Question 1

The _____ is used to polish or trim custom trays,provisional coverage,dentures,and indirect restorations.

Accepted Answer

A)  sandblaster
B)  model trimmer
C)  vacuum former
D)  dental lathe

Question 2

A light gauge of vacuum-formed resin material is used for:

Accepted Answer

A)  bleaching trays.
B)  provisional coverage.
C)  impression tray.
D)  both a and b.

Question 3

Safety precautions in the laboratory include all except:

Accepted Answer

A)  PPE should be worn while working in the laboratory.
B)  manufacturer's instructions should be followed for equipment operation.
C)  this is the appropriate place for eating and drinking in the dental office.
D)  the work areas should be kept clean before and after procedures.

Question 4

When mixing gypsum,it is important to use the correct amount of water and powder.If additional powder is added after mixing has begun,the mix will be:

Accepted Answer

A)  stronger.
B)  weaker.
C)  unaffected.
D)  none of the above.

Question 5

Which of the following gypsum products has the highest powder-to-water ratio?

Accepted Answer

A)  Model plaster
B)  Dental stone
C)  High-strength stone
D)  All gypsum products have the same powder-to-water ratio.

Question 6

When pouring an impression,the plaster should not be placed:

Accepted Answer

A)  in small increments.
B)  in large amounts.
C)  to the same place.
D)  in a continuous flow.

Question 7

A dental assistant should wait _____ minutes before removing a model from an impression.

Accepted Answer

A)  10
B)  15
C)  30
D)  45 to 60

Question 8

A custom impression tray should fit and adapt well to the model and should maintain ____ mm of impression material between itself and the teeth.

Accepted Answer

A)  1 to 2
B)  2 to 3
C)  3 to 4
D)  5 to 6

Question 9

The type of resin that is formed into a diagnostic model using heat and a vacuum is:

Accepted Answer

A)  self-cured.
B)  light-cured.
C)  thermoplastic.
D)  auto-cured.

Question 10

The _________ is the measurement of where the teeth are positioned when the joints are aligned correctly and before the teeth actually come together.

Accepted Answer

A)  bite record
B)  articulator
C)  centric relation
D)  both a and c

Question 11

Type _____ baseplate wax is a softer wax used for denture construction.

Accepted Answer

A)  I
B)  II
C)  III A

Question 12

A plaster mix should not be:

Accepted Answer

A)  completed in 2 minutes.
B)  pressed lightly on the vibrator.
C)  completed in 30 seconds.
D)  mixed slowly. C

Question 13

Light-cured resin tray material should be cured:

Accepted Answer

A)  for 10 minutes.
B)  off the model.
C)  for 2 minutes.
D)  without the spacer.

Question 14

Water should be running through a model trimmer:

Accepted Answer

A)  never.
B)  at all times when trimming.
C)  after trimming.
D)  before trimming only.

Question 15

Air bubbles in a stone cast are caused by:

Accepted Answer

A)  using a vibrator.
B)  adding stone in small increments.
C)  impression material that is too thick.
D)  improper pouring of the impression.

Question 16

The first step in making a custom tray is to:

Accepted Answer

A)  prepare the resin.
B)  make a spacer.
C)  prepare a diagnostic model.
D)  place blockout material. C

Question 17

________ wax is pre-formed with a thin sheet of aluminum foil between the layers.

Accepted Answer

A)  Sticky
B)  Inlay casting
C)  Baseplate
D)  Bite registration

Question 18

When positioning the bite-fork in the patient's mouth during a face-bow registration,the patient should bite:

Accepted Answer

A)  quickly.
B)  firmly.
C)  slowly.
D)  and slide.

Question 19

Infection control in the dental laboratory is:

Accepted Answer

A)  as important as it is when you are with a patient.
B)  not as critical as it is when you are with a patient.
C)  not a consideration because impressions are disinfected before entering the dental laboratory.
D)  all of the above.

Question 20

The powder-to-water ratio for high-strength stone is ___:100.

Accepted Answer

A)  45
B)  30
C)  19
D)  12

Exam 47: Laboratory Materials and Procedures

The _____ is used to polish or trim custom trays,provisional coverage,dentures,and indirect restorations.

Correct AnswerverifiedShow Answer

A light gauge of vacuum-formed resin material is used for:

Correct AnswerverifiedShow Answer

Safety precautions in the laboratory include all except:

Correct AnswerverifiedShow Answer

When mixing gypsum,it is important to use the correct amount of water and powder.If additional powder is added after mixing has begun,the mix will be:

Correct AnswerverifiedShow Answer

Which of the following gypsum products has the highest powder-to-water ratio?

Correct AnswerverifiedShow Answer

When pouring an impression,the plaster should not be placed:

Correct AnswerverifiedShow Answer

A dental assistant should wait _____ minutes before removing a model from an impression.

Correct AnswerverifiedShow Answer

A custom impression tray should fit and adapt well to the model and should maintain ____ mm of impression material between itself and the teeth.

Correct AnswerverifiedShow Answer

The type of resin that is formed into a diagnostic model using heat and a vacuum is:

Correct AnswerverifiedShow Answer

The _________ is the measurement of where the teeth are positioned when the joints are aligned correctly and before the teeth actually come together.

Correct AnswerverifiedShow Answer

Type _____ baseplate wax is a softer wax used for denture construction.

Correct AnswerverifiedA

A plaster mix should not be:

Correct AnswerverifiedC

Light-cured resin tray material should be cured:

Correct AnswerverifiedShow Answer

Water should be running through a model trimmer:

Correct AnswerverifiedShow Answer

Air bubbles in a stone cast are caused by:

Correct AnswerverifiedShow Answer

The first step in making a custom tray is to:

Correct AnswerverifiedC

________ wax is pre-formed with a thin sheet of aluminum foil between the layers.

Correct AnswerverifiedShow Answer

When positioning the bite-fork in the patient's mouth during a face-bow registration,the patient should bite:

Correct AnswerverifiedShow Answer

Infection control in the dental laboratory is:

Correct AnswerverifiedShow Answer

The powder-to-water ratio for high-strength stone is ___:100.

Correct AnswerverifiedShow Answer

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