[External control over the fluoridation of the public water supply in Bauru, SP, Brazil].

Objective: To assess the fluoridation of the public water supply and compare these results with previous data.

Methods: The study was carried out from March 2004-2005 in Bauru, a city of Southeastern Brazil. Every month, on dates established randomly, 60 water samples were collected from the 19 supply sectors of the city, totaling 737 samples. The fluoride concentration in the water samples was determined in duplicate, using an ion-specific electrode (Orion 9609) coupled to a potentiometer. Following analysis, the samples were classified as acceptable or unacceptable according to their fluoride concentration. Descriptive statistical analysis was utilized.

Results: The mean fluoride concentration observed in the different collection months ranged from 0.37 to 1.00 mg/l. Around 85% of the samples were classified as acceptable.

Conclusions: One year after implementing external control, an improvement in the water fluoridation conditions was observed in comparison with previous results obtained in the city. The implementation of water supply fluoridation monitoring by means of surveillance systems must be stimulated: this is fundamental for controlling dental caries.