Production of hydroxyapatite/bioactive glass biomedical composites by the hot-pressing technique

Biomedical composites of hydroxyapatite (HA) and bioactive glass (BG) have been difficult to obtain as a dense body without the undesirable occurrence of thermal reactions and phase degradation. Herein, HA-BG dense composites were produced by the hot-pressing technique. A range of HA-BG powder mixtures (30-50 wt% BG) was fully densified by hot pressing at temperatures as low as similar to 700 degrees-800 degrees C. On the other hand, the HA-BG composites could not be densified by pressureless sintering because their composition was degraded due to a severe thermal reaction. The hot-pressed composites had significantly improved flexural strengths (similar to 60 MPa) as compared with those subjected to pressureless sintering (similar to 30 MPa) or the pure HA control (similar to 40 MPa). The hot-pressed HA-BG composites showed significantly enhanced bioactivity in a simulated body fluid, as well as osteoblast cell activity with respect to the pure HA, confirming their excellent in vitro biocompatibility.