Influence of plasma and ultraviolet treatment of zirconia on initial attachment of human oral keratinocytes: Expressions of laminin γ₂ and integrin β₄

Abstract

Initial attachment of human oral keratinocytes cultured on yttria-stabilized tetragonal zirconia polycrystal (TZP) surfaces that were subjected to UV or oxygen plasma (O2-plasma) treatment was investigated. The viability of the attached cells, mRNA expression of laminin γ₂ and integrin β₄, distribution of laminin γ₂ and integrin β₄, cell area, and cell morphology were assessed. The results showed that no differences in the viability of attached cells were recognized among the conditions. However, expression of laminin γ₂ and integrin β₄ as well as cell morphology were promoted only in O2-plasma specimens even though superhydrophilicity was obtained in both the UV and O2-plasma specimens compared with the untreated control specimen. The photocatalytic activity was believed to be closely involved in the above-mentioned differences. The results of this study suggest that TZP surface treated with oxygen plasma promotes the initial attachment capability of human oral keratinocytes with enhancing the extracellular matrix such as laminin γ₂.