Peri-implant Soft Tissue Cell Behavior on Experimental β-Ti Alloys

Titanium alloys based on Ti6Al4V (TA6V) are widely employed as metallic materials for dental implants owing to their overall mechanical and biological performance. However, challenges remain, particularly the mismatch in elastic modulus between the alloy and bone tissue, as well as concerns regarding the potential release of cytotoxic ions such as aluminum (Al) and vanadium (V). Therefore, optimizing alloy composition is crucial to improve peri-implant tissue integration and enhance long-term implant stability. In this in vitro study, the cytocompatibility of a newly developed β-titanium alloy, Ti20Zr3Mo (at%) free of Al and V and exhibiting a reduced elastic modulus compared to that of TA6V, was evaluated using primary human gingival fibroblasts, representative of peri-implant soft tissues. The experimental alloy was compared to conventional TA6V and commercially pure titanium (Cp-Ti40). Several endpoints were investigated to characterize cell-material interactions. Cell viability and cytotoxicity were analyzed by Live/Dead fluorescence staining, while metabolic activity was assessed using the Alamar Blue assay. Cell adhesion and surface colonization were observed through scanning electron microscopy and confocal laser imaging. In addition, extracellular matrix production, including collagen deposition, was examined to evaluate the potential for soft tissue integration. Results demonstrated that Ti20Zr3Mo alloy supported comparable cell viability to Cp-Ti40 while exhibiting enhanced surface colonization by fibroblasts. These findings suggest that the substitution of Al and V with Zr and Mo in specific proportions may promote suitable fibroblast-Ti-alloy interactions, which could improve peri-implant soft tissue sealing and contribute to the long-term success of dental implants. This work highlights a promising strategy for developing next-generation titanium alloys that combine improved biological responses with suitable mechanical properties, with the ultimate goal of enhancing the long-term clinical performance of dental implants.