Effect of FA addition on bioactivity of bioactive glass coating for titanium dental implant: Part II— Composite coating

Due to the ability of bioactive glasses to form chemical and biological bonds with bone, these glasses have been used as a coating of orthopaedic and dental implants. However, the bioactivity of the glasses might be compromised by incorporating certain compounds such as MgO to reduce the high thermal expansion coefficient of these glasses. Therefore, fluorapatite has been added to maintain and improve bioactivity of the glass coatings.In this study we investigate the effect of FA crystals at two loadings on bioactivity of glass coatings containing 9.9, 16.1 and 22.1 mol% MgO. The glass/FA composite coatings have been fabricated by enamelling technique. The bioactivity of the composite coatings was investigated after 1 month immersion in Tris-buffer solution and SBF. The immersed coating samples were investigated by X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy for any structural changes. The filtrate was analysed using inductively coupled plasma spectroscopy and the released fluoride was measured by fluoride selective electrode. The results indicate that FA crystals have a positive effect on the apatite forming ability of the coatings. This is confirmed by XRD, FTIR and SEM–EDS analyses of composite coatings which showed structural changes that indicate the growing or formation of new FA phases.

► Bioactivity of composite glass/FA coating
► Fluorapatite crystals act as nucleation sites for growing or formation of new apatite phases.
► Effect of surface area of composite coating on ionic dissolution
► Magnesium has an impact on glass coating dissolution.
► The degradation of amorphous component of composite coating required for apatite growth