Methods: This study was approved by the University of Sao Paulo's Animal Research Ethics Committee. Extracted bovine teeth were treated by mechanical and chemical means to produce a sterile bovine material. In total, 16 New Zealand White rabbits were operated under general anaesthesia to create three circular defects in the calvaria using a trephine. One defect was left unfilled, one filled with collected autogenous bone, and the third defect was filled with the dentine-based bone substitute. Following surgery and after a healing period of either 1 or 6 weeks a CT scan was obtained. Following sacrificing, the tissues were processed for decalcified frozen sectioning and stained with Mallory's trichrome to allow histological examination.
Results: The CT data showed the density in the area of the graft material was higher than the surrounding bone and the areas grafted with autologous bone after 1 week and 6 weeks of healing. The area left unfilled remained an empty defect after a healing period of 1 week and 6 weeks. Histological examination of the defects filled with the dentine product after 6 weeks showed soft tissue encapsulation around the dentine particles.
Conclusion: The rabbit calvarial model used in this study is a robust model for the assessment of osteogenic properties of bone materials. Bovine dentine is a biostable material; however, it may not be suitable for repairing large 4-walled defects in the absence of a membrane.