Methods: Three fluoride containing resin composites were analysed in this study; Giomer material Beautifil II (containing pre-reacted glass ionomer), Gradia Direct X (containing fluoro-alumino-silicate glass) and Tetric EvoCeram (containing ytterbium trifluoride). Ten specimens of each material were aged for 43 days; five were aged in deionised water and five aged in lactic acid. A fluoride specific electrode was used to measure the fluoride release from each specimen on days 1, 2, 4,8,15,22,29,36 and 43 post cure. One-way ANOVA followed by post hoc Tukey test comparisons were employed to assess the significance of the effect of composite type, storage medium and storage time on the amount of fluoride released by each material.
Results: The cumulative fluoride release by Beautifil II into both deionised water and lactic acid (pH 4) was significantly (p<0.05) greater than the fluoride released by Gradia Direct X and Tetric EvoCeram into each media respectively, after 43 days aging. Similarly, at each point in time, the cumulative level of fluoride released by Gradia Direct X significantly (p<0.05) exceeded the release by Tetric EvoCeram into both deionised water and lactic acid. Further, the cumulative amount of fluoride released by all three resin composites into lactic acid (pH 4) was greater than each material's respective release into deionised water, after 43 days.
Conclusion: The storage media, storage time and composition are factors that influence the release of fluoride from a resin composite. The sustained ability of the resin composites in the present study to release fluoride, including one of the Giomer class, raises the possibility of fluoride releasing composites inhibiting recurrent caries.