The in vivo performance of an alkali-free bioactive glass for bone grafting, FastOs®BG, assessed with an ovine model

Although bioactive glasses are successfully used as bone substitutes, recent studies have revealed that the high alkali content in these glasses leads to fast in vivo degradation rates that may not match the rate of new bone ingrowth. This prompted us to design and develop novel bioactive glasses that are devoid of alkali but still demonstrate high bioactivity in vitro. This article describes the in vivo performance of an alkali-free bioactive glass with the following composition (Wt %): 13.03 MgO-33.98 CaO-13.37 P2O5-38.84 SiO2-0.77 CaF2 (labelled as FastOs((R))BG). An animal model was used to assess the in vivo performance of FastOs((R))BG, using 45S5 Bioglass((R)) as control. The evaluation was performed through implantation of FastOs((R))BG and 45S5 Bioglass((R)), during one month, in femoral bone defects in sheep. Subcutaneous implantation of both glasses was also performed in order to assess tissue response through a standardized method. Histological and scanning electron microscopy assessment of retrieved subcutaneous and bone samples demonstrated that FastOs((R))BG is biocompatible, osteoconductive, that it can be osteointegrated, and that it is more slowly resorbed than 45S5 Bioglass((R)). These features suggest that FastOs((R))BG is a potential candidate for bone grafting. (c) 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 30-38, 2017.