Fluoride Recharge and Enamel Fluoride Uptake from a Resin Sealant

Objectives: Determine enamel fluoride uptake (EFU) of lesioned adjacent enamel, and fluoride recharge potential from 5000 and 950 ppmF toothpastes & fluoride varnish, of an unfilled light-cured sealant.
Methods: Recharge: Cured 20x1mm CPS disks (n=5) were stored @37°C in 25ml deionized water (DIW). At 1hr,6hr,24hr,2d,3d,4d,7d leachate was collected/replaced. Groups A-B: C5K or CTC toothpaste treatments were applied at 7d,8d,9d; aliquots were collected immediately before, and 1,2,4,6hr after each treatment. Toothpaste-treatment was immersion 2min in 25ml DIW:toothpaste=3:1. Group C: VWV varnish was applied at 7d, removed with razor scraping and acetone wipe @8d; aliquots were collected 1,2,4,6,24,48hr after DIW re-immersion. Data after treatment were compared to immediately before treatment via one-way paired T-test (p<0.05).
EFU: Lesions were formed in 5x5mm mounted polished bovine enamel (obtained from a packing plant) by immersion in carbopol-lactic acid solution pH=5, 96hr, 37C. CPS was applied on mount around perimeter of enamel. Treated & untreated samples were immersed separately in DIW 37C for 2mo (n=10). Microdrilled tooth biopsy samples were taken, digested, fluoride measured & water replaced at 7d,14d,30d,60,90d. Data were analyzed via one-way ANOVA and compared with Tukey’s t-test (p<0.05).
Fluoride was measured with fluoride ion-specific electrode after adding TISAB-II.
Results: Materials shown in Table 1; EFU results in Table 2; recharge results in Tables 3 and 4.
Conclusions: Treatment with C5K, CTC, or VWV resulted in enhanced fluoride release from CPS through six hours afterward; recharge from C5K and CTC is repeatable. EFU from CPS was statistically significantly higher than the untreated control at one week through two months. Unfilled light-cured sealant CPS can repeatably absorb (recharge) and re-release fluoride from topically applied fluorides; fluoride released from CPS penetrates into enamel.