The potential role of bone morphogenetic proteins in periodontal reconstruction

Growth factors and cytokines are currently under investigation as potential therapeutics for the site-specific regeneration of alveolar bone. Many of these factors, including TGF-beta, PDGF, IGF-I, IGF-II, and FGF influence bone growth and resorption, and as such may be useful in the regeneration process. However, these molecules have effects on many other tissue and cell types. In contrast, the bone morphogenetic proteins (BMPs) represent a unique set of differentiation factors that induce new bone formation at the site of implantation instead of changing the growth rate of pre-existing bone. Recombinant human BMP-2 (rhBMP-2), for example, has been shown to induce ectopic bone formation in an in vivo setting. Cell culture studies indicate that rhBMP-2 can cause mesenchymal precursor cells to differentiate into cartilage- and bone-forming cells. Additional animal studies have shown that rhBMP-2 is capable of replacing large (2.5 cm) defects in canine mandibles, healing a variety of long bone defects in orthopedic animal models, and repairing bony defects in animal models of bone lost due to periodontal disease. These results suggest that rhBMP-2 has broad therapeutic potential for dental and cranio/maxillofacial reconstruction.