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.Management Sciences
Category: Impression Materials
Which of the following is correct arrangement of impression material regarding linear contraction in ascending order ?
A. Addition silicone < polyether < polysulfide < condensation silicone
B. Addition silicone < polysulfide < Polyether < condensation silicone
C. condensation silicone < polyether < polysulfide < Addition silicone
D. condensation silicone < polysulfide < polyether < Addition silicone
Which material undergoes hysteresis ?
A. Irreversible hydrocolloid
B. Reversible hydrocolloid
C. Impression plaster
D. Metallic oxide paste
Minimum flow of Type-I impression compound at mouth temperature is___________________?
A. 4%
B. 6%
C. 8%
D. 10%
Rapid removal of rubber impression with a single firm motion results in____________________?
A. Reduced dimensional instability
B. Improved adhesion of the impression to the tray
C. Minimal permanent deformation
D. Reduced contamination by saliva
Before pouring an elastic impression it is washed with slurry of water and stone to______________?
A. Increase gel strength
B. Prevent syneresis
C. Prevent distortion
D. Wash off saliva on impression
Setting time of ZOE is best controlled by______________?
A. Adding a drop of eugenol
B. Adding a drop of water
C. Cooling the glass slab
D. Altering ratio of two pastes
Hysteresis in a hydrocolloid gel is______________?
A. Moisture absorption
B. Temperature lag between gelation and liquefaction temperature
C. Phenomenon of conversion of gel into sol
D. All of the above
Impression compound is characterized by all of the following except_______________?
A. Warps at room temperature
B. Is a thermoset material
C. Shows increased flow when kneaded with water
D. Low coefficient of thermal conductivity
Dimensional stability of hydrocolloid impressions may be achieved by_________________?
A. Using less water powder ratio
B. Storing the impression under water
C. Prolonged manipulation
D. Using humidor
Elastomers except: Polyether are_______________?
A. Hydrophilic
B. Hydrophobic
C. Water loving impression materials
D. Potassium alginates
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