301. The cross linking agent of polysulphide rubber base impression material is______________?

A. Aromatic sulfonate esters
B. Stannous octate
C. Platinum salt catalyst
D. Lead dioxide

302. When making a polysulphide impression for a caste crown, custom trays are usually preferred over stock trays for all of the following reasons except_______________?

A. Custom trays facilitate uniform contraction of impression material
B. Custom trays require less impression material
C. Stock trays may be short in the flange area
D. Impressions made n the custom trays are easier to remove from the mouth

303. Name the accelerator used in Zinc oxide eugenol paste______________?

A. Olive oil
B. Linseed oil
C. Zinc acetate
D. All of these

304. Linear contraction of elostomeric impression with passage of time is highest in______________?

A. Addition silicone
B. Polysulphide
C. Polyetner
D. Condensation silicone

305. Which of the following is true about Agar hydrocolloid impression material ?

A. Liquefies between 71 – 100°C
B. Solidfies between 50 – 70°C
C. Facilitates fabrication of metal dyes
D. Cannot register fine surface details

306. Which one of the following increase the strength and reduce viscosity of agar hydrocolloid impression material_____________?

A. Borax
B. Water
C. Sulfates
D. Carbonates

307. The water powder ratio of alginate is______________?

A. 100 ml of water to 60 gms of powder
B. 40 ml of water to 40 gms of powder
C. 40 ml of water to 15 gms of powder
D. 15 ml of water to 40 gms of powder

308. Best impression material to be used for securing impression after crown preparation_______________?

A. Alginate
B. Agar
C. Elastome
D. Zno paste

309. Which of the following is correct glass transition temperature of Impression compound ?

A. 43.5°C
B. 39°C
C. 65°C
D. 100°C

310. Rough and irregular surface produced on the impression is because of_______________?

A. Air incorporated during mixing
B. Improper application of pressure during impression making
C. Presence of excessive saliva in impression area
D. Due to improper ratio of polymer and monomer


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