Sir, the concepts of minimally invasive dentistry and the concepts of remineralisation are well accepted. But I find it difficult to agree with the conclusions of the reviewer of Ozone: The revolution in dentistry (BDJ 2005; 199: 307) that it is a 'must have' text for twenty-first century dentists.

While ongoing studies may in the future show that this is an effective technique, the current state of the evidence is far from convincing. The book's foreword states:

'Recent technical advances have made it possible for ozone, a powerful disinfectant, to be applied to small areas of dental hard tissues while neighbouring tissues and the lungs are protected from this aggressive gas. Its effectiveness has been demonstrated in several well-planned clinical studies. For example, a recently published clinical trial showed the reversal of root caries using ozone in a double-blind, randomized, and controlled 18-month trial.'1

This contradicts both the recent Cochrane review on Ozone therapy for the treatment of dental caries2 which concludes that 'there is no reliable evidence that application of ozone gas to the surface of decayed teeth stops or reverses the decay process' and the NICE technology appraisal3 which found 'that there was insufficient evidence on the effectiveness of HealOzone treatment for this technology to be recommended, except as part of well-designed RCTs'. I for one would not wish to purchase an ozone machine for the treatment of caries based on the currently available evidence.