title: Photodynamic effects of toluidine blue on human oral keratinocytes and fibroblasts and Streptococcus sanguis evaluated in vitro.
abstract: OBJECTIVE
  Some oral bacteria are susceptible to killing by red light after their sensitization with toluidine blue O (TBO). The photochemotherapy of periodontal disease in vivo would require a therapeutic window where bacteria could be killed without adjacent normal tissue damage.
  
  
  METHODS
  The laser-induced effects of TBO on normal human gingival keratinocytes and fibroblasts have been studied in vitro. For the assessment of viability, the CellTiter 96TM AQueous Non-Radioactive Cell Proliferation Assay was used.
  
  
  RESULTS
  TBO was cytotoxic at low concentrations (5.0 micrograms/ml). Sensitization of keratinocytes and fibroblasts with 2 and 5.0 micrograms/ml TBO, respectively, for 5 min and exposure to light from a 7.3 mW Helium/Neon (HeNe) laser for up to 2 min (0.876J) did not reduce cell viability. However, killing of Streptococcus sanguis was achieved following exposure to HeNe light for 75 sec (0.547J) in the presence of TBO at a concentration of 2.5 micrograms/ml.
  
  
  CONCLUSIONS
  The development of a system for the lethal photosensitization of bacteria responsible for periodontal disease may be possible.
authors.affiliation: Department of Oral Pathology, Eastman Dental Institute, London, United Kingdom.
authors.forename: N S
authors.initials: NS
authors.lastname: Soukos
authors.forename: M
authors.initials: M
authors.lastname: Wilson
authors.forename: T
authors.initials: T
authors.lastname: Burns
authors.forename: P M
authors.initials: PM
authors.lastname: Speight
mesh_terms: D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects*; D005881:Gingiva / Q000187:drug effects* / Q000382:microbiology; D006801:Humans; D066298:In Vitro Techniques; D015603:Keratinocytes / Q000187:drug effects*; D010778:Photochemotherapy; D013298:Streptococcus sanguis / Q000187:drug effects*; D014048:Tolonium Chloride / Q000494:pharmacology*
chemical_list: D014048:Tolonium Chloride