Impact of recombinant human bone morphogenetic protein-2 on residual ridgeresorption after tooth extraction: An experimental study in the rat

Residual ridge resorption begins following tooth extraction and continuousl y reduces alveolar bone volume, potentially creating a significant problem in dental implant treatment. In this study, the role of recombinant human b one morphogenetic protein-2 (rhBMP-2) in residual ridge resorption after to oth extraction was investigated, A polylactic acid/polyglycoiic acid copoly mer-coated gelatin sponge carrier was implanted with or without rhBMP-2 (1 mug) in The mesial root sockets after removal of maxillary first molars in male Wistar rats. Fine structural and histomorphologic analyses were conduc ted 3 to 84 days after implantation, Direct bone formation was first observ ed after 5 days on the rhBMP-2 side, which was transformed into cortical al veolar ridge with a smooth periosteal layer by 84 days, whereas the control side displayed slower healing. Bone histomorphometry revealed greater tota l bone area and increased bone height after 14, 28, 56, and 84 days on the rhBMP-2 side compared to the control side, and differences were significant after 14, 28, and 56 days. Larger numbers of proliferating cells and dense ly populated differentiating mesenchymal cells were observed on the rhBMP-2 side than on the control side in the early stage, and chondrogenesis was n ot observed. The findings indicate that rhBMP-2 may stimulate proliferation and differentiation of mesenchymal cells in the rat maxillary root socket to preserve cortical bone volume in the socket without any evidence of chon drogenesis.