Deck 46: Impression Materials

Question 1

What are preliminary impressions used to make?

A)Diagnostic models
B)Provisional coverage
C)Orthodontic appliances
D)All of the above

Answer 1

All of the above

Question 2

Alginate impressions must be poured within _____ so that distortion does not occur.

A)5 minutes
B)30 minutes
C)1 hour
D)24 hours

Answer 2

1 hour

Question 3

An impression is a positive reproduction of teeth and surrounding oral tissues.The model created from the impression is a negative reproduction of the structures.

A)Both statements are correct.
B)Neither statement is correct.
C)The first statement is correct; the second statement is incorrect.
D)The first statement is incorrect; the second statement is correct.

Answer 3

Neither statement is correct.

Question 4

How can length or depth of the alginate impression tray borders be extended?

A)Utility wax
B)Acrylic
C)Boxing wax
D)Border molding compound

Question 5

Which of the following is an acceptable method for altering the setting time of alginate irreversible hydrocolloid impression material?

A)Increase or decrease the water-to-powder ratio.
B)Change the water temperature.
C)Add a colloidal material to the alginate.
D)Use potassium chloride as an accelerator.

Question 6

What term is used when an alginate impression takes up water either from soaking or wrapping in a wet paper towel?

A)Syneresis
B)Imbibition
C)Tempering
D)Viscosity

Question 7

Which type of impression tray covers only half of a dental arch?

A)Full-arch
B)Section
C)Quadrant
D)Custom

Question 8

Which impression material is used when an extremely accurate final impression is essential?

A)Elastomeric
B)Alginate
C)Reversible hydrocolloid
D)Light-cured

Question 9

Which irreversible hydrocolloid material is used most widely for preliminary impressions?

A)Light-bodied
B)Alginate
C)Polysulfide
D)Polyether

Question 10

Which statement is correct regarding custom impression trays?

A)They are made from a preliminary model after the dentist has prepared the teeth.
B)They can be constructed from resin.
C)They are available only as full-arch trays.
D)They do not require adhesive if they are smooth surface.

Question 11

Which of the following is not considered a classification of impression materials?

A)Preliminary
B)Final
C)Temporary
D)Occlusal

Question 12

Legally,who can take final impressions?

A)Dentist
B)Dental hygienist
C)Dental assistant
D)Laboratory technician

Question 13

Which type of impression is taken to produce a reproduction of the occlusal relationship of the maxilla and mandible teeth when in centric occlusion?

A)Final
B)Preliminary
C)Bite registration
D)Articulated

Question 14

Which type of elastomeric material has the highest viscosity?

A)Light-bodied
B)Regular-bodied
C)Heavy-bodied
D)Putty

Question 15

Why would a dentist request preliminary impressions?

A)To fabricate custom trays
B)To create a working model for indirect restoration
C)To wax up for partial or full dentures
D)To construct implant crowns

Question 16

An impression tray should be sufficiently deep to allow _____ mm of material between the tray and the incisal or occlusal edges of the teeth.

A)0.5 to 1
B)2 to 3
C)4 to 5
D)6 to 7

Question 17

What are the three classifications of impressions used in dentistry?

A)Prospective, retrospective, and introspective
B)Preliminary, functional, and occlusal, or bite, registration
C)Preliminary, final, and occlusal, or bite, registration
D)Diagnostic, functional, and determinative

Question 18

Which material is the most durable for occlusal bite registrations?

A)Softened baseplate wax
B)Polysiloxane
C)Zinc oxide-eugenol (ZOE)
D)Polyether impression material

Question 19

Which of the following is not true regarding an automix system?

A)Elastomeric impression materials are automatically mixed and dispensed via an extruder.
B)The unit can be used with light-bodied material only.
C)It provides appropriate amount of material without waste.
D)Both b and C

Question 20

Which of the four types of elastomeric materials has the best dimensional stability?

A)Polysulfide
B)Polyether
C)Condensation silicone
D)Polysiloxane

Question 21

What percent relative humidity is preferred for storing impressions?

A)10
B)35
C)70
D)100

Question 22

The retromolar area,lingual frenum,tongue space,and mylohyoid ridge are reproduced in a mandibular impression.The median raphe,palate,and incisive papilla are reproduced in a maxillary impression.

A)Both statements are correct.
B)Neither statement is correct.
C)The first statement is correct; the second statement is incorrect.
D)The first statement is incorrect; the second statement is correct.

Question 23

Which factor should be examined when evaluating the quality of an impression?

A)The presence of the retromolar area and maxillary tuberosity are recorded.
B)Anatomical detail is sharp and not distorted.
C)Surfaces are free from voids.
D)All of the above are factors.

Question 24

What position should the EFDA use while taking mandibular and maxillary impressions?

A)Upright
B)Operator
C)Supine
D)Assisting

Question 25

What can be done to alleviate the gag reflex when taking alginate impressions?

