Achieving Complete Human Gingival Fibroblast Collagen Coverage on Implant Abutments Through Vacuum Ultraviolet (VUV) Photofunctionalization

Purpose: To test the hypothesis that surfaces of prosthetic implant abutments treated with vacuum ultraviolet (VUV) light enhance the growth and function of human gingival fibroblasts. Materials and Methods: Implant abutments were treated with 172-nm VUV light for 1 minute. Untreated abutments were included as controls. Their surface properties were characterized using scanning electron microscopy (SEM), contact angle measurements, and chemical composition analysis. Human gingival fibroblasts were cultured on both untreated and VUV-treated abutments to evaluate cell attachment, proliferation, distribution, and collagen production. Cell detachment assays were also performed under various mechanical and chemical stimuli. Results: After VUV treatment, the implant abutments demonstrated a notable transition from hydrophobic to hydrophilic wettability. Surface element analysis revealed a considerable reduction in surface carbon and increase in oxygen and titanium (Ti) elements on the VUV-treated surfaces. On day 1 of culture, 3.9 times more fibroblasts were attached on VUV-treated abutments than on untreated control abutments. Fibroblastic proliferation increased 1.9 to 3.1 times on VUV-treated abutments, along with a significant improvement in the distribution of populating cells. Collagen production on VUV-treated abutments increased by 1.5 to 1.7 times. While untreated abutment surfaces showed voids and a limited spread of collagen deposition, dense and full coverage of collagen was observed on VUV-treated abutments, with a great contrast in the challenging axial surface zone. Cell retention against mechanical and chemical detaching stimuli was increased 11.3 and 4.3 times, respectively, by VUV treatment. Conclusions: Treatment of implant abutments with VUV light for 1 minute resulted in a reduction of surface carbon and a transformation of the surface from hydrophobic to hydrophilic. This led to enhanced attachment, proliferation, and retention of human gingival fibroblasts, along with nearly complete collagen coverage on implant abutments. These in vitro results indicate the promising potential of using VUV photofunctionalized implant abutments to enhance soft tissue reaction and sealing mechanisms.