Efficacy of Cold Atmospheric Plasma on Pathogenicity of Oral Microcosm Biofilms

Abstract

This study aimed to compare the longitudinal efficacy between chlorhexidine gluconate (CHX; 0.12%) and cold atmospheric plasma (CAP) in reducing oral biofilm pathogenicity, utilizing a quantitative light-induced fluorescence-digital (QLF-D) camera. Oral microcosm biofilms were developed for 2 days on 57 hydroxyapatite disks. These biofilms were treated with distilled water for 1 min, CHX for 1 min, and CAP for 2 min over the course of 6 days. The red fluorescence intensities of the biofilms were measured using a QLF-D and expressed as pre- and post-treatment red/green ratios (RatioR/G). The bacterial viability (ratio of the green-stained area to the total stained area, RatioG/G+R) was calculated using live/dead bacterial staining; the total and aciduric bacterial counts were determined. A significant intergroup difference was found between RatioR/G changes according to the treatment period (p < 0.001). The RatioR/G observed within the CAP-treated group was significantly lower compared with the CHX-treated group at every interval of measurement (p < 0.001). The CAP-treated group also exhibited a lower RatioG/G+R and more weakened bacterial aggregation compared with the CHX-treated group (p < 0.05). In the group treated with CAP, the counts of both total and aciduric bacteria were substantially reduced compared with the DW group, with a statistically significant reduction (p < 0.001). Therefore, CAP may be more effective in minimizing oral microcosm biofilm pathogenicity than 0.12% CHX.