Effects of Protective Surface Coating on Fluoride Release and Recharge of Recent Uncoated High-Viscosity Glass Ionomer Cement

The ability to release and recharge fluoride is a property of glass ionomer cement materials, which is an advantage for patients with a high caries risk. The purpose of this study was to evaluate the amount of released and recharged fluoride in recent uncoated high-viscosity glass ionomer cement (Ketac(TM) Universal Aplicap(TM)) with different surface coatings and at different time points. In total, 135 cylindrical-shaped specimens were equally divided into the following three groups: Ketac(TM) Universal Aplicap(TM), Ketac(TM) Molar Aplicap(TM), and Ketac(TM) Fil Plus Aplicap(TM). The different coatings performed on each group were as follows: uncoated, coated with Ketac(TM) Glaze, and coated with G-Coat Plus(TM). The amounts of released and recharged fluoride were measured at 24 h and at weeks 1, 2, 3, and 4. The recharging agent was a 1.23% APF gel. Ketac(TM) Universal Aplicap(TM) showed the highest released fluoride at all time points and the highest recharged fluoride at weeks 1, 2, and 3. Both the Ketac(TM) Glaze- and G-Coat Plus(TM)-coated specimens presented significantly lower released and recharged fluoride ions than the uncoated group at all time points (p < 0.001). Coating with G-Coat Plus(TM) significantly decreased the released and recharged fluoride compared to the coating with Ketac(TM) Glaze at almost all time points (p < 0.05), except for weeks 1 and 2. The application of coating agents reduced the amount of released and recharged fluoride by the Ketac(TM) Universal Aplicap(TM).