Prevalence of Endodontically Treated Premolars and Molars With Untreated Canals and Their Association With Apical Periodontitis Using Cone-Beam Computed Tomography.

Background This retrospective study evaluated the prevalence of untreated canals in root-canal-treated maxillary and mandibular posterior teeth and their association with apical periodontitis (AP) in a Saudi Arabian population. This study is based on a radiographic examination of scans taken using cone-beam computed tomography (CBCT). Methodology The study comprised CBCT scans obtained from 300 individuals (150 women and 150 men) aged 18 to 80 years. Images were evaluated for the presence of AP related to untreated canals of endodontically treated maxillary and mandibular posterior teeth. Disruption in the lamina dura surrounding the breadth of periodontal ligaments at the apical third of the roots was described as a periapical lesion. The outcomes were presented in the form of frequencies and percentages. To assess proportional differences, the chi-square test was performed, with the significance level set at ≤0.05. Results The overall percentage of untreated canals among endodontically treated teeth was 12.46%. The prevalence of untreated canals was the highest in maxillary second molars (38.1%) (p = 0.045). The prevalence of AP among teeth with untreated canals was 85.4%, with 88.5% in the maxilla (p = 0.0347) and 81.8% in the mandible (p = 0.010). Conclusions The prevalence of AP in root-canal-treated teeth with missed canals was high (85.4%), with most identified untreated canals in maxillary and mandibular first molars.