Estimation of fluoride absorption from swallowed fluoride toothpastes

Eight adults ingested five different toothpastes with and without 1,000 ppm (1 microgram/g) fluoride added as NaF or Na2PO3F. The systemic fluoride absorption was estimated by by comparing the areas under salivary fluoride concentration curves produced after the toothpaste ingestion. Of the toothpastes investigated--chalk, dicalcium phosphate dihydrate, silica or alumina with sodium monofluorophosphate, and silica with sodium fluoride--the fluoride absorption was found to be statistically significantly lower only from the dicalcium phosphate dihydrate toothpaste. Measuring changing fluoride levels in saliva appears to be an acceptable non-invasive technique for following systemic fluoride absorption.