Association between High Fluoride Concentration of the Drinking Water and Prevalence of Dental Caries: A Systematic Review

Abstract

Introduction: The inverse relationship between higher fluoride concentration in drinking water and lower levels of dental caries experience was demonstrated by several community trials but the augment about effectiveness and safety is still a matter of debate and requires further research and investigation. While some studies have shown that adding fluoride to drinking water can be a safe and effective way to reduce dental caries, others have raised concerns about potential health risks associated with exposure to high levels of fluoride. This review aims to assess the evidence of adding fluoride to drinking water to reduce dental caries.
Methods: A web search was conducted in medical databases such as PubMed and Embase to identify community trials that aimed to assess the impact of fluoridation of drinking water on the occurrence of dental caries. Two reviewers screened the eligible papers and read the abstract to determine the alignment with the eligibility criteria. After the primary screening, 35 studies were found relevant and included in the review. Inclusion criteria were randomized controlled trials, cohort studies, case-control studies, cross-sectional studies, and systematic reviews that evaluate the effect of fluoride in drinking water on dental caries. Studies that report on the prevalence or incidence of dental caries as an outcome measure, studies that include participants of any age, and studies conducted in any country or setting.
Results: Water fluoridation was first adopted as a health policy in the United States in 1951 and gradually became more widespread, with an estimated 69.2% of Americans drinking fluoridated water by 2006. Several countries adopted water fluoridation programs to varying degrees, including New Zealand, Brazil, and Ireland. However, the process has been discontinued in some areas due to alternative strategies, such as the provision of health services in schools, and concerns about potential health risks. Studies have shown that the high concentration of fluoride in drinking water reduces dental caries but raises the incidence of dental fluorosis. The prevalence of dental caries and dental fluorosis varies between countries and regions, and studies on fluoride concentration in drinking water and its relation to both dental caries and dental fluorosis are limited in some areas, such as in Arab countries.
Conclusions: Studies have shown that high fluoride concentration in drinking water reduces dental caries but raises the incidence of dental fluorosis. The prevalence of dental caries and dental fluorosis varies between countries. Studies on the concentration of fluoride in drinking water and its relation to both dental caries and dental fluorosis are limited in some areas.