In vitro comparative fluoride release, and weight and volume change in light-curing and self-curing glass ionomer...

The purpose of this study was to evaluate and compare in vitro fluoride release from and weight and volume changes of Photac-Fil, a light-curing polymaleinate restorative glass ionomer, with Ketac-Fil, a self-curing glass ionomer, and Ketac-Silver, a metal reinforced glass ionomer. Five discs of each material, measuring 2 mm height and 5 mm diameter, were suspended in separate vials of distilled water and laboratory artificial saliva. Fluoride release into the solutions was measured using a calibrated fluoride-sensitive ion meter initially at 24 hr and then weekly from 1 to 9 weeks. These results were evaluated statistically using repeated measures analysis of variance. Volumes and weights were recorded at the start and end of the experiment and analyzed using the paired t-test. Photac-Fil released similar amounts of fluoride to Ketac-Silver, but significantly less than Ketac-Fil in distilled water (P < or = 0.05). In artificial saliva, Photac-Fil released similar amounts to Ketac-Fil, but significantly more than Ketac-Silver (P < or = 0.05). Photac-Fil volume increased in distilled water and artificial saliva (P < or = 0.05) as did Ketac-Fil and Ketac-Silver in artificial saliva (P < or = 0.05). The only material that demonstrated significant net weight increase was Ketac-Silver in artificial saliva (P < or = 0.05). In summary, differences in fluoride release between these three glass ionomer materials varied as a function of the media in which they were stored. Whereas Ketac-Fil exhibited significantly greater fluoride release than the other materials in distilled water, in artificial saliva Ketac-Fil and Photac-Fil exhibited comparable fluoride release. Dimensional change, as evaluated by volume and weight differences, was also affected by storage media.