Effect of the seating pressure on the adhesive bonding of indirect restorations

Purpose: To evaluate the effect of two different techniques of seating pressure application on the adhesive-dentin bond of indirect restorations. Methods: Eight non-carious human third molars were randomly divided in two treatment groups (four teeth each). Cylindrical composite blocks were luted with a resin cement (Panavia F). In Group 1, the seating pressure was applied for 5 seconds. In Group 2, the resin cylinder was maintained under constant pressure during the entire 3-minute polymerization period of the resin cement. After storing in distilled water for 24 hours, 0.9 x 0.9 mm sticks were produced from these luted specimens for microtensile bond testing and SEM examination. Results: The Student t-test showed a significant difference (P< 0.05) in bond strength between Groups 1 and 2. SEM revealed the presence of structural defects and resin globules on the seating surface of the composites. These features were exclusively identified from Group I specimens and were probably caused by fluid transudation from the underlying dentin through the simplified self-etch adhesive (ED primer).