In situ fluoride retention in enamel and dentine after the use of an amine fluoride dentifrice and amine fluoride/sodium fluoride mouthrinse.

The aim of this in situ investigation was to study the effect of an amine fluoride/sodium fluoride mouthrinse (total F = 250 ppm) in addition to an amine fluoride dentifrice (F = 1,250 ppm) on the amount of acquired fluoride in enamel and dentine. In the partial prosthesis of 12 participants a combined specimen of slightly demineralized enamel and dentine was placed. During two consecutive experiments, each lasting 3 weeks, the participants used an amine fluoride dentifrice alone or in combination with a fluoride mouthrinse. After the in situ period the specimens were retrieved and both the enamel and the dentine specimens were analysed for the amount of KOH-soluble fluoride and structurally bound fluoride. The results showed a significant increase in both KOH-soluble and structurally bound fluoride in enamel and dentine when a fluoride mouthrinse was used. Whether the rinsing procedure was performed immediately after toothbrushing or with a delay of 2 h did not influence the results. Furthermore it was shown that dentine acquired substantially more fluoride than enamel during the experimental period. The results indicate that a fluoride mouthrinse used in addition to a fluoride dentifrice may have a beneficial effect on the protection of enamel and dentine against caries.