Heterocontrole da fluoretação da água de abastecimento público de Alfenas-MG

Abstract

Fluoridation of public water supplies, an important public health measure for control of dental caries, consists of the controlled addition of a fluoride compound with the purpose of adjusting its concentration between 0.7 and 1.2 mg/L, according to the local annual average temperature. Due to the risk of dental fluorosis in children systemically exposed to fluoride during permanent tooth formation, it is justified the heterocontrol, performed by an external agency, aiming at contributing to the maintenance of the quality pattern and the population health protection. The purposes of the present study were to evaluate the fluoride concentration in public water supply in Alfenas-MG during one year, as well as to evaluate possible influences from temperature and rainfall levels in the concentration of fluoride. Water samples were monthly collected in randomly selected dates, from January to December 2018, in the water treatment station, water supply reservoirs and health basic units of the city. The eletrometric method by fluoride ion selective electrode connected to a potentiometer was used for the analysis of fluoride. Samples were classified according to the fluoride level, and those ranging from 0.55 to 0.84 ppm (mg F/L) were considered as “acceptable”, while values out of that interval were considered as “unacceptable”. Samples were also classified regarding to the risk of fluorosis and the benefit of caries prevention. Data were submitted to statistical analysis, with significant level established at 5%. A total of 69.6% of the samples were classified as acceptable and with the maximum benefit related to caries prevention and minimum risk of dental fluorosis. There were significant oscillations in the fluoride levels during the evaluated period, with the higher values observed in the higher rainfall months. However, there was no significant difference in the fluoride levels among the different places of sample collection. Therefore, the population of Alfenas-MG has received water with acceptable levels of fluoride concentration, providing maximum benefit against caries and minimum risk of dental fluorosis. There were oscillations in the fluoride concentration over one year, indicating influence of seasonality in the addition of fluoride and requirement of adjustments. Therefore, the maintenance of the heterocontrol as a permanent measure should be encouraged.