Bond Strength of Resin Cements Using New Universal Bonding Agents

Objectives: The purpose of this study was to determine the effect of new universal bonding agents on the bond strength of dual-cure resin cements to dentin.
Methods: One hundred forty extracted human third molars were mounted in dental stone and sectioned with a saw to remove coronal tooth structure. The teeth were randomly divided into seven groups of twenty based on the use of five universal bonding agents (All-Bond Universal, Bisco; FuturaBond Universal, VOCO; Prime&Bond Elect, Dentsply; Scotchbond Universal, 3M ESPE; Clearfil Universal, Kuraray) compared to two self-etch bonding agents (Clearfil SE Bond and Clearfil SE Bond 2, Kuraray). Each group was further divided into two equal subgroups of ten specimens each with each subgroup tested with either self- or light-cure activation mode of the resin cement (Calibra, Dentsply). The bonding agent was applied per manufacturers’ instructions to the dentin surface of each specimen. The specimens were placed into a jig (Ultradent) and resin cement was inserted into the mold to a height of 3-4 mm and light cured. Specimens were stored for 24 hours in 37⁰C distilled water and tested in shear in a universal testing machine (Instron). A mean shear bond strength value (MPa) and standard deviation were determined per group. Data were analyzed with 2-way ANOVA/Tukey’s (alpha=0.05).
Results: A significant difference was found between groups based on bonding agent (p<0.0001) or curing mode (p=0.026) with no significant interaction (p=0.117).
Conclusions: Light curing of the resin cement in dual-cure mode resulted in significantly greater bond strengths than if the cement was allowed to self-cure. The new simplified universal bonding agents resulted in significantly lower shear bond strength of the resin cement to dentin than the non-simplified, two-step, self-etching bonding agents Clearfil SE Bond or Clearfil SE Bond 2.