Assessment of the Bond Strength of Universal Resin Cements

Objectives: The aim of the present study was to compare the dentin bond strength of two universal resin cements that were either light-cured or auto-cured.
Methods: The buccal and lingual surfaces of eighty bovine incisors were cut until dentin blocks of 2mm in height were obtained. Standardized cone-shaped cavities were prepared using 3131 diamond burs. The cavities were isolated and restored with Filtek Z350 composite resin (3M ESPE). After polymerization, the restorations were removed and cemented with RelyX Ultimate (n = 40) and Duo- Link (n = 40) universal cements, which were applied directly to the cavity without an adhesive system. Ten specimens of each cement were light-cured (40 s) and ten specimens were auto-cured. After water storage (24 hours at 37 ° C), 20 specimens of each cement were subjected to the push-out test. The remaining specimens were assessed after 6 months of water storage, using the same criteria as used for the 24-hour testing. The F test (ANOVA) and the student´s t-test were used for the statistical analysis.
Results: The greatest bond strength was recorded when RelyX Ultimate cement (3M ESPE) was light-cured (24 hours), with a significant difference recorded between the light-cured (13.93 MPa) and auto-cured (4.85 MPa) specimens. No statistically significant differences were found between the tests after 24 hours and after 6 months for this cement. Among the specimens of DUO-LINK cement (Bisco), the greatest bond strength was measured after 6 months, with no statistically significant difference between the light-cured (11.21 MPa) and auto-cured (10.76 MPa) specimens.
Conclusions: Universal resin cements exhibited satisfactory bond strength without the use of an adhesive system, especially when they were light-cured.