ABSTRACT
Purpose: This study evaluates the effect of thermo-mechanical cycling (TMC) on the bond strength of a ceramic to three cobalt-chromium (Co-Cr) and two nickel-chromium (Ni-Cr) alloys. Materials and Methods: One hundred metal-ceramic specimens were prepared. While half of the specimens from each metal-ceramic combination (n = 10) were tested after storage in water at 37°C for 24 hours, the other half were subjected to TMC before testing. The bond strength was evaluated by the flexural strength test according to ISO 9693:1999 (E) recommendations. Results: TMC decreased the bond strength of the tested metal-ceramic systems as compared to the water storage (control groups) (P=0.04). Although metal alloys were significantly different from each other in their bond strength with porcelain (P<0.001), the effect of TMC on the various metal-ceramic systems was not significantly different (P=0.99). Conclusion: It may be concluded that base metal-ceramic bond strength is affected by aging and the effect is relatively the same for all the tested porcelain-metal systems.