INTRODUCTIONFluoride-containing restorative materials have been developed in a bid to prevent recurrent caries. Glass ionomer cements （GICs） are considered to be bioactive materials with a therapeutic action due to continuous fluoride release over extended periods of time 1） . The caries prophylactic effect of GIC is attributed to the latter's discharge of fluoride ions and the subsequent fluoride uptake by enamel and dentin. It is also known that fluoride ions can inhibit the adherence of bacteria or bacterial growth
2）. Recently, fluoride has been incorporated into resin composites and adhesive systems -which have shown secondary caries inhibition in in vitro 3） and in vivo 4） studies. A research study 5） on fluoride release from conventional GIC, resin-modified GIC, compomer, and composite resin materials has been published. It has been found that the quantity of fluoride ions released from fluoride-releasing resin composites is significantly lower than that from GICs and compomers Riding on the increased use of esthetic restorations, resin cements are also extensively used and marketed because of their esthetic advantage. Recently, a fluoride-releasing resin cement has been developed and marketed, which is expected to inhibit secondary caries formation around indirect restorations. However, there is little information on the amount of fluoride release from a fluoride-releasing resin cement under different solutions and curing methods.The purpose of this study, therefore, was to measure the amount of fluoride released from a fluoride-releasing resin cement under different conditions. The hypothesis was that both curing method and storage condition would affect the amount of fluoride release from the resin cement.
MATERIALS AND METHODS
Materials used in this studyThe materials, manufacturers, and batch numbers used in this study are listed in The purpose of this study was to evaluate fluoride ion release from a resin-modified glass ionomer cement（Fuji IILC improved, FLC）and a fluoridated resin cement（Panavia F, PF）following different curing methods and storage conditions. The specimens, which were either light-cured（LC）or chemical-cured（CC） , were stored in either distilled water（DW）or demineralizing solution（DS; pH 4.5）for 1, 3, 7, 15, 30, 60, and 90 days. Fluoride ion release was measured using a fluoride ion-specific electrode. Data（n＝5）were statistically analyzed using one-and three-way ANOVA（p＝0.05） . A "burst effect " was observed in the first week from both materials. However, fluoride ion release from FLC was seven times higher than that from PF. Storage in demineralizing solution accelerated the amount of fluoride release from both materials. In addition, LC yielded a lower amount of fluoride ion release from both materials, as compared to CC. It was concluded that both curing mode and storage medium influenced the amount of fluoride release from the tested materials.
