341. Which of the following is correct regarding chemical setting of condensation silicone_______________?

A. Polymerization occurs with repeated elimination of small molecules
B. Polymerization occurs with elimination of single byproduct
C. By condensation of repeated molecules of monomers
D. Condensation does not occur at all

342. 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

343. To make the vinyl Polysiloxane hydrophilic the following is added_______________?

A. Mineral oil
B. Surfactant
C. Water
D. Plasticizer

344. The role of magnesium chloride in zinc oxide eugenol impression paste_________________?

A. Retarder
B. Modifier
C. Plasticier
D. Accelerator

345. Alginates are made dust free by adding______________?

A. Glycol
B. Glyecrol
C. Glutamic acid
D. alcohol

346. The process of changing the rubber base product or liquid polymer, to a rubber like material is generally known as_____________?

A. Boiling
B. Condensation
C. Vulconization
D. Chain lengthening

347. Which of the following is not true about elastomeric impression ?

A. Single mix material have higher viscosity
B. Shear thinning is related to viscosity of non phase impression material
C. Improper mixing of material can cause permanent deformation of impression
D. Putty – wash technique of impression reduces dimensional change of setting

348. 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

349. 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

350. Which of the following impression material is rigid ?

A. Zinc oxide-eugenol
B. Reversible hydrocolloid
C. Alginate
D. Polysulphide rubber

 

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