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Dentin
Kinds of Dentin Terms modified by Dentin Selected AbstractsTwo-year follow-up of fractured anterior teeth restored with direct composite resin: report of three casesDENTAL TRAUMATOLOGY, Issue 5 2008Emre Ozel Fractures of maxillar central incisors including enamel and dentin were diagnosed. Beveling with diamond bur was performed in all four cases. Dentin was cleaned with tungsten carbid bur. The teeth were etched with 37% phosphoric acid, restored with an adhesive system and microhybrid composite. Finishing and polishing procedures were performed by discs (Sof-Lex) and burs. Restorations were found successful according to modified United States Public Health Service (USPHS) criteria after 2 years in terms of retention, color match, marginal discoloration, secondary caries, marginal adaptation, and surface texture. [source] Surface characteristics of dentin experimentally exposed to hydrofluoric acidEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2003Thomas Pioch The purpose of this study was to test the effect of hydrofluoric acid (HF) on the surface characteristics of dentin in vitro. Dentin was exposed in 50 human molars and divided into five groups according to different etching schedules: (i) no etching, (ii) 15 s HF, (iii) 15 s H3PO4, (iv) 15 s HF and 15 s H3PO4, (v) 15 s H3PO4 and 15 s HF. Teeth were examined under a scanning electron microscope equipped with energy-dispersive X-ray (EDX) or two layers of fluorescence-labeled primer followed by the composite were applied, and the teeth were sectioned and examined using confocal laser scanning microscopy (CLSM). With scanning electron microscopy, no openings of dentinal tubules were found in groups (i), (ii), and (iv). In group (v) only a few tubules were opened and in group (iii) the smear layer was completely removed and tubules appeared open. The EDX analysis revealed that fluoride was incorporated into the dentin surface when HF was used. With CLSM, distinct hybrid layers could be detected only in group (iii). In group (v) the hybrid layer appeared less established compared with group (iii). No dentin hybridization was found in groups (i), (ii), and (iv). It is concluded that HF has the ability to close the openings of dentin tubules which were opened due to etching by phosphoric acid and cannot dissolve the smear layer. [source] AFM Investigation of Mechanical Properties of DentinISRAEL JOURNAL OF CHEMISTRY, Issue 2 2008Sidney R. Cohen Mechanical properties of peritubular dentin were investigated using scanning probe microscopy techniques, namely Nanoindentation and Band Excitation. Particular attention was directed to the possible existence of a gradient in these properties moving outward from the tubular lumen to the junction with the intertubular dentin. Finite element analysis showed that the influence of the boundaries is small relative to the effects observed. Thus, these results strongly support the concept of a lowering of modulus and hardness from the tubular exterior to its periphery, which appear to correlate with graded changes in the mineral content. [source] Adhesion of a self-etching system to dental substrate prepared by Er:YAG laser or air abrasionJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Wanessa C. Souza-Zaroni Abstract The purpose of this study was to assess the microtensile bond strength of a self-etching adhesive system to enamel and dentin prepared by Er:YAG laser irradiation or air abrasion, as well as to evaluate the adhesive interfaces by scanning electron microscopy (SEM). For microtensile bond strength test, 80 third molars were randomly assigned to five groups: Group I, carbide bur, control (CB); II, air abrasion with standard tip (ST); III, air abrasion with supersonic tip (SP); IV, Er:YAG laser 250 mJ/4 Hz (L250); V, Er:YAG laser 300 mJ/4 Hz (L300). Each group was divided into two subgroups (n = 8) (enamel, E and dentin, D). E and D surfaces were treated with the self-etching system Adper Prompt L-Pop and composite buildups were done with Filtek Z-250. Sticks with a cross-sectional area of 0.8 mm2 (±0.2 mm2) were obtained and the bond strength tests were performed. Data were submitted to ANOVA and Tukey's test. For morphological analysis, disks of 30 third molars were restored, sectioned and prepared for SEM. Dentin presented the highest values of adhesion, differing from enamel. Laser and air-abrasion preparations were similar to enamel. Dentin air-abrasion with standard tip group showed higher bond strength results than Er:YAG-laser groups, however, air-abrasion and Er:YAG laser groups were similar to control group. SEM micrographs revealed that, for both enamel and dentin, the air-abrasion and laser preparations presented irregular adhesive interfaces, different from the ones prepared by rotary instrument. It was concluded that cavity preparations accomplished by both Er:YAG laser energies and air abrasion tips did not positively influence the adhesion to enamel and dentin. