Periodontal Repair in Dogs: Evaluation of rhBMP-2 Carriers
This study evaluated candidate carriers for recombinant human bone morphogenetic protein-2 (rhBMP-2)-driven periodontal regeneration. Previous experiments indicated the ability of rhBMP-2 in a particulate delivery system to result in substantial regeneration of bone and periodontal attachment. In the present study, canine demineralized bone matrix (DBM), bovine deorganified crystalline bone matrix (Bio-Oss), an absorbable collagen sponge (ACS) of type I bovine collagen, poly(D,L-lactide-co-glycolide) microparticles (PLGA), and polylactic acid granules (Drilac) were tested for their ability to support rhBMP-2 (0.2 mg/mL implant volume)-driven periodontal regeneration. The implants were tested in routine critical size canine supra-alveolar periodontal defects with transgingival tooth positioning. Contralateral defects in six beagle dogs were semirandomly assigned to receive: DBM/rhB MP-2, DBM (no rhBMP-2), Bio-Oss/rhBMP-2, ACS/rhBMP-2, PLGA/rhBMP-2, or Drilac/rhBMP-2. Animals were sacrificed 8 weeks postsurgery, and block sections of the defects were processed for light microscopy. Substantial bone regeneration was observed in all defects implanted with rhBMP-2. Other measures of periodontal healing, including cementum regeneration and presence of ankylosis, were more variable between the implants. DBM and Bio-Oss performed well as carriers for rhBMP-2-driven periodontal regeneration, although other impediments to their clinical use exist. This study indicates that qualities of the carrier system, including its space-maintaining capacity, can affect the ability of rhBMP-2 to regenerate both alveolar bone and periodontal attachment.