Evaluation of the root and canal morphology of the mesial roots of mandibular first molars in an eastern region of Turkish population using micro computed tomography

Aim: To evaluate the morphology of the mesial roots of mandibular first molars from a Turkish population using micro-CT and to obtain two-dimensional morphometric data that may help clinicians overcome procedural errors during endodontic treatment. Material and Method: 247 mesial roots of mandibular first molars were scanned using micro-CT at a resolution of 10 μm. The percentage frequency distribution of the morphologic configuration of root canals, location of lateral canals and number of apical foramina were determined. Numbers of canals and types of isthmuses observed along the roots were recorded. Analysis of two-dimensional parameters and measurements of dentin thicknesses on furcal aspects of the roots on cross-sectional images at every 2-mm intervals was performed. Results: Most prevalent canal configurations were Type II (24.7%) and Type IV (8.1%). 55 new configurations that were not included in Vertucci and Gulabivala's configuration system were identified. In 21.1% of the roots, third canal was observed at furcation and the prevalence of single root canals increased apically. Most of the isthmuses and lateral canals were detected in the apical part. Area, perimeter, major and minor diameter values decreased towards the apex. Oval canals were more prevalent at 1-mm level and the prevalence of long-oval and flattened canals increased in coronal direction. Dentin thicknesses on distal aspect of the roots decreased apically. Conclusion: The morphology of the mesial root of mandibular first molars varied widely in different levels of the root. The geometric data obtained by micro-CT provided valuable information for endodontic treatment of these roots.