Abstract

Introduction: Dental composites have been extended as the selected material in most of recent restorations. However, the contraction caused by their polymerization remains the main issue. The stress made by this contraction could cause the divide of composite-tooth junction to be severed. Bacteria, liquids, molecules or ions could cross the gap made between the repair and the cavity wall which this process is called micro-leakage. Micro-leakage causes leakage, tenderness, secondary decay, damage to the pulp, marginal discoloration, which finally results in restoration failure. It can be said that the success of resin restoration material depends perfectly on the ability of the enamel and dentin bonds. This research aims to determine the best bonding to decline micro-leakage. Materials and Methods: In this research, 48 human premolar teeth were prepared without decay, restoration, fracture and wear. Each class V standard cavity was prepared on buccal and lingual surfaces. The shaved teeth were randomly divided into 4 groups including 12 ones. They were polished after restoration. All samples of the 4 groups were subjected to the heat cycling. Apex was sealed with adhesive wax and all parts of the tooth were covered with two layers of nail polish. The samples were incubated in 0.5 Fuchsin solution for 24 hours at room temperature. After that, they were washed under the faucet and the nail polish was removed from tooth surface. Teeth were divided into two mesio distal sections by a cutting machine. Samples were observed by stereo microscope. samples were evaluated based on the micro-leakage grading. Kruskal-Wallis, Mann-Whitney and Will Coxson tests were used to evaluate the results. Results: In each group, 48 cavities were examined. The results of this research showed that in none of enamel surface of bindings, micro-leakage was observed. In the dentine area, the least amount of micro-leakage was related to the Clearfil SE Bond. There was no statistically significant difference between the micro-leakage of Clearfil SE Bond and G Premio Bond by Self Etch method (P value> 0.05). Also, there was no significant difference between micro-leakage of GPremio Bond by Self Etch and GPremio Bond by Etch and Rinse method. The micro-leakage of Adper Single Bond 2 was significantly higher in the dentin rather than the other groups .Conclusions: In dentine level, the highest micro-leakage was related to Adper Single Bond 2 bonding and the least one was in Clearfil SE Bond and G Premio Bond by Self Etch method. © RJPT All right reserved.