Tissue-Safe Low-Temperature Plasma Treatment for Effective Management of Mature Peri-Implantitis Biofilms on Titanium Surfaces

The unique screw-shape design and microstructure of implants pose a challenge for mechanical debridement in removing biofilms. Biofilms exhibit increased resistance to antimicrobials relative to single planktonic cells, emphasizing the need for effective biofilm removal during periodontal therapy for peri-implantitis treatment. To tackle this issue, our team evaluated the effectiveness of low-temperature plasma (LTP) for disinfecting titanium discs contaminated with multispecies biofilms associated with peri-implantitis, specifically focusing on biofilms matured for 14 and 21 days as well as biofilms that had formed on Straumann^Ⓡ Ti-SLA implants for 21 days. The biofilms included Actinomyces naeslundii, Porphyromonas gingivalis, Streptococcus oralis, and Veillonella dispar, which were grown in anaerobic conditions. These biofilms were subjected to LTP treatment for 1, 3, and 5 min, using distances of 3 or 10 mm from the LTP nozzle to the samples. Control groups included biofilms formed on Ti discs or implants that received no treatment, exposure to argon flow at 3 or 10 mm of distance for 1, 3, or 5 min, application for 1 min of 14 μg/mL amoxicillin, 140 μg/mL metronidazole, or a blend of both, and treatment with 0.12% chlorhexidine (CHX) for 1 min. For the implants, 21-day-old biofilms were treated with 0.12% CHX 0.12% for 1 min and LTP for 1 min at a distance of 3 mm for each quadrant. Biofilm viability was assessed through bacterial counting and confocal laser scanning microscopy. The impact of LTP was investigated on reconstituted oral epithelia (ROE) contaminated with P. gingivalis, evaluating cytotoxicity, cell viability, and histology. The results showed that a 1 min exposure to LTP at distances of 3 or 10 mm significantly lowered bacterial counts on implants and discs compared to the untreated controls (p < 0.017). LTP exposure yielded lower levels of cytotoxicity relative to the untreated contaminated control after 12 h of contamination (p = 0.038), and cell viability was not affected by LTP (p ≥ 0.05); thus, LTP-treated samples were shown to be safe for tissue applications, with low cytotoxicity and elevated cell viability post-treatment, and these results were validated by qualitative histological analysis. In conclusion, the study’s results support the effectiveness of 1 min LTP exposure in successfully disinfecting mature peri-implantitis multispecies biofilms on titanium discs and implants. Moreover, it validated the safety of LTP on ROE, suggesting its potential as an adjunctive treatment for peri-implantitis.