A new quantitative method to evaluate the in vitro bioactivity of melt and sol-gel-derived silicate glasses

Two melt-derived glasses (45S5 and 60S) and four sol-gel glasses (58S, 68S, 77S, and 91S) have been synthesized. The activation energy for the silicon release was determined, and a very close correlation was observed between this value and published results of the bioactive behavior of the glasses. This relationship can be explained in terms of the influence of chemical composition, textural properties, and structural density on the silanol group formation and silicon dissolution. These measurements provide a quantitative method to evaluate the in vitro bioactivity of SiO2-based glasses. Preliminary studies suggest an activation energy gap (Ea) of 0.35-0.5 eV as a boundary between bioactive and nonbioactive glasses. (C) 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 344-351, 2003.