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Application of crosslinkers to dentin collagen enhances the ultimate tensile strengthJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007Ana Karina B. Bedran-Russo Abstract The stabilization of dentin collagen with biocompatible crosslinking agents may be of clinical importance to improve dentin bond strength. The present study aimed to evaluate the effect of three collagen crosslinking agents on the ultimate tensile strength (UTS) of undemineralized and demineralized dentin. Ten freshly extracted sound molars were sectioned into 0.5 × 0.5 mm2 thick beams. The beams were either demineralized or kept undemineralized. Then, specimens were subdivided into four groups according to treatments,PBS solution (control), 5% glutaraldehyde (GD), 0.5% proanthocyanidin PBS solution (PA), and 0.625% genipin PBS solution (GE). Specimens were kept in their respective solutions for either 4 or 40 h. To assess UTS, specimens were subjected to tensile forces at a crosshead speed of 1 mm/min. Statistical analysis was performed using two-way ANOVA and Fisher's PLSD test (p < 0.05). Statistically significant increases in UTS were observed for demineralized dentin after PA and GE dentin treatment, when compared with those of the control group. Dentin treated with GD showed no statistically significant differences in UTS when compared with that the control. Undemineralized dentin revealed no significant differences as compared to that of the control, regardless of the collagen crosslinkers. The application of two naturally occurring crosslinkers, i.e., PA and GE, to dentin collagen significantly improves UTS, indicating its potential value in restorative dentistry. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Mutans streptococci in subgingival plaque of treated and untreated patients with periodontitisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2001W. A. Van Der Reijden Abstract Background: The etiology of root caries is thought to be identical to coronal caries, though root caries seem to be more complicated because of the higher susceptibility of exposed roots (dentin) by periodontal therapy to demineralization than intact enamel. This implies that mutans streptococci are the most likely pathogens in the development of root caries. Although it is known that both the numbers of mutans streptococci and the frequency of isolation in root caries lesions are negatively correlated with the distance from the gingival margin, the subgingival sulcus has not been considered a possible habitat for mutans streptococci. However, subgingival occurence of mutans streptococci in both untreated and treated periodontal patients has not been documented well in the literature. Objective: To investigate the presence and levels of mutans streptococci in the subgingival plaque of patients (n=154) in different stages of periodontal therapy. The subgingival sulcus may be a possible habitat for mutans streptococci. This localisation of mutans streptococci may be of importance in the development of root caries after periodontal surgery. Materials and methods: In this cross-sectional study, subgingival plaque samples from 154 consecutive adult periodontitis patients were tested for presence and levels of mutans streptococci and putative periodontal pathogens by anaerobic cultures. These patients were divided into 4 groups based on their stage of periodontal treatment: (1) untreated patients; (2) patients after initial periodontal therapy only; (3) patients in the maintenance phase who not underwent periodontal surgery; (4) patients after periodontal surgery. Results: The prevalence of mutans streptococci in the 4 study groups varied from 82% in untreated patients to 94% in maintenance patients. The mean proportion of mutans streptococci was 6.65% in maintenance patients versus 1.86% in untreated patients (p=0.005) and 2.51% in patients after scaling and root planing (p=0.041). Conclusions: The subgingival area is a microbial habitat for mutans streptococci that may be of importance in the development of root caries in periodontitis patients. Zusammenfassung Hintergrund: Es wird angenommen, dass die Ätiologie der Wurzelkaries und der Kronenkaries übereinstimmen, obwohl die Entstehung von Wurzelkaries komplizierter zu sein scheint wegen der erhöhten Empfindlichkeit entblößter Wurzeln (Dentin) für Demineralisation im Vergleich zu gesundem Schmelz. Das bedeutet, dass MS die wahrscheinlichsten Pathogene für die Entstehung der Wurzelkaries sind. Obwohl bekannt ist, dass die Zahl der MS und die Häufigkeit ihres Nachweises aus Wurzelkariesläsionen negativ mit dem Abstand vom Gingivarand korrelieren, wurde die subgingivale Region bisher nicht als möglicher Lebensraum für MS erwogen. Das subgingivale Vorkommen von MS bei behandelten und unbehandelten Parodontitispatienten ist in der Literatur nicht gut dokumentiert. Die subgingivale Region könnte ein möglicher Lebensraum für MS und diese Lokalisation bedeutsam für die Entstehung von Wurzelkaries nach parodontaler Therapie sein. Zielsetzung: Untersuchung des Vorkommens und der Menge von MS in der subgingivalen Plaque von Patienten zu unterschiedlichen Zeitpunkten parodontaler Therapie. Material und Methoden: In einer Querschnittsstudie wurden subgingivale Plaqueproben von 154 Patienten mit Erwachsenenparodontitis auf das Vorkommen und den Anteil von MS und putativer Parodontalpathogene in anaerober Kultur untersucht. Die Patienten wurden nach dem Stadium der parodontalen Therapie in 4 Gruppen unterteilt: (1) unbehandelte Patienten (n=51), (2) Patienten nach abgeschlossener Initialtherapie (Mundhygieneunterweisungen sowie Scaling und Wurzelglättung [SRP]) (n=41), (3) Patienten in der unterstützenden Parodontitistherapie (UPT), die nicht parodontalchirurgisch behandelt worden waren (n=48), und (4) Patienten nach Parodontalchirurgie (n=14). Ergebnisse: Die Prävalenz der MS variierte in den 4 Untersuchungsgruppen von 82% bei unbehandelten bis 94% bei UPT-Patienten. Der mittlere Anteil der MS an subgingivaler Plaque lag bei 6.65% (UPT) im Vergleich zu 1.86% (unbehandelte Parodontitis) (p=0.005) bzw. zu 2.51% (SRP) (p=0.041) und 2.18% nach Parodontalchirurgie (n.s.) Schlußfolgerungen: Die subgingivale Region ist ein Lebensraum für MS, die eine Bedeutung für die Pathogenese der Wurzelkaries bei Patienten mit Parodontitis haben könnte. Résumé L'étiologie des caries radiculaires semble étre identique à celle des caries coronaires bien que les caires radiculaires paraîssent plus compliquées vu la susceptibilité plus importante des racines exposées (dentine) par le traitement parodontal à la même déminéralisation que ne l'est l'émail