Effects of Universal and Conventional MDP Primers on the Shear Bond Strength of Zirconia Ceramic and Nanofilled Composite Resin

Statement of the problem: the clinical success of ceramic depends on the quality of the bond between the zirconia and resin cement. purpose: in the present study, the effects of universal and conventional mdp-containing primers were evaluated on the shear bond strength of zirconia ceramic and nanofilled composite resin. materials and method: thirty blocks of zirconia ceramic (6mm×2mm) were pre-pared. then the inner surfaces were air-abraded and divided into three groups (n= 10) as follows: untreated with primer (control group, i); all- bond universal (group ii) and z-prime plus (group iii). the specimens in each group were bonded with variolink n cement to cylinders of composite resin z350xt. after 24 hour water storage, the shear bond strength test was performed with a universal testing machine at a crosshead speed of 1mm/ min and bond strength values (mpa) were calculated and analyzed with one-way anova and post hoc tukey tests (p< 0.05). the failure mode of each specimen was evaluated under a stereomicroscope and representative specimens were analyzed by scanning electron microscopy (sem). results: the mean shear bond strength values (mpa) were 7.58±1.62, 17.51±1.34 and 22.45±3.60 in groups i, ii and iii, respectively. these results indicated that the shear bond strength were significantly higher in groups ii and iii compared to the control group (p< 0.001). chemical pre-treatment of zirconia with z- prime plus revealed significantly higher bond strength than the all-bond universal adhesive (p< 0.002). all the failure modes were adhesive in the control group (i) and when using primer treatment, mixed failures occurred in 40% and 50% of specimens in groups ii and iii, respectively. conclusion: treatment with both primers resulted in higher bond strength values compared to the control group. the use of z-prime plus treatment in combination with air-abrasion procedure resulted in the highest bond strength.