Loose front teeth: radiological and histological correlation with grooming function in the impala Aepyceros melampus

Casual observations have revealed that the anterior dentition of impala and other antelope is loosely embedded, with the tips of the teeth movable over a distance of 1middot;5 to 2mm. The comb-like anterior dentition of impala Aepyceros melampus is utilized extensively for grooming purposes, and it was hypothesized that the looseness of the teeth might be related to the grooming function. A sample of 12 impala mandibles was obtained from Pilanesberg National Park. Boputhatswana. Six of the incisor canine (IC) complexes were examined macroscopically, radiographically and histologically, while the remaining six were used to determine the alveolar depth relative to total root length, The findings were: (1) wide periodontal ligament spaces, most prominent in the apical region; (2) a loose, highly vascular periodontal ligament; (3) well-developed trans-septal periodontal ligament fibres; and (4) relatively shallow alveoli, with only approximately two-thirds of the roots included within the alveoli. In no case could looseness be ascribed to pathological changes in the periodontal ligament, cementum or alveolar bone. These features suggest that the looseness of the teeth is associated with a see-saw action of the teeth about a fulcrum below the alveolar bone crest. with the maintenance of the closed resting position of the teeth being facilitated by the well-developed trans-septal fibres. It is suggested that the minimal interdental space maintained by this arrangement during grooming assists in the efficient removal of parasites from the pelage by impala.