This study was conducted to determine the influence that network modifiers, sodium (Na+) and strontium (Sr2+), have on the solubility of a SiO2-TiO2-CaO-Na2O/SrO bioactive glass. Glass characterization determined each composition had a similar structure, i.e. bridging to non-bridging oxygen ratio determined by X-ray photoelectron spectroscopy. Magic angle spinning nuclear magnetic resonance (MAS-NMR) confirmed structural similarities as each glass presented spectral shifts between -84 and -85 ppm. Differential thermal analysis and hardness testing revealed higher glass transition temperatures (Tg 591-760 °C) and hardness values (2.4-6.1 GPa) for the Sr2+ containing glasses. Additionally the Sr2+ (~250 mg/L) containing glasses displayed much lower ion release rates than the Na+ (~1,200 mg/L) containing glass analogues. With the reduction in ion release there was an associated reduction in solution pH. Cytotoxicity and cell adhesion studies were conducted using MC3T3 Osteoblasts. Each glass did not significantly reduce cell numbers and osteoblasts were found to adhere to each glass surface.

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This study focuses on evaluating the biocompatibility of a SiO2-TiO2-CaO-Na2O/SrO glass and glass-ceramic series. Glass and ceramic samples were synthesized and characterized using X-ray diffraction. Each material was subject to maturation in simulated body fluid over 1, 7 and 30 days to describe any changes in surface morphology. Calcium phosphate (CaP) deposition was observed predominantly on the Na(+) containing amorphous and crystalline materials, with plate-like morphology. The precipitated surface layer was also observed to crystallize with respect to maturation, which was most evident in the amorphous Na(+) containing glasses, Ly-N and Ly-C. The addition of Sr(2+) greatly reduced the solubility of all samples, with limited CaP precipitation on the amorphous samples and no deposition on the crystalline materials. The morphology of the samples was also different, presenting irregular plate-like structures (Ly-N), needle-like deposits (Ly-C) and globular-like structures (Ly-S). Cell culture analysis presented a significant increase in cell viability with the Na(+) materials, 134%, while the Sr(2+) containing glasses, 60-80% and ceramics, 60-85% presented a general reduction in cell viability, however these reductions were not significant.

This project investigates the mechanical durability of bioactive glasses as a function of structure, solubility and incubation time of a bioactive glass series where Strontium (Sr) and Sodium (Na) are substituted. X-ray diffraction (XRD) was employed to ensure structure of each starting material (amorphous/crystalline). Ion release profiles were used to detect the concentrations of dissolution products of each sample. Hardness Testing was conducted on each sample after 1, 7 and 30 days immersion in sterile de-ionized water at 37 o C.

This project investigates the characterization and solubility of a bioactive glass series where Strontium (Sr) and Sodium (Na) are substituted. X-ray diffraction (XRD) was employed to ensure that each starting material is amorphous. Differential Thermal Analysis (DTA) was used to determine the thermal profile of each material, in particular, the glass transition temperature (T g ), the crystallization temperature (T c1 ) and the melting temperature (T m ). Magic Angle Spinning -Nuclear Magnetic Resonance (MAS-NMR) was used to probe the local 29 Si environment. Simulated Body Fluid (SBF) testing revealed a CaP surface layer on each glass after 7 days.