Purpose: To evaluate the behavior of hybrid abutment crowns fabricated from monolithic lithium disilicate ceramic (LDC) and to compare the influence of different in vitro artificial aging protocols. Materials and Methods: A total of 32 monolithic hybrid abutment crowns of monolithic LDC were fabricated. Of these, 24 were artificially aged using three different protocols up to a 20 year simulation (1.2 × 106, 2.4 × 106, 4.8 × 106 chewing cycles, thermocycling), a control group underwent no artificial aging (n = 8, N = 32). Load-to-failure tests were conducted for all specimens, and failure values were compared (P < .05). Results: All specimens passed in vitro aging. Mean failure load values between 532.6 and 562.8 N were found but did neither differ significantly among the test groups nor from the control group. Conclusions: Within the limitations of this in vitro pilot study, hybrid abutment crowns manufactured from monolithic LDC seem to offer appropriate long-lasting mechanical stability over a simulation period up to 20 years. The failure values and complication pattern seem to be independent of several aging protocols in this test set-up.
