RATIONALE:In 1984, the DMFT12 in Jamaican children was 6.7 (very severe). In 1987, national salt fluoridation was implemented (250 mg F-/kg salt). In 1995, a national survey showed a substantial decrease of caries severity (DMFT12 of 1.8).OBJECTIVES:To see whether the favorable exposure of fluoride was continued.METHODS:Assessment of urinary fluoride parameters based on WHO guidelines. Children were sampled in two urban and two rural sites. Valid nocturnal and daytime urinary collections were obtained from 128 children (mean age 4.7 y). A questionnaire administered to parents provided information on oral hygiene practice, and use of fluoride via salt, dentifrices or supplements.RESULTS:Excretion rate values extrapolated to 24 h were 271 in urban and 330 microgF/24 h in rural, F-concentrations were in the range of 1.13 and 1.30. Almost all children were reported to use toothpaste, most with 600 to 1000 ppm F; 65% of children use more than the recommended amount of toothpaste. Fluoridated salt was consumed by 98% of the children. There was no other apparent usage of fluorides.CONCLUSIONS:Urinary excretion results point to a suboptimal exposure of fluoride, whereas concentrations would suggest an optimal or slightly higher intake. Dentifrices with 500 ppm F should be made available in order to minimize the risk of enamel fluorosis.

This study evaluated urinary fluoride excretion by school children 4-6 years old who were living in a south Texas rural community that had concentrations of fluoride in drinking water supplies generally around the optimal level. We took supervised collections of urine samples in the morning and afternoon at school, and parents of the participating students collected nocturnal samples. We recorded the beginning and end times of the three collection periods and then determined the urinary volume and urinary flow for each of the periods. We measured urinary fluoride concentrations and calculated the urinary excretion rate per hour. The children had breakfast and lunch provided at the school, where the drinking water contained 1.0-1.3 milligrams/liter (mg/L) fluoride. Fluoride concentrations in the tested household water supplies, from wells, ranged from 0.1 to 3.2 mg/L fluoride. The children's average urinary fluoride concentrations found for the day were similar to those for the night, with means ranging from 1.26 mg/L to 1.42 mg/L. Average excretion was 36.4 micrograms/h in the morning, 45.6 micrograms/h in the afternoon, and 17.5 micrograms/h at night. The lower nocturnal excretion rates are easily explained by low urinary flow at night. Based on the 15 hours of urine collected, the extrapolated 24-hour fluoride excretion was 749 micrograms. In conjunction with similar studies, the data from this study will help in developing upper limits for urinary fluoride excretion that are appropriate for avoiding unsightly fluorosis while providing optimal protection against dental decay.