Suck back porosity in the casting can be eliminated by________________?

Related Mcqs:

1. Suck back porosity is due to_________________?

   A. Attached impurities on undersurface of casting
   B. Hot spot
   C. No rapid cooling
   D. Inadequate melting temperature

2. In processing methyl methacrylate, the resin may show porosity if the flask is placed too soon porosity most likely occur_____________?

   A. Throughout the denture
   B. Near the borders
   C. In the thickest part
   D. On the denture surface

3. Impurities in casting is removed by________________?

   A. Annealing
   B. Degassing
   C. Pickling
   D. Conditioning

4. Back pressure porosity can be avoided by________________?

   A. Using asbestos linear
   B. Placing the sprue at least one quarter inch away form the end of casting ring
   C. Preventing rapid heating the investment in burnout oven
   D. Using a short and wide sprue

5. The effects associated with cold working can be eliminated by a heat treatment called______________?

   A. Age hardening heat treatment
   B. Annealing heat treatment
   C. Homogenization heat treatment
   D. Solution heat treatment

6. Addition of large amounts of platinum to a casting gold alloy will________________?

   A. Decrease its strength and ability to be hardened
   B. Decrease its tarnish resistance
   C. Increase its fusion temperature
   D. Redden the alloy

7. 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

8. 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

9. Air bubbles formed on the surface of casting is probably due to________________?

   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

10. Casting shrinkage is compensated by_______________?

    A. Thermal expansion
    B. Hygroscopic expansion
    C. Wax expansion
    D. All of the above