A. High temperature during glazing
B. Low temperature during glazing
C. Improper condensation
D. High firing temperature
Related Mcqs:
- For porcelain fused to metal crown, the porcelain should have ______________?
A. High fusion expansion
B. High fusion temperature
C. Linear coefficient of thermal expansion less than that of metal
D. Linear coefficient of thermal expansion more than that of metal - 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 - Porosity in porcelain at condensation stage depends on_________________?
A. Shape and size of particle
B. Uniform distribution of particle size
C. Number of particles
D. None of the above - In porcelain metal elements are embedded in the matrix of________________?
A. Rubber matrix
B. Glass
C. Plastic
D. Resin matrix - Phenomenon in which porcelain appears different under varying light condition is______________?
A. Translucency
B. Refractive optics
C. Metamerism
D. Opacification - Porcelain binds to metal in PFM crown by_________________?
A. Metallic bind
B. Transparency
C. Chemical bond
D. B and C - Chemical method of strengthening porcelain involves_________________?
A. Exchange of aluminium and sodium ions
B. Exchange of aluminium and potassium ions
C. Exchange of sodium and potassium ions
D. None of the above - When porcelain is basked against metal, it should possess a________________?
A. high fusion expansion
B. high fusion temperature
C. linear coefficient of thermal expansion less than but close to that of metal
D. Linear coefficient of thermal expansion greater than, but close to that of the metal - Condensation shrinkage of porcelain during firing depends on__________________?
A. Rate of arriving at firing temperature
B. Uniformity of particle size
C. Shape and size of particle
D. Type of investment used - To prevent porosity in dental porcelain it should be backed________________?
A. Boric oxide
B. In vacuum
C. For long period
D. Under pressure
