In vitro comparison of 10-minute versus 24-hour shear bond strengths of six dentin bonding systems.

OBJECTIVE

Early bond strengths produced by dentin bonding systems should be sufficient to resist the polymerization shrinkage of resin composite. This study compared the 10-minute and 24-hour shear bond strengths of six dentin bonding systems: One-Step (OS), PermaQuik (PQ), Prime & Bond 2.1 (PB), Scotchbond Multi-Purpose (SBMP), Single Bond (SB), and Tenure Quik with Fluoride (TQ).

METHOD AND MATERIALS

Each bonding system was used to bond composite to visibly moist dentin at 34 degrees C +/- 2 degrees C. The specimens were debonded at 37 degrees C +/- 1 degree C 10 minutes after the start of light curing of the bonding system, and the results were compared with the 24-hour bond strengths. The mode of failure was recorded.

RESULTS

The 10-minute mean shear bond strengths were: OS, 16.4; PQ, 14.3; SB, 14.0; PB, 12.7; TQ, 10.7; and SBMP, 9.3 MPa. The 24-hour mean shear bond strengths were OS, 23.3; PB, 20.8; SB, 20.3; PQ, 19.4; TQ, 11.2; and SBMP, 10.0 MPa. The 10-minute mean shear bond strengths of OS, PQ, PB, and SB bonding systems were significantly less than the 24-hour values. More dentinal fractures and mixed failures were observed with OS, PQ, and PB. Systems with higher bond strengths had more resin penetration into the lateral dentinal branches.

CONCLUSION

The 10-minute mean shear bond strengths were all less than 17 MPa, and the 10-minute bond strengths were less than the 24-hour values.