Fluoride release from conventional glass-ionomer cements and polyacid-modified composite resins

Fluoride release into deionized water from two glass-ionomer cements (Aqua Ionofil and Ceramfil beta) and two polyacid-modified composite resins or compomers (Hytac and Dyract AP) was examined over different time periods. Nine cylindrical specimens (2.5 x 8.5 mm) of each material were prepared and allowed to stand in deionized water. The resulting solutions were analyzed for fluoride by the Alizarin colorimetric method on the 1(st), 7(th), 30(th), and 120(th) days. The smaller release of fluoride from the compomers seemed to be fairly linear from day 7 to day 120, whereas most of the fluoride release from the glass-ionomer cements appeared to have occurred by day 30 and afterwards was very slow to day 120. Overall, the two compomers exhibited less fluoride release than the two conventional glass-ionomer cements, and the differences were statistically significant (p<0.05). The greatest amount of fluoride was released from the conventional glass-ionomer Ceramfil beta, and the least amount from the compomer Dyract, for which only one previous study could be found.