Maturational changes in alveolar bone of adult rats.

Structural and cellular alterations of interproximal alveolar bone were quantified by histomorphometry in 36 Wistar rats over an 18 week period. Half of the rats were fed a standard diet and half were fed a high-sucrose diet from time of weaning. Six animals from each diet group were sacrificed at 10, 18 and 28 weeks of age, one hour after labeling with tritiated thymidine. Autoradiographs were prepared from histological sections, and the interproximal area between first and second maxillary molars was evaluated, Periodontal ligament width, cell populations and cell proliferation were reduced by 18 weeks of age. By 28 weeks of age, significant reductions of bone dimensions were detected and a further decrease in fibroblast proliferation was evident. The influence of diet on the changes observed was relatively minor. Evidence from this investigation supports the concept that changes in alveolar bone are initiated early in the life span of the rat, and provides a quantitative basis for future use of the rat model in similar studies.