Material and Methods: twenty-four human mandibular molar were used in this study. A total of twenty-Four samples were randomly divided into two main groups(12 each) . Group Ⅰ : teeth were prepared and restored by endocrown restorations . Group Ⅱ : teeth were prepared and restored by onlay restorations. Each group was divided into two subgroups ; Subgroup 1: restorations were fabricated from IPS E. Max cad . Subgroup 2 : restorations were fabricated from Vita Enamic . The restorations were cemented using dual cure resin cement, then the specimens were subjected to fracture resistance test.
Results: Two-way ANOVA test, post hoc Tuckey tests and descriptive statistics were used to compare between different designs and materials . The significance level was set to P ≤ 0,05.
The same material with different restorations. Emax , there was no statistically significant difference between endocrown and only as p=0.3 . V . Enamic , there was no statistically significant difference between endocrown and onlay as p=0.95 . The same restoration with different materials . Endo crown, there was statistically significant difference between Emax and v. enamic as p=0.02 . Onlay, there was no statistically significant difference between Emax and v. enamic as p=0.11.
Conclusion: Within the limits of this in vitro study, the following can be concluded:(1) Endocrowns and onlays can be used safely in terms of fracture resistance as both have values which exceed the physiologic requirements..