Bioactive glasses are materials capable of bonding implants to tissues. 45S5 Bio-glass^® is one such material capable of bonding strongly to bone within 6 weeks. It develops a hydroxy-carbonate apatite layer on the implant that is chemically and crystallographically equivalent to the mineral phase of bone. However, it suffers from a mechanical weakness and low fracture toughness due to an amorphous glass network and is not suitable for load-bearing applications. In order to improve its mechanical strength and bioactivity, the present work explores the effects of cobalt oxide additions. Bioactivity of the glass samples was assessed through their hydroxyapatite formation ability by immersing them in the simulated body fluid for different soaking periods. The formation of hydroxyapatite was confirmed by Fourier transform infrared spectrometry, pH measurement and microstructure evaluation through scanning electron microscopy. Densities and mechanical properties of the samples were found to increase considerably with an increase in the concentration of cobalt oxide.

A small amount of nickel oxide is doped in bioglass$^{\circledR}$ system and it is replaced by silica. The use of 45S5 glass composition is one such material able to bond strongly to bone within 42 days. The 45S5 bioglass$^{\circledR}$ system develops a hydroxyl carbonate apatite (HCA) layer, which is chemically and crystallographically similar to mineral phase of bone. But it has low fracture toughness and mechanical weakness due to an amorphous glass network andit is not compatible for load-bearing applications. In the present work, the effect of addition of nickel oxide that annualizes the improvement in its mechanical strength and bioactivity is studied. Bioactivity of base glass and doped glass samples were tested through their HCA abilities by immersing them in simulated body fluid (SBF) for different days. The formation of HCA was confirmed by FTIR spectroscopy and pH measurement. Densities and mechanical properties of samples were also increased considerably by increasing the concentration of nickel oxide.