Effectiveness of water fluoridation in an upper-middle-income country: A systematic review and meta-analysis

Aim: To summarize the information on the effectiveness of community water fluoridation (CWF) on the reduction of dental caries in the context of the wide use of fluoridated toothpaste in Brazil.

Design: A systematic review was conducted regarding the effect of CWF based on studies with Brazilian population groups using the following electronic databases: MEDLINE/PubMed, LILACS, SciELO, and SCOPUS. The literature search was conducted up to August 2019. Studies that compared caries experience in at least two areas, one fluoridated and the other non-fluoridated, by mean dmft/DMFT (decayed, missing, and filled teeth) index or caries prevalence (caries vs. caries-free) were included. Considering the beginning of widespread use of fluoride dentifrice and the time for producing dental caries decline, studies published before 1995 were excluded. Descriptive analysis and meta-analyses were carried out. The effect size was measured by mean difference for dmft and DMFT ± SD and odds ratios on a logarithmic scale for caries prevalence.

Results: Of the 574 studies retrieved, 16 and 10 were included in the qualitative and quantitative analysis, respectively. Fluoridated areas exhibited lower mean dmft/DMFT than non-fluoridated areas did. The mean difference in the dmft between non-fluoridated and fluoridated areas was -2.28 (95% CI -3.26; -1.30) for children aged 5-8 years and -1.12 (95% CI -1.93; -0.32) for those aged 3-12 years; the mean difference in the DMFT was -0.61 (95% CI -0.80; -0.42) for the children aged between 7 and 12 years. The caries prevalence was 1.4 times and 57% lower, respectively, at primary and permanent dentition in fluoridated areas. Heterogeneity was observed in all age groups, ranging from 77.6% to 98.2%.

Conclusion: Community water fluoridation remains effective in preventing dental caries in children younger than 13 years, even with the widespread use of fluoridated toothpaste.