Compositional dependence of bioactivity of glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2

TLDR

The study aimed to determine how glass composition affects bioactivity and to develop a model linking in vivo reactions to composition. In vivo bioactivity was assessed by implanting 26 glasses into rabbit tibia for 8 weeks and examining the implants and surrounding tissue with SEM, light microscopy, and EDXA. Glasses with <59 mol % SiO₂ and 14–30 mol % alkali/alkaline‑earth oxides formed silica‑rich and calcium‑phosphate layers in vivo, indicating bioactivity comparable to established bioactive glasses. © 1997 John Wiley & Sons, Inc., J Biomed Mater Res, 37, 114–121.

Abstract

The bioactivity, i.e., bone-bonding ability, of 26 glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2 was studied in vivo. This investigation of bioactivity was performed to establish the compositional dependence of bioactivity, and enabled a model to be developed that describes the relation between reactions in vivo and glass composition. Reactions in vivo were investigated by inserting glass implants into rabbit tibia for 8 weeks. The glasses and the surrounding tissue were examined using scanning electron microscopy (SEM), light microscopy, and energy-dispersive X-ray analysis (EDXA). For most of the glasses containing < 59 mol % SiO2, SEM and EDXA showed two distinct layers at the glass surface after implantation, one silica-rich and another containing calcium phosphate. The build-up of these layers in vivo was taken as a sign of bioactivity. The in vivo experiments showed that glasses in the investigated system are bioactive when they contain 14–30 mol % alkali oxides, 14–30 mol % alkaline earth oxides, and < 59 mol % SiO2. Glasses containing potassium and magnesium bonded to bone in a similar way as bioactive glasses developed so far. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 114–121, 1997.