Adhesive luting revisited: influence of adhesive, temporary cement, cavity cleaning, and curing mode on internal...

To evaluate microtensile bond strength to Class I cavity floor dentin beneath adhesive inlays that were luted with different adhesives, temporary cements, cleaning methods, and curing modes.

Occlusal cavities (4 x 4 mm, depth 3 mm) were prepared in 96 extracted human third molars. One part of the cavities was temporized with different temporary cements, which were removed after one week using three techniques (scaler or air polishing with Prophypearls or ClinPro powder). Direct resin composite inlays (Clearfil AP-X) were then placed with the luting composite Calibra using three adhesives (XP BOND/SCA, Syntac, OptiBond FL). Teeth were cut into beams and after 24 h of water storage at 37 degrees C, the sticks were subjected to microtensile bond strength evaluation. Samples were subjected to SEM fractographic analysis of failed interfaces.

Contamination with temporary cement reduced dentin bond strengths (p < 0.05). Removing remnants of cements with Prophypearls air polishing resulted in the lowest bond strengths (p < 0.05). Separate light curing of the adhesives did not produce higher dentin bond strengths (p > 0.05). Syntac still worked when Heliobond was omitted (p > 0.05). Immediate dentin sealing prior to temporizing increased internal bond strength (p < 0.05).

The dual-cured adhesive provided higher internal bond strengths between adhesive inlays and dentin. Contamination of dentin with temporary cements is a hazard for excellent dentin adhesion of adhesive inlays. Therefore, immediate dentin sealing and resin coating is promising.