The healing of critical-sized bone defect of rat zygomatic arch with particulate bone graft and bone morphogenetic protein-2

SummaryFor some critical-sized bony defects in the facial bones, it is necessary that the defect be reconstructed using an autologous bone graft from another donor site, not only to ensure stability, but also to derive aesthetic contouring. However, because of the easy gain and easy moulding of particulate bone, it would be easier to reconstruct the defect by using particulate bone graft (PBG) rather than block bone graft (BBG). This study was designed to confirm the usefulness of PBG with bone morphogenetic protein-2 (BMP-2) instead of BBG and to observe its long-term outcome in critical-sized zygomatic arch defects in a rat model. A sample of 18 Sprague-Dawley rats was divided into three groups; a 5-mm critical-sized bone defect was made in both zygomatic arches of all subjects. Each group was treated with different combinations of BMP-2 and PBG. At 2, 4, 8 and 12 weeks after treatment, each defect was compared radiologically. Histological evaluation was performed after 12 weeks. In the first group, the defects with PBG decreased more than in those with no bone graft (P < 0.01). In the second group, defects with PBG and BMP-2 decreased more than in those with PBG alone (P < 0.01). In the third group, there was no significant difference between the group with PBG and BMP-2 and that with in situ bone graft (instead of BBG). In conclusion, PBG with BMP-2 showed satisfactory bone healing without any additional bone graft in the animal model.