Target-Aimed Plasma Treatment for Implant Surface Disinfection

Objectives: The bacterial infection is one main reason for the inflammatory reaction of implant surrounding tissues that can lead to implant loss. A widely accepted therapeutic approach is the decontamination of the implant surface. However, contemporary methods to clean the surface are inefficient, alter the implant surface, leave material remnants on the surface and harm the surrounding tissues. A novel approach for the disinfection of implant surfaces is based on electrical plasma. A gas stream passes an electrical field forming bactericidal reactive species. Although such plasma jets are already in clinical use there is no actual technical setup to selectively treat the implant surface in situ. To approach this task a monopolar electrical plasma specified for medical purpose (Transient Spark Disinfection^®) has been developed. Thanks to its technical realization, the plasma is guided to the site of action: the infected implant surface.
Methods: To evaluate its efficacy, the device has been tested on bacterial cultures and on sand-blasted titanium discs (grade V, diameter 10mm). On agar, Enterococcus faecalis (T9) was applied to a concentration of up to 10⁹ CFU/mm² and treated for 10 seconds with the experimental setup.
In a second setup titanium discs were stored in an E.f. solution for 12 days. The suspension has been changed every day without disturbing the surface of the specimens. Discs were treated with the electrical plasma for 1 minute and the surface of the discs were analyzed using SEM, Life-Dead-Staining or bacteria were removed from the discs and plated out on agar or analyzed with TEM.
Results: On agar plates an eradication of all bacteria was observed within a radius of up to 2 mm around the application tip. The cells on the titanium discs were disintegrated and an almost complete killing of the biofilm was observed.
Conclusions: The application of directed plasma seems to be a promising therapeitcal approach in periimplantitis treatment without any significant thermal effect on the surrounding structures.