Comparison study of root canal disinfection by cold plasma jet and photodynamic therapy

Introduction: This study evaluated and compared the antibacterial effect of plasma and photodynamic therapy (PDT) in root canals infected with Enterococcus faecalis. Methods: One hundred single-rooted extracted human teeth (no treatment) were selected and sterilized. Root canals of teeth were prepared with the crown-down technique and contaminated with Enterococcus faecalis after sterilization, and incubated for one week. To investigate the effect of disinfection, 60 specimens were randomly selected for three disinfection groups: He and He/O-2 plasma (n = 20) in 5-s groups (control, 2, 4, 6 and 8 min treatments) and PDT (n = 20) in 2-s groups (control and PDT treatment). Next, for comparison, 40 remaining teeth were divided into four groups: control, 8 min He plasma, 8 min He/O-2. and PDT. Results of antibacterial action were reported by CFU/mL analysis and the structural changes of biofilm were evaluated by SEM. Results: All groups showed a significant reduction of bacteria after treatment, and He/O-2 plasma was more effective against E. faecalis, followed by PDT and He plasma respectively, further confirmed by SEM. Conclusion: He/O-2 plasma is a strong sterilization method against E. faecalis biofilm and can, therefore, be an effective therapy in endodontics.