651. Wash or corrective impression is done by______________?
A. Alginate
B. Impression paste
C. Impression plaster
D. Rubber base impression material

652. The plasticizers used in polyether impression material is_______________?
A. Colloidal silica
B. polyether polymer
C. Glycol ether
D. Di-vinyl poly (dimethyl siloxane)

653. In reversible hydrocolloid the property by which the transformation from sol to gel and gel to sol is a function of the_____________?
A. Concentration of potassium sulphate
B. Percentage composition by weight of water
C. Concentration of filler and plasticizer
D. Temperature

654. Alginates are_____________?
A. Gel
B. Sol
C. Hydrocolloid
D. Colloid

655. Syneresis is associated with______________?
A. Hydrocolloids
B. Zinc oxide eugenol
C. Elastomers
D. Plaster of paris

656. The advantage of ZOE impression paste_______________?
A. Has dimensional stability
B. Is easy manipulation
C. Does not adhere to tissues
D. Does not require special trays

657. Rinsing of the impression is important to________________?
A. Hydrate the impression
B. Remove saliva
C. Remove excess impression material
D. Accelerate the setting

658. Which is best material for RPD impression_______________?
A. Reversible hydroollioid
B. Irreversible hydrocolloid
C. Impression plaster
D. None of the above

659. Which of the following is not affected by saliva ?
A. Impression paste
B. Impression plaster
C. Silicon impression material
D. None of the above

660. Retarder in Zinc oxide eugenol is______________?
A. Zinc acetate
B. CaCl2
C. Alcohol
D. Glycerine