Influence of Uv-light and Non-thermal Plasma on Rough Titanium Surfaces in Vitro

Aim: The aim of this study was to determine and compare the effects of UV light and non-thermal plasma (NTP) treatment on rough titanium surfaces regarding the changes in wettability, surface chemistry as well as cell attachment and proliferation of murine osteoblast-like cells in vitro. Materials and methods: Sandblasted and acid-etched titanium disks (grade 4) were divided into a non-treated control group and two experimental groups either treated by UV light (0.05 mW/cm2 at λ = 360 nm and 2 mW/cm2 at λ = 250 nm) or by NTP of argon (24W; -0.5 mbar) for 12 minutes each. Wettability was assessed using dynamic contact angle measurement and XPS analysis was performed. Murine osteoblast-like cells (MC3T3-E1) were used for in vitro experiments. Cell attachment was assessed using fluorescin diacetate / propium iodide staining (live-dead-staining) after 2, 24 and 72 hours. Proliferation was determined using an XTT assay. Results: UV light and NTP significantly increased wettability on the titanium surfaces (P 0.001). XPS analysis revealed a significant reduction of carbon remnants after treatment by either method (P 0.002). NTP was even more effective in carbon removal than UV light (P = 0.03). UV light and NTP significantly increased cell attachment compared to the non-treated disks (P 0.001) at any time. NTP led to a significant increased cell proliferation (P = 0.002) compared to the non-treated as well as to the UV-treated disks. Conclusion: UV light and NTP treatment can significantly improve wettability and reduce carbon remnants on rough titanium surfaces. Both methods are able to optimize surface conditions for osteoblast-like cells in vitro. However, further studies are needed to determine the extent of these effects in vivo. Keywords: dental implants, UV-light, non-thermal plasma, titanium, cell adhesion