A retrospective study of dental conditions of captive brown bears (Ursus arctos spp.) compared with free-ranging Alaskan grizzlies (Ursus arctos horribilis)

摘要

The teeth of 63 skulls of brown bears that had lived in the Bernese bear pit between 1850 and 1995 were examined and radiographed for occlusion, loss of teeth, calcified dental plaque and calculus, attrition, and caries. Dental pathology and periodontal status were evaluated with respect to age and location in the dentition. Further techniques (computed tomography, microhardness testing, histological sectioning and scanning electron microscopy) were used in selected cases to verify the macroscopicand radiographic diagnoses. 14 skulls originating from free-ranging wild Alaskan brown bears were examined as a control group. For zoo bears >10 years old, severe enamel and dentinal attrition was observed in canine teeth, with exposed pulp and proximallesions in molar teeth. Deposits of calcified dental calculus were found in various locations and increased with age. A much lower degree of calculus deposition was found in the Alaskan grizzlies, whose average caries frequency was higher but with largeindividual variation and different locations in canine teeth and occlusal lesions in molar and premolar teeth. Radiographic evaluation of perialveolar osteolytic processes revealed a greater frequency of apical and combined apical-marginal lesions of thealveoli in zoo bears >10 years old. It is concluded that the methods used in this study are useful in assessing and comparing the dental health status of free-ranging bears and those living in zoological gardens.