title: Sensitization of periodontopathogenic bacteria to killing by light from a low-power laser.
abstract: Cultures of Porphyromonas gingivalis, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans were treated with a range of photosensitizers and then exposed to light from a 7.3 mW helium/neon laser for up to 80 s. Toluidine blue O (25 micrograms/ml) and methylene blue (25 micrograms/ml) were effective lethal photosensitizers of all 3 target organisms, enabling substantial light dose-related reductions in viable counts. Dihaematoporphyrin ester and aluminium disulphonated phthalocyanine were lethal photosensitizers only of P. gingivalis. In the absence of a photosensitizer, exposure to laser light had no significant effect on the viability of the cultures. If such low doses of light (22 J/cm2) are effective at killing bacteria in vivo, the technique may be useful as a means of eliminating periodontopathogenic bacteria from diseased sites.
authors.affiliation: Microbiology Department, Institute of Dental Surgery, London, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Wilson
authors.forename: J
authors.initials: J
authors.lastname: Dobson
authors.forename: S
authors.initials: S
authors.lastname: Sarkar
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects / Q000528:radiation effects; D017323:Dihematoporphyrin Ether / Q000494:pharmacology; D016967:Fusobacterium nucleatum / Q000187:drug effects / Q000528:radiation effects; D006089:Gram-Negative Anaerobic Bacteria / Q000187:drug effects* / Q000528:radiation effects*; D006371:Helium; D007211:Indoles / Q000494:pharmacology; D007834:Lasers; D008751:Methylene Blue / Q000494:pharmacology; D009356:Neon; D009942:Organometallic Compounds / Q000494:pharmacology; D010510:Periodontal Diseases / Q000382:microbiology; D017319:Photosensitizing Agents / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects / Q000528:radiation effects; D014048:Tolonium Chloride / Q000494:pharmacology
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D014048:Tolonium Chloride; D006371:Helium; D009356:Neon; C064331:aluminum phthalocyanine disulfonate; D017323:Dihematoporphyrin Ether; D008751:Methylene Blue