In Vitro Cellular Response to Chemically Modified Titanium Surfaces for Soft Tissue Contact

Abstract

A dental abutment is the main part of a dental implant pillar with soft tissue contact. It is believed that the composition of the peri-implant mucosa, as well as the soft tissue contact is affected by the abutment surface characteristics. The peri-implant mucosa is mainly made up of connective tissue and epithelium. The production of connective tissue is important during the healing process of a dental implant treatment, and is made of fibroblasts and extracellular matrix. In this study human gingival fibroblasts (HGF-1) as well as 3T3 mouse fibroblasts were used to evaluate the in vitro cellular response to titanium surfaces (Ti), titanium nitride surfaces (TiN) and chemically modified titanium nitride surfaces (TiN1 and TiN2). In total four surface groups were evaluated. Ti-sample discs (Ø=6,25 mm) were used for surface characterization using Scanning Electron Microscopy (SEM), contact angle analysis and 2 D stylus profilometry. The in vitro cellular response was evaluated in terms of morphology, initial cell adhesion, growth and cell migration using SEM and fluorescence microscopy. Results showed that the chemical modifications of the titanium surfaces altered the surface characteristics in terms of wettability and morphology. TiN1-samples showed a higher surface roughness compared to the other samples. The in vitro study showed that no difference in the initial adhesion or in the morphology could be observed when comparing the different groups. However, differences between groups were seen when evaluating cell growth and migration. Cell growth was similar for all groups except for TiN2-samples which did not support cell growth. Cell migration appeared faster for both cell types on TiN-samples as compared to Ti-samples. Migration studies could not be performed on chemically modified titanium nitride samples (TiN1 and TiN2), possibly due to poor cell adhesion. The different cell responses obtained for the different groups cannot be related to a single surface modification as the groups showed different surface characteristics in terms of surface roughness, wettability and chemical composition