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Abstract
This research was designed to measure and compare the rate of fluoride release from two different types of fluoride releasing adhesive systems and the amount of fluoride uptake by dentin at different time intervals namely; one day, one week, one month and three months compared to a non fluoride releasing system. Then to investigate whether leaching out of fluoride from fluoride-releasing adhesives affected the nanoleakage and shear bond strength between resin composite and dentin before and after thermocycling at the aforementioned time intervals.
For fluoride release test, a total of 60 cylindrical specimens were prepared from the different tested adhesive materials (Xeno III, P & B NT and Adper Single Bond 2) and divided equally between the three adhesive systems. Fluoride released in deionized water was assessed using a microprocessor-based portable fluoride meter, readings were recorded every week. ¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬
A total of three hundred intact, sound, freshly extracted permanent human molar teeth, were selected and divided among the performed tests. Specimens were further subdivided and stored for four different storage periods in deionized water till they were treated according to the different testing procedures. Sixty teeth were used in the fluoride uptake test. Class V cavities were prepared on the buccal surface and restored with the investigated materials, then stored till tested. The ESEM was used to determine the amount of fluoride uptake by dentin after sectioning of the teeth longitudinally through the restoration. Analysis of percentage of fluoride present was carried out using EDAX.