Fluoride and restorative materials

Fluoride release and uptake of four common dental restoratives mainly glass ionomer formulations, including a conventional glass ionomer and resin modified glass ionomer and one fluoride releasing composite resin Tetric Ceram] was evaluated. 12 Cylindrical specimens for each of the 4 materials were prepared following manufacturers instructions for manipulation and immersed independently in 25ml of artificial saliva and stored as 4 groups Group I to Group IV. Each group was further divided into 3 sub groups A, B, C. The saliva was changed every day in all the specimens. No treatment was carried out for the specimens in sub group A. The specimens were immersed in 2% sodium fluoride mimicking a fluoridated mouthwash for one minute before changing saliva in sub group B and the specimens were treated by brushing with a fluoridated dentifrice for two minutes before changing saliva in sub group C. The fluoride release was evaluated on the 1st, 7th and 28th day using a fluoride ion specific electrode. The results demonstrated that the conventional glass ionomer and the recently introduced caries stabilizing glass ionomer showed similar patterns and quantity of fluoride release, which was significantly higher than the resin modified glass ionomer, the compomer and the composite resin. The resin modified glass ionomer showed higher fluoride release than the compomer and the composite resin. All the formulations of glass ionomers showed fluoride uptake from the neutral sodium fluoride and the fluoridated dentifrice, by releasing increased amounts of fluoride after treatment, in comparison with the untreated group. However the composite resin showed no fluoride uptake.