Résumé
The purpose of this study was to compare the shear bond strength of three bonding agents known as Excite, Prime and bond NT and Clearfil SE Bond. Sixty premolar teeth were randomly divided into two groups. The buccal surfaces of 30 teeth in group 1 were cut by trimmer to expose the dentin in the coronal portion and those of the teeth in group 2 were cut to expose the dentin in the root portion. Mounted samples in acryl resin were randomly divided into three groups. The Excite bonding agent was used in groups [1-1] and [2-1]; Prime and bond NT in groups [1-2] and [2-2] and finally the Clearfil SE Bond in groups [1-3] and [2-3]. Then, composite Z100 was used to restore all cavities. In coronal sections and in comparison between groups [1-1] and [1-2] there was no significant statistical difference. In radicular sections there was significant difference between [2-1] and [2-2] groups, [2-1] and [2-3] groups and [2-3] and [2-2] groups. Attachment to dentin either in coronal or in radicular sections had more bond strength when we use self etch bonding agent compared to total etch bonding agent. Also the type of bonding agent affects the bond strength in the root, but has little effect in the crown. Bonding agent with ethanol solvent has a greater effect than bonding agent with acetone agent