The Effect of Surface Treatment Methods on the Surface Characteristics and Biological Activity of Zirconia Implants

Zirconia implants are promising alternatives to titanium, yet optimal surface treatment protocols that preserve their surface properties and biocompatibility are not well-established. This study aimed to evaluate the effects of various surface treatment methods-ethylene oxide (EO), hydrogen peroxide plasma (HPP), electron beam (EB), and their combinations-on the surface characteristics and biological performance of fully sintered 3Y-TZP zirconia. Fully sintered 3Y-TZP zirconia slices were treated using EO, HPP, EB, HPP + EO, or HPP + EB. Surface characteristics, including hydrophilicity, hydrocarbon contamination, and elemental composition, were assessed. The biological responses of human bone marrow stromal cells (hBMSCs) and human gingival fibroblasts (HGFs), covering cell proliferation, cytoskeleton development, osteogenic differentiation, and adhesion, were evaluated. While the HPP group did not show the highest hydrophilicity, it effectively prevented hydrocarbon contamination and maintained a substantial Zr concentration. Surfaces treated with HPP demonstrated significant enhancements in hBMSC and HGF proliferation, cytoskeleton development, osteogenic differentiation, and adhesion, outperforming all other groups. Hydrogen peroxide plasma (HPP) surface treatment is a feasible technique for zirconia implants, as it effectively maintains surface integrity and promotes superior biological activity compared to other methods.