Fluoride Release from Glass Ionomer Cement and Resin-modified Glass Ionomer Cement Materials under Conditions Mimicking the Caries Process.

Abstract

The anticaries potential of restorative ionomeric materials should be evaluated under a pH-cycling regime that simulates the caries process of demineralization and remineralization. Ten glass ionomer cement (GIC) materials and five resin-modified glass ionomer cement (RMGIC) materials were evaluated. A resin composite was used as a negative control. Six discs of each material were immersed for 6 and 18 hours each day in demineralizing (De-) and remineralizing (Re-) solutions, respectively. The solutions were changed daily over 12 days, during which the fluoride concentration was determined using an ion-specific electrode. The results were expressed as (1) the daily fluoride concentration in the Deand Re- solutions (μg F/ml), (2) the amount of fluoride released daily in the De- + Re- solution per area of specimens (μg F/cm2/day), and (3) the cumulative release over the 12-day period (μg F/cm2). During the first days, all materials showed a surge in fluoride release, followed by a gradual decline; however, three distinct patterns were observed, specifically: (1) greater fluoride release in the De- solution compared to the Resolution during the study period; (2) an initial higher release in De- solution; and (3) a similar release in both solutions over the whole period. The materials differed statistically (p<0.05) with respect to daily and cumulative fluoride release. One GIC (Maxxion R) and one RMGIC (Resiglass R) had the highest and lowest ability to release fluoride, respectively. In conclusion, the GICs and RMGICs evaluated exhibited distinct qualitative and quantitative patterns of fluoride release under conditions simulating the caries process, which might reflect their anticaries potential.