Parathyroid hormone and enamel formation in rat maxillary incisors.

Parathyroid hormone (PTH) plays an important role in regulating calcium in serum. It is also known to affect bone and dentin formation. The purpose of this investigation was to evaluate enamel formation in normal rats receiving added PTH. It is in two parts: a pilot study where a known method was tested, followed by the main study where the rats were given different doses of PTH. The enamel was examined in both studies and in the main study the ameloblasts were also investigated. Contradictory results were seen. In the pilot study, severe enamel aberrations occurred, while no divergence from normal amelogenesis was noted in the main study. A factor causing the disparate results was the use of a hard tissue marker (oxytetracycline) in the pilot study. It can be concluded that injections of PTH in doses that affect bone and dentin did not cause any changes in normal enamel formation.