SHORT-TERM FLUORIDE RELEASE UPTAKE OF GLASS-IONOMER RESTORATIVES

Objectives. The short-term fluoride release/uptake of four glass ionom er restoratives was measured and compared to the fluoride release afte r exposure to three commercial fluoride gels. Methods. Materials teste d were: 1) Ketac-Fil (ESPE GmbH); 2) Ketac-Silver (ESPE GmbH); 3) Phot ac-Fil (ESPE GmbH); and 4) Fuji II LC (GC Corp.). Twenty discs of each material were fabricated and stored in deionized water at 37 degrees C. Initial fluoride release was measured at 24 h intervals for 7 d, an d 24 h intervals at the end of each week for 5 wk. After 6 wk, samples were divided into groups and each group was treated for 6 min with on e of the following commercial fluoride gels: acidulated phosphate fluo ride (AP Fl, neutral sodium fluoride (NaF), and stannous fluoride (SnF 2). Control specimens were placed in deionized water. After exposure, fluoride measurements were carried out at 24 h intervals for 7 d, and 24 h intervals at the end of 2 wk. Fluoride exposure was repeated, and measurements were again recorded over 3 wk. Results. Initial fluoride release by all materials was highest during the first 24 h and decrea sed sharply over the first week. After exposure to APF, fluoride relea se increased significantly for all materials. Exposure to NaF also res ulted in increased fluoride release for all materials although it was not as high as the increase recorded after exposure to APF. Exposure t o SnF2 did not result in significant fluoride release by any material. Significance. The results of this study suggest that certain fluoride gels may replenish fluoride within some glass ionomers acid thus prol ong their cariostatic potential.