title: Antibacterial Efficacy of Aqueous Ozone in Root Canals Infected by Enterococcus faecalis.
abstract: BACKGROUND
  In endodontics, the elimination of resistant bacteria such as Enterococcus faecalis plays an important role for treatment success in root canals. Therefore, new alternative irrigants (instead of sodium hypochlorite) have been researched to achieve ideal endodontic treatment.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate and to compare the antibacterial effect of aqueous ozone with different concentrations and techniques of application (manual and ultrasonic) against E. faecalis in human root canals.
  
  
  METHODS
  Eighty single-root mandibular premolar teeth were selected, prepared and sterilized. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth were divided into four main groups each has 20 members: NaOCl (positive control) group; 8 ppm aqueous ozone group; 12 ppm aqueous ozone group; and 16 ppm aqueous ozone group. While half of the specimens were disinfected with aqueous ozone by manual technique, the other half was disinfected with the aqueous ozone by ultrasonic technique. Conventional irrigation technique was simultaneously applied with ultrasonic vibration that was produced by VDW.ULTRA device. The disinfection procedures were performed for 180 s to ensure standardization of all the working groups. Paper points (placed in the root canals before and after the disinfection procedures) were transferred to Eppendorf tubes containing 0.5 mL of brain heart infusion broth. Then, 50 μL of the suspension was inoculated onto broth agar media. Microbial colonies were counted, and the data were evaluated statistically using 2-way analysis of variance (ANOVA) and Tukey tests.
  
  
  RESULTS
  Although the antibacterial effect of 16 ppm aqueous ozone using a manual technique had an insufficient effect, its ultrasonic application technique resulted in complete disinfection in the root canals.
  
  
  CONCLUSIONS
  The bactericidal activity of high concentration of aqueous ozone combined with ultrasonic application technique showed efficacy similar to that of 5.25% NaOCl in root canals.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Ihsan
authors.initials: I
authors.lastname: Hubbezoglu
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
authors.forename: Recai
authors.initials: R
authors.lastname: Zan
authors.affiliation: Department of Microbiology, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
authors.forename: Tutku
authors.initials: T
authors.lastname: Tunc
authors.affiliation: Department of Microbiology, Faculty of Medicine, Cumhuriyet University, Sivas, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Sumer
keywords: Disinfection; Enterococcus faecalis; Ozone; Root Canal