Repair Bond Strength of Composite To Zirconia Ceramic Using Two Types of Zirconia Primers

Objectives: this study aimed to assess the effect of application of two types of zirconia primers on repair bond strength of composite to zirconia ceramic. materials and methods: in this in vitro, experimental study, 60 zirconia blocks were divided into five groups and subjected to the application of z-prime plus (zpp), monobond plus (mbp), porcelain bonding resin (pbr), zpp followed by pbr (zpp+pbr) and mbp followed by pbr (mbp+pbr). they were then bonded to z100 composite. the samples were then immersed in water at 37°c for 24 hours, thermocycled for 1000 cycles between 5-55°c and subjected to shear bond strength (sbs) test. the mode of failure was determined under a stereomicroscope and a scanning electron microscope (sem). results: the mean bond strength was the highest in zpp+pbr group followed by mbp+pbr, zpp, pbr and mbp group (22.29±8.86, 15.75±2.81, 12.02±3.24, 3.60±2.92 and 2.92±1.78 mpa, respectively). the effects of type of zirconia primer and use/no use of pbr on sbs were significant (p<0.05). the frequency of adhesive failure in mbp and pbr groups was significantly higher than that in mbp+pbr and zpp+pbr groups (p<0.05). the cohesive failure was significantly more frequent in zpp+pbr group than in zpp, mbp and pbr groups (p<0.05). conclusion: simultaneous application of zirconia primer and pbr is the most efficient technique for repair of all-ceramic zirconia restorations with composite resin.