Methods: The occlusal face of fifteen recently extracted teeth was ground to expose a flat dentin area. Indirect restorations were built with the indirect composite Sinfony (3M/ESPE). The teeth were divided randomly into three groups: Group 1 (control) - the restorations were cemented with the dual resin cement Panavia F; Group 2 - the self-etch "one bottle" adhesive system Clearfil S3 (Kuraray) was applied on the dentin surface before cementation; Group 3 – the dentin was treated with Clearfil S3 (Kuraray) and a layer of the low-viscosity composite Protect Liner layer was applied over the adhesive before cementation. The three groups were cemented with Panavia F. After 24 hours, the specimens were submitted to thermocycling (2,000 cycles at 5-55°C) and load cycling (250,000 cycles, 100 N at 2 Hz). Afterward, the specimens were submitted to microtensile bond strength (µTBS) and failure mode classified by SEM. The data were submitted to ANOVA and Tukey's test (p<0.05). Results: The µTBS results showed significant difference (p<0.05) among groups: Group 3 (14.89 MPa)>Group 2 (12.26 MPa)>Group 1 (9.51 MPa).
Conclusions: The resin coat technique can improve the bond strength of indirect restorations to dentin, mainly when low-viscosity resin composite in association with self-etch adhesive system are used.