Abstract
The composite of bone morphogenetic protein (BMP) and collagen fibers was inserted beneath the calvarial periosteum of 18-month-old rats. Each composite was removed by block resection together with a cranial bone at 1, 2, and 3 weeks after implantation, and evaluated as an onlay graft substitute in a calvarial model by histopathological observations. In BMP/collagen, osteoblast differentiation occurred in the proliferating mesenchymal tissue at 1 week, and bone formation proceeded extensively at 2 weeks. At 3 weeks, the BMP composite was almost replaced by new bone and the bone marrow, and the augmented bone was firmly connected with original bone. However, in collagen alone, neither cartilage nor bone formation was found. These results suggested that the composite of BMP and collagen was an effective absorbable material with osteoinductivity as an onlay graft substitute, and may be clinically applicable to biological bone reconstruction in aged patients.
