RESUMO
In 2000 it was suggested that there was a new, fast and simple way to treat dental caries based on the outcomes of an in vitro study of the antimicrobial effect of ozone, a form of active oxygen, on caries lesions in dental roots. The aim of the review of literature described in this article was to determine the effectiveness of active oxygen in the treatment of dental (root) caries as demonstrated by in vivo research of frail older people'. From the results it became clear that the quality of the various trials is not very high and that there is, at least at the present time, an insufficient solid scientific evidence base that the use of ozone is an effective treatment for dental (root) caries. It is, however, still too early to conclude that active oxygen, in whatever form, cannot contribute positively to the fight against caries.