Enhancement of fluoride release from glass ionomer cement following a coating of silver fluoride

Background: This study investigated the extent to which a coating of 10% silver fluoride (AgF) on discs of glass ionomer cements (GICs) would enhance the release of fluoride ion into eluting solutions at varying pH. Materials and methods: Forty discs each of Fuji IX, Fuji VII and of Vitrebond were prepared in a plastic mould. Twenty discs of each material were coated for 30 seconds with a 10% solution of AgF. Five discs each of coated and uncoated material were placed individually in 4ml of differing eluant solutions. The eluant solutions comprised deionized distilled water (DDW) and three separate acetate buffered solutions at pH 7, pH S and pH 3. After 30 minutes the discs were removed and placed in five vials containing 4ml of the various solutions for a further 30 minutes. This was repeated for further intervals of time up to 216 hours, and all eluant solutions were stored. Fluoride concentrations in the eluant solutions were estimated using a fluoride specific electrode, with TISAB IV as a metal ion complexing and ionic concentration adjustment agent. Cumulative fluoride release patterns were determined from the incremental data. Results: The coating of AgF greatly enhanced the level of fluoride ion release from all materials tested. Of the uncoated samples, Vitrebond released the greater concentrations of fluoride ion, followed by Fuji VII. However, cumulative levels of fluoride released from coated samples of the GICs almost matched those from coated Vitrebond. Conclusions: It was concluded that a coating of 10% AgF on GICs and a resin modified GIC greatly enhanced the concentration of fluoride released from these materials. This finding might be applied to improving protection against recurrent caries, particularly in high caries risk patients, and in the atraumatic restorative technique (ART) of restoration placement.