ABSTRACT
Marginal seal in class V Cavities and determining the best restorative material to decrease microleakage of them is very important in operative dentistry. To evaluate the microleakage of class V cavity preparations restored with three different types of resin composite and resin modified glass Ionomer. Two class V cavities were prepared in buccal surface of 32 recently extracted premolar teeth. The occlusal margin of each restoration was on enamel and the gingival margin on dentin. Teeth were randomly assigned to four groups of 8 teeth and restored as follows: Group I: microhybrid resin composite [Z250]; Group II: nano composite [supreme]; Group III: Flowable composite [3M]; Group IV: resin modified glass Ionomer [vitremer]. In all groups the manufacture instructions were strictly followed. All teeth were immersed in 50% Silver Nitrate during 4 hours and developing solution for 8 hours after thermocycling. The teeth were longitudinally sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney test. There was no evidence of microleakage on the enamel margins in any groups. When the margins were in dentin vitremer and flowable composite had the less and the most level of microleakage in dentinal margin respectively [P<0.05]. There was no significant differents in other groups of dentinal margin. Vitremer has an efficterness role and flawable composite has a weakness role in reducting microleakage of dentinal margin