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Repair of bone defects remains a major concern in plastic and maxillofacial surgery. Based on modern concepts of tissue engineering, periosteum has gained attention as a suitable osteogenic material. We tested the hypothesis that surgically released and immediately repositioned periosteum would exhibit high osteogenic capacity upon grafting in a rat calvarial defect. Seven days after periosteum was released from the tibia and immediately repositioned, the "primed periosteum graft" (PPG; n = 15) was placed into a critical-sized defect of rat calvaria and the process of bone formation was evaluated histologically, immunohistologically, and radiographically at 7, 14, and 21 days after grafting. Findings were compared with a nonprimed periosteal graft (NPG; n = 15). Endochondral ossification was observed in both the PPG and NPG. The PPG showed higher expression of proliferative cell nuclear antigen, bone morphogenetic protein, and vascular endothelial growth factor than the NPG. Three-dimensional radiographic examination revealed significantly increased bone formation in the PPG than in the NPG (P < 0.01). These findings suggested that surgical stimulation of the periosteum enhanced the osteogenic potential of periosteal cells. This method may be suitable for the clinical repair of bone defects.

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Grafted periosteum has a rich potential to induce heterotopic bone formation. In the current study the authors investigate whether autogenous periosteal grafts can regenerate the mandibular head in a rabbit model. They removed the mandibular head of Japanese white rabbits and grafted tibial periosteum to the cut surface of the mandible. Grafted periosteum was observed histologically and radiographically at day 7, 14, 21, and 45 after surgery. At day 7 after grafting, grafted tissue showed remarkable cell proliferation. By 14 days these cells had differentiated into chondrocytes to form cartilage, and endochondral ossification took place after 21 days. At 45 days after surgery, soft X-ray findings showed a newly formed mandibular head, which was similar histologically to that of a normal mandibular head. The cut mandible without periosteal graft showed no regeneration. These findings indicate that grafted periosteum can regenerate the mandibular head without special procedures such as bone fixation in a rabbit model, and suggest that this technique may be useful clinically.