Dentin formation after corticosteroid treatment. A clinical study and an experimental study on rats

The overall aim of this series of studies was to determine whether the extensive narrowing of the dental pulp chamber seen in dental radiographs of patients with end stage renal disease was related to the method of treatment of the renal disease. The treatments studied were immunosuppression, renal transplantation and hemodialysis. A strong correlation was found between narrowing of the dental pulp chamber and renal transplantation. In the immunosuppression group and in the renal transplantation group, the patients received immunosuppressive drugs, mainly corticosteroids and azathioprine. Significantly higher doses of corticosteroids had been given to patients showing narrowing of the dental pulp chamber than to patients without such narrowing. The total plasma clearance of the corticosteroids received was measured among transplanted patients. The total plasma clearance was lower in patients with narrowing of the dental pulp chamber than in patients without narrowing. The morphology of the corticosteroid induced dentin in premolars from five deceased patients who had received one or more renal transplants each was compared with that in extracted teeth from five healthy individuals. The results of this study showed that dentin formation after high dose corticosteroid treatment in humans seems to start with a widening of the predentin zone, followed by extensive mineralisation causing substantial reduction of the dental pulp chamber within a few years after the start of treatment. In an experimental study on rats, it was shown that intravenous administration of high doses of corticosteroids induced dentin formation along the pulp chamber walls in the molars. Energy dispersive X-ray microanalysis was used for estimation of the calcium and phosphorus content of the dentin in rat teeth. The calcium and phosphorus composition of the corticosteroid induced dentin was found to be equal to that of normal dentin in control rat molars, which might imply that the mineralisation process was not affected by the corticosteroid treatment and thus the quality of the corticosteroid induced dentin might be equal to normal dentin regarding the calcium and phosphorus composition. In a scanning microscopy study of the morphology of the corticosteroid induced dentin in rat incisors, it was found to be equal to that of normally formed dentin.