The impact of stopping or reducing the level of fluoride in public water supplies on dental fluorosis: a systematic review.

Nor Azlida Mohd Nor,Barbara L Chadwick,Damian Jj Farnell,Ivor G Chestnutt

doi:10.1515/reveh-2019-0059

Nor Azlida Mohd Nor, Barbara L Chadwick + Show 2 more

Open Access

https://doi.org/10.1515/reveh-2019-0059

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Abstract

The increased availability of fluoride and concern over the impact of fluorosis, have led to guidance suggesting a decrease or cease in the optimal concentration of fluoride in water fluoridation schemes. To date there have been no systematic reviews looking at both impact of fluoride reduction and total cessation. This review aimed to examine the impact of stopping or reducing the level of fluoride in public water supplies on dental fluorosis. Multiple databases were searched (MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and the Web of Science). Two reviewers independently screened sources, extracted data and assessed study quality. Results were synthesised qualitatively and quantitatively. The main outcome measure was the prevalence of dental fluorosis. Six studies of cross-sectional design were included. Two studies were scored as evidence level B (moderate) and the remaining four publications were evidence level C (poor). Meta-analysis indicated fluorosis prevalence was significantly decreased following either a reduction in the concentration of fluoride or cessation of adding fluoride to the water supply (OR:6.68; 95% CI:2.48 to 18.00). The evidence suggests a significant decrease in the prevalence of fluorosis post cessation or reduction in the concentration of fluoride added to the water supply. However, this work demonstrates that when studies are subject to current expectations of methodological and experimental rigour, there is limited evidence with low methodological quality to determine the effect of stopping or reducing the concentration of fluoride in the water supply on dental fluorosis.

Highlights

Outlook: The evidence suggests a significant decrease in the prevalence of fluorosis post cessation or reduction in the concentration of fluoride added to the water supply
Systematic reviews have acknowledged the benefits of water fluoridation as a whole population approach to caries prevention and the only side effect reported of this population approach is dental fluorosis [1,2,3]
In comparison to other studies included in the review, only this study reported an increase in fluorosis prevalence after 7 years of water fluoridation cessation [14]

Summary

Introduction

Systematic reviews have acknowledged the benefits of water fluoridation as a whole population approach to caries prevention and the only side effect reported of this population approach is dental fluorosis [1,2,3]. Water fluoridation has proved a successful approach to caries prevention, over time a number of countries have reviewed their fluoridation policy in light of alternative means of fluoride delivery. A previous review reported water fluoridation had ceased in 13 countries between 1956 and 2003 [4]. The main reason reported for this approach is that traditional levels of water fluoridation [(at a concentration of 0.8–1 ppm F (parts per million) fluoride (F)] maybe too high given increasing exposure to other sources of fluoride, leading to an increased prevalence of fluorosis [5,6].

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