Cone-Beam Computed Tomography Assessment of Mandibular Molar Root and Canal Morphology in a North African Population

The aim of this study was to evaluate roots and root canal morphology of mandibular first and second permanent molars in a Tunisian population using cone-beam computed tomography (CBCT), providing detailed anatomical data to support clinical endodontic practice.

This retrospective, descriptive study included 100 CBCT scans from patients referred to the University Dental Clinic of Monastir between January and December 2024. A total of 400 mandibular molars (200 first and 200 second molars) were analyzed. Only teeth with fully developed roots and no prior endodontic treatment were included. Morphological features were assessed in axial, sagittal, and coronal CBCT views. The number of roots, number of canals per root, and canal configurations were recorded based on Vertucci's classification. The presence of radix entomolaris and radix paramolaris was also noted. Statistical analysis was performed using the Chi-square test (p ≤ 0.05).

Mandibular first molars exhibited predominantly two-rooted anatomy (98%), with 2% presenting a third distolingual root (radix entomolaris). Second molars displayed more variation, with 5% showing a single root, 4% with three roots, and 1% with four roots. Canal configuration analysis revealed that the mesial root of first molars most commonly exhibited Vertucci Type IV (83.7%), while distal roots showed a predominance of Type I (60.2%). In second molars, mesial roots also frequently presented Type IV (51.1%), whereas distal roots overwhelmingly exhibited Type I (94.4%). Three- and four-rooted molars were more commonly found in second molars. Sex and side differences were not statistically significant (p = 0.579 and p = 0.4, respectively), but root morphology was significantly associated with tooth type (p = 0.003).

This CBCT-based study provides the first comprehensive analysis of mandibular molar root and canal morphology in a Tunisian population. The findings confirm substantial anatomical variability, particularly in second molars, and underscore the importance of population-specific data for improving diagnostic accuracy and enhancing the outcomes of endodontic therapy.