Low-temperature plasma on peri-implant–related biofilm and gingival tissue

Background: Evaluate the effect of low-temperature plasma (LTP) on an anaerobic biofilm and on the biological response of an in vitro reconstituted gingival epithelium tissue. Methods: Porphyromonas gingivalis W83 biofilm was cultured on titanium discs and reconstituted gingival tissues were submitted to similar treatment conditions. Treatments: LTP1—plasma treatment for 1 minute, LTP3—plasma treatment for 3 minute, CHX—0.2% chlorhexidine for 1 minute, GAS—gas only (no plasma) for 3 minute, and NEGATIVE—no treatment. TRITON group was included as a positive control for tissue analysis. Counting of viable colony forming units (CFU/mL) and confocal laser scanning microscopy were performed to evaluate LTP's antimicrobial effect. EpiGingival tissue was evaluated through cytotoxocity, viability, histology, and imunnohistochemistry (Ki67, vascular endothelial growth factor-A vascular endothelial growth factor A [VEGF-A], and terminal deoxynucleotidyl transferase dUTP nick end labeling terminal deoxynucleotidyl transferase dutp nick end labeling [TUNEL] expression). Results: LTP1 and LTP3 presented significantly different reduced CFU/mL reduction in comparison to the negative control (Ρ < 0.001), but it was not as effective as the positive control (CHX). Low cytotoxicity and high viability were observed in gingival epithelium of NEGATIVE, GAS, CHX, and both LTP groups. The morphologic analysis of gingival epithelium revealed minor cell damage in the plasma groups (score 1). LTP1, LTP3, GAS, and NEGATIVE groups exhibited less than 5% of basal layer positive cells. LTP1, LTP3, GAS, and CHX groups were not positive for TUNEL assay. LTP1 and LTP3 showed the most positivity for VEGF. Conclusions: LTP treatment can be considered as an effective method for reducing P. gingivalis biofilm on implant surfaces, while being safe for the gingival epithelium. Furthermore, plasma treatment may be associated with cell repair.