Fracture Resistance of Non-metallic Molar Crowns Manufactured with CEREC 3D

Objectives: To compare fracture strength and fatigue resistance of ceramic (ProCAD, Ivoclar-Vivadent)(C) and resin composite (Paradigm MZ100, 3M/ ESPE)(R) crowns made with CEREC-3D. Methods: A prepared ivorine molar tooth was duplicated to produce 40 identical prepared specimens made of epoxy resin (Viade). Twenty (C) crowns and 20 (R) were cemented to their dies using resin cement. Ten of each group were subjected to compressive loading to fracture. The remaining 10 of each group were subjected to mechanical cyclic loading for 500,000 cycles. The survivors were subjected to compressive loading to fracture. Results: No significant difference in mean fracture load was found between the two materials. However, only 30% of the (C) crowns vs. 100% of the (R) crowns survived the cyclic loading test. Conclusions: (R) crowns demonstrated higher fatigue Resistance than (C) crowns in-vitro and might better resist cracking in-vivo.MAS