Question 1

Why is it important to use vinyl gloves or bare hands to mix polyvinyl putty materials?

Accepted Answer

A)   Many patients are allergic to latex.
B)   Latex gloves retard the setting of the material.
C)   Latex gloves accelerate the setting of the material.
D)   A and C are correct.
E)   A and B are correct.F) A) and E)
G) B) and E)

Question 2

The ANSI-ADA specification requires no more than ____% permanent deformation when an alginate is compressed 20% for 5 seconds.

Accepted Answer

A)   2
B)   5
C)   25
D)   50
E)   95F) A) and D)
G) C) and D) B

Question 3

Higher rates of alginate deformation result in higher compressive and tear strengths. Alginate impressions are more likely to tear during removal from the mouth when they are removed rapidly.

Accepted Answer

A)   Statement 1 is correct; statement 2 is correct.
B)   Statement 1 is correct; statement 2 is incorrect.
C)   Statement 1 is incorrect; statement 2 is correct.
D)   Statement 1 is incorrect; statement 2 is incorrect.E) A) and C)
F) A) and D)

Question 4

Alginate impression material may be referred to as which type of material?

Accepted Answer

A)   Polyether
B)   Addition silicone
C)   Condensation silicone
D)   Irreversible hydrocolloid
E)   Reversible hydrocolloidF) A) and B)
G) A) and C) D

Question 5

What is an advantage of using an elastomeric impression material over an irreversible hydrocolloid?

Accepted Answer

A)   Less expensive
B)   Reversible process
C)   Greater dimensional accuracy
D)   Best material for study modelsE) All of the above
F) None of the above

Question 6

What is an accepted method for modifying an impression tray?

Accepted Answer

A)   Heating the tray to alter the configuration
B)   Applying rope wax to the flanges
C)   Adding compound to the edges
D)   None of the aboveE) None of the above
F) All of the above

Question 7

Alginate should be mixed by adding powder to water. Alginate should be mixed with a narrow, pliable spatula.

Accepted Answer

A)   Statement 1 is correct; statement 2 is correct.
B)   Statement 1 is correct; statement 2 is incorrect.
C)   Statement 1 is incorrect; statement 2 is correct.
D)   Statement 1 is incorrect; statement 2 is incorrect.E) All of the above
F) A) and C)

Question 8

Which solutions are used to disinfect an impression?

Accepted Answer

A)   Alcohol
B)   Iodophor
C)   Sodium hypochlorite
D)   All of the above
E)   Only B and CF) A) and D)
G) A) and E)

Question 9

The dimensional change of polyethers is higher than that of the addition silicones. The polyether absorbs water and changes dimensions if stored in contact with water until equilibrium is reached.

Accepted Answer

A)   Statement 1 is correct; statement 2 is correct.
B)   Statement 1 is correct; statement 2 is incorrect.
C)   Statement 1 is incorrect; statement 2 is correct.
D)   Statement 1 is incorrect; statement 2 is incorrect.E) A) and D)
F) A) and C)

Question 10

At final seating, the incisal edges and cuspal tips should be ________ the surface of the tray.

Accepted Answer

A)   contacting
B)   about 1 to 2 mm from
C)   about 3 to 4 mm from
D)   at least 6 mm fromE) C) and D)
F) A) and B) B

Question 11

Sodium phosphate acts as a(n)  ________ during the setting reaction of alginate hydrocolloid.

Accepted Answer

A)   initiator
B)   retarder
C)   sweetener
D)   accelerator
E)   disinfectantF) All of the above
G) B) and C)

Question 12

When is alginate hydrocolloid recommended?

Accepted Answer

A)   Preparation of study models
B)   Impressions of cavity preparations
C)   In the preparation of athletic mouth protectors
D)   For A, B, and C
E)   For A and CF) A) and D)
G) A) and E)

Question 13

Alginates, when properly mixed by hand, should develop a _________ consistency free of __________ in less than 1 minute for the normal set material and should be suitable for making impressions in the mouth.

Accepted Answer

A)   thixotropic; bubbles
B)   thixotropic; graininess
C)   smooth and creamy; bubbles
D)   smooth and creamy; graininessE) A) and B)
F) A) and C)

Question 14

Which of the following are correct regarding silicone putties?

Accepted Answer

A)   May be mixed with bare hands
B)   Should not be mixed with bare hands
C)   Should not be mixed when latex rubber gloves are worn
D)   A and C
E)   B and CF) A) and B)
G) A) and C)

Question 15

How should a maxillary impression tray fit?

