Morphology of Deciduous Canines in Asian Apes

The aim of this study was to determine the morphology and sexual dimorphism of the deciduous canines of Asian apes (Hylobates lar and Pongo pygmaeus). The lingual view of the maxillary deciduous canines of gibbons showed a triangular pyramidal shape with a strong mesiodistal symmetry. The center of the crown had a median lingual ridge. This feature differed from that of the other great apes. In the mandible, the crown was distorted to a square shape having the heel-like protrusion of the distal crown base. The maxillary deciduous canines of the orangutan were roughly pyramidal lingually. The lingual ridge was a thick, broad ridge. It ran from the crown apex along the mesial groove to just before the cervical ridge. The mandibular canines had a distorted square shape due to the heel-like protrusion of the distal crown base. Characteristic of the deciduous teeth was that the ridges were highly expanded and very well developed. Sex differences in tooth size were not significant for gibbons, but were significant for orangutans.