A technology assessment report 1 concerning public water fluoridation was abstracted in the Health Technology Assessment database. The best available evidence suggests that water fluoridation reduces caries prevalence. The degree to which caries is reduced is not clear from the data available. The possible negative effects include dental fluorosis. There is no evidence of association of water fluoridation and bone fractures nor an association to cancer. Authors conclude that there is little high quality evidence on water fluoridation. The ethical, environmental, costs and legal issues fell outside the scope of this review.
A systematic review 3 included 214 studies. The quality of studies was low to moderate. Water fluoridation was associated with an increased proportion of children without caries and a reduction in the number of teeth affected by caries (range of mean difference -5% to 64%, median 14.6%). The range (median) of mean change in decayed, missing and filled teeth was 0.5 to 4.4 (mean 2.25) teeth. A dose-dependent increase in dental fluorosis was found. At a fluoride level of 1 ppm an estimated 12.5% (95% CI 7.0% to 21.5%) of exposed people would have fluorosis that they would find aesthetically concerning.
In Finland in 1973 the score of decayed and filled teeth was 43% lower in a fluoridated area than in a low-fluoride area 4. In 1982 there was no difference, reflecting other methods of providing fluoride and free preventive dental care to all children.
Comment: The quality of evidence is downgraded by study quality (low or modest quality in the original studies) but upgraded by consistent findings.
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