Diopside (CaO•MgO•2SiO2)-fluorapatite (9CaO•3P2O5•CaF2) glass-ceramics: potential materials for bone tissue engineering

Glass-ceramics in the diopside (CaMgSi2O6)-fluorapatite [Ca-5(PO4)(3)F] system are potential candidates for restorative dental and bone implant materials. In the present study, a series of glasses along the diopside-fluorapatite binary system have been prepared with varying diopside/fluorapatite ratios for their potential applications in bone tissue engineering. The glasses were obtained from compositions with fluorapatite contents varying between 0 and 40 wt%. The sintering ability and crystallization kinetics of as obtained amorphous glasses have been studied through hot-stage microscopy (HSM) and differential thermal analysis (DTA), respectively, while crystalline phase evolution in sintered GCs has been followed by X-ray diffraction (XRD) adjoined with the Rietveld-R.I.R. technique and scanning electron microscopy (SEM). Further, biodegradation and apatite forming ability of glass-ceramics were investigated by immersion of glass-ceramic discs in simulated body fluid (SBF) solution while chemical degradation and weight loss of glass-ceramics were studied by immersion in Tris-HCl in accordance with the ISO 10993-14 standard. The addition of fluorapatite (10-25 wt%) in the diopside glass system significantly enhanced the sintering ability of glass-ceramics and improved their apatite forming ability along with their biodegradation behaviour. Moreover, the in vitro cellular responses to glass-ceramics showed good cell viability and significant stimulation of osteoblastic differentiation, suggesting the possible use of the glass-ceramics for bone regeneration.