intact. Ceci a comme conséquence que les Streptocoques mutans sont vraisemblabement les pathogènes les plus problables dans le dévelopment des caries radicularies. Bien qu'il soit connu que les nombres de Streptocoques mutans autant que la fréquence de l'isolation des lésions carieuses radiculaires soient en corrélation négative avec la distance depuis la gencive marginale, le sulcus gingival n'a pas été considéré comme habitat possible pour les Streptocoques mutans. Cependant, l'occurence sous-gingivale des Streptocoques mutans chez les patients avec parodontite traitée ou non n'a pas été suffisamment documentée dans la littérature. Le but de cette étude a été d'analyser la présence et les niveaux de Streptocoques mutans dans la plaque sous-gingivale de 154 patients à différentes étapes de leur traitement parodontale. Le sillon sous-gingival pourrait dont être un habitat possible pour les Streptocoques mutans. Cette localisation peut être importante dans le dévelopment des caries radiculaires après le traitement parodontal. Dans cette étude croisée des échantillons de plaque sous-gingivale ont été prélevés chez 154 patients adultes avec parodontite pour vérifier la présence et les niveaux de Streptocoques mutans et d'autres pathogènes parodontaux putatifs par culture anaérobie. Les patients étaient divisés en 4 groupes suivant le stade de leur traitement parodontal: non-traité, traitement initial seulement, phase de maintien mais sans chirurgie, et patient après chirurgie parodontale. La fréquence globale des Streptocoques mutans dans les 4 goupes variaient de 82% chez les patients non-traités à 94% chez ceux au stade de maintenance. La proportion moyenne de Streptocoques mutansétaient de 6.65% chez les patients en maintenance versus 1.86% chez les patients non-traités (p=0.005) et de 2.51% chez les patients après détartrage et surfaçage radiculaire (p=0.041). L'aire sous-gingivale est donc un habitat microbien pour les Streptocoques mutans qui pourraient être assez importants dans le développement des caries radiculaires chez les patients souffrant de parodontite. [source] Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2001B. Ga Abstract Objectives: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. Material and methods: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80mJ/p and 100mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. Results: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. Conclusion: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins. Zusammenfassung Ziele: Das Ziel dieser in vitro Studie war es, die Wirkung von Er:YAG- und Nd:YAG-Laser auf die Morphologie, chemische Struktur und die Diffusionsprozesse zu evaluieren. Material und Methoden: 60 Proben von Wurzeln wurden für eine Minute entweder mit einem Er:YAG-Laser und 60 mJ/p, 80 mJ/p und 100 mJ/p oder einem Nd:YAGLaser und 0.5 W, 1.0 W und 1.5 W bestrahlt. Die Rasterelektronenmikroskopie (REM) wurde verwendet um die Morphologie zu bestimmen, Infrarotspektroskopie (IR) zur Messung der Veränderung in der chemischen Struktur und die eindimensionale paramagnetische Elektronenresonanz-Bildgebung (1-D EPRI) wurde verwendet um die Diffusions-Koeffizienten in den dentalen Wurzelproben abzuschätzen. Ergebnisse: Die Behandlung mit dem Er: YAG-Laser resultierte in der Ausbildung tiefer Krater mit exponiertem Dentin. Die morphologischen Veränderungen der Wurzeloberfläche nach Bestrahlung mit dem Nd: YAG-Laser waren Brüche, Kraterbildung, Aufschmelzen des Wurzelminerals und Bildung wiederverfestigter poröser Globuli. Mit dem Er:YAG-Laser gelang es nicht die Intensität der Amid-peaks I, II oder III zu verändern. Im Gegensatz dazu reduzierte die Behandlung mit dem Nd:YAG-Laser im Vergleich mit der Kontrolle bei der höchsten Leistungseinstellung von 1.5 W die Intensität der Amid-Peaks II und III. In allen mit Er: YAG und Nd:YAG behandelten Wurzelproben waren die Wurzeldiffusionskoeffizienten signifikant erhöht. Schlussfolgerung: Diese Studie demonstrierte, dass der Er:YAG-Laser nur die Morphologie und die Diffusionsprozesse der Wurzeloberfläche beeinflusst, während der Nd: YAG-Laser auch die chemische Struktur der Wurzelproteine verändert. Résumé Morphologie, structure chimique et processus de diffusion de surfaces radiculaires après irradiation au lasers Er:YAG et Nd:YAG But: Le but de cette étude in vitro était d'évaluer les effets des lasers Er:YAG et Nd:YAG sur la morphologie, la structure chimique et les processus de diffusion des surfaces radiculaires. Matériaux et méthodes: 60 échantillons de racines furent irradiés pendant 1 min chacun par 60 mJ/p, 80 mJ/p et 100 mJ/p avec le laser Er:YAG ou par 0.5 W, 1.0 W et 1.5 W avec le laser Nd:YAG. La microscopie électronique à balayage (SEM) a été utilisée pour déterminer la morphologie, la spectroscopie infra rouge pour mettre en évidence les altérations de la structure chimique et l'imagerie en une dimension par résonnance magnétique électronique (1-DEPRI) fut utilisée pour estimer les coefficients de diffusion dans les échantillons de racines dentaires. Résultats: Le traitement au laser Er:YAG entrainait la formation de cratères profonds avec de la detine exposée. Les altérations morphologiques de la surface radiculaire après irradiation au laser Nd:YAG prenaient la forme de félures, de cratères, fusion du minéral radiculaire et formation de globules poreux resolidifiés. Le laser Er:YAG n'arrivait pas à altérer l'intensité des pics Amide I, II our III. Au contraire, le traitement au laser Nd:YAG, en utilisant la plus haute puissance de 1.5 W, réduisait l'intensité des pics Amide II et III, par rapport au contrôle. Les coefficients de diffusion étaient significativement augmentés pour toutes les racines traitées par les lasers Er:YAG et Nd:YAG. Conclusions: Cette étude démontre que le laser Er:YAG a une influence sur seulement la