A)Use fast-set alginate, because it allows the impression tray to be removed from the mouth much sooner than if using normal set alginate.
B)Do not overload the posterior regions of the trays.
C)Have the patient take deep breaths through the nose.
D)All of the above can be done.

Question 26

What does the term syneresis mean as it relates to alginate impression?

A)Water evaporates from the impression.
B)The mix changes colors.
C)Excess moisture is absorbed by the impression.
D)The mixing time is increased.

Question 27

How is an alginate impression disinfected?

A)Spray the alginate with glutaraldehyde.
B)Submerse it in disinfecting solution overnight.
C)Wet it with isopropyl alcohol.
D)Spray the alginate with an intermediate-level disinfectant.

Question 28

Why must impression trays be rigid?

A)Support the material in the patient's mouth.
B)Warp the completed impression.
C)Both a and b are correct.
D)Neither are correct.

Question 29

What is the purpose of the potassium alginate in impression alginate?

A)It slows set time.
B)It adds bulk to the material.
C)It accelerates set time.
D)It thickens the material.

Question 30

How should alginate material be loaded into a maxillary impression tray?

A)Heavier in the anterior and labial areas
B)Heavier in the palatal area
C)Evenly in the tray
D)Heavier toward the posterior

Question 31

Which statement is true regarding alginate impression material?

A)It changes color as it sets.
B)It can be normal set or fast set.
C)It can be supplied with flavoring.
D)All of the above are possible traits.

Question 32

What are the three curing stages of impression materials?

A)First impression, setting phase, final impression
B)Initial set, final set, final cure
C)Initial impression, curing stage, final impression
D)First set, curing set, final set

Question 33

Which material is commonly used when taking a bite registration?

A)Alginate
B)Polysiloxane
C)Polysulfide
D)None of the above

Question 34

How are alginate impressions removed from the mouth?

A)Use a gentle rocking movement.
B)Use one quick, snap-out motion.
C)Twist the tray sideways.
D)Use a vigorous back-and-forth action.

Question 35

Which portion of the maxillary impression tray should be seated in the mouth first?

A)Anterior
B)Posterior
C)Right side
D)Left side

Question 36

Why would utility wax be placed on a maxillary impression tray?

A)Maximize anatomic coverage of the posterior teeth.
B)Modify the trays to accommodate a high palate.
C)Permanently alter the impression tray.
D)Both a and b are correct
E)All of the above are correct.

Question 37

Which instructions would be given to a patient obtaining a bite registration?

A)Bite with the posterior teeth first.
B)Close normally and gently.
C)Occlude with lateral movements.
D)Bite with the anterior teeth first.

Question 38

Alginate material that is not setting or setting too rapidly can be the result of which factor?

A)Expired shelf life
B)Humidity
C)Improper storage
D)All of the above

Question 39

How will a water temperature of 80° F (26.6° C)affect an alginate mix?

A)It will make the mix set faster.
B)It will not change the setting time.
C)It will make the mix set slower.
D)It will render the mix useless.

Question 40

Which listed criteria would not be acceptable on an alginate impression?

A)Free of voids, air bubbles, and tears
B)Anatomic areas clearly defined
C)Peripheral borders clearly defined
D)Void of frena and tuberosities

Question 41

Which statement is an advantage of an Automix unit system for impressions?

A)No mixing saves materials.
B)It increases productivity.
C)Less time is spent on infection control.
D)All of these are advantages.

Question 42

Elastomeric materials use an Automix system.The extruder gun insert is either catalyst or base.

A)Both statements are correct.
B)Neither statement is correct.
C)The first statement is correct; the second statement is incorrect.
D)The first statement is incorrect; the second statement is correct.

Question 43

How is the impression tray prepared for an elastomeric impression?

A)Stops placed
B)Spacers placed
C)Coated with adhesive
D)Treated with lubricant

Question 44

Which of the following is not correct regarding reversible hydrocolloids?

A)Plastic stops are used during the impression.
B)The impression procedure requires the use of three conditioning baths for the material.
C)The material is 85% agar and 15% water.
D)Either tray or syringe material can be used for the impression.

Question 45

What type of impression tray is required with reversible hydrocolloid impressions?

A)Perforated
B)Disposable
C)Water-cooled
D)Plastic

Question 46

Which type of reversible hydrocolloid material is the most viscous?

A)Syringe
B)Plate
C)Tempered
D)Tray

Question 47

Although technique may vary,when assisting a dentist in taking an elastomeric impression,mix the light-bodied material first.

Question 48

Which material should be used if a more durable impression material is needed for bite registration?

A)Polysulfide
B)Zinc oxide-eugenol
C)Polysiloxane
D)Reversible hydrocolloid

Question 49

Which material is one of the most popular impression materials used for bite registration?

A)Polysulfide
B)Zinc oxide-eugenol
C)Polysiloxane
D)Reversible hydrocolloid