title: Effect of fiber insertion depth on antibacterial efficacy of photodynamic therapy against Enterococcus faecalis in rootcanals.
abstract: OBJECTIVE
  This in vitro study evaluated the effect of fiber insertion depth on antimicrobial efficacy of antimicrobial photodynamic therapy (aPDT) using a photosensitizer (PS; toluidine blue) and a red light-emitting diode (LED) in root canals infected with Enterococcus faecalis.
  
  
  METHODS
  Single-rooted extracted teeth were prepared with nickel-titanium-instruments, sterilized, contaminated with E. faecalis, and incubated for 72 h. Roots were randomly divided into four experimental groups: PS only, LED only, aPDT with LED in the apical third, aPDT with LED in the coronal third, as well as into infection and sterile controls (each n = 10). Samples were taken by collecting standardized dentine shavings from the root canal walls. After serial dilution and culturing on blood agar, colony-forming units (CFU) were counted.
  
  
  RESULTS
  Both aPDT groups showed a CFU reduction of 1-2 log10steps compared with the infection control, whereas the effect of fiber insertion depth was negligible (<0.5 log10steps). CFU reduction of approximately 0.5 log10steps for PS alone was detected compared with the infection control, but PS alone was less effective than both aPDT groups. No antibacterial effect was detected for LED alone.
  
  
  CONCLUSIONS
  aPDT reduced E. faecalis within the root canal, whereas fiber insertion depth had a negligible influence on antimicrobial effectiveness of aPDT.
  
  
  CONCLUSIONS
  The insertion depth of the light-emitting diode may not influence the antibacterial efficacy of photodynamic therapy against E. faecalis in straight root canals.
authors: Department of Preventive Dentistry, Periodontology and Cariology, University Medical Center, Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany. troedig@med.uni-goettingen.de.
authors: Tina
authors: T
authors: Rödig
authors: Private Dental Practice, Hannover, Germany.
authors: Sarah
authors: S
authors: Endres
authors: Department of Mathematical Sciences, University of Texas at Dallas, Richardson, TX, USA.
authors: Frank
authors: F
authors: Konietschke
authors: Institute for Medical Microbiology, Center for Hygiene and Human Genetics, University of Göttingen, Göttingen, Germany.
authors: Ortrud
authors: O
authors: Zimmermann
authors: Institute of Anatomy and Embryology, University Medical Center, Göttingen, Germany.
authors: Hans Georg
authors: HG
authors: Sydow
authors: Department of Preventive Dentistry, Periodontology and Cariology, University Medical Center, Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors: Annette
authors: A
authors: Wiegand
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D014048:Tolonium Chloride
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D014048:Tolonium Chloride
keywords: Disinfection; Enterococcus faecalis; Fiber; Insertion depth; Photodynamic therapy; Root canal