Long-term resin bond to densely sintered aluminum oxide ceramic

Background: Densely sintered aluminium oxide ceramic is a popular material for ceramic copings and all-ceramic restorations. A strong, predictable, and long-term durable resin bond is key for long-term clinical success of bonded alumina-based restorations. Purpose: The purpose of this study was to measure and compare in vitro shear bond strengths of three resin cements with and without their corresponding silane coupling/bonding agent to air particle-abraded densely sintered aluminum oxide ceramic after long-term water storage and thermocycling. Materials and Methods: Composite resin cylinders were bonded to air particle-abraded samples of densely sintered aluminum oxide ceramic with Noribond DC® (Noritake Dental Supply, Inc., Aichi, Japan), Panavia 21® EX (Kuraray, Osaka, Japan), and Variolink II® (Ivoclar Vivadent, Schaan, Liechtenstein), which were used with and without their corresponding silane coupling and bonding agents (n = 15). All specimens (N = 90) were stored for 180 days in water and subjected to repeated thermocycling for a total of 12,000 cycles before shear bond strength was tested. Data were analyzed with the Kruskal-Wallis test and the Wilcoxon two-sample rank sum test at the 5% level of significance. Results: Most groups had no or only minimal bond strength to densely sintered alumina after simulated aging. Panavia had the highest bond strength without silane/bonding agent application. Noribond with its silane/bonding agent revealed the highest overall bond strength, which was significantly greater than that of either Variolink or Panavia after silanization. Conclusions: Resin cements revealed significantly different bond strengths, and the use of silane coupling and bonding agents had various effects on the resin bond to pure densely sintered alumina.