OBJECTIVE: This study investigated the pulpal effect of topically applied betamethasone to the dentin of rat molars in the vascular phase of inflammation. MATERIAL AND METHODS: Deep cavities were prepared on the occlusal face of the maxillary right and left 1st molars with non-refrigerated inverted-cone steel burs at low speed. Three groups were formed: Group I was composed of right 1st molars; Group II was composed of left 1st molars that received the application of a drop of betamethasone on dentin surface for 5 min; and Group III (control) was composed of right 2nd molars that received no cavity preparation or betamethasone application. Changes in the vascular characteristics of the pulp tissue were checked by calculating the pulp vascular area in relation to its total area and the number of blood vessels per unit area. Data were subjected to ANOVA and Tukey's test (?=0.05). RESULTS: Group I presented a significantly larger number of vessels (p<0.05) than Group II. Regarding the vascular/total area ratio (%), Group I presented statistically significantly higher values (p=0.01) than Groups II and III. CONCLUSION: Betamethasone applied on the dentin of rat teeth proved to reduce the vascular phase of pulp inflammation regarding vessel diameter and number of blood vessels.

OBJECTIVE: This study evaluated whether smear layer removal has any influence on the filling of the root canal system, by examining the obturation of lateral canals, secondary canals and apical deltas. MATERIAL AND METHODS: Eighty maxillary and mandibular canines were randomly divided into two groups, according to their irrigation regimen. Both groups were irrigated with 1% NaOCl during canal shaping, but only the teeth in Group II received a final irrigation with 17% EDTA for smear layer removal. The root canals were obturated with lateral condensation of gutta-percha and the specimens were cleared, allowing for observation under the microscope. RESULTS: In Groups I and II, 42.5% and 37.5% of the teeth, respectively, presented at least one filled canal ramification. Although a larger number of obturated ramifications was found in Group I, there were no statistically significant differences between the two groups (p = 0.4957). CONCLUSIONS: Smear layer removal under the conditions tested in this study did not affect the obturation of root canal ramifications when lateral condensation of gutta-percha was the technique used for root canal filling.