title: Evaluation of the effect of photoactivated disinfection with Radachlorin(®) against Streptococcus mutans (an in vitro study).
abstract: BACKGROUND
  The use of photoactivated disinfection has had a significant medical and technological effect in bacterial inactivation, as an alternative to conventional antimicrobial methods. The main goal of this study was to investigate the effect of photoactivated disinfection on Streptococcus mutans, when Radachlorin(®) was used as a photosensitizer.
  
  
  METHODS
  Streptococcus mutans samples of two different initial concentrations were treated with Radachlorin(®) gel (0.1%), irradiated by the light of a He-Ne laser (633nm), with energy density of 6J/cm(2), and cell viability was evaluated after culturing.
  
  
  RESULTS
  It was observed that the combination of Radachlorin(®) and laser was more effective than Radachlorin(®) or laser alone (p<0.05), in reduction of S. mutans and Radachlorin(®) was cytotoxic, in the dark, only for the lower concentration of bacteria. Lower concentration of S. mutans resulted in higher amount of killing, in the case of using Radachlorin(®) with or without laser.
  
  
  CONCLUSIONS
  The photoactivation of Radachlorin(®) using a He-Ne laser could inactivate S. mutans to a significant level. In addition Radachlorin(®) might be cytotoxic in the dark, for the lower concentration of bacteria.
authors.affiliation: Department of Dentistry, AJA University of Medical Sciences - Laser Research Center, Faculty of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Fekrazad
authors.forename: Majid
authors.initials: M
authors.lastname: Bargrizan
authors.forename: Sepideh
authors.initials: S
authors.lastname: Sajadi
authors.forename: Soodabeh
authors.initials: S
authors.lastname: Sajadi
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D058491:Bacterial Load / Q000187:drug effects; D002735:Chlorophyllides; D003624:Darkness; D004203:Disinfection / Q000379:methods*; D004338:Drug Combinations; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use; D008422:Materials Testing; D050296:Microbial Viability / Q000187:drug effects; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000008:administration & dosage / Q000627:therapeutic use*; D011829:Radiation Dosage; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D002735:Chlorophyllides; D004338:Drug Combinations; D017319:Photosensitizing Agents; D011166:Porphyrins; C072905:chlorin p6; C006969:chlorin; C062985:phytochlorin