Low-fluoride dentifrice and the effect of postbrushing rinsing on fluoride availability in saliva

Post-brushing water rinsing may reduce the risk of fluoride (F) ingestion from dentifrice, however the decreased salivary F bioavailability may compromise any consequent anticaries benefits. As the use of low-F concentration dentifrices is still a matter of debate, a comparison was made between the salivary F bioavailability after brushing with a conventional F dentifrice followed by a water rinse and after brushing with a low-F dentifrice without post-brushing rinse.

In a crossover, blind study, F concentration in saliva of 5 adult volunteers was determined after brushing with a low-F dentifrice (500 microg F/g) or with a conventional F concentration dentifrice (1100 microg F/g), followed or not by a 15-mL water rinse.

Salivary F bioavailability was reduced by 2.5 times when a water rinse was used (p<0.05), irrespective of dentifrice concentration, and it was 2 times lower for the low-F dentifrice (p<0.05). The salivary F bioavailability was similar when the low-F dentifrice was used without post-brushing rinse and the conventional F dentifrice was followed by a rinse (p>0.05).

Habits of post-brushing rinse should be taken into account on the recommendation of dentifrice use by young children, considering the risks and benefits balance of F use.