Abstract:

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 hydroxyapatite（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（P <0.05）. 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.

Key words: bone morphogenetic protein 7, gene therapy, bone regeneration, osseointegration