431. Direct filling gold formed by electrolytic precipitation is called by all the terms EXCEPT______________?

A. Crystalline
B. Granular gold
C. Mat gold
D. Sponge gold

432. When Gold fused with porcelain is fired at very high temperature greenish discoloration of cervical margin is due to________________?

A. High firing temperature
B. Disintegration of opaque layer
C. Presence of copper
D. Formation of excess oxides

433. Powdered gold is___________________?

A. Made by a combination of chemical precipitation and atomization
B. Made by electrolytic precipitation
C. Made by beating pure gold at high temperatures
D. Made by milling pure gold ingots

434. Which of the following is true about direct filling gold______________?

A. Properly condensed mat gold has no voids
B. Whatever may be the type voids are inherent
C. Voids can be avoided with manual condensation
D. None of the above

435. The malleting force is directed______________?

A. Perpendicular to the walls
B. Parallel to long axis of crown
C. 45° to the wall
D. None of the above

436. Pitting of direct filling old restoration usually results from_________________?

A. Using contaminated gold foil
B. Poor finished preparation
C. Improper stepping of condenser point
D. Using small condenser point

437. The cohesive gold used as bulk filler is_____________?

A. Electra alloy
B. Mat gold
C. Spherical gold
D. Gold foll

438. Chemical tempering in porcelains is done to interrupt crack propagation by______________?

A. Transformation toughening
B. Dispersion of crystalline phase
C. Inducing residual compressive strength
D. All of the above

439. To prevent porosity in dental porcelain it should be backed________________?

A. Boric oxide
B. In vacuum
C. For long period
D. Under pressure

440. Pyroplastic flow of porcelain is due to___________________?

A. High temperature during glazing
B. Low temperature during glazing
C. Improper condensation
D. High firing temperature

 

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