Osteoblast growth, after cleaning of biofilm-covered titanium discs with air-polishing and cold plasma

Aim To investigate the effects of a combined biofilm removal with an optimized air polishing and a cold plasma device on cells in vitro. Materials and Methods A 7-day-old biofilm was removed from rough titanium discs with an air-polishing device with erythritol powder (AP) or with a cold atmospheric pressure argon plasma (CAP) device or in combination of both (AP + CAP). The removal efficacy was evaluated by subsequent cell seeding of osteoblast-like cells (MG-63). The cell spreading was analysed after 5 days of incubation by scanning electron microscopy. Separately, the surface hydrophilicity was analysed by measuring the water contact angle (WCA) of the disc for each treatment method. Results The mechanical plaque removal with AP rendered specimen conducive for cell growth, 85% of the surface was covered with cells. An advantage of the combination of AP + CAP was not detectable compared to AP (cell coverage ranged from 57% up to 75%). After sole CAP treatment, microorganisms re-grew and destroyed all cells. The WCA was reduced by all treatment methods. Conclusion An AP treatment has the potential to remove biofilm from rough implant surfaces completely. In contrast to our hypothesis, the combination of plasma and AP treatment did not enhance osteoblast spreading.