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.

Objective This retrospective study aimed to investigate the prevalence and location of the second mesiobuccal (MB2) canal in the mesiobuccal root of the maxillary first molar (MFM) and the maxillary second molar (MSM) through cone-beam computed tomography (CBCT) imaging. Methods One thousand two hundred CBCT images of the MFM and MSM were divided equally and analyzed. To standardize the methodology of MB2 detection, the observation and measurements were located at the pulpal floor by 1 mm apically. The distances between canals were calculated from the center point of the MB2 canal (PMB2) to the center point of both the first mesiobuccal canal (PMB1) and the palatal canal (PP). The data were provided in the form of frequencies and percentages. The chi-square test was used to analyze the differences among maxillary molars, while the significance level was set at 0.05. Results The prevalence of the MB2 canal in the MFM and MSM was 46.7% (p=0.020) and 17.7% (p=0.457), respectively. Additionally, the prevalence of the MB2 canal was more frequent in females. The average distance between PMB1 and PMB2 for MFM and MSM was 1.87±0.42 mm and 1.24±0.76 mm, respectively. Furthermore, the average distances of PMB2 and PP were 0.74±0.21 mm and 0.43±0.18 mm for MFM and MSM, respectively. Conclusion The MB2 canal was found in 386 (32.2%) of the maxillary molars. The Saudi people have a high possibility of discovering the MB2 canal. The CBCT is a useful and high-precision diagnostic tool not only for detecting but also for locating in vivo MB2 canal in the mesiobuccal root of maxillary molars.

Objectives: This retrospective study aimed to assess the prevalence of the C-shaped canal system in mandibular first and second molars in a Saudi Arabian population using cone-beam computed tomography (CBCT). Materials and Methods: The sample included 300 CBCT images from adults aged 18 to 80 years (38.7 ± 17.9) (150 females and 150 males). All images were analyzed to detect the C-shaped root canal according to Fan’s criteria. We also categorized our findings according to the gender and direction of the longitudinal groove. Data were reported as frequencies and percentages. The Chi-squared test was used to analyze proportional differences, with the significance level set at ≤0.05. Results: The C-shaped canals were observed in 146 mandibular first molars (24.33%) and 182 second molars (30.33%). Male patients had a significantly higher prevalence of C-shaped canals in mandibular second molars than females (P=0.003). The longitudinal groove was most typically detected on the root's lingual surface (53.35%). Conclusion: The incidence of the C-shaped canal in a Saudi Arabian population was 27.33% in the mandibular molars. The longitudinal groove was mostly on the lingual surface. Males showed a higher prevalence of the C-shaped canal than females.