Fluoride in saliva and plaque following use of fluoride-containing mouthwashes

The sensitivity of methodology for measuring the concentration of fluorine species in saliva and in plaque has been tested. Human subjects mouth-rinsed daily with aqueous solutions of NaF and Na2FPO3. Samples of unstimulated whole saliva and of plaque were collected twice weekly at least 18 hr after treatment application. Oral fluoride concentrations rose from placebo values for approximately two weeks before attaining equilibrium and returned to baseline when daily mouthrinsing was stopped. Mean elevated oral fluoride concentrations increased significantly with increasing applied NaF concentration in the range 0-1000 ppm F (0-0.053 mol/L). There appeared to be a linear relationship between saliva and plaque fluoride. The ability of fluoride treatments to sustain elevated oral fluoride levels between daily applications may be of major importance in caries control.