Low-Temperature Plasma as an Approach for Inhibiting a Multi-Species Cariogenic Biofilm

Inhibitory effect of helium cold atmospheric plasma on cariogenic biofilms

This study aimed to determine the effects of low-temperature plasma jet produced in gas helium (LTP-helium) on cariogenic biofilms composedby Streptococcusmutans, Streptococcus sanguinis and Streptococcus gordonii, and also by the combination of Candida albicans, Lactobacillus acidophilus and S. mutans. Biofilms were treated for 1, 3, 5, and 7 minutes. A 0.12% chlorhexidine solution was used as the positive control and sterile physiologic solution was the negative control. Biofilm viability was analyzed by viable cell recovery, scanning electron microscopy, and confocal laser scanning microscopy. All assays were performed intriplicate in three independent experiments. Multispecies biofilms exposed to LTP-helium had a significant reduction in viability when compared to the negative control (p < 0.0001). For biofilm formedby S. mutans, S. sanguinis, and S. gordonii, LTP treatments for 5 and 7 minutes caused similar reduction of morethan 2 log10. Also, a significant reduction in the viability of biofilms formedby C. albicans, L. acidophilus, and S. mutans was detected (p < 0.0001). In conclusion, LTP-helium reduced theviability of cariogenic biofilms with different microbial compositions, which indicates that LTP-helium is a potential tool for developing new protocols for dental caries prevention and treatment.

Exploring the efficacy of in-vitro low-temperature plasma treatment on single and multispecies dental cariogenic biofilms

The primary aim of this study was to investigate the impact of treatment with low-temperature plasma (LTP) for varying exposure durations on a multispecies cariogenic biofilm comprising C. albicans, L. casei, and S. mutans, as well as on single-species biofilms of L. casei and C. albicans, cultured on hydroxyapatite discs. Biofilms were treated with LTP-argon at a 10 mm distance for 30 s, 60 s, and 120 s. Chlorhexidine solution (0.12%) and NaCl (0.89%) were used as positive (PC) and negative controls (NC), respectively. Argon flow only was also used as gas flow control (F). Colony-forming units (CFU) recovery and confocal laser scanning microscopy (CLSM) were used to analyze biofilm viability. LTP starting at 30 s of application significantly reduced the viability of multispecies biofilms by more than 2 log10 in all treated samples (p < 0.0001). For single-species biofilms, L. casei showed a significant reduction compared to PC and NC of over 1 log10 at all exposure times (p < 0.0001). In the case of C. albicans biofilms, LTP treatment compared to PC and NC resulted in a significant decrease in bacterial counts when applied for 60 and 120 s (1.55 and 1.90 log10 CFU/mL, respectively) (p < 0.0001). A significant effect (p ≤ 0.05) of LTP in single-species biofilms was observed to start at 60 s of LTP application compared to F, suggesting a time-dependent effect of LTP for the single-species biofilms of C. albicans and L. casei. LTP is a potential mechanism in treating dental caries by being an effective anti-biofilm therapy of both single and multispecies cariogenic biofilms.

Antibacterial efficacy of non-thermal atmospheric plasma against Streptococcus mutans biofilm grown on the surfaces of restorative resin composites

The aim of this study was to evaluate the antimicrobial efficacy of non-thermal atmospheric plasma (NTAP) against Streptococcus mutans biofilms. Resin discs were fabricated, wet-polished, UV sterilized, and immersed in water for monomer extraction (37 °C, 24 h). Biofilms of bioluminescent S. mutans strain JM10 was grown on resin discs in anaerobic conditions for (37 °C, 24 h). Discs were divided into seven groups: control (CON), 2% chlorhexidine (CHX), only argon gas 150 s (ARG) and four NTAP treatments (30 s, 90 s, 120 s, 150 s). NTAP was applied using a plasma jet device. After treatment, biofilms were analyzed through the counting of viable colonies (CFU), bioluminescence assay (BL), scanning electron microscopy (SEM), and polymerase chain reaction (PCR). All NTAP-treated biofilm yielded a significant CFU reduction when compared to ARG and CON. BL values showed that NTAP treatment for 90 s, 120 s or 150 s resulted in statistically significantly lower metabolic activity when compared to the other groups. CHX displayed the lowest means of CFU and BL. SEM showed significant morphological changes in NTAP-treated biofilm. PCR indicated damage to the DNA structure after NTAP treatment. NTAP treatment was effective in lowering the viability and metabolism of S. mutans in a time-dependent manner, suggesting its use as an intraoral surface-decontamination strategy.

Application of Plasma Technology in Bioscience and Biomedicine

Plasma technology has been an integral part of research in life sciences for decades through its role in the manufacture and modification of material surface characteristics of many common laboratory consumables, and it is still of interest in many fields, including the treatment of biomaterials and implants [...]

Applications of Cold Atmospheric Pressure Plasma in Dentistry

Plasma is an electrically conducting medium that responds to electric and magnetic fields. It consists of large quantities of highly reactive species, such as ions, energetic electrons, exited atoms and molecules, ultraviolet photons, and metastable and active radicals. Non-thermal or cold plasmas are partially ionized gases whose electron temperatures usually exceed several tens of thousand degrees K, while the ions and neutrals have much lower temperatures. Due to the presence of reactive species at low temperature, the biological effects of non-thermal plasmas have been studied for application in the medical area with promising results. This review outlines the application of cold atmospheric pressure plasma (CAPP) in dentistry for the control of several pathogenic microorganisms, induction of anti-inflammatory, tissue repair effects and apoptosis of cancer cells, with low toxicity to healthy cells. Therefore, CAPP has potential to be applied in many areas of dentistry such as cariology, periodontology, endodontics and oral oncology.