Fluoride Release, Enamel Fluoride Uptake and Dentin Tubule Occlusion From A Novel Dimethicone-Based Fluoride Varnish

Purpose: To measure the fluoride release and enamel fluoride uptake from a new dimethicone-based fluoride varnish (Profisil) and Duraphat fluoride varnish, and determine if the varnishes occlude dentin tubules. Methods: The fluoride release of both varnishes was measured from specimens with a constant surface area to volume ratio in a water bath. The fluoride uptake of demineralized enamel cores treated with both varnishes was studied over 24 hours using ion-specific electrodes to determine fluoride content and atomic absorption spectroscopy to determine calcium content. Scanning electron microscopy (SEM) was used to examine the occlusion of dentin tubules and the surface of enamel after treatment with varnish. Results: Duraphat varnish released 68±7.1 ppm of fluoride per gram of varnish after 24 hours. Profisil varnish released 65±6.3 ppm of fluoride per gram of varnish after 24 hours. Duraphat varnish specimens had a fluoride content of 2.5±1.8 mg F/g enamel before application of the varnish, which increased to 285±62 mg F/g enamel after 24 hours. Profisil varnish specimens had a fluoride content of 2.4±2.1 mg F/genamel before application of the varnish, which increased to 272±74 mg F/g enamel after 24 hours. SEM images depicted that both varnishes occluded open dentin tubules and left mineral deposits on the surface of the enamel. Conclusions: Both varnishes released significant amounts of fluoride and significantly increased the fluoride uptake of demineralized enamel. Moreover, the new varnish induced occlusion of the tubules and induced mineral growth on the surface of the enamel.