Chemical Bonding of Nanorod Hydroxyapatite to the Surface of Calciumfluoroaluminosilicate Particles for Improving the Histocompatibility of Glass Ionomer Cement

Glass ionomer cement (GIC) is composed of anionic polyacrylic acid and a silica-based inorganic powder. GIC is used as a filling material in the decayed cavity of the tooth; therefore, compatibility with the tooth tissue is essential. In the present study, we aimed to improve the histocompatibility of GIC by introducing nano-hydroxyapatite (nHA), a component of teeth, into a silica-based inorganic powder. CFAS-nHA was prepared by chemically bonding nanorod hydroxyapatite (nHA) to the surface of calciumfluoroaluminosilicate (CFAS). The synthesis of CFAS-nHA was confirmed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The prepared CFAS-nHA was mixed with polyacrylic acid and cured to prepare GIC containing nHA (GIC-nHA). Cytocompatibility tests of GIC-nHA and GIC were performed using osteoblasts. Osteoblast activity and bone formation ability were superior after GIC-nHA treatment than after control GIC treatment. This enhanced histocompatibility is believed to be due to the improvement of the biological activity of osteoblasts induced by the HA introduced into the GIC. Therefore, to enhance its compatibility with dental tissues, GIC could be manufactured by chemically bonding nHA to the surface of GI inorganic powder.