Bioactivity and mechanical properties of Na2O·CaO·SiO2·P2O5 modified glasses

The purpose of this work was to study the influence of B2O3 and Al2O3 additions on the bioactivity and mechanical properties (modulus of rupture; MOR) of eight glasses in the Na2O·CaO·SiO2·P2O5 system, so that a bioactive glass with the good mechanical properties compares to others is obtained. For investigating their bioactive capacity these glasses were soaked in a simulated body fluid (SBF) at different time intervals. The changes in surface structure were examined by scanning electron microscopy (SEM) and EDX line scan and X-ray microanalysis to determine the compositional profiles through the substrate up to the surface. In some glasses the presence of a rich calcium and phosphorous layer was observed that, according to other studies, correspond to the apatite layer growing in all glasses with B2O3/Al2O3 ratio between 0.5 and 0.55. For MOR determination of these glasses, the three point loading test was used.