LAUSR

INTRODUCTION Fused root variations of the root canal system increase the complexity of the inner root canal system anatomy. The aim of the present study was to determine, in in vivo conditions, the proportion of periapical lesions in association with endodontically treated maxillary and mandibular molars with fused roots presenting previous root canal treatment by assessing preexisting data via cone-beam computed tomographic volumes. METHODS A total of 1160 CBCT scans with an overall sample of 20,836 teeth were screened. A global count of 3701 maxillary molars and mandibular second molars were included in the study. The Cohen kappa test and interclass correlation coefficient tested the intra- and interrater reliability, respectively. The percentage of periapical lesions associated with molars with or without root fusion was determined. Proportions were expressed with 95% confidence intervals (CIs). The z test for proportions was used to analyze differences between subgroups, and an odds ratio was calculated in order to understand the association between periapical lesions and root configuration. RESULTS Fused molars presented a prevalence of periapical lesions in endodontically treated teeth of 74.0% (95% CI, 65.2%-82.8%), whereas nonfused molars had a proportion of periapical lesions in root canal-treated teeth of 69.5% (95% CI, 65.2%-73.8%; P > .05). Endodontically treated molars with fused roots presented with 1.3 higher odds of being associated with periapical lesions than endodontically treated molars with nonfused roots. CONCLUSIONS A tendency of a higher proportion of periapical lesions was found in the fused rooted molars with a history of root canal treatment when compared with nonfused teeth; however, no statistically significant difference was noted.