Deck 46: Impression Materials

Question 1

A _____ tray covers half of a dental arch.

A)full-arch
B)section
C)quadrant
D)custom

Answer 1

quadrant

Question 2

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
B)2 to 3
C)6 to 8
D)10 to 12

Answer 2

2 to 3

Question 3

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

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

Answer 3

Temporary

Question 4

The length or depth of the alginate impression tray borders can be extended by adding _____ to the tray.

A)utility wax
B)acrylic
C)boxing wax
D)border molding compound

Question 5

Custom impression trays:

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

Question 6

A preliminary impression would be used for:

A)custom trays.
B)indirect restorations.
C)partial or full dentures.
D)implants.

Question 7

The three classifications of impressions in dentistry are:

A)prospective, retrospective, and introspective.
B)preliminary, functional, and occlusal, or bite, registration.
C)preliminary, final, and occlusal, or bite, registration.
D)diagnostic, functional, determinative.

Question 8

A(n) _____ is taken to produce a reproduction of the occlusal relationship of the maxillary and mandibular teeth when the mouth is occluded.

A)final impression
B)preliminary impression
C)bite registration
D)articulated impression

Question 9

An impression is a _____ reproduction of teeth and surrounding oral tissues,and the model created from the impression is a _____ reproduction of the structures.

A)positive; positive
B)positive; negative
C)negative; positive
D)negative; negative

Question 10

The irreversible hydrocolloid material used most widely for preliminary impressions is:

A)light-bodied material.
B)alginate.
C)polysulfide.
D)polyether.

Question 11

Preliminary impressions are used to make:

A)diagnostic models.
B)provisional coverage.
C)orthodontic appliances.
D)all of the above.

Question 12

Elastomeric impression materials are mixed by using:

A)a paper pad and spatula.
B)an automix system.
C)mixing bowl and a spatula.
D)both a and b.

Question 13

Which of the following is the most durable material for occlusal bite registration?

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

Question 14

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

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

Question 15

If an alginate impression is stored in water or in a soaked paper towel,the alginate will absorb the additional water and expand.This property is called:

A)syneresis.
B)imbibition.
C)tempering.
D)viscosity.

Question 16

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

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

Question 17

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 18

A(n) _____ impression material is used when an extremely accurate final impression is essential.

A)elastomeric
B)alginate
C)reversible hydrocolloid
D)light-cured

Question 19

Final impressions are taken by the:

A)dentist.
B)dental hygienist.
C)dental assistant.
D)laboratory technician.

Question 20

Which type of elastomeric material has the highest viscosity?

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

Question 21

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

A)Use fast-set alginate, as 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 may be done.

Question 22

Alginate impressions should be removed from the mouth by:

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

Question 23

When taking a wax bite registration,the patient is directed to:

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 24

Alginate impression material can:

A)change color as it sets.
B)be normal set or fast set.
C)be supplied with flavoring.
D)all of the above.

Question 25

Impression trays must be rigid enough to:

A)support the material in the patient's mouth.
B)warp the completed impression.
C)both a and b.
D)neither of the above.

Question 26

Impression disinfection:

A)should be performed in the laboratory.
B)should be performed before leaving the treatment area.
C)should be performed wherever the assistant has the time.
D)is not necessary, provided the impression has been thoroughly rinsed.

Question 27

The _____ portion of the maxillary tray should be seated in the mouth first.

A)anterior
B)posterior
C)right side
D)left side

Question 28

Syneresis in an alginate impression occurs when:

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 29

The atmosphere that is best for storing impressions is ____% relative humidity.

A)70
B)10
C)45
D)100

Question 30

The retromolar area,lingual frenum,tongue space,and mylohyoid ridge are reproduced in which impression?

A)Maxillary
B)Mandibular
C)Both a and b
D)Neither a nor b

Question 31

Impression inspection and evaluation include:

A)the presence of the retromolar area and maxillary tuberosity.
B)sharp anatomical detail.
C)a surface free from voids.
D)all of the above.

Question 32

Alginate material not setting or setting too rapidly may be the result of:

A)expired shelf life.
B)humidity.
C)improper storage.
D)all of the above.

Question 33

Criteria for an acceptable alginate impression include all of the following except:

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 34

When loading a tray for an upper impression,place:

A)more material toward the anterior and labial edge.
B)more material in the palatal area.
C)the material evenly in the tray.
D)more material toward the posterior and palatal areas.

Question 35

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 it useless.

Question 36

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

A)Slow set time.
B)Add bulk to material.
C)Accelerate set time.
D)Thicken the material.

Question 37

Putting utility/rope wax on maxillary alginate trays will:

A)maximize anatomical coverage of the posterior teeth.
B)modify the trays to accommodate a high palate.
C)permanently alter the impression tray.
D)a and b only.
E)all of the above.

Question 38

Alginate impressions may be disinfected by:

A)spraying the alginate with glutaraldehyde.
B)submersion in disinfecting solution overnight.
C)wetting with isopropyl alcohol.
D)spraying the alginate with an intermediate-level disinfectant.

Question 39

The three curing stages are:

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 40

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

A)Upright
B)Operator
C)Subsupine
D)Four-handed dentistry

Question 41

Which 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

If a more durable impression material is needed for bite registration,_____ may be selected.

A)polysulfide
B)zinc oxide-eugenol (ZOE)
C)polysiloxane
D)reversible hydrocolloid

Question 43

Which is not true regarding reversible hydrocolloids?

A)Plastic stops are used during the impression.
B)The impression procedure requires the use of 3 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 44

Which type of reversible hydrocolloid material is the most viscous?

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

Question 45

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

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

Question 46

One of the most popular impression materials used for bite registration is:

A)polysulfide.
B)zinc oxide-eugenol (ZOE).
C)polysiloxane.
D)reversible hydrocolloid.

Question 47

Most of the elastomeric material used requires the use of a(n) _____ on the tray.

A)stop
B)spacer
C)adhesive
D)lubricant

Question 48

Elastomeric materials use an automix system; what does the extruder gun consist of?

A)A tube of catalyst and base of the same viscosity
B)A tube of light- and heavy-body material
C)Either of the above
D)Neither of the above

Question 49

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