Background: Prevention of micro-leakage plays an important role in the success of composite restorations. This has led scientists to find newer composite restorative materials. Materials and Methods: Twenty-four human freshly extracted molar was randomly selected for this study. The teeth were stored in 0.1% thymol solution diluted in 0.4% saline. Class V cavities were prepared at the cemento-enamel junction on the buccal surfaces of each tooth. One coat of seventh generation bonding agent G-bond (GC Japan) was applied to all the samples. The samples were randomly divided into two groups of 12 samples each. All the samples were restored with composite resin using single increment technique as per the grouping. The teeth were then stored at 370°C water, except when they were removed from storage and subjected to thermo cycling for 1000 cycles in water between 50°C and 550°C for 30 s in each bath and 15 s transfer between bath. After thermo cycling, the samples were dried superficially, and two coats of nail varnish applied to the entire sample surface, leaving a 1 mm window around the restored cavity margins. All teeth were immersed in 2% methylene blue solution for 24 h at room temperature. The teeth were sectioned in the bucco -lingual direction across the center of the restoration using a slow speed saw (Isomet 1000, Buchler, USA). The sectioned teeth were examined by two calibrated inspectors for dye penetration levels. Results: Mann-Whitney U-test showed that there was no significant difference in dye leakage between Group I and Group II. However, at experimental level, when observing the enamel and dentinal margin, Group II showed a greater degree of leakage than Group I. Conclusion: In the present study, it was observed that self-etch adhesive systems and single increment technique are beneficial as they help in reducing the application time and technique related sensitivity.

Aim:To analyze the difference in the micro-tensile bond strength of specimens made with two different adhesive systems and compare them with two homogenous substrates.Materials and Methods:Sixty permanent mandibular molars were mounted in acrylic blocks and sectioned with exposed dentin surfaces. Samples were then divided into four groups. To Group-I Adper Single Bond 2 and to Group-II Adper Self-Etch plus bonding agents were applied. For Group-I and Group-II beams consisted of resin composite in the upper half and dentin in the lower half. In Group-III beams were made of only dentin. In Group-IV beams were made of only composite. Fifteen specimens of each group were taken for the micro-tensile bond strength test.Statistical Analysis:The results are analyzed using one-way analysis of variance and Critical Difference test.Results:The interface bonded with the two adhesive systems had lower micro-tensile bond strength than those of dentin and resin composite and the self-etching adhesive Adper Self-Etch plus had comparable bond strength with total-etch adhesive Adper Single Bond 2.Conclusion:The bond strength values for current adhesive systems cannot be compared to the micro-tensile bond strength of dentin and resin composite, and self-etching adhesives have comparable bond strength with total-etch adhesives.