Accepted Answer

A)   Leave a 2-mm border around the alveolar process
B)   Cover the distal of the most posterior tooth.
C)   Include the maxillary tuberosity.
D)   Extend past the mucobuccal fold.E) A) and C)
F) B) and C)

Question 16

Which of the following factors limit the accuracy of wax bite registrations?

Accepted Answer

A)   Distortion on removal
B)   Release of internal stress on storage
C)   Minimal dimensional changes from mouth to room temperature
D)   A, B, and C
E)   A and BF) A) and B)
G) A) and C)

Question 17

What is the best method for delaying the setting of alginate?

Accepted Answer

A)   Increase the water temperature.
B)   Reduce the water temperature.
C)   Use a thinner mix of alginate.
D)   Use a thicker mix of alginate.E) A) and B)
F) None of the above

Question 18

What is/are the advantage(s)  of using premeasured packets of alginate impression material?

Accepted Answer

A)   Impervious to moisture
B)   Less expensive than cans
C)   Premeasured for a full arch
D)   All of the above
E)   Only A and CF) A) and E)
G) B) and C)

Question 19

Measurement of dimensional changes showed that immersion of alginate impressions for _________ did not affect their clinical accuracy.

Accepted Answer

A)   10 minutes
B)   30 minutes
C)   1 hour
D)   5 days
E)   2 weeksF) B) and C)
G) None of the above

Question 20

Which of the following ingredients of alginate hydrocolloid reacts with dissolved alginate to form insoluble calcium alginate?

Accepted Answer

A)   Calcium sulfate
B)   Potassium sulfate
C)   Sodium phosphate
D)   Sodium or potassium alginate saltE) A) and C)
F) C) and D)

Exam 8: Impression Materials

Why is it important to use vinyl gloves or bare hands to mix polyvinyl putty materials?

Correct AnswerverifiedShow Answer

The ANSI-ADA specification requires no more than ____% permanent deformation when an alginate is compressed 20% for 5 seconds.

Correct AnswerverifiedB

Higher rates of alginate deformation result in higher compressive and tear strengths. Alginate impressions are more likely to tear during removal from the mouth when they are removed rapidly.

Correct AnswerverifiedShow Answer

Alginate impression material may be referred to as which type of material?

Correct AnswerverifiedD

What is an advantage of using an elastomeric impression material over an irreversible hydrocolloid?

Correct AnswerverifiedShow Answer

What is an accepted method for modifying an impression tray?

Correct AnswerverifiedShow Answer

Alginate should be mixed by adding powder to water. Alginate should be mixed with a narrow, pliable spatula.

Correct AnswerverifiedShow Answer

Which solutions are used to disinfect an impression?

Correct AnswerverifiedShow Answer

The dimensional change of polyethers is higher than that of the addition silicones. The polyether absorbs water and changes dimensions if stored in contact with water until equilibrium is reached.

Correct AnswerverifiedShow Answer

At final seating, the incisal edges and cuspal tips should be ________ the surface of the tray.

Correct AnswerverifiedB

Sodium phosphate acts as a(n) ________ during the setting reaction of alginate hydrocolloid.

Correct AnswerverifiedShow Answer

When is alginate hydrocolloid recommended?

Correct AnswerverifiedShow Answer

Alginates, when properly mixed by hand, should develop a _________ consistency free of __________ in less than 1 minute for the normal set material and should be suitable for making impressions in the mouth.

Correct AnswerverifiedShow Answer

Which of the following are correct regarding silicone putties?

Correct AnswerverifiedShow Answer

How should a maxillary impression tray fit?

Correct AnswerverifiedShow Answer

Which of the following factors limit the accuracy of wax bite registrations?

Correct AnswerverifiedShow Answer

What is the best method for delaying the setting of alginate?

Correct AnswerverifiedShow Answer

What is/are the advantage(s) of using premeasured packets of alginate impression material?

Correct AnswerverifiedShow Answer

Measurement of dimensional changes showed that immersion of alginate impressions for _________ did not affect their clinical accuracy.

Correct AnswerverifiedShow Answer

Which of the following ingredients of alginate hydrocolloid reacts with dissolved alginate to form insoluble calcium alginate?

Correct AnswerverifiedShow Answer

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B

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D

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B

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Alginates, when properly mixed by hand, should develop a _ consistency free of __ in less than 1 minute for the normal set material and should be suitable for making impressions in the mouth.

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