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.Management Sciences
Category: Impression Materials
Alginate impression material is similar to Agar-agar impression material in the following respect________________?
A. Gelation increase in both on increase in temperature
B. Mixing time is increased to reduce the setting time
C. Deformation during removal of impression occurs due to distortion of gel fibers
D. Both can be re-used for fresh impressions
Syneresis is associated with______________?
A. Hydrocolloids
B. Elastomers
C. Zinc oxide eugenol
D. Plaster of paris
Which of the following best describes the working time of impression material ?
A. After the start of appearing elastic properties of impression material
B. Just after the start of appearing elastic properties of impression material
C. The time for start of mixing till just before the start of appearing elastic properties of impression material
D. Loss of lusture of impression material
During setting of alginate impression materials________________?
A. Trisodium phosphate reacts with sodium alginate
B. Trisodium phosphate reacts with calcium sulphate
C. Colloidal changes to sol
D. Material in contact with soft tissues sets last
What is the minimum thickness of the elastomeric impression material for an accurate impression_______________?
A. 2 mm
B. 2-4 mm
C. Greater than 3 mm
D. Maximum in the area of operation
The best way to remove a hydrocolloid impression from the patient’s mouth is____________?
A. Slight rocking of the impression to disengage it from the undercut
B. Wetting the periphery of the impression with moist cotton to break the peripheral seal
C. Sudden jerking of the impression to prevent tearing
D. Supporting the impression along with the tray to prevent disengaging of the tray alone
Rough surface of elastomeric impression results from_______________?
A. Inadequate mixing
B. Air bubbles
C. Too rapid polymerization
D. Incomplete polymerization caused by premature removal from mouth
Type I and Type II zinc oxide impression paste differ with respect to_______________?
A. Their use
B. Their hardness after setting
C. Water content
D. Eugenol content
Trisodium phosphate in alginate acts are_______________?
A. Retarder
B. Reactor
C. Accelerator
D. Plasticizer
Palatal secretions affect the setting of all the impression materials except_______________?
A. Silicone
B. Agar-agar
C. Impression paste
D. Impression plaster
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