morphologie et les processus de diffusion des surfaces radiculaires alors que le laser Nd:YAG modifie également la structure chinique des protéines radiculaires. [source] Microtensile Bond Strength of Luting Materials to Coronal and Root DentinJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2005RICARDO WALTER DDS ABSTRACT Purpose:: The purpose of this study was to evaluate the microtensile bond strength (,TBS) of two dual-cured resin cements and a glass ionomer cement to coronal dentin versus root dentin. Materials and Methods: RelyX Unicem (3M ESPE, St. Paul, MN, USA) and Panavia F (Kuraray Medical Inc., Tokyo, Japan) were the resin cements used and FujiCEM (GC Corp., Tokyo, Japan) was the glass ionomer cement used. Once separated, the labial coronal and root surfaces of six bovine incisors were ground with 600-grit SiC papers to expose middle dentin. Then, the dentin surfaces were treated following the manufacturers'instructions and a 1 mm thick layer of each material was applied to the flattened coronal and root surfaces. Each material was cured following the manufacturers'recommendations and a composite buildup was made over the cured luting materials for testing purposes. After 24 hours in water at 37°C, the teeth were sectioned into 1 mm × 1 mm × 6 mm beams and tested for ,TBS. The data were analyzed by one- and two-way analysis of variance and Fisher's Protected Least Squares Differences test (p < .05). Results: The ,TBSs to coronal and root dentin were similar within each cement. Comparing the materials, RelyX Unicem presented the highest ,TBS, followed by Panavia F and FujiCEM, respectively (p < .0001). Conclusions: Although there were differences in ,TBS among the materials tested, no significant differences were found between bond strengths to coronal and root substrates. [source] Dentin matrix proteins and soluble factors: intrinsic regulatory signals for healing and resorption of dental and periodontal tissues?ORAL DISEASES, Issue 2 2004TA Silva Dentin contains numerous polypeptides and signaling molecules sequestered in a mineralized matrix. The exposure and release of these molecules occur as a consequence of injury to the pulp and periodontal ligament, which may result from luxation, orthodontic movement or infections of tooth and periodontal structures. When released at these sites, dentin constituents have the potential to act on different surrounding cells, including periodontal cells, osteoblasts, osteoclasts and inflammatory cells, and to affect the course of dental disease. Experimental studies have highlighted the interactions between dentin and cells from tooth and periodontal tissues and reveal dentin to be a cell adhesive, signaling and migratory stimulus for various mesenchymal and inflammatory cells. These results support the hypothesis that dentin molecules might function as regulatory signals for the healing and resorption of dental and periodontal tissues. Data from recent and classical investigations are summarized, many open questions are discussed, and current hypotheses concerning the mechanisms of tooth resorption and periodontal healing are outlined. Many questions regarding the importance of dentin as a source of multifunctional molecules remain unanswered and provide important directions for future studies. [source] Influence of dentin on pH of 2% chlorhexidine gel and calcium hydroxide alone or in combinationDENTAL TRAUMATOLOGY, Issue 3 2010Laila Gonzales Freire Most of the times, these objectives are not achieved solely by chemomechanical preparation, and intracanal dressing may be necessary. In these cases, calcium hydroxide is used as a root canal dressing due to its well-known and recognized antimicrobial activity. Chlorhexidine has a wide spectrum of antimicrobial activity and its association with calcium hydroxide has been recommended in an attempt to amplify antimicrobial effects of calcium hydroxide. It is also known that dentin exerts a buffering effect under wide pH variations, and may be responsible for decreasing the antimicrobial activity of drugs inside the root canal. The objectives of this study were to assess the pH of 2% chlorhexidine gel and calcium hydroxide alone or in combination, as well as the influence of dentin on the pH of these compounds. Dentin powder was obtained from bovine teeth and added as 1.8% to the volume of the medications. All substances were individually stored in plastic flasks, in triplicate. A pH meter was used at five different moments to assess pH in viscous medium: immediately after preparation and after 24 h, and 7, 14, and 21 days. Results were analyzed by paired Student's t -test. Statistically significant differences were observed in the 2% chlorhexidine gel group alone or associated with calcium hydroxide and added of dentin powder (P < 0.05). Mean pH values indicated the influence of dentin powder because of a significant increase in pH. Calcium hydroxide with propylene glycol as the vehicle always showed high pH, demonstrating that this compound was not affected by the presence of dentin. [source] The three-dimension finite element analysis of stress in posterior tooth residual root restored with postcore crownDENTAL TRAUMATOLOGY, Issue 1 2010Gang Fu Some researchers have analyzed the stress of the anterior teeth after postcore crown restoration, but the stress of the posterior teeth after such restoration has not been reported. We used three-dimension finite element methods to analyze the stress magnitude and distribution of remaining dentin in posterior tooth residual root restored with postcore crown. The binding material, loading direction, number, length and material of posts were studied. Methods:, The models of residual root of maxillary first molar restored with postcore crown were created by CT scanning, mimics software and abaqus software. Different number, length