Influence of Surface Coating Material on Fluoride Release and Recharge.

Objectives: The aim of this study was to evaluate the influence of surface coating materials on fluoride release and recharge for three glass ionomer cements (GIC).
Methods: Specimens were placed in vials containing water to allow fluoride release, and later, to assess recharge of fluoride after fluoride application. In the release stage, the water was collected every 6 h on the first day, then daily through day 7, and on days 14 and 21. In the recharge stage, on day 22, specimens were subjected to fluoride gel application. Subsequently, specimens were immersed in 5.0 mL of water. The water was changed on days 22, 28, 35, and 42. Three-Way Analysis of Variance and the Student-Newman-Keuls test were applied.
Results: Groups that did not receive the surface coating material showed higher fluoride release when compared to groups that received it. Resin-modified GIC showed higher fluoride release when compared with conventional GIC. However, for groups with surface protection, the fluoride release showed no statistically significant difference when comparing conventional and resin-modified GIC. After fluoride application, among the groups that did not receive surface protection, the profile of fluoride release was higher for Vitremer^® followed by Fuji II LC^® and Ketac Molar^® groups, respectively. For the groups that received surface protection the fluoride release was similar each other.
Conclusions: It was possible to conclude that the materials tested exhibit satisfactory fluoride ion release and recharge abilities, but the application of surface protection significantly decreases the release of fluoride.