The formation of a hydroxyl bond and the effects thereof on bone-like apatite formation on a magnesia partially stabilized zirconia (MgO-PSZ) bioceramic following CO₂ laser irradiation

For the purpose of improving the bioactivity of a magnesia partially stabilized zirconia (MgO-PSZ) and to explore a new technique for inducing OH group and apatite formation, a CO₂ laser has been used to modified the surface properties. The bioactivity of the CO₂ laser modified MgO-PSZ has been investigated in stimulated human fluids (SBF) with ion concentrations almost equal to those in human blood plasma. Some hydroxyl groups were found on the MgO-PSZ following CO₂ laser treatment with selected power densities. The surface melting on the MgO-PSZ induced by CO₂ laser processing provides the Zr⁴⁺ ion and OH^- ion, in turn, the incorporation of the Zr 4+ ion and the OH - ion creates the Zr-OH group on the surface. After 14 days of SBF soaking, the apatites formed on the MgO-PSZ with relatively high amount of hydroxyl groups generated by the CO₂ laser treatment, while no apatite was observed on the untreated with few hydroxyl groups. It exhibits that the Zr-OH groups on the MgO-PSZ surface is the functional groups to facilitate the apatite formation. The increased surface roughness provides more active sites, meantime, increased surface energy benefits to the adsorption and reaction on the surface.