Micro-CT Evaluation of Mandibular First Molar Root Dentine Thickness in a Black South African Sample Using a Novel Software Program

Background/Objectives: Successful endodontic treatment depends on preserving sufficient radicular dentine to prevent perforations. Mandibular first molars present with complex root morphology and “danger zones,” especially of the mesial root. This study aimed to address the limited South African dentine thickness data. Methods: This cross-sectional study evaluated 77 first mandibular molars obtained from 45 Black South African mandibular micro-CT scans. A novel software program developed for this study was used for the first time to generate automated orthogonal virtual sections and measurements at 0.1 mm intervals along the entire root length adapting to its curved axis. Statistical analyses were performed to assess variations according to root surface, root level, sex, side, and age. Results: Despite statistically significant effects of co-factors on dentine thickness, variations between left and right molars, sexes, or in relation to age were not significant. In both roots dentine thickness tapered toward the apex. Thinner dentinal walls were noted in the mesial root (on distal aspect 0.98 mm at furcation tapering to 0.28 mm at apex) than the distal. Up to the apical third, buccal and lingual surfaces remained significantly thicker (2.61 and 2.48 mm respectively at furcation tapering to 0.66 and 0.52 mm at the apex) than mesial and distal. Conclusions: Comprehensive three-dimensional data on mandibular first molar dentine thickness in a Black South African sample is provided. Dentine thickness was thinner than reported using micro-CT scans and a novel software program (Unity 2022.3 LTS, Unity Technologies, San Francisco, CA, USA), emphasizing the need for increased clinical caution. Findings should be cautiously applied and experimentally validated.