A. Vaporization of silver from the walls of contaminated furnaces
B. Surface diffusion of silver from the marginal metal
C. More rapid silver diffusion in sodium containing glass
D. Silver ionization by porcelains with high oxygen potential
Related Mcqs:
- The castability of chromium-cobait base metal alloys when compared to gold based noble metal alloys is_______________?
A. More
B. Less
C. Equal
D. Depends on the alloy type - Dental porcelains are crystalline materials of________________?
A. Rubber
B. Plastic
C. Organic substances
D. Glass - 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 - 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 - A type of immediately occuring reaction in which antigens combine with antibodies already attached to the surface of mast cells and basophils is called_____________?
A. Type I hypersensitivity
B. Type II hypersensitivity
C. Type III hypersensitivity
D. Type IV hypersensitivity - Ceramics fired to metals are processed by_______________?
A. Heat pressing
B. Machining
C. Sintering
D. Slip casting - Compared with dental alloys, CERAMICS show____________________?
A. High ductility
B. High hardness
C. Low esthetic value
D. Susceptibility to brittle fracture - Coefficient of thermal expansion of metal-ceramic alloys is________________?
A. Same as porcelain
B. More than porcelain
C. Less than porcelain
D. More than or equal to porcelain but not less - Cobalt-Chrominum alloys contains_______________?
A. 30% cobalt and 60% chrominum
B. 60% cobalt and 30% chrominum
C. 1% palladium
D. 20% gold - Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______________?
A. Platinum
B. Copper
C. Silver
D. Gold