and material of posts were used in the modeling. The posts were cemented with zinc-phosphate cement or composited resin. A load of 240 N was applied to the occlusal surface in four directions and tensile, shear, and von Mises stresses were calculated. Result:, (i) The maximum stress on remaining dentin changed irregularly as the number and length of posts changed. (ii) The maximum stress on remaining dentin decreased slightly as elastic modulus of the material of posts increased. (iii) The maximum stress on bonding layer and remaining dentin was lower when bonded with resin luting agent than with zinc-phosphate cement. (iv) The maximum stress on remaining dentin increased markedly as loading angle increased. Conclusion:, The number, length, material of posts, bonding material and loading angle all have influence on the magnitude and distribution of stress. The influence of loading angle is most apparent. [source] Studies on dentin grafts to bone defects in rabbit tibia and mandible; development of an experimental modelDENTAL TRAUMATOLOGY, Issue 1 2009Lars Andersson This property may possibly be used as an alternative or supplement to bone grafting to defective areas after trauma prior to treatment with osseointegrated implants. Hence, the objective of this study was to investigate if dentin can be used as a graft in bone defects in an experimental rabbit model. Materials and Methods:, Eight New Zealand White Rabbits were used to prepare bone cavities either in the angle of the mandible or tibia. Six of the eight tibial and six of the eight mandibular bone defects were filled with dentin blocks from human premolars which were extracted for orthodontic treatment. Two mandibular and two tibial bone cavities were used as controls and all the rabbits were sacrificed after 3 months. Radiographic and histological examinations were performed. Results:, There was a difference in healing pattern between the mandibular and tibial defects. In the mandible, the dentin blocks were resorbed to a larger extent and more often surrounded by fibrous tissue, probably due to the fact that the dentin blocks were mobile because of the thin mandibles and muscular activity in that area. Only some dentin blocks were ankylosed with the mandibular bone. In the tibia however, all dentin blocks were fused to bone over a large area. Osseous replacement resorption was seen. In control cavities, bone formation was seen but was never complete. No signs of inflammatory changes were seen in any fused grafts. Conclusions:, Dentin grafts have a potential to be incorporated in bone without inflammation and can be used as bone inducer and later replaced by bone. Thus, rabbit tibia served as a better model for further studies of this phenomenon when compared to the mandible. [source] Comparative assessment of time-related bioactive glass and calcium hydroxide effects on mechanical properties of human root dentinDENTAL TRAUMATOLOGY, Issue 1 2009Monika Marending These materials have a disinfecting capacity similar to Ca(OH)2, but bear the advantage of bioactivity. However, because bioactive glasses initially act as alkaline biocides just as Ca(OH)2 does, they may also negatively affect mechanical dentin properties over time. This was assessed in the current study using standardized human root dentin bars. Specimens were immersed in 1:20 (wt vol,1) suspensions of nanometric bioactive glass 45S5 or calcium hydroxide for 1, 10, or 30 days. Control specimens were immersed in pure saline for 30 days (n = 20 per group). Subsequently, modulus of elasticity (E) and flexural strength (FS) of the specimens were determined. Results were compared between groups using one-way anova and Scheffé's post-hoc test. Ca(OH)2 caused a significant (P < 0.001) 35% drop in mean flexural strength values compared to the control treatment after 10 days. No further change was observed between 10 days and 30 days. Bioactive glass caused a 20% drop in mean flexural strength as compared to the control after 10 days. However, this difference did not reach statistical significance (P > 0.05). No effects of either material on dentin modulus of elasticity values were observed. It was concluded that the calcium hydroxide suspension affected the dentin more than the bioactive glass counterpart; however, the effect was self-limiting and probably restricted to superficial dentin layers, as suggested by the mere decrease in flexural strength but not in modulus of elasticity values. [source] Two-year follow-up of fractured anterior teeth restored with direct composite resin: report of three casesDENTAL TRAUMATOLOGY, Issue 5 2008Emre Ozel Fractures of maxillar central incisors including enamel and dentin were diagnosed. Beveling with diamond bur was performed in all four cases. Dentin was cleaned with tungsten carbid bur. The teeth were etched with 37% phosphoric acid, restored with an adhesive system and microhybrid composite. Finishing and polishing procedures were performed by discs (Sof-Lex) and burs. Restorations were found successful according to modified United States Public Health Service (USPHS) criteria after 2 years in terms of retention, color match, marginal discoloration, secondary caries, marginal adaptation, and surface texture. [source] Effect of crown fracture on the surrounding periodontiumDENTAL TRAUMATOLOGY, Issue 3 2008Janaína Cristina Gomes To reach the long axis of the tooth, an impact device was applied to eight teeth of four adult dogs to produce trauma. Crown fractures involving the enamel and dentin, with or without pulpar exposure and without dislocation, mobility or gingival bleeding were analyzed within the post-trauma periods of 30 min, 1, 3, and 7 days. The force of impact that resulted in coronary fracture, although dissipated at the time of fracture, reverberated in the surrounding periodontium and may