The present study aimed to assess the prevalence of apical periodontitis (AP) in an urban Brazilian population according to gender, age group and tooth type. Data were collected from clinical files containing the medical and dental histories and periapical radiographs of 1,126 patients treated at the School of Dentistry at Universidade do Estado do Rio de Janeiro between March 2000 and December 2010. A total of 15,724 periapical radiographs were evaluated. All the radiographs were evaluated by two independent, previously calibrated endodontists (kappa = 0.88). Periapical areas on the radiographs were classified as N (normal) or AR (apical radiolucency). The frequency of AP and the 95% Confidence Interval (95%CI) were calculated according to gender, age group and tooth type. Differences between groups were calculated using the Z-test at a significance level of 5% (p < 0.05). AP was present in 7.87% of the samples, with 16.70% occurring on previously endodontically treated teeth and 44.65% occurring on teeth referred for endodontic treatment (TR-RCT). The frequency of AP was higher among females (64%) than among males (35%). The central and lateral maxillary incisors were the most frequently affected teeth. The frequency of AP was higher among individuals between 30 and 49 years of age. In this population, AP was more prevalent among females and among individuals between 30 and 49 years of age, and the central and lateral maxillary incisors were the most frequently affected teeth.

This study evaluated, in vitro, the cytotoxicity of six root canal sealers after 12, 24 and 72 h of contact time, using an endothelial ECV-304 cell line. The MTT assay was used for analysis of cell viability. Twelve specimens of each sealer were prepared and randomly assigned to 6 groups according to the commercial brands (n=4/time). A control group was also formed, which was not subjected to the contact with sealers. To assess the effects of sealers on endothelial cells, the specimens were placed in culture plate wells and incubated at 37°C with 5% CO 2 and 100% humidity. MTT assays were performed in quadruplicate after 12, 24 and 72 h of contact of the sealer specimens with monolayers. Statistical analysis was performed by two-way ANOVA with Bonferroni post-hoc test at a significance level of 5%. Analysis of absorbance in the experimental groups showed that GuttaFlow presented the lowest cytotoxicity, with a mean absorbance of 0.048, followed by Pulp Canal Sealer (0.038), Sealer 26 (0.038), Endo Densell (0.036) and Pulp Fill (0.035). The control group had a mean absorbance of 0.098. Based on the results, Endofill and GuttaFlow were the most and the least cytotoxic sealers, respectively.