Fluoride release and re-release from various esthetic restorative materials

Purpose: To measure the amount of fluoride release and re-release after re-charge from two commonly used esthetic restorative materials and compare it to a new experimental material. Methods: 30 standardized discshaped specimens were fabricated using resin-based composite (Z100), resin-modified glass-ionomer cement (Vitremer) and a new experimental material which is a self-curing resin-based composite with light curing option. 10 specimens were made from each material. The specimens of each group were immersed separately in 10 ml distilled water. Fluoride release was measured after 1,7, 14 and 30 days using a fluoride-specific ion electrode and an ion-analyzer. The specimens were then exposed to 2.0% neutral sodium fluoride foam (0.9% fluoride ion). The amount of fluoride rereleased was measured at Days 1,7, 14 and 30. Results: An ANOVA indicated a statically significant variance among the groups (P< 0.001). The experimental group demonstrated significantly less fluoride release at Day 1 compared to Day 31 (first day after 2% sodium fluoride application). At Days 7, 14 and 30 there was significantly more fluoride release than Day 7, 14 and 30 after the topical fluoride application (P< 0.001). There was significantly more fluoride release from Vitremer than the experimental material at Days 1 and 7. However, similar release was observed at Days 14 and 30 for Vitremer and experimental material, but not for Z100. Both Vitremer and the experimental material showed significantly more release of fluoride compared to Z100 at all time points.