generate not only light histological alterations with a rapid re-establishment of the tissues, but also an intense inflammatory condition required as long as 7 days to clear up. The gravity of these inflammatory reactions unleashed in these teeth's periapical tissues depends on the absorption of impact by the periodontal structures and the individual susceptibility of each organism. [source] Surgical extrusion of a crown-root fractured immature permanent incisor: 36 month follow-upDENTAL TRAUMATOLOGY, Issue 6 2007Zuhal K Abstract,,, Crown-root fracture is defined as a fracture involving enamel, dentin and pulp and can be classified as either complicated or uncomplicated. The tooth with crown-root fracture presents a lot of problems during coronal restorations and extraction was formerly used in many cases. But loss of a permanent incisor in a young patient may create severe emotional problems and alternative treatment approaches must be considered. This report presents the successful results of a surgical extrusion of a complicated crown-root fractured, immature permanent incisor in a 9-year-old boy. Examination 36 months after the trauma indicated that the treatment had provided functional and esthetic results. [source] Severe periodontal damage by an ultrasonic endodontic device: a case reportDENTAL TRAUMATOLOGY, Issue 2 2007John D. Walters Abstract,,, Heat produced within a root canal during use of an ultrasonic instrument can be conducted through the dentin into periodontal ligament, bone and soft tissue. If severe in intensity or long in duration, it can induce damage to these tissues. This report describes a case in which an ultrasonic endodontic instrument apparently induced severe damage to alveolar bone, gingiva and nasal mucosa in a 42-year-old female. Overheating of a maxillary central incisor caused necrosis of soft tissue and bone on the facial and mesial aspects and triggered a protracted inflammatory response in the adjacent nasal cavity. To relieve the severe discomfort associated with this damage, the patient chose to have her maxillary incisors extracted and replaced by a removable partial denture. A defect in the soft tissue and bone was present at a follow-up visit 10 months after the extractions. While morbidity of this nature is rare, this case reinforces the need to maintain adequate cooling of ultrasonic instruments. [source] An alternative method for fabricating a custom-made metal post with a ceramic coreDENTAL TRAUMATOLOGY, Issue 3 2005Sabire Deger Abstract,,, The restoration of anterior non-vital teeth with metal posts and cores and all-ceramic restorations may lead to compromised esthetics because of the semitranslucence of ceramics and the metallic color of the underlying post and cores. This article presents a technique that combines the optical properties of ceramic cores with the mechanical properties of custom-made cast metal posts. The technique involves heat pressing of the core from leucite-enriched glass-ceramic to the underlying custom-made metal post and may provide additional esthetic benefit for anterior teeth especially with little remaining coronal dentin and with small root volume. [source] Dental trauma in Turkish children, ,stanbulDENTAL TRAUMATOLOGY, Issue 2 2003Betul Kargul Abstract,,, Numerous studies focus on visits to dental clinics for emergent dental problems. Many are all-inclusive, studying traumatic injuries as well as visits for infection and other causes. Epidemiologic studies have focused on the investigation of the prevalence or incidence of dental injury. The patients were evaluated at Pediatric Dentistry, Marmara University Dental School, ,stanbul over a 2-year period. For these 300 patients (446 teeth), specific diagnoses were evaluated. Dental injuries that presented most frequently in permanent dentition were crown fractures of enamel only and crown fractures of enamel and dentin. The most frequently presented dental injury in primary dentition were avulsions and crown fractures of enamel. The more frequent treatments for primary teeth were examination only. Bandage restoration, space maintainer were common procedures for permanent teeth. [source] The prevalence of traumatic injuries treated in the pedodontic clinic of Ankara University, Turkey, during 18 monthsDENTAL TRAUMATOLOGY, Issue 6 2002Abstract , , ,The purpose of this study was to evaluate the type and prevalence of dental injuries referred to Ankara University, School of Dentistry, Department of Pedodontics, Turkey. One hundred and forty-seven patients with 234 traumatized teeth presented during 18-month interval. Of the 147 patients, 85 were boys and 62 were girls. The most frequent trauma occurred in the age of 11 years. The maxillary central incisors were found to be the most affected tooth in both primary and permanent dentition injuries. The maxillary arch is involved in a higher percentage of trauma cases (95.72%). The most common cause of injuries are falls (67.34%). In the primary dentition, the most common type of injury is extrusive luxation (38.23%) and in the permanent dentition, it is fracture of enamel,dentin without pulpal involvement (50.5%). From 147 patients, only 82 presented to our clinic within 1 h and 10 days after the injury time. It reveals that there is a need to inform the public of what they should do in cases of dental trauma, and how important it is to contact a dentist immediately. [source] Hypothermic insult to the periodontium: a model for the study of aseptic tooth resorptionDENTAL TRAUMATOLOGY, Issue 1 2000C. W. Dreyer Abstract , The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200,250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The results also indicated that progression of the resorptive process required periodic exposure to the injury, in the absence of which repair to the damaged root