Root and Canal Morphology of Mandibular Second Molars in a Yemeni Population: A Cone-beam Computed Tomography

: This study aimed to identify and characterize root and canal morphology and the prevalence of C-shaped canals of mandibular second molars (MSMs) in a Yemeni population using cone-beam computed tomography (CBCT). Methods: Three-dimensional digital images of 500 MSMs with mature roots were taken from 250 Yemeni individuals and analyzed for the following features: number of roots, shape and type of roots, type of canal configuration in each root, prevalence of C-shaped canal, and primary variations in the morphology of root and canal systems. Chi square and Fisher’s exact tests were employed for statistical analysis. Results: 89.6% of MSMs had two separate roots, 9% had two fused roots, 0.6% had three separate roots and 0.8% had one root. Mesial root was mostly ribbon-shaped (60.5%) and distal root was mostly kidney-shaped (50.7%). Type II and Type I canal configurations were the most frequent in mesial (56.9%) and distal (91.3%) roots, respectively. C-shaped canals were found in 9%. Six variants were found with variant 3 being the most common (71%). Conclusion: Yemeni MSMs are mainly two-rooted. The prevalence of three- and one-rooted MSMs was relatively low. Various canals configurations were found in MSMs among this sample of Yemeni population. The clinicians should consider C-shaped roots and canals when treating Yemeni MSMs and should be aware of their morphological variations to ensure successful root canal treatment. Although bilateral similarity of many anatomical features of MSMs was found, individual evaluation of each MSM is necessary while performing endodontic treatment on both sides.