Dental abnormalities in aging sand rats (Psammomys obesus)

Sand rats transferred from their natural environment to laboratory conditions develop diabetes, cataracts, vertebral lesions, liver tumors, malocclusion and gingival inflammation. In the present study 43 sand rats of different ages were randomly chosen from a colony maintained for 13 years in the laboratory. Macroscopical, microscopical and radiographical examinations of the dental apparatus showed marked abnormalities in animals older than 6 months. The incisors were affected more than molars with an asymmetry between the right and left side of the jaw. Pathological alterations in the incisors included variations in length and curvature, lateral inclination, coronal fractures and pulpal calcifications. The enamel on the buccal aspect of these teeth had a scalloped appearance with corresponding metaplastic changes and folding of the ameloblastic layer. Coronal fractures were also found in molar teeth and were accompanied by marked hypercementosis. These changes are consistent with those reported in rodents with induced hormonal imbalance and may be associated with the diabetic state of aging sand rats. These gerbils are suggested as a model for studying the role of age-related disorders in the pathogenesis of certain dental abnormalities.