Abstract
A histo-chemical study of the influence of cortisone on the lower incisors of fetal and post-natal albino Wistar rats was undertaken in order to determine the cellular effects of the hormone. A precocious development of the lower incisors was first noted in the fetal rats at 18 days of age. Concomitantly there was an increased alkaline phosphatase and ribonucleic acid content of the ameloblasts and odontoblasts as well as an increased glycogen content of the stratum intermedium. In the post-natal rats premature histological differentiation and eruption was noted after a single hormone injection. After 6 days of hormone treatment marked overgrowth of the alveolar bone, degeneration of the ameloblas-tic layer and disorganization of the periodontal connective tissue was seen. It was concluded that cortisone exerts its influences on the tooth by modifying the alkaline phosphatase-RNA system.