441. 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
442. Porcelain is best fired__________________?
A. In open air
B. Under air compression
C. When several layer are fired simultaneously
D. Under minimum pressure
443. Porosity in porcelain can be prevented by_______________?
A. Thoroughness of condensation
B. Rapidity of firing
C. High firing temperature
D. All of the above
444. Which of the following is the main constituent of porcelain__________________?
445. The best tissue tolerated material for crown and bridge_______________?
A. Highly polished porcelain
B. Highly polished acrylic
C. Highly glazed porcelain
D. Highly polished metal
446. Dental porcelains are crystalline materials of________________?
C. Organic substances
447. The main purpose of adding metallic oxides in ceramic is________________?
A. Colour matching
D. None of the above
448. 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
449. Stage recognized in the firing of dental porcelain given below. Which of state is not correct ?
A. Cold stage bisque
B. Low bisque
C. Medium bisque
D. High bisque
450. The maximum shrinkage during firing proces in ceramic occurs in__________________?
A. High Bisque stage
B. Low Bisque stage
C. Medium Bisque stage
D. Fusion stage