LAUSR

Abstract Zr-incorporated CaO-P 2 O 5 -SiO 2 -SrO-ZrO 2 (BG-Zr) bioactive glasses were prepared through the sol-gel process by adding zirconium oxychloride to the synthesis batch as the zirconia precursor. The added amount of ZrO 2 was 5, 8 and 11 wt%, respectively, to replace the same amount of CaO. The effect of ZrO 2 on the solubility, bioactivity and structural properties of BG-Zr were investigated. The differential thermal analysis (TG/DTA) and X-ray diffraction (XRD) indicated that the addition of ZrO 2 to the base glass composition increased its crystallization temperature as well as weakened its crystallization tendency. Zr 4+ ion substituted for Ca 2+ favors covalent O-Zr-O bonding formation, making the glass network stronger, and thus BG-Zr glasses exhibit enhanced bending strength. Immersion tests in hydroxymethylaminomethane (Tris) buffer and simulated body fluid (SBF) show BG-Zr glasses to exhibit slower dissolution rate and lower rate of apatite formation with increasing ZrO 2 content compared to the base glass, which is likely associated with their structure stabilization and lower solubility.