Histological Study of the Parathyroid Hormone in the Critical Defect Healing in Skulls

Objectives: The aim of this study was to evaluate, through histological analysis, the cranial bone repair after local application of parathyroid hormone.
Methods: Fourty-two male rats were divided into three groups: control group (C), Sponge Group (E) and PTH Group. A 5mm critical-size defect was created in the calvaria of all animals. In Group C, the defects were filled only with blood clot, in Group E defects were filled with hydrolyzed collagen sponge and covered with bovine cortical membrane, while in the PTH group the defects were filled with hydrolyzed collagen sponge soaked in PTH and covered with bovine cortical membrane. The groups were subdivided for euthanasia at 15 and 60 days postoperatively. Histological analysis was performed.
Results: The results showed that in most of the specimens of Group C at the time of 15 and 60 days, the defects were filled with collagen fibers, in Group E with collagen fibers as well as chronic and remaining inflammation membrane, and in the PTH group defects were filled with dense connective tissue, chronic inflammation and bone formation permeating the connective tissue.
Conclusions: It follows that the local use of PTH favors the formation of cranial bone.