Early response of fibroblasts and epithelial cells to pink-shaded anodized dental implant abutments: an in vitro study

Purpose: This research aimed to assess whether pink-shaded anodized surfaces could enhance the adhesion of soft tissue cells compared with untreated machined titanium surfaces. Materials and Methods: Two types of Ti-Al-V titanium samples were prepared: machined titanium (Ti) and anodized titanium (AnoTi). The microstructure was studied by means of a scanning electron microscope. X-ray photoelectron spectroscopy (XPS) was carried out as well. The wetting properties were investigated by the sessile drop technique with water and diiodomethane. To investigate the biologic response in vitro, the epithelial cell line HaCaT and the fibroblastic cell line NHDF were used. Cell adhesion, morphology, and proliferation were evaluated. Results: The microstructure of the tested surfaces was irregularly smooth for both types of samples with no relevant morphologic differences. The XPS and HR-XPS performed on the AnoTi samples confirmed the presence of Ti, O, and C, along with Ti oxides. Following the optical contact angle measurements, the anodization process induced a slight transition toward the hydrophobic regime. Consequently, the surface free energy values differed significantly between the anodized and the machined samples. Anodized Ti significantly increased the adhesion and proliferation of both epithelial cells and fibroblasts when compared with the pristine Ti controls. Conclusion: Compared with the clinical standard, anodized surfaces could enhance the adhesion of the two major cell types within the peri-implant soft tissues, which makes pink anodization a promising option for implant dentistry.