title: Cold plasma therapy of a tooth root canal infected with enterococcus faecalis biofilms in vitro.
abstract: BACKGROUND
  Complete sterilization of an infected root canal is an important challenge in endodontic treatment. Traditional methods often cannot achieve high-efficiency sterilization because of the complexity of the root canal system. The objective of the study was to investigate in vitro the feasibility of using a cold plasma treatment of a root canal infected with Enterococcus faecalis biofilms.
  
  
  METHODS
  Seventy single-root teeth infected with E. faecalis biofilms were divided into 7 groups. Group 1 served as the negative control group (no treatment), and group 7 was the positive control group with teeth treated with calcium hydroxide intracanal medication for 7 days. Groups 2 to 6 included teeth treated by cold plasma for 2, 4, 6, 8, and 10 minutes, respectively. The disinfection of the E. faecalis biofilm was evaluated by colony-forming unit (CFU) counting. Scanning electron microscopy was used to evaluate the structural changes of the E. faecalis biofilm before and after plasma treatment. Confocal scanning laser microscopy was used to investigate the vitality of the microorganisms in the biofilm before and after plasma treatment.
  
  
  RESULTS
  A significant decrease in the number of CFUs was observed after prolonged cold plasma treatment (based on the statistical analysis of the teeth in groups 2-6). Compared with the positive control group, cold plasma treatment of 8 or 10 minutes (groups 5 and 6) had a significantly higher antimicrobial efficacy (P < .05). The scanning electron microscopic analysis showed that the bacteria membrane was ruptured, and the structure of the biofilm was fully destroyed by the plasma. Confocal scanning laser microscopic studies indicated that the plasma treatment induced E. faecalis death and destruction of the biofilm.
  
  
  CONCLUSIONS
  The cold plasma had a high efficiency in disinfecting the E. faecalis biofilms in in vitro dental root canal treatment.
authors.affiliation: Department of General Dentistry, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Pan
authors.forename: Ke
authors.initials: K
authors.lastname: Sun
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Liang
authors.forename: Peng
authors.initials: P
authors.lastname: Sun
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhu
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
authors.forename: Kurt H
authors.initials: KH
authors.lastname: Becker
mesh_terms: D058491:Bacterial Load / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D002126:Calcium Hydroxide / Q000627:therapeutic use; D019551:Dental Disinfectants / Q000627:therapeutic use*; D003786:Dental Pulp Cavity / Q000382:microbiology* / Q000648:ultrastructure; D004203:Disinfection / Q000379:methods; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000648:ultrastructure; D005240:Feasibility Studies; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy*; D006801:Humans; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D058626:Plasma Gases / Q000627:therapeutic use*; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000379:methods; D012390:Root Canal Therapy / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D019551:Dental Disinfectants; D058626:Plasma Gases; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide