Relationship Between Mandibular Premolar Root Canal Morphology and Distolingual Root in Mandibular First Molars Using Cone-Beam Computed Tomography.

This study aimed to assess the relationship between the root canal morphology of mandibular premolars (MPs) and the presence of distolingual roots (DLRs) in mandibular first molars (MFMs) in a Turkish population. Anatomical symmetry and the complexity of MPs' canal configurations were also analysed using cone-beam computed tomography (CBCT). CBCT images from 3000 individuals were examined, comprising 18 000 mandibular teeth (4 MPs and 2 MFMs per subject). Root canal types were classified according to Vertucci's system and evaluated based on sex, symmetry and the presence of DLRs. DLRs were detected in 41.23% of individuals and were significantly more frequent in females (p < 0.001). Complex canal configurations were found in 64.83% of MPs. A significant association was observed between DLR presence and increased canal complexity in MPs (p < 0.001). These findings indicate that the presence of DLRs is highly related to morphological variation in the premolar region.