Fluoride release from conventional, resin-modified and hybrid glass ionomer cements

Summary Introduction The aim of the study was to quantify and compare fluoride release from four different glass ionomer cement products (GICs). Materials and Methods Standardized disk-shaped samples (5x2mm; n=5/group) of GIC restorative materials: conventional (Fuji IX, GC Corp., Japan), resin-modified (Fuji II LC, GC) and hybrid glass ionomer cement (Equia Forte, GC) and a conventional GIC liner/base material (Alfagal, Galenika, Serbia) were tested for fluoride release up to 21 days postsetting. Each sample was immersed in 5 mL of fresh deionized water during each time interval. Universal microhybrid composite (Filtek Z250, 3M EPSE, USA) and adhesive (Adper Single Bond, 3M ESPE) were used as negative controls. Fluoride release was measured using an F-selective electrode (Cole-Parmer, USA) and an ion meter (Oakton 700, Cole-Parmer, USA). Data were statistically analyzed using one-way ANOVA, regression and correlation analysis at 0.05. Results The highest total fluoride release was measured from Alfagal (386±61 ppm/g), and significantly less from Equia (188±29 ppm/g), Fuji IX (143±11 ppm/g) and Fuji II LC (104±14 ppm/g) (p < 0.05). All GICs showed the highest fluoride release during the first 24 hours post-setting. After 3 days, fluoride release slowed down reaching a plateau for all materials. Regression and Pearson correlation analysis showed significant inverse relationship between fluoride release and sample mass and density (p<0.001). Conclusion Of the three GICs indicated for use as restorative materials, Equia Forte released the highest fluoride concentration. Fluoride release was material and density dependent, with higher release occurring from lower density GICs.