The Influence of Missed Canals on the Prevalence of Periapical Lesions in Endodontically Treated Teeth: A Cross-sectional Study

Abstract Introduction Untreated root canals may have a direct impact on the prognosis of root canal treatment. The objective of this cross-sectional study was to evaluate the association of missed canals with periapical lesions in endodontically treated teeth. Methods One thousand one hundred sixty preexisting cone-beam computed tomographic scans from 8 different health centers were assessed between January 2018 and December 2018 by 5 independently calibrated observers. Two thousand three hundred five endodontically treated teeth were identified in a sample of 20,836 teeth (27,046 roots). All endodontically treated teeth were evaluated for the presence or absence of missed root canals and periapical lesions. The z test for proportions was used to analyze differences between groups, and an odds ratio was calculated in order to analyze the association between missed canals and lesions. P  Results The prevalence of missed canals was 12.0%, and teeth with untreated canals were associated with periapical pathology in 82.6% of the cases. The root presenting with the highest percentage of missed canals (62.8%) was the mesiobuccal root of the maxillary first molar, being associated with periapical lesions in 75.2% of cases. Maxillary molar mesiobuccal roots presenting with a missed canal were 3.1 times more likely to be associated with periapical pathology than maxillary molars with all canals identified and treated. Conclusions The association between untreated root canals and the presence of periapical lesions noted in the present study shows that missed canals have a significant impact on treatment prognosis.