title: Evaluation of photo-activated disinfection effectiveness with methylene blue against Porphyromonas gingivalis involved in endodontic infection: An in vitro study.
abstract: BACKGROUND
  Eradication or suppression of microbial pathogens is a major goal in endodontic infection therapy. Sub-lethal doses of photo-activated disinfection (sPAD) as a new treatment method might be able to control the microorganisms involved in endodontic infections normally treated with PAD. This study evaluated the effect of sPAD using methylene blue (MB) in combination with diode laser irradiation on the growth and biofilm formation ability of Porphyromonas gingivalis as an endodontic pathogen.
  
  
  METHODS
  The anti-microbial and anti-biofilm potential of sPAD against P. gingivalis were assessed at sub-lethal doses of MB and irradiation by diode laser on colony forming unit and crystal violet assays, respectively.
  
  
  RESULTS
  MB-sPAD using 25μg/mL at a fluency of 117.18J/cm2and 50-100μg/mL at a fluency of 93.75J/cm2significantly P. gingivalis growth when compared to the control. MB at 100μg/mL at a fluency of 117.18J/cm2in MB-mediated PAD showed a significant inhibitory effect on biofilm formation in P. gingivalis compared with MB-sPAD.
  
  
  CONCLUSIONS
  High doses of MB-mediated sPAD exhibited anti-microbial and anti-biofilm potential activity, whereas lower doses of MB-mediated sPAD did not display this ability. Therefore, the dose of PAD used in vivo should be taken into account for endodontic treatment.
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Pourhajibagher
authors.affiliation: Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush
authors.affiliation: Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran; Innovative Research Center, Islamic Azad University, Mashhad branch, Mashhad, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Raoofian
authors.affiliation: Pediatrics Infectious Disease Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Pourakbari
authors.affiliation: Private practice, Tehran, Iran.
authors.forename: Roghayeh
authors.initials: R
authors.lastname: Ghorbanzadeh
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Bazarjani
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: abahador@sina.tums.ac.ir.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
mesh_terms: D016866:Bacteroidaceae Infections / Q000188:drug therapy / Q000382:microbiology*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004203:Disinfection / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008751:Methylene Blue / Q000008:administration & dosage*; D010485:Periapical Periodontitis / Q000188:drug therapy / Q000382:microbiology*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000502:physiology
chemical_list: D017319:Photosensitizing Agents; D008751:Methylene Blue
keywords: Biofilm formation; Endodontic infection; Methylene blue; Photo-activated disinfection; Porphyromonas gingivalis; Sub-lethal dose