A. Improper casting pressure
B. Improper heating of the investment
C. Improper angulation of sprue
D. Improper wetting of the wax pattern by the investment
Related Mcqs:
- The porosity formed due to simultaneous nucleation of solid grains and gas bubbles at the first moment that metal freezes at the mold walls is called__________?
A. Pinhole porosity
B. Gas inclusion porosity
C. Micro porosity
D. Subsurface porosity - Flux is used during casting to________________?
A. Remove the oxides formed on the gold alloy
B. Lower the melting point
C. Replace casting wax
D. Speed the burnout process - Asbestos liner is used in a casting ring to________________?
A. Facilitate venting of the mold
B. Retard the heating of the investment
C. Permit expansion of the world
D. All of the above - Resistance to corrosion in a cobalt-chrome casting is due to presence of_______________?
A. High quality iron
B. Chrome
C. Cobalt
D. Nickel - Glossy smooth margins of a casting are due to_____________?
A. Shrinkage of alloy on cooling
B. Investment breakdown
C. Incomplete wax elimination
D. Incomplete gas elimination - Fins and spines on the casting is seen due to_______________?
A. Prolonged heating:
B. Rapid heating me
C. Water film contamination
D. Too high pressure during casting - The wetting of an adherent surface by an adhesive is related to________________?
A. Surface energy of the adherent
B. Surface texture of the adherent
C. Surface tension of the adherent
D. Nature of the adherent that is crystalline or amorphous - Casting flux is used to_______________?
A. Prevent the oxidation of the metal during melting
B. increase the melting point of the flux
C. Flaring the point of the sprue attachment
D. None of the above - Modern dental noble metal casting alloys generally have equiaxed fine grain structures because of the incorporation of small amounts of______________?
A. Chromium
B. Indium
C. Irridium
D. Palladium - Which zone is the hottest and efficient burning zone of the flame used for casting ?
A. Oxidizing zone
B. Reducing zone
C. Combustion zone
D. None of the above
