Fluoride release and re-release from a bioactive restorative material.

PURPOSE: To compare the amount of fluoride release and re-release of three different restorative materials.

METHODS: The three restorative materials included a resin-based composite (Z100TM, 3M-ESPE), a resin-modified glass ionomer cement (VitremerTM, 3M-ESPE) and a bioactive material (Activa Bioactive-RestorativeTM, Pulpdent,). Ten disks were fabricated from each material. The disks were immersed in deionized water and stored. Samples were taken from each vial on Days 1, 7, 14 and 30 for fluoride ion analysis. Each disk was then exposed to 2.0% neutral sodium fluoride gel (0.9% fluoride ion, Dentsply), immersed in deionized water and stored. Samples were taken on Days 1, 7, 14 and 30 for fluoride ion analysis utilizing a fluoride-specific ion-analyzer.

RESULTS: Z100 released less fluoride on Days 1 (P< 0.001), 7 (P= 0.001) and 14 (P< 0.022) for Phase I (initial release) than Phase II (re-release). Vitremer and Activa released less fluoride on Days 7, 14 and 30 (P< 0.001) for Phase II than Phase I. For all intervals of Phase I, Vitremer released the most fluoride, Activa released the second most, and Z100 released the least. These results were the same for Days 7, 14 and 30 of Phase II. The level of fluoride release from Activa was less than that of Vitremer, and greater than that of Z100 for all intervals of Phase I. The results were the same for all but one interval of Phase II.

CLINICAL SIGNIFICANCE: This in vitro study evaluated the fluoride release and subsequent re-release of fluoride following a topical fluoride treatment to analyze if the materials were truly bioactive. The results indicate the bioactive material does uptake fluoride and re-release it which could offer inhibition to caries at restoration margins.