title: Light activated disinfection: an alternative endodontic disinfection strategy.
abstract: BACKGROUND
  An improved light activated disinfection technique utilizing a specific photosensitizer formulation, liquid optical-conduit, oxygen-carrier and light energy of appropriate wavelength has been introduced recently. This study tested the efficacy of this improved light activated disinfection on ex vivo biofilms of Enterococcus faecalis at two different stages of maturation.
  
  
  METHODS
  Eighty-five tooth sections were prepared and endodontic biofilm of E. faecalis were grown within the root canal. In stage 1, conventional light activated disinfection (LAD), chemical disinfectant (sodium hypochlorite) and improved LAD were tested on four-day-old (immature) biofilms. In stage 2, conventional LAD, improved LAD and chemomechanical disinfection (alone and in combination with improved LAD) were tested on four-week-old (mature) biofilms.
  
  
  RESULTS
  Sodium hypochlorite and improved LAD showed the ability to significantly inactivate bacteria in four-day-old biofilms when compared to the control and LAD (p < 0.05). Inactivation of bacteria from deeper dentine was higher in improved LAD than sodium hypochlorite. In four-week-old biofilms, a combination of chemomechanical disinfection and improved LAD produced significant bacterial killing compared to either chemomechanical disinfection or improved LAD alone.
  
  
  CONCLUSIONS
  This study highlighted the potential of improved LAD to kill bacteria within dentinal tubules. In combination with chemomechanical preparation, the improved LAD significantly inactivated four-week-old biofilm bacteria.
authors.affiliation: Restorative Dentistry, Faculty of Dentistry, National University of Singapore, Singapore.
authors.forename: Z
authors.initials: Z
authors.lastname: Lim
authors.forename: J L
authors.initials: JL
authors.lastname: Cheng
authors.forename: T W
authors.initials: TW
authors.lastname: Lim
authors.forename: E G
authors.initials: EG
authors.lastname: Teo
authors.forename: J
authors.initials: J
authors.lastname: Wong
authors.forename: S
authors.initials: S
authors.lastname: George
authors.forename: A
authors.initials: A
authors.lastname: Kishen
mesh_terms: D000704:Analysis of Variance; D018441:Biofilms / Q000528:radiation effects*; D015169:Colony Count, Microbial; D019551:Dental Disinfectants / Q000528:radiation effects / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000382:microbiology / Q000528:radiation effects*; D004203:Disinfection / Q000379:methods*; D004708:Endodontics / Q000295:instrumentation / Q000379:methods; D013293:Enterococcus faecalis / Q000528:radiation effects*; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D054023:Lasers, Semiconductor; D008027:Light; D008751:Methylene Blue / Q000528:radiation effects / Q000627:therapeutic use; D017319:Photosensitizing Agents / Q000528:radiation effects / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D019551:Dental Disinfectants; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D012973:Sodium Hypochlorite; D008751:Methylene Blue