Porous titania-coated zirconia: preparation and osteogenic performance evaluation

Zirconia implants are increasingly prevalent in dental applications due to their superior aesthetic outcomes, excellent mechanical properties, and remarkable biocompatibility. However, zirconia implants face challenges such as insufficient bioactivity and limited osseointegration capability, which compromise their long-term stability. In this study, porous titania (TiO₂) coatings were developed on zirconia surfaces to enhance their osteogenic activity. Zirconia substrates were immersed in a mixed solution of zirconium oxychloride (ZrOCl₂) and TiO₂ in a water bath. By regulating the concentration of the treatment solution according to the hydrolysis characteristics of ZrOCl₂, TiO₂ coatings with different porous morphologies were formed during the dense sintering process of zirconia ceramics. The surface characteristics, mechanical strength and bonding strength of coatings of different zirconia samples were tested. The MC3T3-E1 cells were seeded on zirconia discs to evaluate the bioactivity of porous TiO₂ coatings. To assess the <i>in vivo</i> response of porous TiO₂-coated zirconia, the samples were implanted into rat femurs, followed by systematic analysis. Firmly bonded porous TiO₂ coatings were generated on the zirconia surface, significantly enhancing surface roughness and hydrophilicity without adversely affecting the mechanical strength of zirconia. Through <i>in vitro</i> cell experiments, porous TiO₂-modified zirconia could promote cell proliferation, spreading and osteogenic differentiation. Furthermore, <i>in vivo</i> assessments confirmed that porous TiO₂-coated zirconia exhibited superior osseointegration effect. The preparation of porous TiO₂-coated zirconia is an effective method to improve the osteogenic performance of zirconia implants, which is of significant importance for promoting the widespread application of zirconia implants.