The effect of adrenal glucocorticoid administration on eruption rates and tissue dimensions in rat mandibular incisors.

A quantitative investigation was undertaken to evaluate the changes which occur in the dental tissues of the rat incisor following the systemic administration of adrenal glucocorticoid hormone. Of the 53 rats used in the 5 week experiment, 21 acted as untreated controls while the remaining 32 each received weekly subcutaneous injections of 0-1 ml Depo-Medrone. Throughout the experimental period the mandibular incisor eruption rates of a selection of both groups of rats were recorded. Transverse ground sections were prepared from the left mandibular incisor of each animal. Measurements taken on sections prepared at a standard reference level enabled comparisons to be made between control and hormone-treated animals in the dimensions of their incisor dentine and pulp. The results indicated that maintaining mature rats in a hyperglucocorticoid state caused a significant increase in incisal eruption rate, together with a thinning of the dentine walls and an increase in size of the pulp chambers of these teeth.