title: Effectiveness of different laser systems to kill Enterococcus faecalis in aqueous suspension and in an infected tooth model.
abstract: OBJECTIVE
  To assess the antibacterial action of laser irradiation (Nd:YAG, KTP), photo activated disinfection (PAD) and 2.5% sodium hypochlorite (NaOCl) on Enterococcus faecalis, in an aqueous suspension and in an infected tooth model.
  
  
  METHODS
  Root canals of 60 human teeth with single straight canals were prepared to apical size 50, autoclaved, inoculated with an E. faecalis suspension and incubated for 48 h. They were randomly allocated to four treatment and one control groups. After treatment, the root canals were sampled by flushing with physiological saline, and the number of surviving bacteria in each canal was determined by plate count and solid phase cytometry. The same experimental or control treatments were completed on aqueous suspensions of E. faecalis, and the number of surviving bacteria was determined in the same way.
  
  
  RESULTS
  In aqueous suspension, PAD and NaOCl resulted in a significant reduction in the number of E. faecalis cells (P < 0.001), whilst Nd:YAG or KTP had no effect. In the infected tooth model, only the PAD and NaOCl treated teeth yielded significantly different results relative to the untreated controls (P < 0.001).
  
  
  CONCLUSIONS
  The laser systems as well as PAD were less effective than NaOCl in reducing E. faecalis, both in aqueous suspension and in the infected tooth model.
authors.affiliation: Department of Operative Dentistry and Endodontology, Dental School, Ghent University, Gent, Belgium.
authors.forename: M A
authors.initials: MA
authors.lastname: Meire
authors.forename: K
authors.initials: K
authors.lastname: De Prijck
authors.forename: T
authors.initials: T
authors.lastname: Coenye
authors.forename: H J
authors.initials: HJ
authors.lastname: Nelis
authors.forename: R J G
authors.initials: RJ
authors.lastname: De Moor
mesh_terms: D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology; D013293:Enterococcus faecalis / Q000187:drug effects / Q000528:radiation effects; D016908:Gram-Positive Bacterial Infections / Q000628:therapy*; D006358:Hot Temperature; D006801:Humans; D053844:Lasers, Solid-State; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D010778:Photochemotherapy / Q000379:methods; D012388:Root Canal Irrigants / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology
chemical_list: D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite