Internal anatomy, direction and number of roots and size of human mandibular canines.

The internal anatomy, direction and number of roots and size were studied on 830 extracted human mandibular canines. The internal anatomy was studied using the methyl salicylate clearing method, which showed that 98.3% of these teeth presented a single root, with 92.2% presenting one canal and one foramen, 4.9% with two canals and one foramen, and 1.2% with two canals and two foramina. The incidence of two-rooted canines was low, 1.7%. As to direction of the roots, 51% were straight, 14.6% presented mesial, 25.5% distal, 1.0% lingual, 3.2% buccal, and 4.4% sigmoid curvatures. The mean length of the teeth was 25.5 mm, ranging from 20.3 mm to 32.8 mm.