Response in Rat Incisor Dentin to Injected Strontium, Fluoride, and Parathyroid Extract

¹ Department of Histology, College of Dentistry, University of Illinois, Chicago, Illinois

Contrary to the conclusions reached from examination of hematoxylin-stained sections, the responses in dentin produced by NaF, SrCl₂, and PTE were not identical. When examined in microradiographs the strontium and PTE responses contained a hypomineralized component but no hypermineralized component, while the fluoride response included both. The hypomineralized components in the strontium and PTE responses were wider than that of the fluoride response. These differences strongly suggest that the etiology of the response is different for each of these causative agents.

The doses of PTE necessary to produce a response were much greater than those known to produce substantial changes in serum, indicating that changes in serum calcium, phosphate, and citrate are not likely to be crucial causative factors for the response. Responses were detectable with doses that did not produce gross induration or ulceration at the injecting site, indicating that tissue injury at the injection site is not a likely etiologic factor. The variations seen in individual teeth with each agent could not be related to the agent or dose used.