Prevalence of apical periodontitis and quality of root canal among the Iranian adult population: A cross-sectional radiographic study

Background: Apical periodontitis (AP) prevalence has been reported to be very high in Iran, and endodontic treatment quality greatly affects this prevalence. This study aimed to estimate the quality of root canal fillings and AP prevalence in Iran in 2020. Methods: This was a cross-sectional study on 1089 panoramic radiographs of people over 18 years of age with at least 10 teeth, selected from radiology clinics in different provinces of Iran. The radiographs were evaluated by two postgraduate students in endodontics. The presence or absence of AP lesions, sex, age, length of root filling, type of tooth, specific error in root canal treatments, use of post or pin restorations, and geographical region were recorded. Mixed model Logistic regression was utilized to analyze the data with SPSS software version 21. Results: The total number of teeth examined in the radiographs was 25,247. The mean age of the participants was 30.4±13.9 years. In endodontically treated and non-endodontically treated teeth, the prevalence of AP was 19% (95% CI=18.5%–19.4%) and 1% (95% CI=0.8%–1.1%), respectively. Teeth with definitive errors in root canal treatment had higher odds of AP than teeth without definitive errors (P=0.012, OR=1.6). The odds of AP in teeth with underfilling and overfilling were higher than in teeth with an adequate root canal obturation length (P=0.001, OR=2.8 and P=0.005, OR=4.4, respectively). Conclusion: The prevalence of AP in endodontically treated teeth was high, and more measures are needed to increase the quality of root canal treatment in the Iranian healthcare system.