Fabrication, s-SNOM Characterization and <i>in vitro</i> Testing of Laser-Induced Periodic Surface Structures for Dental Abutment Applications

Surface modification of titanium (Ti) and titanium alloy (Ti6Al4V) for medical implants is frequently required to improve material characteristics and reduce predisposing factors to bacterial invasion and infection. In case of dental abutments, due to close contact of the material with peri-implant soft tissue, it is expected that the surface supports gingival cell adhesion while preventing bacterial diffusion at the interface. Laser surface texturing has demonstrated the possibility to fabricate micro- and nanostructures on large-scale surfaces of various materials with new characteristics and functionalities. Here, we demonstrate the possibility to generate large-scale laser-induced periodic surface structures (LIPSS) by picosecond laser-texturing of Ti and Ti6Al4V surfaces, in a contamination-free approach. Uniform LIPSS formation is confirmed by morpho-chemical analyses using a scanning electron microscopy and a scanning near-field optical microscopy. The behavior of primary human gingival epithelial cells (hGEpiCs) and gingival fibroblast cells (hGFCs) on laser modified surfaces was evaluated to assess samples biocompatibility. It was shown that LIPSS fabricated on titanium substrates promote more favorable cellular response, including better cell attachment and higher proliferation rates of hGEpiCs. Meanwhile, LIPSS on Ti6Al4V surfaces enhance hGFCs adhesion and proliferation which is essential for improving tissue healing around dental implants. Moreover, laser texturing on Ti6Al4V surfaces induces lower expression of alpha-SMA protein which is associated with fibrosis development, showing positive implications for peri-implant soft tissue integration in implantology.