New Bioactive Glass and Changes in Porosity during the Growth of a Carbonate Hydroxyapatite Layer on Glass Surfaces

The synthesis of a bioactive glass with a composition (in mole %) SiO2 (55), CaO (41), P2O5 (4) was carried out by the sol−gel method. The in vitro bioactivity of this glass was assessed by following the changes in surface composition and morphology after soaking in simulated body fluid (SBF) for several periods. Also the porosity of the glass was studied by considering the changes of that porosity when a carbonate hydroxyapatite (CHA) layer grows on the glass surface. The glass synthesized in this work shows a high degree of porosity due to its elevated content in Ca(II), which is released from the glass to the media. This dilution of Ca2+, which gives rise to macropore enhancement together with the saturation of the media, leads to a fast growth of CHA on glass surface and pores.