Fluoride release and uptake by aged resin-modified glass ionomers and a polyacid-modified resin composite

Little has been reported of the relationship of fluoride release and weight loss, and the effects of use of different fluoride agents on restorations, for the new generation of glass ionomer cements. The objectives of this st udy were to compare fluoride release of fresh and aged specimens of a polya cid-modified resin composite (Dyract), and of three resin-modified glass io nomer cements (Fuji II LC, Photac-Fil, Vitremer); and to correlate fluoride release and weight loss of aged specimens after recharging with three diff erent fluoride agents. All materials showed high initial fluoride release i mmediately after uptake when using the agents. However, the levels of fluor ide release dropped rapidly soon afterwards. Although initial fluoride rele ase was significantly different between Dyract and the three resin-modified glass ionomers, when different fluoride agents were used on aged specimens after recharging, no significant differences were found after the first fe w hours. Linear regression analyses also showed no correlation between cumu lative fluoride release and weight loss. Possible beneficial oral health ef fects may only be expected by frequent exposure of these materials to fluor ide agents.