Root Number, Canal Number, and Vertucci Root Canal Configuration of Permanent Mandibular First Molars in a Northeastern Iranian Population: A Cone-Beam Computed Tomography Study

Abstract Background and Aim: Knowledge of root and canal morphology of mandibular first molars is crucial for successful endodontic treatment. This study aimed to evaluate the root morphology and root canal configuration of mandibular first molars using Cone-Beam Computed Tomography (CBCT) in a selected population. Materials and Methods: In this retrospective cross-sectional study, CBCT scans of mandibular first molars meeting the inclusion criteria were evaluated. A total of 186 teeth from 136 patients were included after excluding low-quality scans and metallic artifacts. Axial, sagittal, and coronal slices were thoroughly analyzed. Data regarding the number of roots, presence of anatomical variations (such as Radix Entomolaris), and root canal configurations (according to Vertucci’s classification) for both mesial and distal roots were recorded. Statistical analysis was performed to assess potential correlations with patient sex and tooth side. Results: Out of 186 evaluated teeth, 96.8% were two-rooted, and 3.2% exhibited Radix Entomolaris (RE). The mesial roots predominantly presented with two canals (97.8%), with Vertucci Type III (1-2-1) being the most prevalent configuration (33.3%), followed by Type IV (30.1%). In contrast, the distal roots mainly showed a single root (96.8%) and predominantly presented Vertucci Type I configuration (79.6%). No statistically significant correlation was found between canal configurations and patient sex or side (P > 0.05). Conclusion: Mandibular first molars in this population exhibited high anatomical complexity, particularly in mesial roots with multi-canal configurations. CBCT imaging is highly recommended for preoperative identification of anatomical variations and complex canal systems to improve endodontic treatment outcomes.