Effect of Bio-Oss loading with rAAV-BMP7 on regeneration of bone defects around dental implant

Objective To evaluate in vivo gene delivery of Bio-Oss coated with adeno-associated virus-mediated human bone morphogenetic protein 7(rAAV-BMP7/Bio-Oss) for bone regeneration around dental implants. Methods In vitro rAAV-BMP7 were constructed and compounded with Bio-Oss. In 6 male New Zealand rabbits, two hydroxya- patite(HA) coated titanium dental implants were placed respectively to each animal in the bilateral tibia metaphysis. Before implantation, a standardized gap(8 mm in width, 4 mm in depth) was created between the implant surface and the surrounding bone walls. Rabbits were randomly divided into three groups(group A, B, C). Gaps of group A were filled with rAAV-BMP7/Bio-Oss(n=4), gaps of group B were filled with Bio-Oss alone(n=4), and gaps of group C were filled with nothing(n=4). The rabbits were sacrificed at 4 and 8 weeks respectively, and the sclerous tissue slices obtained, then histology and histomorphometric analysis were conducted. Results Histological and histomorphometric analysis revealed an enlarged bone-forming area in the bone defects of group A and B at 4 and 8 weeks after implantation. Greater bone-implant contact was achieved with rAAV-BMP7/Bio-Oss than with Bio-Oss alone and this difference was statistically significant(P0.05). Conclusion rAAV-BMP7/Bio-Oss can induce a stronger peri-implant bone reaction and larger new bone formation than Bio-Oss alone in the treatment of bone defects adjacent to titanium dental implants.