Bioactivity and Cytotoxicity of Oxynitride Glasses

Different kinds of bioactive materials are used as bone substitutes. In particular, bioglasses containing Si, Ca, Na and O, bind to host tissues with a stable chemical bond. The phenomenon of bioactivity is associated with the formation of a crystallized hydroxycarbonated apatite (HCA) layer on the bioglass surface when soaked in a simulated physiological fluid. This layer is similar to the mineral phase of bone. However, they do not have sufficient strength for use in load-bearing situations and therefore improving their mechanical properties would allow their use in more robust applications. Within the previously studies, we have shown that the density, glass transition temperature, hardness and elastic modulus have increased linearly with nitrogen content. The purpose of this work was to study the effects of nitrogen addition on the bioactivity in a simulated body fluid (SBF) and cytotoxicity tests have complemented the study.