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.