Monitoring fluoride exposure with fingernail clippings
Whitford, G.M.
Schweizer Monatsschrift für Zahnmedizin 115(8): 685-689
2005
ISSN/ISBN: 0256-2855 PMID: 16156172 Document Number: 594784
The purpose of this review is to discuss new information regarding the relationship between the level of fluoride exposure and the corresponding fluoride concentrations in fingernail clippings. While there are several techniques available to extract fluoride from fingernails prior to analysis with the electrode, the HMDS-facilitated diffusion method is the most popular. Fluoride enters fingernails at the growth end and reaches the distal end approximately three months later. The fluoride concentration in the clipping reflects the average fluoride intake and plasma concentration during the period when the clipping was formed. Therefore, the concentration in the clipping is directly related to the average fluoride exposure that occurred during a 1-2 week period (depending on the length of the clipping) about three months ago and not to recent and possibly variable exposures that occur during the day. Published studies have demonstrated that fingernail fluoride concentrations reflect fluoride exposures from drinking water, toothpaste and the work environment and can be expected to do so for any source of intake including salt.