Fabrication of CaO-SiO₂-B₂O₃ porous glass-ceramics by self-foaming method

Porous bioceramics as bone filler have been fabricated by various methods. In this study, the method that porous CaO-SiO₂-B₂O₃ bioactive glass-ceramics can be prepared by self-foaming was introduced, and the mechanism for this self-foaming was investigated. Considering weight loss and thermal expansion, B₂O₃ volatilization is the reason for this self-foaming. As the sintering temperature increased, pore size and porosity(66-90%) was increased and interconnection between pores collapsed. Poor interconnetion can be improved by HCl treatment or soaking in SBF. The skeleton consisted of 5μm needle-shaped grains. The compressive strength of this porous glass-ceramics was 15.93±0.49 MPa. and this value was higher that that (0.5-2MPa) of other porous bioceramics fabricated by various methods. The stress-strain curves showed that this porous ceramics was elastic and flexible like bone. In-vitro test showed this porous glass-ceramics were bioactive and biodegradable. So, this porous glass-ceramic can be believed to be osteoconductive and have good mechanical property.