AimTo evaluate the effects of non-equilibrium plasma in the treatment of ligature-induced peri-implantitis in beagle dogs. Materials and MethodsSix beagles received 12 implants installed in the position of the fourth mandibular premolars. Ligature-induced peri-implantitis was initiated at 3months post-implantation. When approximately 40% of the supporting bone was lost, the ligatures were removed. The implants were subjected to the muco-periosteal scaling and chlorhexidine irrigation with or without plasma irrigation. Three months later, clinical, radiographic and microbiological analyses were performed. Block biopsies were prepared for micro-CT and histomorphometric analysis. The primary outcome was the difference in bone healing of peri-implant sites, and the secondary outcomes included changes in clinical parameters (SBI, PD) and bacterial detection. ResultsAt baseline, no significant differences were observed between the two groups. At 3months post-treatment, the plasma group showed a significantly higher bone level than the control group (p<0.05), a significantly decreased detection of bacteria (Porphyromonas gingivalis and Tannerella forsythia) (p<0.05), and a significant improvement in clinical examination (p<0.05). ConclusionsWithin the limits of this study, non-equilibrium plasma treatment as an adjunct to the conventional therapy is a feasible approach for the treatment of peri-implantitis.