Determination of fluoride intake from urinary fluoride excretion data in children drinking fluoridated school milk

Twenty-four-hour urine samples were collected from each of thirteen 5- to 6-year-old children both under customary conditions of fluoride intake (i.e. usual diet including milk containing 0.5 mg fluoride and usual oral hygiene procedures with fluoride toothpaste) and during a 4-day study period in which their customary fluoride intake was replaced with standard fluoride doses. The 24-hour fluoride excretion under customary conditions of fluoride intake was 0.30 mg and in response to fluoride doses in the range of 0.5-2.0 mg it was in the range 0.26-0.61 mg. Using data obtained during the study period for all subjects combined, the fluoride intake from all sources under customary conditions was estimated as 0.76 mg, representing a fractional fluoride excretion of 39%. It is concluded that these children are possibly receiving suboptimal amounts of fluoride.