Water fluoridation as a marker for sociodental inequalities

The aim of this study was to investigate the associations between the Human Development Index at city level (HDI-M) in the state of Paraná, Brazil, and the length of time of population exposure to water fluoridation (time span) with the respective mean decayed, missing and filled teeth (DMF-T) of schoolchildren in the state, looking at possible inequalities in these associations.

The HDI-M of 323 cities in the state of Paraná, Brazil, was correlated to the duration of exposure to water fluoridation, calculated in number of days. Correlation between the HDI-M and the DMF-T indexes for 12-year-old children was also performed.

Correlations were statistically significant, showing that in the cities with a better HDI-M, water fluoridation had been implemented earlier (squared coefficient correlation of 22%). The fluoridation time span accounted for around 11% of the variance in the DMF-T indexes of the cities. The correlation indicated that locations with a better HDI-M had a better DMF-T, owing to the probable mediating effect of receiving fluoridation earlier. Furthermore, the cost of water fluoridation to benefit the population that has access to this public health measure has been estimated at USD 0.15 per capita/year.

It is possible to conclude that this low-cost measure is able to improve oral health status in general. Nevertheless, in the Brazilian areas studied, fluoridation seems to reflect existing social development inequalities, as it was first made available in more socially developed areas, thus bearing an influence on their higher DMF-T performance to date.