occurred. [source] Circulation in normal and inflamed dental pulpENDODONTIC TOPICS, Issue 1 2007ELLEN BERGGREEN In the pulp, arteries branch into a capillary network before they leave the pulp as venules through the apical foramina. The tissue has low compliance, as it is enclosed in dentin, and has a relatively high blood flow and blood volume. The interstitial fluid pressure (IFP) and colloid osmotic pressure are relatively high whereas the net driving blood pressure is low. The high pulsatile IFP is probably the major force for propelling lymph in the dental pulp. Vasodilation in neighboring tissue as well as arteriovenous (AV) shunts in the pulp itself can contribute to a fall in total and coronal pulpal blood flow, respectively. The pulp blood flow is under nervous, humoral, and local control. Inflammatory vascular responses, vasodilation, and increased vessel permeability induce an increase in IFP that can be followed by a temporarily impaired blood flow response. Lipopolysaccharides (LPS) from bacteria may cause endothelial activation in the pulp, leading to vasoconstriction and reduced vascular perfusion. Lymphatic vessels are identified with specific lymphatic markers in the pulp but so far, little is known about their function. Because of the special circulatory conditions in the pulp, there are several clinical implications that need to be considered in dental treatment. Received 13 February 2009; accepted 28 August 2009. [source] Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restorationEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2010Andy C. Ritts Ritts AC, Li H, Yu Q, Xu C, Yao X, Hong L, Wang Y. Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration. Eur J Oral Sci 2010; 118: 510,516. © 2010 Eur J Oral Sci The objective of this study was to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces used for composite restoration. Extracted unerupted human third molars were prepared by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated using a non-thermal atmospheric argon plasma brush for various periods of time. The molecular changes of the dentin surfaces were analyzed using Fourier transform infrared spectrophotometry/attenuated total reflectance (FTIR/ATR), and an increase in the amount of carbonyl groups was detected on plasma-treated dentin surfaces. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars and analyzed using tensile testing. Student,Newman,Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s of plasma treatment. However, the bonding strength to plasma-treated inner dentin did not show any improvement. It was found that plasma treatment of the peripheral dentin surface for up to 100 s resulted in an increase in the interfacial bonding strength, while prolonged plasma treatment of dentin surfaces (e.g. 5 min) resulted in a decrease in the interfacial bonding strength. [source] Ten-years degradation of resin,dentin bondsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2010Masanori Hashimoto Hashimoto M, Fujita S, Nagano F, Ohno H, Endo K. Ten-years degradation of resin,dentin bonds. Eur J Oral Sci 2010; 118: 404,410. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The purpose of this study was to evaluate the durability of resin,dentin bonds in 10-yr water-storage testing. Resin,dentin bonded bulk specimens were prepared using six commercially available resin adhesives. The resin,dentin bonded specimens were stored in water for 24 h (control group) or for 10 yr (experimental groups). After each storage period, the specimens were sectioned to make specimen beams and then subjected to a microtensile bond test. After the bond test, fractured surfaces were examined by scanning electron microscopy (SEM). In addition, interfacial observation of silver nanoleakage was performed using the backscatter electron mode of SEM. The bond strengths of four of the six adhesive systems tested decreased significantly after 10 yr. However, no significant bond-strength reduction was recorded for the other two systems. The interfacial observations showed water tree propagation in the bonding resin layer as a typical morphological change after aging for five of the six adhesives tested. Water tree propagation may be a symptom of degradation in the resin bonding layer of resin,dentin bonds. [source] The location and characteristics of two populations of dental pulp cells affect tooth developmentEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2009Yoshinori Sumita This study investigated the characteristics of two dental pulp cell populations during the early stages of crown formation in porcine teeth. A transplantation method was developed to reproduce epithelial cell,mesenchymal cell interactions during odontogenesis (tooth development). The technique allowed two types of cells/tissue to be combined in vivo. Populations of cells localized in the cervical loop epithelium region, dental pulp horn, and dental pulp core chambers were isolated and dissociated into single cells. Each population was examined for its gene-expression pattern using both semiquantitative and quantitative reverse transcription,polymerase chain reaction (RT-PCR) analyses, and for its tissue-formation capability by combining the cervical loop epithelial cells with either pulp horn cells or pulp core cells on biodegradable collagen scaffolds that were subsequently examined using histology and immunohistology. Gene-expression patterns showed that pulp horn cells were more mature than pulp core cells. Cervical loop epithelial cells combined with pulp horn cells mainly reconstituted dentin,cementum structures. By contrast, cervical loop epithelial cells combined with pulp core cells reconstituted enamel,dentin structures. These results suggest that mesenchymal cells residing in a specific location of the pulp possess a specific tissue-formation potential when