Evaluation of Guided Bone Regeneration Using the Bone Substitute Bio-Oss® and a Collagen Membrane in a Rat Cranial Bone Defect Model

The value of using the xenogeneic bone substitute Bio-Oss and a collagen membrane for guided bone regeneration (GBR) was evaluated. Five-millimeter bone defects were created in the cranial bones of 15, 15-week-old, male Sprague-Dawley rats, fi ve of which were left unfi lled (Group A), fi ve were fi lled with Bio-Oss (Group B), and fi ve were fi lled with Bio-Oss and a collagen membrane (Group C). They were evaluated by micro-computed tomography (micro-CT) Weeks 8 after bone defect creation. The animals were euthanized in Week 8, and tissue samples were taken. The sampled tissue was evaluated by the Kawamoto technique for preparing nondecalcifi ed frozen sections. On micro-CT, radiopacities in the bone defects were evident in Groups B and C, but not in Group A. The amount of radiopacity tended to be greater in Group C than in Group B. Histologically, no new bone formation was observed in Group A. In Groups B and C, new bone formation around the Bio-Oss was apparent and some osteoblastic cells were observed along the new bone. The Bio-Oss was not absorbed up to Week 8, suggesting that it may be a potential bone regeneration scaff old. The combined use of a collagen membrane anchored the Bio-Oss in close contact with the cranial bone, suggesting that it may help create a favorable environment for bone formation. The combination of Bio-Oss and a collagen membrane in GBR may be useful for bone defect regeneration.