Effects of a zirconate coupling agent incorporated into an experimental resin composite on its compressive strength and bonding to zirconia.

Aim: To assess in vitro the compressive strength of an experimental zirconate coupling agented resin composite and its bonding to dental zirconia ceramics.

Methods: Various ratios (1.5-4.0wt%) of a zirconate coupling agent, NZ-33(®), zirconium(IV)-2,2[(bis-2-propenolatomethyl)butanolato-tris-2-methyl-2-propenoato-O)] were incorporated in an experimental bis-GMA/MMA-based resin composite formulation with silica fillers. Compressive strength of the experimental resin composite and shear bond strength (SBS) of the resin composite to zirconia were evaluated by using a universal testing machine. Specimens were stored in dry condition, in water storage for 7 days and for 14 days, to a total of twenty test groups. The data were analyzed by one-way ANOVA and Tukey post hoc test (α=0.05).

Results: SBS of resin-to-zirconia bonding and compressive strength both have significant increase at 1.5wt% and 3.0wt% NZ-33(®) (p<0.05). However, water storage for 7 days (p>0.05) and 14 days (p>0.05) significantly decreased SBS of the experimental resin-to-zirconia with no significant difference between groups (p>0.05).

Conclusions: An addition of a zirconate coupling agent used might strengthen the biomechanical properties of the experimental resin composite.