A. They evolve hydrogen when cast if they are not fully cured
B. They exhibit a very low setting shrinkage
C. They have a lower tear resistance than polysulphide rubbers
D. They set by condensation polymerisation
Related Mcqs:
- 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 - Best impression material to be used for securing impression after crown preparation_______________?
A. Alginate
B. Agar
C. Elastome
D. Zno paste - 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 - 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 - Which of the following impression materials is easy to pour and difficult to remove the stone cast from the impression ?
A. Addition polysilicone
B. Condensation polysilicone
C. Polyether
D. Polysulfide - 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 - Palatal secretions affect the setting of all the impression materials except_______________?
A. Silicone
B. Agar-agar
C. Impression paste
D. Impression plaster - Agar impression materials differ from alginate impression materials in that the former sets by_______________?
A. Mechanical action of saliva
B. Physical change
C. Evolution
D. Chemical change - 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 - All of the following statements about an alginate impression are EXCEPT________________?
A. It should be rapidly displaced from the mouth
B. It may exhibit fluid exudates on the surface as a result of imbibition of water
C. It will take up water and expand if kept wet
D. It will shrink as a result of syneresis
