Abstract
Tusk disorders are common in elephants.1 The exposed position of this hypsodont incisor, its special shape and structure, and its use for digging, carrying, and behavioral display2 make it clear, that this tooth can easily be injured. Tusk disorders in free-ranging elephants, which play probably, from an evolutionary standpoint, a distinct role as a limiting factor, should, therefore, show a fast and complete healing. Tusk injuries of zoo animals, however, frequently require medical treatment. In order to provide information about the healing mechanisms in tusks and the surrounding bone tissue we investigated the remaining tusk and the skull of a female, approximately 40-year-old African elephant (Loxodonta africana) by means of gross anatomic dissection and histologic staining techniques. This elephant had been kept at the Vienna zoo and was euthanatized in January 2000 because of severe disorders of the locomotor apparatus, which were resistant to treatment. The extra-alveolar part of its left tusk had fractured in September 1996 and the pulp cavity was opened. In the following days procaine penicillin and dihydrostreptomycin were administered intramuscularly and the distal part of the remaining tusk, which revealed a longitudinal cleft, was cut off. A distal section of the remaining pulp tissue was extracted and the pulp cavity was closed with a gauze wick drenched in lincomycin-solution. The gauze wick was removed 1 week later. At the time of the elephant’s death the pulp cavity of the left tusk appeared completely closed with secondary dentin and the alveolar part of the tusk did not show signs of a pathologic alteration. The dental pulp tissue nearly 15 cm from the distal end of the remaining tusk reveals large arteries and anisotropic collagenous fibers. The alveolar cavity of the right tusk, which was totally extirpated, is filled up with bone tissue, leaving only a small osseous duct on the bony palate. The prominence on the laterodorsal surface of the right incisivum and maxilla, which is normally produced by the dental root of a tusk, is completely reduced. The tusk of the elephant and its surrounding bony elements, therefore, reveal an enormous healing ability,2,3 which is in striking contrast to the human tooth.
Literature Cited
1. Allen JL, Welsch B, Jacobson ER, Turner TA, Tabeling H. Medical and surgical management of a fractured tusk in an African elephant. J Am Vet Med Assoc. 1984;185:1447–1449.
2. Briggs M, Black D, Roach R. Extraction of an infected tusk in an adult African elephant. In: Proceedings of the American Association of Zoo Veterinarians. 1986:9.
3. von Solodkoff M. An elephant tusk with a spear injury. Tieraerztl Prax. 1992;20:102–109.