title: Antimicrobial efficacy of photodynamic therapy, Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm.
abstract: BACKGROUND
  Lasers have been recommended in final root canal disinfection protocol, however, there is no clear evidence about their efficacy against bacteria in biofilms. The aim of the study was to evaluate and compare the disinfection effect of antimicrobial photodynamic therapy (aPDT), Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm.
  
  
  METHODS
  The study sample consisted of 65 dentine slices, which were inoculated with E. faecalis and incubated anaerobically for three weeks. The dentine discs were randomly allocated to one of the following experimental groups: aPDT (100 mW, 10 mg/ml phenothiazinium chloride, 1 min), Nd:YAG laser (2 W, 15 Hz, 4×5 s), QMiX solution (1 min). Positive controls did not receive any treatment and negative controls were treated with 5.25% NaOCl. To harvest surviving adherent cells, each dentine sample was transffered to a test tube containing of TSB, serial ten-fold dilutions were made and aliquot of 1 ml was plated onto blood agar plates and incubated for 48 h. Colony forming units grown were counted and transformed into actual counts based on the dilution factor. The remaining viable cells after each protocol were analysed by FISH.
  
  
  RESULTS
  The aPDT and the QMiX solution were equally effective, with the reduction rate of E. faecalis CFUs of 98.8% and 99.3% respectively (p=1.107). The Nd:YAG laser caused 96% reduction of E. faecalis (P<0.001).
  
  
  CONCLUSIONS
  The aPDT and the QMiX solution showed similar antibacterial efficacy against old E. faecalis biofilm, followed by Nd:YAG irradiation.
authors.affiliation: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10000 Zagreb, Croatia. Electronic address: bago@sfzg.hr.
authors.forename: Ivona
authors.initials: I
authors.lastname: Bago Jurič
authors.affiliation: Department of Clinical and Molecular Microbiology, University Clinical Hospital Centre, 10000 Zagreb, Croatia.
authors.forename: Vanda
authors.initials: V
authors.lastname: Plečko
authors.affiliation: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10000 Zagreb, Croatia.
authors.forename: Ivica
authors.initials: I
authors.lastname: Anić
authors.affiliation: Department of Clinical and Molecular Microbiology, University Clinical Hospital Centre, 10000 Zagreb, Croatia.
authors.forename: Sanja
authors.initials: S
authors.lastname: Pleško
authors.affiliation: Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia.
authors.forename: Suzana
authors.initials: S
authors.lastname: Jakovljević
authors.affiliation: Department of Restorative Dentistry and Endodontics, Faculty of Dentistry, University of Nice-Sophia Antipolis, 06357 Nice, France.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Rocca
authors.affiliation: Department of Restorative Dentistry and Endodontics, Faculty of Dentistry, University of Nice-Sophia Antipolis, 06357 Nice, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Medioni
mesh_terms: D000890:Anti-Infective Agents / Q000008:administration & dosage; D001645:Biguanides / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development* / Q000528:radiation effects; D003131:Combined Modality Therapy; D013293:Enterococcus faecalis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D010778:Photochemotherapy / Q000295:instrumentation* / Q000379:methods; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011108:Polymers / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D000890:Anti-Infective Agents; D001645:Biguanides; D017319:Photosensitizing Agents; D011108:Polymers; C557698:QMix root canal irrigant
keywords: Laser; Nd:YAG; Photodynamic therapy; Root canal infection