Effect of polymerization mode on bond strengths of resin adhesive/cement systems

The purpose of this study was to examine the effect of resin adhesive/cement system primer and cement polymerization mode (auto- vs dual-polymerized) on the shear bond strength to dentin.

Dentin surfaces of 90 bovine teeth were polished to 600 grit. The dentin was etched for 15 seconds with phosphoric acid, rinsed, and blotted. Three adhesive systems, All-Bond 2, Prime & Bond 2.1 Dual-Cure, or Scotchbond Multi-Purpose Plus, were applied. Three primer polymerization methods were used with each system: dual-polymerized, autopolymerized, or strictly following manufacturers' recommendations. Resin cements, which were also either auto- or dual-polymerized, were applied to dentin using gelatin capsules. Shear bond strengths were determined using an Instron universal testing machine.

The greatest bond strength, 15.4 MPa, was found with the Scotchbond system when the primer was dual-polymerized and the cement was autopolymerized. The lowest bond strength, 7.5 MPa, was found with All-Bond 2/Duo-Link, when the primer and cement were dual-polymerized. The autopolymerization mode produced the highest mean bond strength for All-Bond 2, while dual-polymerization of primer and cement resulted in the highest mean bond strength for Prime & Bond 2.1. Scotchbond Multi-Purpose Plus was least affected by the polymerization method. Two-way ANOVA showed that the interaction between the type of adhesive system and the method of polymerization significantly influenced bond strength (p = .0001).

The effect of the primer polymerization method on ultimate bond strength was different for each adhesive system evaluated. More research is needed to elucidate the interaction between adhesive system and method of polymerization on bonding of resin cements to dentin.