British Experts Question Value of HealOzone Treatment

Stephen Barrett, M.D.
January 1, 2006

HealOzone is al alleged treatment in which teeth are exposed to ozone gas that kills some of the germs responsible for tooth decay. Its promoters claim that the procedure is (a) able to reverse, arrest, or slow down the progression of dental caries (cavities), (b) is useful for sterilizing cavities before fillings are inserted, and (c) is useful for sterilizing root canals before filling them as part of root canal treatment. However, there is good reason to doubt that its use has any practical value.

The HealOzone treatment system comprises an ozone delivery device, a mineral-reducing agent used by the dentist and a ‘patient kit’ (fluoride-containing toothpaste, mouthwash and mouth spray) for home use. The ozone unit was initially developed by CurOzone USA Inc. (a Canadian company) and subsequently manufactured under licence and distributed by KaVo-Dental GmbH & Co. (Germany) under the name “HealOzone.” Its use has been pioneered by Professor Edward Lynch and colleagues at Queen’s University in Belfast, Northern Ireland. The device is certified (CE marked) in the United Kingdom as a medical device for managing certain types of caries, but it is not approved by the U.S. Food and Drug Administration. CurOzone and KaVo state that more than 2,000 HealOzone devices are being used in dentists´ offices in Europe, Australia, Canada, and New Zealand [1].

Tooth decay is caused by bacteria. The mechanism is acid attack on the tooth (demineralization), followed by bacterial invasion. Acid is secreted by microorganisms in organized plaque, which sticks to the tooth surface. HealOzone treatment is administered by placing a small cup over the affected tooth to form a seal and pumping ozone gas into the tooth for up to 2 minutes to kill the bacteria. After that, a special liquid is dripped onto the tooth to remove any remaining ozone and acid and help the weakened enamel start to harden again through remineralization. The patient is given a kit containing fluoride toothpaste, mouthwash and mouth spray to use for several weeks to help the remineralization process. The average estimated cost of adding HealOzone to conventional treatment ranges from £18 to £21 per tooth, depending on the type of caries [2].

Key Questions

It is well known that ozone gas can kill bacteria. But the key question is whether brief exposure to ozone gas has any practical value in dental practice. The National Institute for Health and Clinical Excellence (NICE)—an independent British organization that reviews medical technology—has evaluated the evidence related to caries by asking and answering several questions:

  • For managing pit and fissure caries, is the HealOzone procedure more effective than the combination of oral hygiene, diet advice, chlorhexidine/fluoride varnish, and fissure sealant? If so, is it a cost-effective alternative?
  • For managing non-cavitated root caries, is the HealOzone procedure more clinically effective than the combination of oral hygiene, diet advice, and varnish? If so, is it cost-effective?
  • For managing cavitated caries, how often, if at all, is ‘HealOzone procedure’ an alternative to fillings?
  • For managing cavitated caries, does the application of ozone gas and of a remineralising solution to the cavity before restoration prolong the life of a filling? If so, is it cost-effective?

In July 2005, NICE issued a detailed report which concluded:

Only a limited number of randomized controlled studies (five full-text reports and five studies reported as abstracts) were available for assessing the effects of ozone for the management of root carious lesions and pit and fissure carious lesions. Of these only one was published in a refereed journal, but lacked some study details, whilst the remaining studies were derived from PhD theses, unpublished reports, or conference proceedings. All full-text studies with the exception of the Holmes study were conducted by the same research team who developed the procedure, led by Professor Lynch of Queen’s University, but Holmes was at one time part of the same group, having done his PhD in Belfast. The methodological quality varied across studies and information on method of randomization, concealment of allocation, blinding procedures, and statistical methods was lacking in many of them. Therefore interpretation of studies results was not straightforward. A quantitative synthesis of results was not feasible due to the differences amongst studies of intervention, dosage of ozone, and outcome measures. . . . [2:51

Nearly all the research to date comes from the same group who developed and pioneered the procedure, and have the greatest experience in its use. There is a need for large, well-conducted randomized controlled trials to assess the effectiveness and cost-effectiveness of HealOzone for the management of both occlusal and root caries. In particular, future trials:

  • should be conducted by independent research teams
  • should be proper randomized so that an equal number of lesions—or paired lesions—per mouth are allocated to intervention groups
  • should apply appropriate statistical methods for the analysis of ‘paired-data’ on a patient basis; should use validated and reproducible criteria for the assessment
  • should measure relevant outcomes such as reduction in caries reasonable period of time (at least 2 years)
  • should mask participants and outcome assessors
  • should provide both a statistical and a clinical interpretation
  • should conform to the CONSORT guidelines for reporting controlled trials.

There also appears to be a need for evaluation of the different methods of assessing caries severity. The base case might be clinical examination, with benefits and costs of more sophisticated techniques assessed [2:86-87].

Any treatment that preserves teeth and avoids fillings is welcome. However, the current evidence base for HealOzone is insufficient to conclude that it is a cost-effective addition to the treatment of occlusal and root caries [2].

KaVo recommends using a device that it markets (the DIAGNOdent) to assess caries. The NICE report states that the validity of this device has yet to be demonstrated [2:29].

Based on its investigation, NICE recommends against National Health Service coverage of HealOzone procedures unless they are part of a clinical trial.

The Bottom Line

Early crown or root caries often can be arrested by remineralizing solutions alone, or by pit and fissure sealants. Whether using ozone treatments provide added benefit is yet unproven. Additional studies should be done as outlined by the NICE. KaVo has responded that more research is being done and that it hopes NICE will review new findings sooner than its scheduled 2008 review date [1].

The standard way to “sterilize” a root canal is to use dilute sodium hypochlorite solutions (bleach), which kills germs by generating free radicals. The process is simple and inexpensive. Hypochlorite solutions also act as tissue solvents and can remove debris. If residual bacteria are present, ozone would do the same thing with a gas instead of a liquid. However, not all root canals that require treatment are infected. While HealOzone’s technology is intriguing, a great deal of study will be needed to determine whether it is more effective and cost-effective than other methods.

  1. KaVo statement in response to NICE review. KaVo Web site, Aug 2005.
  2. Brazzelli M and others. HealOzone for the treatment of tooth decay (occlusal pit and fissure caries and root caries). London, UK: National Institute for Health and Clinical Excellence (NICE), July 2005.

This article was posted on January 1, 2006.