Plasma treatment effects on destruction and recovery of Porphyromonas gingivalis biofilms

Abstract

The objective of this study was to investigate the treatment effects of non-thermal atmospheric gas plasmas (NTAP) on destruction and the recovery (or re-colonization) of Porphyromonas gingivalis (P. gingivalis) in biofilms. P. gingivalis is a well-known keystone periodontal pathogen strongly associated with periodontal diseases, especially periodontitis. P. gingivalis biofilms were formed on stainless steel coupons and treated for 1, 2, and 5 minutes by NTAP of pure argon gas and argon+oxygen gas mixture. MTT assay, colony forming unit (CFU) counting assay and confocal laser scanning microscopy (CLSM) were used to assess the destruction efficiency. In addition, the plasma treated biofilms were re-cultured in the medium supplemented with antibiotics and oxidative stress sources to determine the synergy of the NTAP with other antimicrobial agents. The results showed the plasma treatment could result in 2.7 log unit reduction in bacterial load. The recovered biofilm CFU with NTAP treatment combined with sub minimal inhibition concentration of amoxicillin was 0.33 log units less than the biofilm treated with amoxicillin alone. The recovered biofilm CFU in NTAP groups was about 2.0 log units less than that in the untreated controls under H2O2 treatment. There was approximately 1.0 log unit reduction of biofilm CFU in plasma treated biofilm compared with untreated control under paraquat treatment. The plasma treated biofilms exhibited less resistance to amoxicillin and greater susceptibility to hydrogen peroxide (H2O2) and paraquat, suggesting that NTAP may enhance biofilm susceptibility to host defense. These in vitro findings suggested that NTAP could be a novel and effective treatment method of oral biofilms that cause periodontal diseases.

Porphyromonas gingivalis: A scoping review

“…The use of NTAP plus a mixture of argon gas and oxygen, in an in vitro experiment, showed in confocal laser scanning microscopy, a reduction in the bacterial load of P. gingivalis, in addition to creating a lower resistance to antibiotics [35] .…”

The applications of cold atmospheric plasma in dentistry

“…The efficiency of biofilm destruction depends on the biofilm structure and treatment times, suggesting the need for further research to optimize the treatment process. [ 68 ] The impact of non‐thermal plasma therapy on zirconia surfaces contaminated with P. gingivalis was a subject of a different preclinical study performed by Lee et al in 2022. The goal of the study was to determine the therapeutically beneficial time frame for plasma therapy in terms of osteoblast activity and bacterial adhesion.…”

The therapeutic perspective of cold atmospheric plasma in periodontal disease

“…CAP‐mediated antimicrobial properties against periodontal pathogens have been frequently reported (De Morais Gouvêa Lima et al, 2022; Hong et al, 2022; Jungbauer et al, 2022; Li et al, 2017; Lima et al, 2021). Recently, Lima et al reported that exposure to helium CAP jet significantly inhibited the biofilm viability of P. gingivalis in an in vitro study (De Morais Gouvêa Lima et al, 2022).…”

“…The subsequent loss of cell membrane integrity led to the accumulation of intracellular ROS/RNS, which reinforced oxidative stress and caused cell apoptosis or necrosis (Li et al, 2017). Additionally, in an interesting study, the authors proposed a hypothesis that in addition to the direct bactericidal effect, CAP could block the recolonization of P. gingivalis biofilms and enhance the susceptibility of P. gingivalis biofilms to antibiotic therapy as revealed by results of bacterial load detection (Hong et al, 2022). However, these in vitro bacterial biofilm models with single microorganism species may be far from realistic in the periodontal pockets of patients with PD.…”

“…Our previous study provided clear evidence that CAP significantly decreased clinical attachment loss (CAL) and alveolar bone absorption in the treatment of experimental periodontitis in beagle dogs (Tang et al, 2022). CAP was able to inhibit diverse periodontal pathogens involved in the initiation of PD (Hong et al, 2022; Jungbauer et al, 2022; Küçük et al, 2020; Lima et al, 2021). Moderate periodontal inflammatory response contributed significantly to resisting periodontal pathogens, but the excessive inflammation eventually broke down the periodontium in controls.…”