Effects of CO₂ laser irradiation on the wettability and human skin fibroblast cell response of magnesia partially stabilised zirconia

Human skin fibroblast cells in vitro responses on the surface of a bioinert zirconia ceramic partially stabilised with magnesia partially stabilised zirconia (MgO-PSZ) bioinert ceramic before and after CO₂ laser treatment were investigated to find the interrelationship between the cell adhesion, wettability and laser parameters. Contact angle, θ , measurements of a set of test liquids were a clear indication that surface treatment of the MgO-PSZ with a CO₂ laser brought about a reduction in θ, indicating that the wettability of the MgO-PSZ had been enhanced. A relationship was found between the wettability and the microstructure of the MgO-PSZ surface and laser processing parameters. It was subsequently deduced that the factors active in causing the observed modification in the wettability of the MgO-PSZ were the increases in the surface O₂ content and the polar component of the surface energy, γ _sv ^p, the latter resulting from surface melting and resolidification. Moreover, the investigation into the human skin fibroblast cell response revealed that the CO₂ laser treatment of the MgO-PSZ had resulted in a surface favourable for cell adhesion, as the extent of cell attachment and adhesion on the MgO-PSZ surface was enhanced depending on laser parameters. Such an improvement in cell adhesion, which could be greatly beneficial to developing enhanced bonding at the tissue and implant interface, was influenced by the surface properties of the modified MgO-PSZ, particular wettability.