1131. Microbrasion involves the use of :
A. Sulphuric acid
B. Acetic acid
C. Phosphoric acid
D. Hydrochoric acid *
1132. Enamel etched by a tooth conditioner but not covered with a fissure sealant will :
A. Remineralize within a month
B. Remineralize within 3 months *
C. Absorb stain and discolor the tooth
D. Leave the tooth more susceptible to caries attack
1133. Over- trituration of silver alloy and mercury ?
A. Reduce contraction
B. Strengthens lathe-cut alloy more than spherical alloy amalgam, but weakens lathe-cut alloy *
C. Decrease creep
D. Gives a dull and crumbly amalgam mix
1134. Which of the following statements is true regarding lathe-cut silver alloy?
A. Requires least amount of mercury
B. Achieves lowest compressive strength at 1 hour *
C. Has tensile strenght , both at 15 minutes and > days is comparable to high copper
D. Has lower creep value
1135. Minimum depth of lesion to be visible on radiograph is ?
A. 40 um
B. 50 um
C. 100 um
D. 500 um *
1136. Which of the following material can be confused with caries ?
A. Amalgam
B. Gutta percha
C. Composite *
D. ZoE
1137. The optimum ratio of the lenght of the pin into amalgam to that of dentin should be :
A. 1:1 *
B. 2:1
C. 3:1
D. 4:1
1138. The cavosurface angle of amalgam cavity preparation should be :
A. Beveled
B. Rounded
C. Right angle *
D. None
1139. What is the disadvantage of using ” winged” rubber dam retainer ?
A. It doesn’t provide extra retention of rubber dam
B. It interference with the placement of matrix band *
C. They do not allow attachment of the dam to retainer
D. None of the above
1140. Diamond particle sizes of 125-150 mm is categorized as :
A. Fine
B. Coarse *
C. Very fine
D. Medium