Microtensile vs. Flexural Bond Strength for Bond Strength Assessment
Author(s): Annan Ahmed Elkassaby*, Mohamed M Kandil and Ghada Atef Alian
Introduction: Bond strength tests indicate the performance of different substrates bonded in the oral cavity. Purpose: To evaluate the reliability of the flexural bond strength test as a valid substitute for the microtensile bond strength test. Materials and Methods: Two resin matrix ceramic material (RMC) blocks (Vita Enamic and Lava Ultimate) were subjected to 4 surface treatments: Diamond bur roughening (DBR), DBR + silane application, Hydrofluoric (HF) acid etching (9.5%) and HF acid etching (9.5%) + silane application. The universal bond adhesive was applied following the surface treatments followed by the incremental packing of composite resin. RMC/composite blocks for each group were sectioned by using low-speed cutting saw to produce beam-shaped specimens. These specimens were tested with a universal testing machine for microtensile and flexural bond strength. Data were analyzed using ANOVA, independent t-test, Chi-square test, and Weibull analysis. Results: Lava Ultimate showed significantly higher bond strength values than Vita Enamic. Lava Ultimate showed that DBR + saline application surface treatment had significantly high bond strength values. Vita Enamic showed that DBR + saline application and HF acid etching + saline application had the highest bond strength values. According to Weibull's analysis, the flexural bond strength test showed a higher consistency than the microtensile bond strength test. Conclusion: The flexural bond strength test is a reliable, easy alternative to the highly technique-sensitive microtensile bond strength test.