The purpose of this study was to compare microleakage and marginal hybrid layer in class Ⅴ restorations using two one-bottle adhesives and one self-etching adhesive.

Class Ⅴ cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on buccal and lingual surfaces of 30 extracted human molar teeth. Prepared teeth were randomly divided into three treatment groups (n=30) and restored with three adhesives and composites: Single Bond/Filtek Z-250 (Group 1), Prime&BondNT/Esthet∙X (Group 2), UniFil Bond/UniFil F (Group 3).

For microleakage, samples were stored in room temperature water for 24 hours, thermocycled, stained with 2% methylene blue dye, sectioned into halves, scored and analysed using Mann-whitney test and Wilcoxon signed rank sum test.

For marginal hybrid layer, samples were sectioned into halves, treated with 10% phosphoric acid for 5 seconds, stored in 5% NaOCL solution for 24 hours, dried and gold coated. Occlusal and gingival margins of each sample were inspected under SEM.

The results of this study were as follows;

Microleakage at the occlusal margins was not evident in group 1 and group 2, but it showed in group 3 (p<0.05).

In coclusion, the effect of dentin adhesives on microleakge in class Ⅴ composite restorations was excellent when one-bottle adhesives were applied on enamel margin, and it was good when a self-etching adhesive was applied on dentinal margin. There was no corelation between microleakage and thickness of marginal hybrid layer.