combined with epithelial cells. [source] Distribution of SIBLING proteins in the organic and inorganic phases of rat dentin and boneEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2008Bingzhen Huang The SIBLING protein family is a group of non-collagenous proteins (NCPs) that includes dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), and osteopontin (OPN). In the present study, we compared these four proteins in different phases of rat dentin and bone. First, we extracted NCPs in the unmineralized matrices and cellular compartments using guanidium-HCl (G1). Second, we extracted NCPs closely associated with hydroxyapatite using an EDTA solution (E). Last, we extracted the remaining NCPs again with guanidium-HCl (G2). Each fraction of Q-Sepharose ion-exchange chromatography was analyzed using sodium dodecyl sulfate,polyacrylamide gel electrophoresis (SDS,PAGE), Stains-All stain, and with western immunoblotting. In dentin, the NH2 -terminal fragment of DSPP and its proteoglycan form were primarily present in the G1 extract, whereas the COOH-terminal fragment of DSPP was present exclusively in the E extract. The processed NH2 -terminal fragment of DMP1 was present in G1 and E extracts, whereas the COOH-terminal fragment of DMP1 existed mainly in the E extract. Bone sialoprotein was present in all three extracts of dentin and bone, whereas OPN was present only in the G1 and E extracts of bone. The difference in the distribution of the SIBLING proteins between organic and inorganic phases supports the belief that these molecular species play different roles in dentinogenesis and osteogenesis. [source] Effect of dentin conditioning on dentin permeability and micro-shear bond strengthEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2007Danuchit Banomyong The purpose of this study was to compare fluid flow rates across dentin surfaces treated with four conditioners. The effect of conditioning on the micro-shear bond strengths of glass ionomer cement (Fuji IX GP) and resin-based adhesives (Single Bond 2 or Clearfil SE Bond) were also investigated. Under a simulated pressure of 1.3 kPa, two dentin conditioners, phosphoric acid, and a self-etching primer were applied to the dentin surfaces. Dentinal fluid flows at baseline and after conditioning were recorded for 15 min each. The conditioned surfaces were examined using a scanning electron microscope. The micro-shear bond strengths of the glass ionomer cement and of the resin-based adhesives bonded to conditioned dentin surfaces were evaluated while simulated intrapulpal pressure was maintained at 0 or 1.3 kPa. Only the dentin surface etched with phosphoric acid showed a significant increase in permeability. Micro-shear bond strengths of Fuji IX GP were not affected by conditioning the dentin surfaces or by bonding at different intrapulpal pressures (0 or 1.3 kPa). The effects on bond strengths of resin-based adhesives depended on the system used. The simulated positive intrapulpal pressure during bonding significantly affected the adherence of Single Bond 2, whereas Clearfil SE Bond was unaffected. [source] Determination of elastic modulus of demineralized resin-infiltrated dentin by self-etch adhesivesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2007Genta Yasuda The purpose of this study was to determine ultrasonically the changes in elastic modulus of demineralized adhesive-infiltrated dentin. Dentin disks were obtained from bovine incisors and shaped into a rectangular form. The specimens were immersed in single-step self-etch adhesives, then stored in distilled water and run through thermal cycles between 5 and 60°C. The longitudinal and shear wave sound velocities and the elastic modulus were determined using ultrasonic equipment composed of a pulser-receiver, transducers, and an oscilloscope. After 24 h of storage, the elastic modulus of mineralized dentin was 16.9 GPa and that of demineralized dentin was 2.1 GPa. The immersion of demineralized dentin in adhesives significantly increased the elastic modulus to 3.3,5.9 GPa. After 30,000 thermal cycles, the elastic modulus of dentin was 32.4 GPa, whereas that of demineralized adhesive infiltrated dentin was 3.1,4.1 GPa. Thermal stresses did not cause adhesive-infiltrated demineralized dentin to deteriorate, as measured by elastic modulus. [source] Splicing site mutations in dentin sialophosphoprotein causing dentinogenesis imperfecta type IIEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2006Heidi Holappa 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. [source] Spectroscopic investigation of the function of aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution as a dentin desensitizerEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2006Chuangye Qin Fourier-transform (FT)-Raman and -infrared (IR) spectroscopy were employed to investigate the function of the aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution (Gluma) as a desensitizer. 2-Hydroxyethylmethacrylate (HEMA), glutaraldehyde (GA), and the mixture of HEMA/GA (i.e. Gluma) were used to interact with dentin, collagen, hydroxyapatite (HAP), and bovine serum albumin (BSA) individually. All the interactions were monitored by an FT-Raman spectrometer. FT-IR spectroscopy was also used in this study. The results show that HEMA could be absorbed by dentin and collagen; GA could cross-link collagen and BSA; and when BSA was added to Gluma, polymerization of HEMA occurred. The results suggest that Gluma acts as a desensitizer whereby, first, GA reacts with part of the serum albumin in dentinal fluid, which induces a precipitation of serum albumin, then, second, a reaction of GA with serum albumin induces polymerization of HEMA. The function of Gluma as a desensitizer to block dentinal tubules occurs via these two reactions. [source] | ||||||||||||||||||||||||||||||||||