The cutting edge in cariology is not cavity preparation: current disease-management concepts are better fulfilled by strategies to arrest early caries without destroying the healthy tooth structure. Any recommended clinical treatment requires proof of effect, especially when new technology and novel management concepts are involved. The authors of this Cochrane Review critically evaluated available clinical research concerning ozone treatment and conclude that the evidence is limited. The review reveals a particularly high number of conference abstracts relative to peer-reviewed published research.

Ozone gas is a strong oxidising agent with the ability to kill bacteria upon contact. Since carious lesions must be accessible, the research largely involves root caries and occlusal fissures. Clinical evidence of significant initial microbicidal effect has recently been published for root caries.1 The lack of control lesions and of any monitoring of bacterial recolonisation compromise the value of the 3.0–5.5-month follow-up, however.

There is no evidence that ozone-treated oral lesions do not become re-infected over time. A private-practice controlled clinical trial using multiple (five) applications over 18 months has noted significant root lesion hardening.2 Only ‘leathery’ root lesions were treated in these studies but it has been shown that aggressive conventional preventive treatment can be effective in controlling this type of root caries.3

Fissures are one of the most caries-prone plaque stagnation sites. Preventive strategies other than sealants have proved relatively ineffective to date. Ten-year radiological evidence indicates that sealed restorations can halt the progress of even established dentinal caries.4 Important questions, therefore concerning ozone treatment including depth, consistency, duration and significance of microbicidal effect remain. The treatment frequency and long-term outcomes on different types of lesions and populations are still uncertain.

Practitioners need to be aware of the limitations of the available data. This Cochrane Review should be of immense value to stimulate and guide appropriately conducted clinical validation studies. Until then the jury is still out on the clinical implications of this emerging technology.

Practice point

  • There is a need for more evidence of appropriate rigour before the clinical implications of this emerging technology can be evaluated.