title: No reliable evidence that ozone gas stops or reverses tooth decay.
abstract: METHODS
  The Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials, Medline and Premedline, Embase, CINAHL (Cumulative Index to nursing and Allied Health Literature)l and the Allied and Complementary Medicine Database were searched. The journal Quintessence was searched by hand and KaVo Dental (Biberach, Germany) manufacturers of HealOzone apparatus were contacted for any additional published or unpublished trials.
  
  
  METHODS
  Inclusion was assessed independently by at least two reviewers. Trials were only included if they met the following criteria: randomisation in a controlled trial; single surface in vivo carious lesion accessible to ozone application; clear allocation concealment; ozone application to the lesions in the intervention group; no such application of ozone in the control group; and outcomes measured after at least 6 months.
  
  
  METHODS
  Reviewers independently extracted information in duplicate. A paucity of comparable data did not allow meta-analytic pooling of the included studies.
  
  
  RESULTS
  Three trials were included, with a combined total of 432 randomised lesions (137 participants). Forty-two conference papers, abstracts and posters were excluded (from an unknown number of studies). The risk of bias in all studies appeared high. The analyses of all three studies were conducted at the level of the lesion, which is not independent of the person. For this reason, pooling of data was not appropriate or attempted. Individual studies showed inconsistent effects of ozone on caries, across different measures of caries progression or regression. Few secondary outcomes were reported, but one trial reported an absence of adverse events.
  
  
  CONCLUSIONS
  Given the high risk of bias in the available studies and lack of consistency between different outcome measures, there is no reliable evidence that application of ozone gas to the surface of decayed teeth stops or reverses the decay process. There is a fundamental need for more evidence of appropriate rigour and quality before the use of ozone can be accepted into mainstream primary dental care or can be considered a viable alternative to current methods for the management and treatment of dental caries.
authors.affiliation: Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Dorothy
authors.initials: D
authors.lastname: McComb