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

Objective 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. Methods A systematic review was conducted regarding the effect of community water fluoridation (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, those 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 in comparison to non-fluoridated areas. 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%IC -0.80; -0.42) for the age between 7 and 12 years. The caries prevalence was 1.4 times lesser and 57% lower respectively at deciduous and permanent dentition in fluoridated areas. Heterogeneity was observed in all age brackets, ranging from 77.6 to 98.2%. Conclusion CWF remains effective in preventing dental caries in younger than 13 years-old, even with the widespread use of fluoridated toothpaste.