Destruction of oral biofilms formed in situ on machined titanium (Ti) surfaces by cold atmospheric plasma

Abstract

The decontamination of implant surfaces represents the basic procedure in the management of peri-implant diseases, but it is still a challenge. The study aimed to evaluate the degradation of oral biofilms grown in situ on machined titanium (Ti) discs by cold atmospheric plasma (CAP). ∼ 200 Ti discs were exposed to the oral cavities of five healthy human volunteers for 72 h. The resulting biofilms were divided randomly between the following treatments: CAP (which varied in mean power, treatment duration, and/or the gas mixture), and untreated and treated controls (diode laser, air-abrasion, chlorhexidine). The viability, quantity, and morphology of the biofilms were determined by live/dead staining, inoculation onto blood agar, quantification of the total protein content, and scanning electron microscopy. Exposure to CAP significantly reduced the viability and quantity of biofilms compared with the positive control treatments. The efficacy of treatment with CAP correlated with the treatment duration and plasma power. No single method achieved complete biofilm removal; however, CAP may provide an effective support to established decontamination techniques for treatment of peri-implant diseases.

Keywords:

• in situ biofilm
• machined titanium surfaces
• decontamination
• cold atmospheric plasma
• peri-implant diseases

Acknowledgments

This study was supported by the Saarland University (grant T 6031500-09). The authors thank Dr Alexander Huwig (Friadent, Mannheim, Germany) for providing the Ti discs, KaVo Dental GmbH, Biberach/Riß, Germany, for providing the diode laser device, Dr Natalia Umanskaya, Dr Melanie Chapat, Janine Priebe, Qian Li, Marie Henkes and Hadia Ghanoum for technical assistance, as well as Mrs Anja Niemeyer-Rupf for critical reading of the manuscript. The authors declare no conflicts of interest.