contains glutaraldehyde (GA) and 2-hydroxyethyl methacrylate (HEMA), and Teethmate Desensitizer (TD) is a powder comprising tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) that is mixed with water. Deionized water was used as a negative control (CTR). Thirty discs with a thickness of 1.2 mm were cut from the coronal dentin of the third molars and cleaned with 0.5 M EDTA (pH 7.4). After being mounted in a split-chamber device, the discs were pressurized with water at 1 kPa and 3 kPa in order to measure flow rates with a highly sensitive micro-flow sensor and to calculate hydraulic conductance as a baseline value (BL). Following the application of GLU, TD, and CTR (n=10), hydraulic conductance was remeasured with intermittent storage in water after 15 min, 1 d, 1 w, and 1 m. Reduction in permeability (PR%) was calculated from hydraulic conductance. Data were statistically analyzed using nonparametric methods (α<0.05). Representative discs were inspected by SEM. Results PR% for GLU and TD were 30-50% 15 min and 1 m after their application. Post hoc tests indicated that PR% of CTR was significantly greater than those of GLU and TD at all time points tested. The PR% of GLU and TD were not significantly different. SEM examinations showed noncollapsed collagen meshes at the tubular entrances after GLU, and crystalline precipitates occluding the tubular orifices after TD, whereas CTR specimens showed typical patterns of etched dentin. Conclusions The present study on hydraulic conductance in dentin discs treated with two chemically different desensitizing agents and water as a control demonstrated that both products may be characterized as effective. PMID:28198974

  3. Fibroepithelial Polyp of the External Auditory Canal: A Case Report and a Literature Review

    Directory of Open Access Journals (Sweden)

    Nobuaki Tanaka

    2013-01-01

    Full Text Available This paper reports the first case of fibroepithelial polyp arising independently of the external auditory canal. A 16-year-old female patient presented to our clinic for aural fullness of the left side. Physical examination revealed a papillomatous tumor at the posterior wall of the inlet of the left external auditory canal. After biopsy, which yielded a diagnosis of benign papilloma, the patient underwent tumor excision. Final diagnosis was fibroepithelial polyp. One week after resection, aural fullness had resolved. Fibroepithelial polyp is a benign lesion and occurs mainly in the skin, ureteropelvic system, and genitals. In the head and neck area, there are reports on fibroepithelial polyp of the tongue, piriform fossa, inferior nasal turbinate, and tonsil, in addition to the skin, but none on independent fibroepithelial polyp of the external auditory canal. Excision of fibroepithelial polyp of the external auditory canal is advisable, especially in the presence of any symptoms, and should be preceded by confirmation of nonmalignancy by biopsy, if possible.

  4. Soft dentin results in unique flexible teeth in scraping catfish