Mandibular canines with additional roots: An ex vivo study of the external and internal morphology

The aim of this study was to investigate the root and root canal morphologies of mandibular canines with additional roots using cone-beam computed tomography. Seventy-seven extracted two-rooted and one-three-rooted permanent human mandibular canines were selected. Aspects of the external morphology evaluated were crown length, root length, total length, root bifurcation distance from the cementoenamel junction, root size, and direction of the root curvature in the apical third. Features of internal morphology assessed were root canal number per root, root canal bifurcation distance from the cementoenamel junction, and the angle between the buccal or lingual canal and the main canal. The root size and length presented considerable diversity. Most of the roots bifurcated at the middle third and exhibited a buccal curvature. The main root canal bifurcated coronally in two root canals, a buccal and a lingual. The majority of the buccal and lingual root canal angles were blunt. The presence of a third root in a specimen was a novel finding of this study.