Fingernail may not be a reliable biomarker of fluoride body burden from dentifrice

• Published in: Brazilian dental journal Vol. 21; no. 2; p. 91
• Main Authors: Lima-Arsati, Ynara Bosco Oliveira, Martins, Carolina Castro, Rocha, Lília Alves, Cury, Jaime Aparecido
• Format: Journal Article
• Language: English
• Published: Brazil 2010
• Subjects: Biomarkers - analysis; Biomarkers - metabolism; Body Burden; Cariostatic Agents - administration & dosage; Cariostatic Agents - adverse effects; Cariostatic Agents - analysis; Cariostatic Agents - metabolism; Female; Fluoridation; Fluorides - administration & dosage; Fluorides - adverse effects; Fluorides - analysis; Fluorides - metabolism; Fluorides, Topical - administration & dosage; Fluorides, Topical - adverse effects; Fluorides, Topical - analysis; Fluorides, Topical - metabolism; Fluorosis, Dental - prevention & control; Humans; Infant; Longitudinal Studies; Male; Nails - chemistry; Nails - metabolism; Prospective Studies; Reference Values; Reproducibility of Results; Sensitivity and Specificity; Toothpastes - administration & dosage; Toothpastes - analysis
• ISSN: 1806-4760

Fingernail has been suggested as a biomarker of fluoride (F) body burden, but there is no consensus if it would be a reliable indicator of F exposure from dentifrice. Therefore, the present study was conducted to investigate if fingernails would have sensitivity to detect F exposure from dentifrice in young children. Twenty-three 1-3-year-old children living in the city of Piracicaba (0.72 ppm F in water), Brazil, were enrolled in two phases of different F exposure: in phase A (1st to 11th week), they were exposed to the combination of F from diet (solids and liquids) and dentifrice (1,500 microg F/g as MFP), and in phase B (12th to 29th week), only to F from diet (the use of F dentifrice was interrupted). Fingernails were weekly clipped during 35 weeks for F determination. F intake from diet and dentifrice in each phase was also determined. Both analyses were made with ion-specific electrode. F intake (Mean +/- SD) was significantly higher (p<0.01) when the children were exposed to F from diet+dentifrice than only to F from diet (0.086 +/- 0.032 and 0.040 +/- 0.009 mg F/day/kg body weight, respectively). However, F concentrations in nails collected during the whole experimental period of 35 weeks presented great variation with no trend of decreasing after F dentifrice intake interruption. The findings suggest that fingernail may not be a reliable F biomarker of body burden from dentifrice.