RESUMO
<p><b>OBJECTIVE</b>To evaluate the effect of desensitizer on shear bond strength of adhesive system.</p><p><b>METHODS</b>Twenty specimens were made and divided randomly into an experiment group and a control group. In the experiment group, the dentin bonding surface was applied with Green Or and in the control, the dentin bonding surface was untreated. The IPS-Empress specimens were bonded to the dentin bonding specimens using Variolink II adhesive system. The shear bond strength of all testing samples was determined with Instron testing machine. The surfaces of the drawing sections were observed using the scanning electron microscope (SEM).</p><p><b>RESULTS</b>The shear bond strength of the experimental group and the control group was (5.53 +/- 0.96) MPa and (7.32 +/- 1.34) MPa respectively and there was statistically significant difference between two groups (P = 0.003). In the experimental group, adhesive failure was the most prevalent type of failure, while in the control group, cohesive failure was the most prevalent type.</p><p><b>CONCLUSIONS</b>The application of Green Or on the dentin bonding surface decreased the shear bond strength between dentin and IPS-Empress specimens when using Variolink II adhesive system.</p>