Prevalence and morphology study of distolingual root in mandibular first and second molars in Thai population: a cone-beam computed tomography analysis.

Background: To investigate the prevalence and morphological characteristics of distolingual roots in permanent mandibular molars among a Thai population using a cone-beam computed tomography (CBCT).

Methods: This retrospective study consisted of two parts: prevalence and morphology study. A total of 5228 permanent mandibular first and second molars from 2623 Thai patients were included in the prevalence study, and CBCT images were analyzed to identify the presence of distolingual roots. Additionally, 288 teeth with distolingual roots were subjected to further analysis to assess their root morphology, canal configuration, and orifice location. Statistical analyses were performed using descriptive statistics, Pearson's chi-square test, paired t-test, and other appropriate methods.

Results: The prevalence of distolingual roots in permanent mandibular molars was 9.14% among the examined teeth and 14.94% among the examined patients. The majority of distolingual roots were classified as type C according to Carlsen and Alexandersen's classification, and type III according to Song's classification. Additionally, the vast majority of teeth exhibited Vertucci type I canal configuration. Further analysis revealed that the mean interorifice distances between DB-DL, ML-DL, and MB-ML orifices were 3.01 ± 0.6 mm, 3.43 ± 0.57 mm, and 2.61 ± 0.59 mm, respectively. The angle and radius of curvature of distolingual roots in the proximal view were greater than those in the clinical view (p < 0.001).

Conclusions: This study provides comprehensive insights into the prevalence and morphological characteristics of distolingual roots in permanent mandibular molars among a Thai population. These findings emphasize the importance of thorough preoperative assessment and awareness of root morphology variations to enhance the success of endodontic treatment.