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.Management Sciences
Category: Metallurgy
Gypsum bonded investment should not be heated over______________?
A. 700°C
B. 1,300°C
C. 1,063°C
D. 900°C
Investment material used for cobalt-chromium alloys is_____________?
A. Gypsum bonded
B. Phosphate bonded
C. Silica bonded
D. None of the above
Air bubbles formed on the surface of casting is probably due to________________?
A. Improper casting pressure
B. Improper heating of the investment
C. Improper angulation of sprue
D. Improper wetting of the wax pattern by the investment
Ideal requirement of metal ceramic casting____________?
A. Low fusing ceramic and high fusing alloys
B. Matching of coefficients of thermal expansion of ceramics and alloy
C. Bonding between ceramic and alloy
D. All of the above
Incomplete casting is the result of_____________?
A. More porous investment in the mould
B. Narrow sprue diameter
C. Hollow sprue pin
D. Large reservoir
The base constituents of dental waxes come from three main sources except______________?
A. Animal
B. Mineral
C. Insect
D. Vegetable
Silver plated dyes use an electrolytic bath of_______________?
A. Silver fluorides
B. Silver cyanide
C. Silver bromide
D. Silver iodide
Indium in metal alloys_______________?
A. Improve bonding
B. Harden the metal ceramic Ag-Pd alloy
C. Both A and B
D. None of the above
Microstructure of cobalt chromium alloy in cast condition is______________?
A. Fibrous
B. Homogeneous
C. Inhomogenous
D. amorphous
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