Zirconia activation by ultraviolet irradiation and O₂ plasma to obtain hydrophilic surface for implantology

High strength ceramics, such as yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP), have great prominence in the field of implantology due to their mechanical, chemical and physical properties, meeting some needs of titanium implants, mainly as it regards oral aesthetics. The purpose of the present study was to obtain sandblasting-acid etching treated surfaces of Y-TZP discs, and a hydrophilic surface, which improves the osseointegration process, using ultraviolet ray (UV) irradiation or O₂ plasma surface treatments. The results presented similar surface morphology before and after UV irradiation and O₂ plasma treatment, and a difference regarding average roughness, due to the removal of impurities inside the macropores. The contact angle was better for O₂ plasma (1.8°) than for UV irradiation (17.1°), and x-ray Excited Photoelectron Spectroscopy XPS supported the confirmation of hydrophilicity, presenting a decrease in surface carbon percentage. The XRD spectrum proved that after UV irradiation or O₂ plasma treatments, the Y-TZP phases were kept unchanged, assuring the initial properties of the material. Biologically, on smooth surfaces, with average roughness of 0.090 μm, fibroblasts growth and adhesion were better than on rough surfaces, with average roughness of approximately 2.258 μm. The results of this study proved the effectiveness of different surface treatments on Y-TZP, obtaining hydrophilicity on rough surfaces and lower cell attachment than in smooth surfaces. Further studies reporting on surface roughness, superhydrophilicity and fibroblast growth are recommended. (paper)