Circadian alimentary intake of fluoride was estimated in the group of 18 children of the mean age of 4,75 years and of 20,69 kg body weight by means of the double plate method in two stages within 6 months. Fluoride from food samples was extracted by the micro diffusion method.
The contents of extracted fluoride from solid food and fluoride in beverages was measured potentiometrically by means of fluoride ion sensitive electrode. The mean circadian fluoride intake in the first stage of study amounted to 0,274 mg/day, in the second stage 0,330 mg/day, which in the recalculation to mg fluoride/kg of bw/day amounted to 0,014 resp. 0,015.
The calculated fluoride intake reached the bottom of the optimal fluoride intake threshold (0, 05-0, 07 mg/kg bw/day). When adding the possible intake of fluoride from swallowed fluoride tooth paste the total intake has already fully fallen into the rank of the intake threshold.