The Roles of Revascularization and Resorption on Endurance of Craniofacial Onlay Bone Grafts in the Rabbit

A total of 32 New Zealand white rabbits underwent subperiosteal implantation of fresh autogenous unicortical calvarial and iliac crest grafts on their snouts with microscrew rigid fixation. After 3 and 10 days, vascularity was assessed by latex casting, and osteoclastic activity was determined by histochemical staining for tartrate-resistant acid phosphatase. After 70 days, volumetric analysis and tartrate-resistant acid phosphatase staining were performed on six animals. The calvarial grafts demonstrated greater volume maintenance than the iliac bone (72 percent versus 32 percent, p < 0.025). There were significantly greater osteoclastic activity and revascularization in the cancellous portion of calvarial and iliac crest bone grafts by the 10th day of onlay grafting. Minimal activities were present at the cortical bone. Because calvarial grafts contain more cortical bone, its superior volume maintenance can be understood by the architectural influence on revascularization and resorption.