Determination of fluoride release from light-cured glass-ionomers and a fluoridated composite resin from the viewpoint of curing time.

The purpose of this study was to investigate the fluoride releasing pattern of several visible light-curing glass-ionomers and one fluoride-containing filling material, from the viewpoint of curing time. Standardized blocks of Time Line (Caulk-USA), XR-Ionomer (Kerr-USA), Vitrebond (3M-USA) and Heliomolar-Ro (Vivadent-Lichtenstein) were light cured for 20, 40 and 60 s, and then stored in deionized distilled water at 37 degrees C for 24, 48, 72 h and 7 days. The water was changed every day and measurements of the fluoride released from the materials were made daily. The results were compared statistically with the results obtained from Ketac-Bond (Espe-Germany) prepared in the same manner. The levels were highest for the first 24 h; in the following days they decreased rapidly. The fluoride-releasing patterns of all these materials were similar to each other. The fluoride release was the highest from XR-Ionomer, and the lowest from Heliomolar-RO. For Time Line glass-ionomer, the fluoride release from 20 s cured blocks was significantly higher than the fluoride release from 40 and 60 s cured blocks at the end of 1 week. It was observed that the fluoride release from Ketac-Bond was significantly lower than XR-Ionomer and Vitre-Bond and higher than Time Line and Heliomolar-Ro.