Purpose: To assess the effectiveness of using silane before cementing laboratory resins, by means of microtensile bond strength test.
Methods: 40 human molars were selected, cleaned and stored in a 0.1% thymol solution. The occlusal surfaces of these teeth were removed and flattened until dentin was exposed. Next, the laboratory resin blocks were cemented (Adoro or Artglass) with Single Bond and Rely X adhesive cementing systems, by the same cementing protocol, the only difference between the groups being whether or not silane was applied. The teeth to which the blocks were cemented were prepared to obtain stick-shaped test specimens with an approximate area of 1.00 mm2 (+/- 0.12 mm2) for the microtensile bond strength tests. Afterwards, under x2.5 magnification, the fracture modes were visually classified as adhesive, cohesive or mixed.
Results: ANOVA (P < or = 0.05) showed that there were significant differences in the microtensile values between the indirect composites studied. The highest microtensile bond strength values were found with the Artglass (58.08 MPa without silane, 49.76 MPa with silane), and lowest values with Adoro (37.08 MPa without silane, 39.52 MPa with silane). There were no differences in the microtensile bond strength values, with or without silane application. The fractures were considered predominantly adhesive in 68.3%, mixed in 25.8% and cohesive in 5.9% of cases. The use of silane did not contribute significantly to increasing microtensile bond strength during laboratory resin cementation.