LOOSE FRONT TEETH - RADIOLOGICAL AND HISTOLOGICAL CORRELATION WITH GROOMING FUNCTION IN THE IMPALA AEPYCEROS-MELAMPUS

Casual observations have revealed that the anterior dentition of impal a and other antelope is loosely embedded, with the tips of the teeth m ovable over a distance of 1.5 to 2 mm. The comb-like anterior dentitio n of impala Aepyceros melampus is utilized extensively for grooming pu rposes, and it was hypothesized that the looseness of the teeth might be related to the grooming function. A sample of 12 impala mandibles w as obtained from Pilanesberg National Park, Boputhatswana. Six of the incisor-canine (IC) complexes were examined macroscopically, radiograp hically and histologically, while the remaining six were used to deter mine the alveolar depth relative to total root length. The findings we re: (1) wide periodontal ligament spaces, most prominent in the apical region; (2) a loose, highly vascular periodontal ligament; (3) well-d eveloped trans-septal periodontal ligament fibres; and (4) relatively shallow alveoli, with only approximately two-thirds of the roots inclu ded within the alveoli. In no case could looseness be ascribed to path ological changes in the periodontal ligament, cementum or alveolar bon e. These features suggest that the looseness of the teeth is associate d with a see-saw action of the teeth about a fulcrum below the alveola r bone crest, with the maintenance of the closed resting position of t he 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 parasi tes from the pelage by impala.