Evaluation of Antibacterial Effects of Cold Atmospheric Plasma, Calcium Hydroxide, and Triple Antibiotic Paste on Enterococcus faecalis Biofilm in the Root Canal System: An In Vitro Study

One of the essential factors in successful endodontic therapy is the effective cleaning and disinfection of the root canal. This study aimed to determine the effect of cold plasma on infected root canals with Enterococcus faecalis and compare its antibacterial effect with the conventional medicaments in vitro.

Sixty-tree single-root teeth were extracted. Canals were cleaned and shaped. Ten teeth were selected as the negative control randomly. The rest of the teeth were incubated at 37°C for 21 days to form E. faecalis biofilm. The specimens were divided into six groups; each group had 10 teeth. In group 1 (the positive control group of calcium hydroxide and triple antibiotic paste [TAP]), methylcellulose was placed in the root canal; in group 2, calcium hydroxide was placed in the root canal for 12 days; in group 3, 10 mg/mL of TAP was placed in the root canal for 12 days; in group 4, helium/oxygen plasma jet was used for 10 minutes. Group 5 was considered as a positive control of plasma, and group 6 was the negative control. After treatment, F4 Pro-Taper rotary file was used to collect root canal microbial biofilms. Bacterial suspensions were serially diluted, and the percentage of growth reduction for each group was obtained by dividing the logarithm of CFU/mL of each group by CFU/mL of the control of the same group.

The CFU/mL of TAP and plasma-treated samples was significantly lower than that of the control groups; however, there were no significant differences between the control group and the samples treated by calcium hydroxide. The most percentage of CFU reduction was in the TAP-treated group compared with plasma and calcium hydroxide-treated groups.

The application of cold plasma effectively inhibited the growth of E. faecalis and reduced bacterial biofilm. Also, in the present study, 10 mg/mL of TAP caused the complete elimination of E. faecalis. Calcium hydroxide had the most negligible effect on E. faecalis biofilm elimination.