In vitro and in vivo studies have recently shown that silicon nitride (Si3N4) is an osseoconductive and potential osseoinductive biomaterial. Even though the amount of bone mineral produced by Si3N4 was inferior when compared to commercial Bioglass (R), it strongly stimulated the production of extracellular matrix and collagen tissues. Consequently, this study was designed to determine if appropriate mixtures of Bioglass (R) and Si3N4 might improve the ratio of mineral apatite to its biological matrix. Commercial 45S5 Bioglass (R) powder was mixed with 5 and 10 mol% Si3N4 powder, followed by melting, cooling, crushing, and comminution. The composite powders had modified morphologies and chemical structures including a reduced average particle size, a reduction of oxygen in the Si-O backbone structure, and trapped CO2 gas which was converted into calcium carbonate. When exposed to human osteosarcoma cells within an osteogenic medium, the 5 mol% Si3N4 composite powder resulted in higher amounts of hydroxyapatite while the 10 mol% Si3N4 powder provided in a more balanced combination of collagen and mineral fractions closer to the natural composition of native human bone. (C) 2018 Published by Elsevier Ltd.
