title: Antibacterial action of photoactivated disinfection {PAD} used on endodontic bacteria in planktonic suspension and in artificial and human root canals.
abstract: OBJECTIVE
  To measure antibacterial action of photoactivated disinfection (PAD) on endodontic bacteria in planktonic suspension and root canals.
  
  
  METHODS
  Four bacteria, Fusobacterium nucleatum,Peptostreptococcus micros, Prevotella intermedia and Streptococcus intermedius, were tested in suspension. After mixing equal volumes of Tolonium chloride and bacterial suspension for 60s, each 200 microL of concentration (>10(6)cfu mL(-1)) was irradiated with light at 633+/-2 nm. Each energy dose/Tolonium chloride concentration combination was tested eight times, with controls. Prepared root canals in Training Blocs and extracted human teeth were inoculated with S. intermedius followed by 10 mg L(-1) Tolonium chloride or saline. Bacteria in canals were sampled before and after light irradiation. Student t-test assessed significance of changes in viable bacteria produced by treatment of either light or Tolonium chloride alone and light/Tolonium chloride combinations.
  
  
  RESULTS
  In suspension, reductions in bacteria were highly significant (P<0.01) for light/Tolonium chloride combinations compared to light or Tolonium chloride alone. Maximum mean log reductions of 1.14 (P. intermedia), 2.48 (P. micros), 2.81 (F. nucleatum) and 6.73 (S. intermedius) were at 4.8 J/20 mg L(-1). Antibacterial action was increased by energy dose increase (not always significantly), but not by Tolonium chloride concentration. In control canals mean log reductions of 0.42 (Blocs) and 0.38 (teeth) from initial levels were not significant. PAD mean log reductions of 2.40 (Blocs) and 2.01 (teeth) were highly significant. Changes for PAD/energy dose combinations were not significant.
  
  
  CONCLUSIONS
  PAD killed endodontic bacteria at statistically significant levels compared to controls. Kills varied with bacterial species.
authors.affiliation: Department of Biomaterials in Relation to Dentistry, Medical Science Building, Queen Mary University of London, Mile End Road, London E1 4NS, UK. j.a.williams@qmul.ac.uk
authors.forename: Jill A
authors.initials: JA
authors.lastname: Williams
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Pearson
authors.forename: M John
authors.initials: MJ
authors.lastname: Colles
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001419:Bacteria / Q000187:drug effects*; D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D016967:Fusobacterium nucleatum / Q000187:drug effects / Q000254:growth & development; D006801:Humans; D053685:Laser Therapy; D010462:Peptostreptococcus / Q000187:drug effects / Q000254:growth & development; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D018713:Prevotella intermedia / Q000187:drug effects / Q000254:growth & development; D034367:Streptococcus intermedius / Q000187:drug effects / Q000254:growth & development; D014048:Tolonium Chloride / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D014048:Tolonium Chloride