fluoride release from three glass ionomers after exposure to sodium fl uoride and acidulated phosphate fl uoride gels

background: glass ionomer (gi) restorations exposed to fl uoride have the ability to slowly release fl uoride. therefore, the aim of this study was to investigate fl uoride release from three gis before and after exposure to sodium fl uoride (naf) and acidulated phosphate fl uoride (apf). materials and methods: fifteen disc-shaped samples (6 mm in diameter and 2 mm in thickness) from three gis (fuji ii, fuji ix, chem flex) were made and suspended in a polypropylene recipient containing 10 ml distilled water and stored at 37°c. at the 13th day, the samples of each gi were randomly divided into 3 groups. groups 1 and 2 were exposed to naf and apf gels for 4 min and group 3 served as control in distilled water. the fl uoride released was measured at day 1, 4, 10, 13, 14, 17, 20 and 23 by potentiometer. data were analyzed by one-way anova and tukey test. p < 0.05 was considered as signifi cant. results: fluoride release was highest after 24 h for the tested gis, but fuji ii demonstrated the least amount. fuji ix showed the highest fl uoride release followed by chem flex. exposure to fl uoride gels signifi cantly increased fl uoride release for all materials (p < 0.05). the amount of fl uoride release for the three gis was signifi cantly higher in apf groups during the test period. conclusion: highly viscous conventional gis (fuji ix and chem flex) released higher quantity of fl uoride. key words: acidulated phosphate fl uoride, dental caries, fl uoride release, glass ionomer, sodium fl uoride