Functional reconstruction of the non-human primate mandible using recombinant human bone morphogenetic protein-2

The purpose of this study was to evaluate the long-term functional properties of regenerated bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) in segmental bone defects of primate mandibles. The 30-mm defects were created in the mandibles of six young monkeys and the mandibles were fixed with titanium plates. Then 9 mg of rhBMP-2 permeating a poly-D, L-lactic-co-glycolic acid-coated gelatin sponge (PGS) was implanted into the bone defect. Dental implants were placed into the regenerated mandible 20 weeks after surgery, then suprastructures were placed and masticatory force loading was begun 8 weeks after the insertion of the dental implants. Bone formation and the quality of new bone were evaluated radiologically and histologically at 15 and 30 weeks after surgery, and 4 and 24 weeks after masticatory force loading. The resected mandibles were completely regenerated with the rhBMP-2-induced bone. Excellent remodelling and consolidation of new bone were observed after loading. This study demonstrated that the new bone induced by rhBMP-2 in large segmental defects was maintained and functional for at least 1 year. Bone regeneration induced by rhBMP-2 holds promise as a future therapy and may be an effective alternative to autogenous bone grafts for implant dentistry and reconstructive surgery.