Sir, contrary to the hypothesis presented by Neurath et al. (BDJ 2014; 217: 55), variations between hospitals in policies and practices for recording HES data on tooth extractions under a general anaesthetic are unlikely to account for the magnitude of the differences in extraction rates observed by Elmer et al. in their comparative study of the mainly fluoridated West Midlands and mainly non-fluoridated north-west (BDJ 2014; 216: E10).

The findings of the Elmer et al. study are strengthened by the subsequent larger analysis conducted by Public Health England, whose fluoridation monitoring report (March, 2014) found that there were 45% fewer hospital admissions of 0- to 4-year-olds for dental caries (primarily to have decayed teeth extracted under a GA) in fluoridated local authorities of England compared with non-fluoridated authorities. It is unlikely that all or most hospitals in the fluoridated parts of England – which range geographically from Northumberland to Bedfordshire – are following one set of recording practices whilst all or most hospitals in the non-fluoridated parts are following another.

There can surely be no dispute that water fluoridation reduces dental caries prevalence. Three systematic reviews of the worldwide evidence between 2000 and 2007 found that it does.1,2,3 Neurath et al. imply that the fluoridation effectiveness studies reviewed by York were of poor quality. However, all the studies included were categorised in the report as Level B or 'moderate' quality.

A recent analysis of studies in ten different countries published since 1990 found significantly lower rates of decay in primary and secondary teeth, including after the application of advanced statistical techniques to adjust for potentially confounding factors.4

A finding that GA extraction rates are lower in fluoridated than non-fluoridated areas is therefore logical, unsurprising and of interest to policy-makers seeking to address stubbornly high dental caries rates in parts of England. Further research into this aspect of the benefits of water fluoridation would be helpful.