In vitro enamel and cementum fluoride uptake from three fluoride-containing composites

The incorporation of fluoride into restorations is desirable because of its cariostatic action. The purpose of this study was to determine fluoride release and fluoride uptake by enamel and cementum from three visible light-cured fluoride-containing composites. Seven circular discs of each composite were prepared and the amount of fluoride released into distilled water was determined at daily intervals for 14 days and then after 30, 60 and 90 days. The fluoride concentration in enamel and cementum was determined in three successive depths by an acid etch biopsy procedure. The composite slabs were made and ligated to the enamel and cementum surfaces and the teeth were immersed in synthetic saliva for 7 days. After removal of the composite slabs, three successive biopsies were again performed. Then the teeth were immersed in 1 M KOH for 24 h and similar biopsies done. The fluoride concentrations were adjusted to standardized depths of 10microm, and the total and bound fluoride uptake calculated. The amounts of fluoride released were significantly different among the three composites. The fluoride released decreased sharply after 1 day and then gradually reached a plateau. As for the enamel and cementum fluoride uptake, FluorEver showed the largest uptake followed by FluoroCore and then Pertac-Hybrid.