Effect of two universal adhesives on microshear bond strength of resin cement to zirconia

Abstract

Background. Considering the increasing demand of patients for esthetic and durable restorations, zirconia, with its excellent mechanical properties, has overcome most of the limitations of all-ceramic restorations. However, bonding to zirconia is still challenging. Objectives. This study compared the effect of 2 universal adhesives on the microshear bond strength of resin cement to zirconia after 24 h and 6 months of water storage. Material and methods. This in vitro experimental study was performed on 56 zirconia (Prettau® Zirco-nia) blocks, which were randomly divided into 2 groups. The Scotchbond™ Universal single-component adhesive and the All-Bond Universal™ 2-component adhesive were used. The PANAVIA™ F 2.0 resin cement was bonded to all samples, and they were stored in distilled water for 24 h and 6 months. The microshear bond strength test was then performed, and the data was analyzed using the Kruskal–Wallis and Mann–Whitney tests. Results. After 24 h of water storage, the All-Bond samples showed significantly higher microshear bond strength than the Scotchbond samples (p < 0.001), but at 6 months, the microshear bond strength of Scotchbond was higher. The bond strength of All-Bond decreased after 6 months (p < 0.001), but no significant change occurred in the bond strength of the Scotchbond samples over time. Conclusions. The microshear bond strength of resin cement to zirconia depends on the type of adhesive and the duration of water storage. The Scotchbond Universal adhesive resulted in a stronger bond in the long term.