Antimicrobial efficacy of direct air gas soft jet plasma for oral bacterial biofilm eradication and treatment

Abstract

The aim of this study was to evaluate the antimicrobial efficacy of an air gas soft jet CAP for its potential use in removing oral biofilms, given that plasma-based technologies have emerged as promising methods in periodontology. Two types of biofilms were developed, one by Streptococcus mutans UA 159 bacterial strain and the other by a complex mixture of saliva microorganisms isolated from a patient with periodontitis. This latter biofilm was characterized via Next Generation Sequencing to determine the main bacterial phyla. The CAP source was applied at a distance of 6mm for different time points. A statistically significant reduction of both CFU count and XTT was detected after 60s of CAP treatment, while the treatment for 120s resulted in both biofilms eradication. CLSM analysis supported CAP effectiveness in killing the microorganisms inside the biofilm and in reducing the thickness of the biofilm matrix. Cytotoxicity tests demonstrated the possible use of CAP without important side effects towards human gingival fibroblasts cell line. The current study showed that CAP treatment was able to eradicate preformed biofilms developed by both S. mutans and the complex mixture of saliva microorganisms, representing a potential innovative strategy to counteract oral pathogens responsible for periodontal diseases.