title: Ex vivo antimicrobial efficacy of strong acid electrolytic water against Enterococcus faecalis biofilm.
abstract: OBJECTIVE
  To observe the antimicrobial effect of strong acid electrolytic water (SAEW) against an Enterococcus faecalis (E. faecalis) biofilm when used as a root canal irrigant.
  
  
  METHODS
  The effect of SAEW, sodium hypochlorite (5.25%; NaOCl) and sodium chloride (0.9%; normal saline) on E. faecalis biofilm vitality on coverslips was observed by confocal laser scanning microscopy (CLSM). Thirty-five root canals from extracted human teeth were sterilized prior to contamination with E. faecalis for four weeks. Bacterial samples were collected with sterile paper points and plated onto BHI agar plates for 48 h. Root canal walls were observed by scanning electron microscopy before and after instrumentation, together with root canal irrigation with SAEW, NaOCl or normal saline, with or without ultrasonic vibration. Antimicrobial effectiveness was established by counting colony-forming units and analysed by two-way anova.
  
  
  RESULTS
  Confocal laser scanning microscopy revealed that SAEW decreased E. faecalis biofilm vitality, and the proportion of dead bacteria increased in accordance with increasing treatment time. Most bacteria in the biofilms were killed after 10-min treatment. No significant difference was observed between SAEW and NaOCl groups at the same treatment time (P > 0.05) or in the susceptibility of E. faecalis to SAEW and NaOCl (P > 0.05) in extracted human teeth with or without ultrasonic activation. SAEW and NaOCl were more effective against E. faecalis biofilm than normal saline, and antimicrobial efficacy was significantly enhanced by ultrasonic vibration (P < 0.05).
  
  
  CONCLUSIONS
  Strong acid electrolytic water effectively killed E. faecalis in a biofilm both on coverslips and in the root canals of extracted human teeth.
authors.affiliation: Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China; Department of Stomatology, the 161 Hospital of PLA, Wuhan, China.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Gu
authors.forename: C
authors.initials: C
authors.lastname: Zhao
authors.forename: A J
authors.initials: AJ
authors.lastname: Sloan
authors.forename: H
authors.initials: H
authors.lastname: Lv
authors.forename: Q
authors.initials: Q
authors.lastname: Yu
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D015169:Colony Count, Microbial; D004573:Electrolytes; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000302:isolation & purification; D066298:In Vitro Techniques; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D012388:Root Canal Irrigants / Q000494:pharmacology*; D014867:Water
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D004573:Electrolytes; D012388:Root Canal Irrigants; D014867:Water
keywords: Enterococcus faecalis; bacterial biofilm; confocal laser scanning microscope; scanning electron microscope; strong acid electrolytic water