Evaluation of carbonate apatite as a bone substitute in rat extraction sockets from the perspective of mesenchymal stem cells.

Carbonate apatite (CO3Ap) is a major inorganic bone component and an effective bone substitute. To clarify the function of CO3Ap, we compared differences among CO3Ap, hydroxyapatite (HAp), and β-tricalcium phosphate (β-TCP) by focusing on mesenchymal stem cells (MSCs) that have a role in wound healing. For in vivo experiments, maxillary molars were removed and the bone substitute was inserted. MSC accumulation around extraction sockets was significantly promoted in CO3Ap and β-TCP groups. For in vitro experiments, MSCs were cultured with bone substitutes. The differentiation potential and amount of calcium deposition were significantly lower in CO3Ap and HAp groups than in the β-TCP group. Increases in insulin-like growth factor-I and vascular endothelial growth factor were found only in the CO3Ap group. CO3Ap-filled extraction sockets accumulated MSCs, and MSCs cultured in the presence of CO3Ap produced large amounts of growth factors. These results suggest that CO3Ap promotes healing of tooth extraction sockets.