Caries and fluoridated water in two Brazilian cities in the first decade of the 21st century

Abstract

Abstract Background Despite health policies must be shaped by scientific evidence, there is no data to prove that water fluoridation increases preventive benefit to dental caries in addition to that provided by the widespread use of fluoride toothpaste. Methods A double census population survey was conducted in two Brazilian small cities, differentiated only by exposure or not, for at least 5 years, to fluoridated water, in 2014. The magnitude and experience of caries were assessed using the dmft (at 5-6-year-old; N = 233), DMFT (at 11-12-year-old; N = 312) and SiC (at 11-12-year-old; N = 105) indexes. Associations were tested by Pearson's chi-square statistics and prevalence ratio (PR) between unexposed (NE) and exposed (E) to fluoridated water. Results Deciduous dentition: Although caries experience (dmft≥1) was not associated with exposure to fluoridated water (chi-square=2.77, p = 0.96, α = 5%), there was a significant difference in the magnitude which the disease reached the population: the mean dmft were 2.74 in those exposed and 4.17 in unexposed. PR (NE/E) was 1.21 indicating that exposure to fluoridated water corresponded to a 21% lower prevalence rate, compared to those unexposed. Permanent dentition: Although caries experience (DMFT≥1) was not associated with exposure to fluoridated water (chi-square=1.78; p = 0.18; α = 5%), a significant difference was observed in the magnitude with which the disease reached the population: the means of DMFT were 1.76 in those exposed and 2.60 in unexposed and the means of SiC were 4.04 and 6.16, respectively. PR (NE/E) was 1.13 indicating little expressiveness in prevalence difference. Conclusions Exposure to fluoridated water implied a lower mean value of the dmft, DMFT and SiC indexes at a level of 50%, although in the presence of concomitant universal exposure to fluoridated dentifrice. The maintenance of water fluoridated in Brazil and other countries as an effective public health measure is strongly supported by this research results. Key messages This research is in the interest of all countries to decide whether, even with access to fluoridated toothpastes, it is worth adding fluoride to the waters that supply their populations. The study's approach is unprecedented and describes innovative possibilities of using cross-sectional studies to evaluate the results and impacts of public oral health policies.