Evaluation of the prevalence and morphology of middle meziyal canals in mandibular molars with bifid apex using micro-CT

Introduction: This study aimed to compare internal morphology of mesial roots with and without a bifid apex in mandibular molars using micro-computed tomography (micro-CT). Materials and Methods: Ninety extracted mandibular molars were allocated to bifid (n=45) and non-bifid (n=45) groups. Specimens were scanned with SkyScan 1172 (pixel size 13.68 μm); images were reconstructed (NRecon) and analyzed in CTAn/CTVol. Recorded outcomes included number of orifices and main apical foramina, number of main canals at coronal/middle/apical thirds, presence of a middle mesial canal (MMC), and MB–ML interorifice distance. Data were analyzed using Student's t-test, Mann–Whitney U test, and chi-square test, with statistical significance set at 0.05. Results: Bifid roots demonstrated a significantly higher number of main canals across coronal, middle, and apical thirds (p <.05) and a greater prevalence of MMC (p <.05). In two-orifice roots, the MB–ML interorifice distance was significantly larger in bifid compared with non-bifid roots (p <.05). Vertucci configuration distributions differed markedly between groups, with bifid roots predominantly exhibiting Type V (n = 14) and Type IV (n = 12) patterns, along with additional complex variants (23, 232, 1323), whereas non-bifid roots more frequently presented Type I (n = 14), Type III (n = 11), and Type VI (n = 5). Conclusion: The mesial roots of mandibular molars having bifid apex exhibited more complex canal morphology, characterized by a higher number of main canals, increased MMC prevalence, greater interorifice distances, and distinct Vertucci configuration patterns compared with non-bifid roots.