الفهرس 
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Abstract
Two parallel groups (35 specimens each) will be examined in this study.
1. Flexural strength (23)
Flat specimens from each group (14 specimens) will be prepared with 65 mm length, 10 mm width, and 2.5 mm thickness according to the ADA specification No 12. (24) 7 specimens will be thermo-cycled in the thermocycling machine for 500 cycles between 5⁰C and 55⁰C in distilled water. The remaining specimens will be stored in distilled water at 37⁰C in the incubator for 24 hours as a state known as thermo-cycle zero. Each specimen will be mounted on universal testing machine. Three point bending test will be carried out with a distance of 50 mm between the two supporting points and cross head speed of 0.5 mm/min.
The flexural strength will be calculated according to the following equation:
FS = 3PI (MPa)
2bd²
Where,
P= Fracture load.
I= Distance between the two supporting points.
b= Width of the test specimen.
d= Thickness of the test specimen.
2. Impact strength test (25)
Specimens from each group (14 specimens) will be prepared for impact strength test according to the method described in the ISO standard (ISO 179-1 : 2010). Bar shaped specimens 75 mm length, 10mm wide and 10 mm thick, notched at the center. 7 specimens will be thermo-cycled in thermo-cycling machine for 500 cycles between 5⁰C and 55⁰C in distilled water. The remaining of specimens will be stored in distilled water at 37⁰C in the incubator for 24 hours at a state known as thermo-cycle zero. Measurement will be conducted using charpy’s impact tester.