Objective:

To determine the concentration and excretion of fluoride in urine of 24 hours in 4 age groups and fluoride exposure in nails, without and with fluoridation of the salt, after a period of interruption of seven months. Cartago 2004-2005.

Methodology:

Non-probabilistic and sequential sample of 127 individuals distributed in four population groups (4-6, 10-12, 15-17 and 35-60 years of age). The analysis of fluorine in urine, water and salt was performed with the specific electrode. Nail fluoride analysis was performed by diffusion analysis provided with hexamethyldisiloxane (HMDS). The concentration of fluoride in urine, nails, water and salt, as well as the excretion of fluoride in urine was calculated.

Results:

In the period without fluoridated salt (phase 1), 90.5% of salt samples had less than 15.8 mgF / kg (average 22.7 mgF / kg) and water averaged 0.25 mgF / L; In the period with fluorided salt (phase 2) the average fluoride in salt was 143.5 mgF / kg, always with the water concentration of 0.25 mgF / l. The 24-hour urinary excretion and fluoride concentration at 7 months without fluoridated salt in both cases was lower in phase I in all four age groups. With fluoridated salt (phase II) excretion increased by 80% on average in all age groups. In contrast, the fluoride concentration in nails was higher during phase 1, without significant differences between groups or between phases.

Conclusion:

The interruption of fluoridation of salt in Costa Rica allowed the measurement of the presence of this element in the sentinel population (control), confirming that the organism maintains the fluoride still for 7 months after stopping ingesting fluorine independent of age. The measurement of the concentration of fluoride in nails could constitute a method of measuring this element to complement the study of fluorine in the human organism.

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