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AIM: To evaluate the agreement between six currently available periapical radiography-based methods for measuring the root canal curvatures in mesial roots of mandibular first molars, assessed by two examiners with different proficiency levels. METHODOLOGY: Non-endodontically treated mesial roots of 41 human mandibular first molars were radiographed using the parallelling technique. Two independent observers (a specialist in endodontics and radiology and a final-year dental student) assessed their root canal curvature using the methodologies described by Schneider (1971, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 32, 271), Weine (1982, Endodontic therapy), Berbert and Nishiyama (1994, Revista Gaúcha de Odontología, 356), Luiten et al. (1995, Journal of Endodontics, 21, 26), Hankins and ElDeeb (1996, Journal of Endodontics, 22, 123) and Pettiette et al. (1999, Journal of Endodontics, 25, 230). Intra- and inter-examiner reliability was assessed using the intraclass correlation coefficient. The differences in curvature angle measured by the different methods were compared using the one-way anova for repeated measures test, followed by Tukey's post hoc analysis. The effect was calculated using the Cohen's d method. To determine the agreement between methods, the Bland-Altman analysis was used. The significance level was set at 5%. RESULTS: Agreement for the observers was excellent (>0.81) for the six methods considered. For the angle comparisons between methods, the maximum differences were for Schneider versus Weine (35.77°) and Luiten versus Hankins (35.14°), whilst the highest percentage of angles with a difference >10° were Weine versus Luiten and Berbert versus Pettiette (90%) and the comparison Weine versus Hankins presented with the lowest frequency (15%). Excellent agreement was found for five comparisons: Weine versus Luiten (0.940), Berbert versus Pettiette (0.917), Weine versus Pettiette (0.907), Luiten versus Pettiette (0.904) and Berbert versus Luiten (0.812). Compared to Schneider's method, the other methods showed a tendency of increasing difference as the angles became more acute. The other methods exhibited linear differences, remaining constant for smaller and larger angles. CONCLUSIONS: Reliability was excellent for all methods assessed separately. Maximum differences in curvature angles were found when comparing Schneider versus Weine and Luiten versus Hankins. Excellent agreement was found for Weine versus Luiten, Berbert versus Pettiette, Weine versus Pettiette, Luiten versus Pettiette and Berbert versus Luiten. In the presence of dilacerations, the method by Schneider was less sensitive.

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BACKGROUND/AIM: Dental trauma is a public health issue with a high prevalence in children. The aim of this study was to evaluate the level of knowledge of dentists in Rio Grande do Sul, Brazil, of the management of traumatic dental injuries, using the International Association of Dental Traumatology (IADT) Guidelines as a reference. MATERIALS AND METHODS: An electronic questionnaire investigating personal and professional characteristics and 12 questions about dento-alveolar trauma, was sent to all registered dentists of the Regional Council of Dentistry of Rio Grande do Sul (n=14 753). The respondents were grouped according to the sociodemographic and professional profiles and the data were evaluated by the Student-T test or one-way ANOVA, with Tukey's post-hoc, with α = 5%. RESULTS: A total of 1414 dentists responded to the survey (9.59% response rate). The overall mean self-reported knowledge of dental trauma was 5.87 ± 1.57, of a maximum possible score of 12. Some factors associated with a higher knowledge of the IADT guidelines were: female gender, previous clinical experience, years from qualification, self-reported knowledge, and academic postgraduate degree. Dentists who are specialized in endodontics (6.58 ± 1.63) and pediatric dentistry (6.05 ± 1.44) achieved higher levels of knowledge on dental trauma. Analysis of the characteristics (gender, location, and proportion of specialists) of the respondents confirmed that they were representative of the target population. CONCLUSION: The overall level of knowledge of dentists from Rio Grande do Sul of the IADT guidelines is moderate. These results highlight the need for continuing education on dento-alveolar trauma in this population.

