Does bottled drinking water have anti-dental caries properties? A Systematic review and meta-analysis

BACKGROUND AND AIM: The growing consumption of bottled water has raised concerns about its quality. The optimal concentration of trace elements such as fluoride in drinking water is of significance for public health. Water with the optimal fluoride concentration is considered one of the most cost-effective ways to prevent dental caries in communities. The aim of the present study was to conduct a systematic review and meta-analysis of studies on fluoride content of bottled water. METHODS: In this study, medical and non-medical databases were searched using a comprehensive and sensitive search strategy. Retrieved citations were imported into an Endnote library. The quality of the studies was checked using the Joanna Briggs Institute (JBI) checklist. The data extracted from the studies included country, reported fluoride concentration level in bottled and tap water, the region of sampling, fluoride determination method, number of assessed brands, and study year. The data were analyzed using random-fixed effects and meta-regression methods in Stata software. RESULTS: A total of 32 papers from 16 countries were included in the review. Half of the studies compared the laboratory-determined content to the label-claimed fluoride content. The results of the meta-analysis showed high heterogeneity in the investigated papers. CONCLUSION: The fluoride content of bottled water had significant discrepancies with the optimal level. The contradiction between the label-claimed fluoride content and that determined after accurate testing was a prevalent finding. The existing legislation does not effectively guarantee the accurate labeling of fluoride content and more rigorous supervision is required.