Ex vivo study comparing three cold atmospheric plasma (CAP) sources for Biofilm Removal on Microstructured Titanium

The aim of the present experimental study was to test three different plasma sources on the removal of 72 h oral biofilms. It was hypothesized that cold atmospheric plasma (CAP) lowers biofilm coverage significantly. In vivo biofilms were formed on sand-blasted/acid-etched titanium discs (n = 40) mounted on splints worn for 72 h by eight volunteers. Specimens were randomly divided into five groups: CAP I received indirect plasma application, CAP II received direct plasma application, CAP III received microwave-driven pulsed plasma application (90 s each). The chlorhexidine (CHX) group was cleaned with a curette and rinsed with CHX. Biofilms of a control group received no treatment. After treatment, all specimens were rinsed for 10 s using a dental air/water spray (2 bar). The vitality of microorganisms was detected by cultivation on agar plates for 24 h and 48 h. The presence of biofilms and their quantity on the titanium samples was investigated by fluorescence microscopy (FM) using live/dead staining. A biofilm's quality was analyzed by scanning electron microscopy (SEM). All treated samples showed a reduced growth on agar plates compared with the control group. FM analysis showed significantly lowered biofilm coverage in all treatment groups compared with the negative control group (t test, p < 0.05). Within the plasma treatment groups, there was a significant difference between CAP II and CAP III ( p = 0.032). SEM showed disintegrated biofilms in all test groups. CAP reduces and disintegrates oral biofilms. Adjuvant application plasma could lead to more effective antimicrobial therapies for peri-implantitis.