Effect of mouthrinsing after toothbrushing with a fluoride dentifrice on human salivary fluoride levels.

In a recent clinical trial of sodium monofluorophosphate dentifrices, oral rinsing habits were found to influence dental caries. Thus an oral fluoride clearance study has been undertaken which was designed to test a possible mechanism for the observed effects. Eight subjects brushed with one of the trial dentifrices and then rinsed using 1 of 8 procedures of varying thoroughness. The salivary fluoride concentration measured 5 min after dentifrice application decreased significantly with increasing rinse volume, rinse duration, and rinse frequency (p less than 0.01, analysis of variance). The area under the clearance curve determined over a further 3 h was significantly higher (300%; p less than 0.01) following use of the least thorough rinsing procedure (5 ml x 2 s once) as compared with the corresponding area under the clearance curve following the most thorough procedure (20 ml x 10 s twice). These findings indicate that rinsing habits may play an important role in the oral retention of fluoride from dentifrices which may, in turn, affect their clinical efficacy.