Effectiveness of ozone against endodontopathogenic microorganisms in a root canal biofilm model

• Published in: International endodontic journal Vol. 42; no. 1; pp. 3 - 13
• Main Authors: Huth, K. C., Quirling, M., Maier, S., Kamereck, K., AlKhayer, M., Paschos, E., Welsch, U., Miethke, T., Brand, K., Hickel, R.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2009
• Subjects: Anti-Infective Agents, Local - administration & dosage; Anti-Infective Agents, Local - pharmacology; antimicrobials; biofilm; Biofilms - drug effects; Buffers; Candida albicans; Candida albicans - drug effects; Chlorhexidine - administration & dosage; Chlorhexidine - analogs & derivatives; Chlorhexidine - pharmacology; Colony Count, Microbial; Dental Pulp Cavity - microbiology; Dose-Response Relationship, Drug; endodontics; Enterococcus faecalis - drug effects; Gases; Humans; Hydrogen Peroxide - administration & dosage; Hydrogen Peroxide - pharmacology; microbiology; Oxidants - administration & dosage; Oxidants - pharmacology; Oxidants, Photochemical - administration & dosage; Oxidants, Photochemical - pharmacology; ozone; Ozone - administration & dosage; Ozone - pharmacology; Peptostreptococcus - drug effects; Peptostreptococcus micros; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; root canal; Root Canal Irrigants - administration & dosage; Root Canal Irrigants - pharmacology; Sodium Hypochlorite - administration & dosage; Sodium Hypochlorite - pharmacology; Solutions; Time Factors
• ISSN: 0143-2885; 1365-2591
• DOI: 10.1111/j.1365-2591.2008.01460.x

Aim  To assess the antimicrobial efficacy of aqueous (1.25–20 μg mL−1) and gaseous ozone (1–53 g m−3) as an alternative antiseptic against endodontic pathogens in suspension and a biofilm model. Methodology  Enterococcus faecalis, Candida albicans, Peptostreptococcus micros and Pseudomonas aeruginosa were grown in planctonic culture or in mono‐species biofilms in root canals for 3 weeks. Cultures were exposed to ozone, sodium hypochlorite (NaOCl; 5.25%, 2.25%), chlorhexidine digluconate (CHX; 2%), hydrogen peroxide (H2O2; 3%) and phosphate buffered saline (control) for 1 min and the remaining colony forming units counted. Ozone gas was applied to the biofilms in two experimental settings, resembling canal areas either difficult (setting 1) or easy (setting 2) to reach. Time‐course experiments up to 10 min were included. To compare the tested samples, data were analysed by one‐way anova. Results  Concentrations of gaseous ozone down to 1 g m−3 almost and aqueous ozone down to 5 μg mL−1 completely eliminated the suspended microorganisms as did NaOCl and CHX. Hydrogen peroxide and lower aqueous ozone concentrations were less effective. Aqueous and gaseous ozone were dose‐ and strain‐dependently effective against the biofilm microorganisms. Total elimination was achieved by high‐concentrated ozone gas (setting 2) and by NaOCl after 1 min or a lower gas concentration (4 g m−3) after at least 2.5 min. High‐concentrated aqueous ozone (20 μg mL−1) and CHX almost completely eliminated the biofilm cells, whilst H2O2 was less effective. Conclusion  High‐concentrated gaseous and aqueous ozone was dose‐, strain‐ and time‐dependently effective against the tested microorganisms in suspension and the biofilm test model.