title: Efficacy of gasiform ozone and photodynamic therapy on a multispecies oral biofilm in vitro.
abstract: Ozone gas and photodynamic therapy (PDT) have been claimed to be antimicrobially effective. This study assessed their antimicrobial potential in vitro. Mature six-species oral biofilms were treated as follows (n = 9 per group): (i) a 60-s application of gasiform vacuum-ozone or vacuum alone (on wet or air-dried biofilm samples); (ii) PDT (i.e. methylene blue in combination with or without a diode soft laser, and a soft laser alone); or (iii) antimicrobial solutions: immersion of biofilms for 60 s in 0.2 and 2% chlorhexidine or in 0.5 and 5% hypochlorite solution. Treatment with chlorhexidine or hypochlorite served as a positive control, whereas untreated samples served as negative controls. Colony-forming units on blood agar were counted. Only the 5% hypochlorite solution was able to totally eliminate the microorganisms in the biofilm. The observed reduction of viable counts by vacuum-ozone application and PDT was less than one log(10) step. Under the conditions of the current study, gasiform ozone and PDT had a minimal effect on the viability of microorganisms organized in a cariogenic biofilm.
authors.affiliation: Clinic of Preventive Dentistry, Periodontology and Cariology, University if Zurich, Zurich, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Müller
authors.forename: Bernhard
authors.initials: B
authors.lastname: Guggenheim
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Schmidlin
mesh_terms: D000190:Actinomyces / Q000187:drug effects; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects; D002417:Cattle; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology*; D016967:Fusobacterium nucleatum / Q000187:drug effects; D007834:Lasers; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D010083:Oxidants, Photochemical / Q000494:pharmacology*; D010126:Ozone / Q000494:pharmacology*; D010778:Photochemotherapy; D019533:Streptococcus oralis / Q000187:drug effects; D016986:Streptococcus sobrinus / Q000187:drug effects; D014618:Vacuum; D014678:Veillonella / Q000187:drug effects
chemical_list: D000891:Anti-Infective Agents, Local; D010083:Oxidants, Photochemical; D010126:Ozone