title: The antimicrobial effectiveness of photodynamic therapy used as an addition to the conventional endodontic re-treatment: a clinical study.
abstract: BACKGROUND
  The purpose of the study was to evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) used as an adjunct to the endodontic re-treatment in the eradication of microorganisms from previously filled root canals.
  
  
  METHODS
  The study sample consisted of 21 randomly selected patients with root filled and infected root canal system with chronic apical periodontitis on incisors or canines, who have had previously endodontic treatment. Microbiological samples from the root canals were collected after accessing the canal, following the endodontic re-treatment and after the aPDT procedure. During instrumentation, the root canals were irrigated with 2.5% sodium hypochlorite (NaOCl), and the final irrigation protocol included 17% ethylenediaminetetraacetic acid followed by NaOCl. Root canals were filled with a phenothiazinium chloride and irradiated with a diode laser (λ=660 nm, 100 mW) for 1 min. Microbiological samples from the root canals were cultivated on selective plates, and the identification was done by micromorphology, macromorphology and different API strips as well as bacterial counts (colony forming units).
  
  
  RESULTS
  Fourteen bacteria species were isolated from the root canals initially, with a mean value of 4.57 species per canal. Although endodontic re-treatment alone produced a significant reduction in the number of bacteria species (p<0.001), the combination of endodontic treatment and aPDT was statistically more effective (p<0.001). No bacteria were cultivated from the main root canals of 11 teeth.
  
  
  CONCLUSIONS
  The results indicated that the aPDT used as an adjunct to the conventional endodontic therapy achieved a significant further reduction of intracanal microbial load.
authors.affiliation: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10 000 Zagreb, Croatia. Electronic address: bago@sfzg.hr.
authors.forename: Ivona Bago
authors.initials: IB
authors.lastname: Jurič
authors.affiliation: Department of Clinical and Molecular Microbiology, University Clinical Hospital Centre, 10 000 Zagreb, Croatia. Electronic address: vplecko@gmail.com.
authors.forename: Vanda
authors.initials: V
authors.lastname: Plečko
authors.affiliation: Department of Oral Surgery, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10 000 Zagreb, Croatia. Electronic address: dganric@sfzg.hr.
authors.forename: Dragana Gabrić
authors.initials: DG
authors.lastname: Pandurić
authors.affiliation: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10 000 Zagreb, Croatia. Electronic address: anic@sfzg.hr.
authors.forename: Ivica
authors.initials: I
authors.lastname: Anić
mesh_terms: D000328:Adult; D018407:Bacterial Physiological Phenomena / Q000187:drug effects* / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects* / Q000528:radiation effects; D003131:Combined Modality Therapy; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000382:microbiology* / Q000528:radiation effects; D005260:Female; D005491:Focal Infection, Dental / Q000382:microbiology* / Q000517:prevention & control*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D018915:Root Canal Preparation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D017319:Photosensitizing Agents
keywords: Endodontic re-treatment; Laser; Photodynamic therapy; Root canal infection