Bonding potential of self-adhesive luting agents used at different temperatures to lute composite onlays

To assess whether the bonding potential to dentin of self-adhesive resin cements was affected by their pre-cure temperature.

Composite overlays (Paradigm MZ100, 3M ESPE) were luted on 100 extracted molars with G-Cem (GC Corp.), BisCem (Bisco), Multilink Sprint (Ivoclar Vivadent), SAC-A (Kuraray Co.), XP Bond/Calibra (Detrey Dentsply). The cements were used at pre-cure temperatures that recur in their handling (4 degrees C refrigerator, 24 degrees C room and 37 degrees C intraoral), as well as following pre-heating up to 60 degrees C. Microtensile bond strengths to dentin were measured and compared with statistical tests. Scanning electron microscope observations of cement-dentin interfaces were performed.

The bond strength of G-Cem and Calibra was not significantly affected by temperature changes from refrigerator storage to intraoral application. At any assessed pre-cure temperature the total-etch luting agent Calibra achieved a significantly stronger adhesion than the auto-adhesive cements. Limited to null adhesion was yielded by BisCem and SAC-A. The procedure of 60 degrees C pre-heating, proposed in previous studies for restorative resin composites, was of no use for the tested luting agents. Only the total-etch luting agent Calibra developed a distinct hybrid layer. The self-adhesive cements exhibited a more superficial interaction with dentin.

Regardless of the pre-cure temperature, the bonding potential of the self-adhesive resin cements was inferior to that of the total-etch luting agent tested as control. The adhesive properties of the BisCem and SAC-A were extremely scarce.