Evaluation of the relationship between obturation length and presence of apical periodontitis by CBCT: an observational cross-sectional study

Objective: The aim of this study was to evaluate the relationship between length of root canal obturation (RCO) and the presence of apical periodontitis (AP) in different dental groups using cone-beam computed tomography (CBCT) analysis. Materials and methods: A total of 392 roots with canal treatment performed for more than 4 years were evaluated using CBCT. Distances from the apex to the tip of filling material were measured and classified as more than 2 mm short of the apex, approximately 1–2 mm short of the apex, at the apex, and beyond the apex. Odds ratio, confidence interval, and the χ 2 test were used for statistical analyses. Results: The frequency of AP was significantly greater in molars than in the other tooth groups (p < 0.05). Moreover, RCO that ended 1–2 mm short of the apex was associated with a lower prevalence of AP in molars and premolars (p < 0.05) and in anterior teeth (p < 0.1) when compared with RCO at the apex, more than 2 mm short of the apex, or beyond the apex. When the RCO reached the apex, there was no difference in the presence of AP among dental groups (p > 0.05). Conclusion: The length of RCOs can influence the presence of AP, with molars showing a higher prevalence. RCOs ending 1–2 mm short of the apex are associated with an absence of AP. Clinical relevance: The length of obturation is related to the presence of apical peridontitis and consequently to the success of endodontic treatment.