Abstract :
Purpose : The aim of this study was to compare between Monolithic Translucent Zirconia (Y-TZP) and IPS e.max press in marginal fit and fracture strength. Materials and methods, forty ceramic crowns were fabricated, : Then divided into 4 groups: Group A: Ten monolithic TZI CAD/CAM zirconia crowns (n=10) Group B: Ten monolithic IPS e.max press crowns (n=10), Group C: Ten veneered ZI CAD/CAM zirconia core (n=10), Group D: Ten veneered IPS e.max press core (n=10),then Each group was subdivided into two subgroups: Subgroup 1: Samples not subjected to thermocycling (n=5) as control. Subgroup 2: Samples subjected to thermocycling (n=5). The crowns were cemented to corresponding epoxy resin dies. The marginal fit was measured and scanned with digital microscope. The fracture strength of restoration was measured by using universal testing machine with a load 5 KN. The obtained data were collected, tabulated and statistically analyzed. Results of marginal fit: Results showed that, the vertical marginal gap values of all groups were within the clinically acceptable range. Results of fracture resistance: The fracture strength of monolithic translucent Y-TZP is (3484.28 N) considerably higher than monolithic IPS e.max press (1515.45 N), followed by veneered ZI zirconia (1483.84 N), and finally veneered IPS e.max press (1091.64 N) after thermocycyling. Conclusions: The vertical marginal gap values observed were all within the clinically acceptable range (120 μm). The monolithic crown groups recorded higher fracture strength than veneered groups.