PERIODONTAL REPAIR IN DOGS - EVALUATION OF RHBMP-2 CARRIERS

This study evaluated candidate carriers for recombinant human bone mor phogenetic protein-2 (rhBMP-2)-driven periodontal regeneration. Previo us experiments indicated the ability of rhBMP-2 in a particulate deliv ery system to result in substantial regeneration of bone and periodont al attachment. In the present study, canine demineralized bone matrix (DBM), bovine deorganified crystalline bone matrix (Bio-Oss), an absor bable collagen sponge (ACS) of type I bovine collagen, poly(D, L-lacti de-co-glycolide) microparticles (PLGA), and polylactic acid granules ( Drilac) were tested for their ability to support rhBMP-2 (0.2 mg/mL im plant volume)-driven periodontal regeneration. The implants were teste d in routine critical size canine supra-alveolar periodontal defects w ith transgingival tooth positioning. Contralateral defects in six beag le dogs were semirandomly assigned to receive: DBM/rhBMP-2, DBM (no rh BMP-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 th e defects were processed for light microscopy. Substantial bone regene ration was observed in all defects implanted with rhBMP-2. Other measu res of periodontal healing, including cementum regeneration and presen ce of ankylosis, were more variable between the implants. DBM and Bio- Oss performed well as carriers for rhBMP-2-driven periodontal regenera tion, although other impediments to their clinical use exist. This stu dy 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.