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Objective: This study aimed to evaluate the canal cen-tering ability and topography of BioRaCeTM (BR), Wi-zard CD PlusTM (WP), and Wizard NavigatorTM (WN) instruments. Materials and method: mesiobuccal roots of upper first molars were selected and randomly dis-tributed in three groups (n=10), according to the rota-ry system used for instrumentation. Canal transporta-tion was assessed at 2, 4, 6, and 8 mm from the root apex, by subtracting cone bean computed tomography (CBCT) images taken before and after preparation. The root canal center was marked in pre- and post-prepa-ration images, and the distance between these points was measured in bucco-palatal (BP) and mesio-distal (MD) directions. New instruments were analyzed un-der scanning electron microscopy (SEM) regarding their surface finishing, topographical features, and surface defects. The SEM images were obtained at the tip of the instrument, and at 5 mm from the tip. Data of the canal centering ability were analyzed by two-way ANOVA (? = 0.05). Results: regardless of root level (2, 4, 6, and 8 mm), all groups presented canal transportation in both directions. Significant differences were not detected (p > 0.05). Surface finishing was regular in the BR group with rounded transitional angle. Cutting edges had a sharp angle in BR and WN groups, while WP instru-ments had a flattened angle. Conclusion: despite such topographical differences between the rotary instru-ments tested, none of them were able to exactly main-tain the original root canal center, and no significant differences were observed among groups.

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INTRODUCTION: This study compared the combined use of sodium hypochlorite (NaOCl) and chlorhexidine (CXH) with citric acid and CXH on dentinal permeability and precipitate formation. METHODS: Thirty-four upper anterior teeth were prepared by rotary instrumentation and NaOCl. The root canal surfaces were conditioned for smear layer removal using 15% citric acid solution under ultrasonic activation and a final wash with distilled water. All teeth were dried, and 30 specimens were randomly divided into three equal groups as follows: positive control group (PC), no irrigation; 15% citric acid + 2% CHX group (CA + CHX); and 1% NaOCl + 2% CHX group (NaOCl + CHX). All roots were immersed in a 0.2% Rhodamine B solution for 24 hours. One-millimeter-thick slices from the cementum-enamel junction were scanned at 400 dpi and analyzed using the software ImageLab (LIDO-USP, Sao Paulo, Brazil) for the assessment of leakage in percentage. For scanning electron microscopy analysis, four teeth, irrigated for NaOCl + CHX samples, were split in half, and each third was evaluated at 1,000x and 5,000x (at the precipitate). RESULTS: Using the analysis of variance test followed by the Bonferroni comparison method, no statistical differences between groups were found when analyzed at the cervical and medium thirds. At the apical third, differences between the PC and NaOCl + CHX (p < 0.05) and CA + CHX and NaOCl + CHX could be seen (p < 0.05). CONCLUSION: The combination of 1% NaOCl and 2% CHX solutions results in the formation of a flocculate precipitate that acts as a chemical smear layer reducing the dentinal permeability in the apical third.

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The purpose of this study was to evaluate the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) in endothelial cells within the dental pulp of human primary and young permanent teeth and the spatial distribution of VEGFR-2-positive cells. Nine sound primary teeth and 4 sound young permanent teeth were evaluated by immunohistochemistry with a human anti-VEGFR-2 antibody. Stained tissue sections were analyzed qualitatively under light microscopy. Here we observed that endothelial cells of both primary and permanent teeth showed positive immunostaining for VEGFR-2. Notably, VEGFR-2-positive cells in the primary teeth tended to be found close to the subodontoblastic layer, whereas the spatial distribution of VEGFR-2 immunostaining in the permanent teeth was more uniform. In conclusion, VEGFR-2 was expressed in the microvascular endothelial cells of both primary and young permanent teeth, which suggests that these cells are capable of responding to the morphogenetic and survival signals mediated by VEGF.

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The aim of the present study was to assess the risk of deviation of the root canals prepared by 3 HERO rotary systems, used solely or in association, by means of preoperative and postoperative imaging of a cross-section of their coronal, middle, and apical thirds. Fifty mesiobuccal canals of human first molars were randomly divided into 5 groups of 10 specimens each: group A, HERO 642; group B, HERO 642 + HERO Apical; group C, HERO Shaper; group D, HERO Shaper + HERO Apical; group E (control), NitiFlex files. Fisher exact test showed that the differences between the percentages of the presence of deviation and the differences observed between the proportions of instrumented and noninstrumented walls were not statistically significant. No system presented absolute effectiveness, because each of them produced morphologic changes and failed to instrument all the walls of the root canals. A level of significance of .05 was adopted.

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