Enhancing the soft-tissue integration of dental implant abutments-in vitro study to reveal an optimized microgroove surface design to maximize spreading and alignment of human gingival fibroblasts

Within this work, we demonstrate the influences of different microgrooved surface topographies on the alignment and spreading of human gingival fibroblast (HGF) cells and present the optimal parameters for an improved soft-tissue integration design for dental implant abutments for the first time. Microgrooves with lateral widths from 2.5 to 75 mu m were fabricated by UV-lithography and wet etching on bulk Ti6Al4V ELI material. The microstructured surfaces were compared to polished and ground surfaces as current state of the art. The resulting microtopographies were analyzed using vertical scanning interferometry and scanning electron microscopy. Samples loaded with HGF cells were incubated for 8 and 72 hr and cell orientation, spreading, resulting area, and relative gene expression were analyzed. The effect of contact guidance occurred on all microstructured surfaces yet there is a clear preferable range for the lateral widths of the microgrooves between approx. 11.5 and 13.9 mu m and depths between 1.6 and 2.4 mu m for an abutment surface design, where cell orientation and spreading maximizes. For structures larger than 30 mu m, cell orientation, spreading and even gene expression of intercellular adhesion molecule-1 and yes-associated protein decrease.