LACK OF A SIGNIFICANT RELATIONSHIP BETWEEN TOENAIL FLUORIDE CONCENTRATIONS AND CARIES PREVALENCE

The relationship between fluoride (F) concentrations in toenails and prevalence of caries using the International Caries Detection and Assessment System (ICDAS-II) criteria was evaluated. Fifty-four children (4-13 years of age) from Rio de Janeiro, Brazil, had their teeth surfaces examined and toenails clipped and analyzed for F. Toenail F concentrations in children presenting ICDAS-II less than or equal to 10 or >10 were compared by unpaired t test with Welch correction. Dichotomized data were analyzed by Fisher's exact test. Children presenting ICDAS-II less than or equal to 10 (n=23) had 1.85 plus or minus 1.32 (Mean plus or minus SD) mu g/g [F]; these values were higher than children having ICDAS-II>10 (n=31), whose toenails had 1.58 plus or minus 0.78 mu g/g [F], a nonsignificant difference. The sensitivity and specificity of toenail F concentrations in identifying children with ICDAS-II less than or equal to 10 were 0.22 and 0.77, respectively. We conclude that children with low caries prevalence tend to have higher toenail F concentrations, but the validity of this biomarker as a diagnostic tool for caries prevalence is low, possibly owing to the fact that the mechanism of action of F on caries control appears to be essentially topical.