title: The susceptibility of Streptococcus mutans to antibacterial photodynamic therapy: a comparison of two different photosensitizers and light sources.
abstract: Streptococcus mutans is the main etiological agent for dental caries. Recently, photodynamic therapy (PDT) has been introduced as a new modality in bacterial decontamination.
  
  
  OBJECTIVE
  This in vitro study was carried out to evaluate the susceptibility of Streptococcus mutans to antibacterial PDT using two different photosensitizers and light sources.
  
  
  METHODS
  Standard suspensions of S. mutans were exposed to laser light at 662 nm and Radachlorin or LED 630 nm in combination with Toluidine blue O (TBO). Radiation-only groups, photosensitizer alone, and groups with no treatment were used as controls. Bacterial suspension from each treatment was subcultured onto the surface of Mueller-Hinton agar plates and bacterial growth was assessed. The results were analyzed by analysis of variance and Tukey test (p<0.05).
  
  
  RESULTS
  PDT with TBO and Radachlorin® significantly reduced S. mutans viability, whereas no difference was observed between two groups of PDT. In the groups treated just with the photosensitizer or irradiated alone, no significant reduction of S. mutans colonies was observed.
  
  
  CONCLUSIONS
  S. mutans colonies were susceptible to either 662 nm laser or LED light in the presence of Radachlorin and TBO respectively with no priority.
authors.affiliation: Laser Research Center of Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Neda
authors.initials: N
authors.lastname: Hakimiha
authors.affiliation: Laser Research Center of Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Khoei
authors.affiliation: Microbiology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
authors.affiliation: Laser Research Center in Medical Sciences, AJA University of Medical Sciences, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Fekrazad
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003131:Combined Modality Therapy / Q000379:methods; D003731:Dental Caries / Q000517:prevention & control; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D008027:Light; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015203:Reproducibility of Results; D013295:Streptococcus mutans / Q000187:drug effects*; D013997:Time Factors; D014048:Tolonium Chloride / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D014048:Tolonium Chloride