Zirconia-based materials have become increasingly popular in the development of metal-free tooth-coloured dental implants due to their superior aesthetic appearance, high biocompatibility and outstanding mechanical properties [1]. However, implant failure due to insufficient osseointegration or peri-implantitis still represent a great concern among the dental community [2,3]. To overcome those biological complications, surface modification of zirconia has been explored in order to improve the implant-tissue interaction [4].

Considering that, this work was aimed at investigating the effect of topographical modification strategies on the biological properties of 3Y-TZP, in terms of cell and bacterial response. Concretely, the surface of 3Y-TZP was modified by two approaches: laser patterning and chemical etching treatment. On the one side, a femtosecond laser was used to introduce microscale modifications by fabricating microgroove structures on the surface of 3Y-TZP. On the other side, hydrofluoric acid etching was performed to produce homogeneous sub microscale roughness. The resulting topography and surface damage were assessed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy techniques (SEM). The microstructure and wettability changes were characterized by X-Ray diffraction (XRD) and contact angle technique, respectively. Furthermore, human mesenchymal stem cell (hMSC) response was evaluated in terms of cell adhesion, proliferation and differentiation. Finally, bacterial adhesion to the modified surfaces was investigated using Staphylococcus aureus and Pseudomonas Aeruginosa strains.

The topographical features obtained after the two surface modifications performed in this work significantly influenced the biological response. The periodic microgrooves generated by the laser treatment allowed hMSCs attachment and favoured cell alignment and migration, and induced bacteria confinement inside of the grooves. In the case of the chemical etching, such a surface was able to increase cell adhesion, proliferation and differentiation, while displaying antibacterial properties. Thus, the combination of laser micropatterning and etching represents a powerful strategy to fine tune the biological response at the surface of 3Y-TZP for biomedical applications.