2 – Bioactive glass structure and solubility

Since their discovery, bioactive glasses have been regarded as excellent candidates for the design and manufacture of biomaterials, thanks to their excellent biocompatibility, variable porosity in line with their partial reabsorption capacity that depend on synthesis methods used. The fact that makes this phenomenon possible is highly complex on account of the large number of factors related to the nature of the material, especially the surface topography and matrix structure. Understanding the structure and physicochemical behavior of bioactive glasses is a fundamental step in making significant progress towards the design of a new generation of materials. To achieve this, it is necessary to combine both theoretical models and characterization techniques that are particularly sensitive to structural modifications. This chapter presents a comparative theoretical and experimental study to elucidate structural aspects of bioactive glasses, produced using sol-gel and melting methods in the SiO2-CaO-MgO-Na2O-P2O5 system. The influence of the network connectivity on the “in vitro” bioactive behavior is disclosed and the bioactivity limits of glasses as a function of their effective composition established.