title: Bactericidal effects of Nd:YAG laser irradiation and sodium hypochlorite solution on Enterococcus faecalis biofilm.
abstract: OBJECTIVE
  The aim of this study was to evaluate the bactericidal effects of Nd:YAG laser on biofilm of Enterococcus faecalis.
  
  
  BACKGROUND
  It is difficult to eliminate bacterial biofilms with routine endodontic preparation techniques. It might be possible to eliminate biofilms remaining in the root canals of teeth with lasers.
  
  
  METHODS
  The root canals of 60 extracted teeth were prepared and E. faecalis biofilms were formed within the root canals. Then the teeth were randomly divided into four groups of 15. Group 1 samples did not undergo any interventions, to serve as controls. Group 2 samples underwent a 3-W laser beam for 10 sec. The root canals in group 3 were irrigated with 1% sodium hypochlorite for 15 min and then irradiated with a 3-W laser beam for 10 sec. The root canals in group 4 were irrigated with 1% sodium hypochlorite for 15 min. Dentin chips were collected from the root canal walls and weighed. Then the chips were used to prepare a suspension. The classic colony-forming unit (CFU) counting technique was used to determine remaining bacterial counts.
  
  
  RESULTS
  The bacterial counts in groups 2 and 4 had decreased to 54% and 2.39% of the control group, respectively. In group 3 no bacterial growth was observed. There were no significant differences between groups 1 and 2 (p>0.05).
  
  
  CONCLUSIONS
  Based on the results of the present study, the effect of Nd:YAG laser beam on E. faecalis biofilm is less than that of sodium hypochlorite solution. A combination of laser and sodium hypochlorite results in complete elimination of E. faecalis biofilm.
authors.affiliation: Dental and Periodontal Research Center, Endodontic Department, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Rahimi
authors.forename: Shahriar
authors.initials: S
authors.lastname: Shahi
authors.forename: Seddigheh
authors.initials: S
authors.lastname: Gholizadeh
authors.forename: Sahar
authors.initials: S
authors.lastname: Shakouie
authors.forename: Sahand
authors.initials: S
authors.lastname: Rikhtegaran
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Soroush Barhaghi
authors.forename: Morteza
authors.initials: M
authors.lastname: Ghojazadeh
authors.forename: Mohammad
authors.initials: M
authors.lastname: Froughreyhani
authors.forename: Majid
authors.initials: M
authors.lastname: Abdolrahimi
mesh_terms: D018441:Biofilms / Q000528:radiation effects*; D003131:Combined Modality Therapy; D013293:Enterococcus faecalis / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects*; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000627:therapeutic use*
chemical_list: D012973:Sodium Hypochlorite