Materials and Method:104 intact premolar teeth were used to evaluate the etching pattern and microshear bond strength. They were divided in two groups: 52 teeth for enamel studies and 52 teeth for dentin studies. mid-coronal region of buccal aspect of the teeth were prepared for our study.two self–etch primers,clearfil SE Bond and clearfil S3 Bond were applied in one and two coats,respectively,on enamel and dentin surfaces,forming our eight study groups.One specimen of each group was selected for SEM evaluation and other specimens were used to be bonded with composite beams for micro-shear bond strength measurement with Instron universal testing machine.Then data were analyzed with ANOVA.
Results:There were no significant differences in micro – shear bond strength values of two self-etch primers in one or two coats application on both enamel and dentin.
The mean of micro–shear bond strength values of specimens treated using self-etch primer,Clearfil SE Bond,was significantly higher than values of specimens treated with self–etch adhesive,Clearfil S3 Bond, in dentin but there was no difference for enamel samples.
Conclusion:By application of two–step self etch adhesive, Clearfil SE Bond, the sufficient bond strength can be achieved in short time periods even in one layer and double application of primer does not affect the bond strength.The most important question about self-etch adhesive is the bond effectiveness of these adhesives in long time periods.