Sol-gel glasses as precursors of bioactive glass ceramics

The aim of this work was to study the influence of the composition and thermal treatment on the in vitro bioactivity of glasses and glass ceramics obtained by the sol-gel method, to obtain bioactive glass ceramics in a simpler system than those at present. For this purpose, gels in the systems SiO2-CaO (70S: 70/30) and SiO2-CaO-P2O5 (55S: 55/41/4) were heated at temperatures ranging between 700 and 1400 degreesC. The samples were characterized by DTA/TG, XRD, FTIR, SEM, and EDS and an in vitro bioactivity study in SBF was carried out. The results showed that all materials obtained (glasses or glass ceramics) were bioactive. The bioactivity was influenced by the initial gel composition, by the thermal treatment, and by the different phases present in the glass ceramics. In glasses the bioactivity decreased with the stabilization temperature. In the glass ceramics the bioactivity was favored by the presence of pseudo-wollastonite (most soluble phase of CaSiO3) and of tricalcium. phosphate.