title: Effect of a Benzalkonium Chloride Surfactant-Sodium Hypochlorite Combination on Elimination of Enterococcus faecalis.
abstract: BACKGROUND
  The purpose of this investigation was to determine the effect of a sodium hypochlorite-surfactant combination on the removal of Enterococcus faecalis from infected teeth.
  
  
  METHODS
  Sixty-four extracted human single canal anterior teeth were prepared with rotary instrumentation and sterilized. Teeth were divided into 4 groups, N = 16. Three experimental groups were inoculated with E. faecalis and cultured for 21 days before use: positive control group, no irrigation; NaOCl group, irrigated with 5 mL 6% NaOCl; and NaOCl/BAK group, irrigated with 5 mL 6% NaOCl/0.008% benzalkonium chloride (BAK). The negative control group received medium only and no inoculate. Paper point sampling of the canals was obtained before irrigation (S1) for all 4 groups and for 2 groups after irrigation (S2) to determine remaining colony-forming units. After sampling, all teeth were split in half and evaluated for bacterial viability colony-forming units and penetration of dentinal tubules by using fluorescent vital dye staining and confocal laser scanning microscopy.
  
  
  RESULTS
  Comparison of pre-irrigation and post-irrigation paper point samples from the 2 irrigated groups showed a significant reduction in bacterial canal load (P < .001, Kruskal-Wallis), with a significantly lower load in the NaOCl/BAK group than in the NaOCl group (P = .001, Mann-Whitney U test); 68.8% of the NaOCl/BAK samples gave no recoverable counts. In contrast, no significant difference between these groups was found for counts recovered from dentin. Confocal laser scanning microscopy showed no differences in tubule penetration.
  
  
  CONCLUSIONS
  The addition of BAK to NaOCl significantly reduced the number of remaining bacteria within the canal after irrigation compared with NaOCl alone.
authors.affiliation: U.S. Army Dental Activity, Fort Gordon, Georgia.
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Baron
authors.affiliation: U.S. Army Dental Activity, Fort Gordon, Georgia. Electronic address: kimberly.w.lindsey.mil@mail.mil.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Lindsey
authors.affiliation: U.S. Army Dental Activity, Fort Gordon, Georgia.
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Sidow
authors.affiliation: U.S. Army Dental Activity, Fort Gordon, Georgia.
authors.forename: Douglas
authors.initials: D
authors.lastname: Dickinson
authors.affiliation: Department of Clinical Investigation, Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia.
authors.forename: Augustine
authors.initials: A
authors.lastname: Chuang
authors.affiliation: Department of Clinical Investigation, Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia.
authors.forename: James C
authors.initials: JC
authors.lastname: McPherson
mesh_terms: D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D001548:Benzalkonium Compounds / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D003804:Dentin / Q000382:microbiology; D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D014070:Tooth / Q000382:microbiology*
chemical_list: D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D012973:Sodium Hypochlorite
keywords: Benzalkonium chloride; Enterococcus faecalis; biofilm; dentin tubules