Overall, the CATFISH study adds to the body of evidence supporting the view that fluoridation improves dental health and is a cost-effective intervention. It is unrealistic to expect all studies of the same intervention to reveal an identical effect on a population.

The recent non-UK studies report a greater impact on reducing the incidence and cost of tooth decay than the CATFISH study. Interestingly, the seemingly 'modest' benefits reported by CATFISH would be perceived as much more compelling if the authors had calculated and reported the PF differences, for example, the 36% reduction in the proportion of children with four or more dmft.

As the CATFISH study states, 'a single study cannot hope to provide definitive answers'; however, it can add to the existing evidence base within the context of the study's limitations. Dental practitioners, public health officials and health policymakers should recognise the strengths and limitations of CATFISH. Accordingly, they should be aware of the findings from the recent Canadian, American and Israeli studies on the impact of ceasing fluoridation. By doing so, they can offer appropriate guidance to patients and adopt evidence-based policies.