Mixture designs applied to glass bioactivity evaluation in the Si–Ca–Na system

Two mixture designs, permitting the reduction of experiment number, are applied to the SiO2–CaO–Na2O system in order to study two properties of bioglasses: bioactivity and HCA layer thickness. Samples are composed of 42–55% SiO2, 13.5–48% CaO and 10–35% Na2O. The bioactivity is studied with Fourier transform infra red spectroscopy (FTIR) and the thickness of HCA layer is measured with the help of scanning electron microscopy coupled with energy dispersive spectroscopy (SEM–EDS). The aim of this work is to correlate these two properties with the composition of glasses, establishing mathematical formulas. Several domains of interesting glasses were obtained, some of them with a fast reaction time, others developing a thick HCA layer. Some compositions, seeming to be more interesting than Hench’s 45S5, could have been pointed out.