Enhancement of Biomimetic Apatite Forming Ability of Calcium Phosphate Glass-Ceramic by a Hydrothermal Treatment

Abstract

60CaO·30P2O5·7Na2O·3TiO2 glass-ceramic, which consists of crystalline β-Ca3(PO4)2 and β-Ca2P2O7 phases with a small amount of glassy calcium phosphate phase including sodium and titanium ions, has an apatite-forming ability in simulated body fluid (SBF) at 37°C; on the glass-ceramic, the bonelike apatite forms after 20 days of soaking in SBF. In the present work, the apatite-forming ability in SBF of the glass-ceramic was enhanced by a hydrothermal treatment in water at 140°C for 1h; the glass-ceramic was completely covered with bonelike apatite after 10 days of soaking. The phosphate glassy phase around the surface dissolved drastically during the treatment but almost no titanium ion dissolved. X-ray photoelectron spectroscopic analysis implied that the hydrated titania groups, which may induce nucleation of the apatite, form newly around the surface during the treatment.