Micro-computerized Tomography Analysis: Effect of Parathyroid Hormone in Critical-size Defect Healing Created in Rats Calvaria

Objectives: Recent studies have shown that the use of parathyroid hormone (PTH) favors the growth and bone remodeling. The aim of this study was to analyze, by computed microtomography (micro-CT), the cranial bone repair of critical-size defects treated locally with a single dose of PTH.
Methods: Twenty-one rats were randomly divided into 3 groups: control group (C), Sponge Group (E) and PTH Group. In calvaria from all animals, a 5 mm critical-size defect was created. 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, and the PTH group defects were filled with hydrolyzed collagen sponge soaked in PTH and covered with bovine cortical membrane. Animals were euthanized at 60 days after surgery. The specimens were scanned by micro-CT and the newly formed bone volume was measured with a specific program, and the data were submitted to statistical analysis.
Results: PTH group had a higher percentage of new bone formation, but with no significant difference.
Conclusions: It is concluded that the local use of PTH leads to increased bone formation compared to the other group at the time of 60 days postoperatively.