461. Which of the following releases single wavelength of energy ?
D. Argon lasers
462. The melting point of titanium is __________ degree celsius?
463. Electrolyte used for plating copper dies is________________?
A. Ionic copper
B. Copper cyanide
C. Silver cyanide
D. Acidic copper sulphate
464. Greening occuring when porcelains are fired on silver free alloys may be attributed to________________?
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
465. Compared with dental alloys, CERAMICS show____________________?
A. High ductility
B. High hardness
C. Low esthetic value
D. Susceptibility to brittle fracture
466. 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
467. The first porcelain tooth material was introduced by______________?
468. Which of the following bur is used in the preparation of cavity restored with porcelain fused to metal ?
A. Carbide bur
B. Diamond bur
C. Stainless steel bur
D. Diamond but for porcelain and carbide bur for metal
469. Quartz is Dental porcelain is______________?
D. Crack minimzer
470. In method of firing: A shorter firing period at a higher temperature is considered better_______________?
A. A large time period at a lower temperature is preferred
B. A long firing period at a very high temperature is preferred
C. A short firing period at a very low temperature is preferred
D. none of these
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