The effect of application sustained seating pressure on adhesive luting procedure

Objectives: To evaluate the effect of short versus long application seating pressure on the bond strength of resin blocks, luted with a dual-cured resin cement (Panavia F) to pre-coated or non pre-coated dentin with an hydrophobic light-cured adhesive (Clearfil Protect Bond). Methods: Sixteen non-carious human third molars were randomly divided into six Groups (four teeth each). Cylindrical composite blocks were luted with Panavia F (Group Ia) and with Clearfil Protect Bond with Panavia F (Group IIa) and seating pressure was applied for 5 s. In Groups Ib and IIb, the two bonding procedures were respectively repeated, but the resin cylinder was maintained under constant pressure during the entire 3 min polymerization period for the resin cement. After storing in distilled water for 24 h, 0.9 mm × 0.9 mm sticks were produced from these luted specimens for microtensile bond testing and SEM examination. Results: The use of Clearfil Protect Bond with Panavia F produced higher bond strengths than the use of Panavia F (p < 0.05). Extending the time of pressure application up to 3 min increased the bond strength (p < 0.001) and improved the integrity of the interfacial quality. Significance: The application of sustained seating pressure during luting procedures and the additional use of a hydrophobic light-cured adhesive both improve the final bond strength of the resin cement.