241. The base constituents of dental waxes come from three main sources except______________?

A. Animal
B. Mineral
C. Insect
D. Vegetable

242. The standard perforated tray for us with alginate impression materials may be brought to more customized contour by_______________?

A. Utility wax
B. Base plate wax
C. Beading wax
D. Boxing wax

243. 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

244. Function of carnauba wax_________________?

A. To provide a smooth and glossy surface
B. Increase toughness
C. Decrease toughness
D. Decrease flow at room temperature

245. Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______________?

A. Platinum
B. Copper
C. Silver
D. Gold

246. Softening heat treatment of alloy increases_________________?

A. Tensile strength
B. Proportional limit
C. Ductility
D. Hardness

247. The function of a sprue is to_______________?

A. Form an opening of molten metal to enter the mold
B. Help polish cast restorations
C. Eliminate air bubbles on the wax pattern
D. Reproduce fine detail

248. Stabilization of stainless steel is achieved by adding____________?

A. Carbon
B. Chromium
C. Nickel
D. Titanium

249. The yield strength of AUstenite (NiTi alloy) is______________?

A. 100 Mpa
B. 240 Mpa
C. 560 Mpa
D. 700 Mpa

250. A highly polished surface on a metallic dental restoration aids considerably in the prevention of the____________?

A. Dimensional change
B. Thermal conductivity
C. Warpage
D. Tarnish and corrosion

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