Dental Materials Test 4

39 Questions | By Bfrenkel003 | Last updated: Mar 22, 2022 | Total Attempts: 4956

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About gypsum materials and periodontal dressings

Questions and Answers

1.

Alginate impression material is:
- A.
  
  Expensive compared to other impression materials
- B.
  
  Easy to use
- C.
  
  Not affected by gain or loss of water
- D.
  
  Well known for its long-term stability
2.

Impression materials that have mechanical properties permitting considerable elastic deformation but that return to their original form are classified as:
- A.
  
  Thermoplastic
- B.
  
  Elastometric
- C.
  
  Inelastic
- D.
  
  Resins
3.

Dr Jones requested that you mix alginate and take an impression. While measuring the water, you got involved in conversation and did not notice how warm ir was. This oversight will:
- A.
  
  Make the mix unstable
- B.
  
  Lengthen the gelation time
- C.
  
  Not affect gelation time
- D.
  
  Shorten the gelation time
4.

Which of the following dental materials is an example of an aqueous elastometric?
- A.
  
  Impression compound
- B.
  
  ZOE impression paste
- C.
  
  Polysulfide
- D.
  
  Irreversible hydrocolloid
- E.
  
  Addition silicone
5.

The brown paste used in rubber base is called the:
- A.
  
  Polymer
- B.
  
  Accelerator
- C.
  
  Base
- D.
  
  Filler
6.

Dental impression compound is known as a/an
- A.
  
  Chemoplastic material
- B.
  
  Irreversible material
- C.
  
  Hydroelastic material
- D.
  
  Thermoplastic material
7.

The term used for the setting of hydrocolloid impression materials is
- A.
  
  Crystallization
- B.
  
  Polymerization
- C.
  
  Curing
- D.
  
  Gelation
8.

The populatrity of agar impression material is limited by the:
- A.
  
  High cost
- B.
  
  Need for special equipment
- C.
  
  Poor reproduction of detail
- D.
  
  Difficulty in pouring the impression
9.

When an agar impression slightly contracts and exudes water, it is termed:
- A.
  
  Imbibition
- B.
  
  Gelation
- C.
  
  Syneresis
- D.
  
  Hysteresis
10.

Addition silicones are the most popular type of rubber impression materials. The reason for this is cost.
- A.
  
  True, false
- B.
  
  False, true
- C.
  
  Both true
- D.
  
  Both false
11.

Custom impression trays are made on a model of the patient's arch. Therefore, to make a custom tray, an alginate impression is also needed.
- A.
  
  True, false
- B.
  
  False, true
- C.
  
  Both true
- D.
  
  Both false
12.

Mrs Smith has not been to the dentist for several years. It was found that she needed extensive restorative treatment to which she agreed. You were asked to take impressions as the first step of her care. The impression material of choice would be:
- A.
  
  Agar
- B.
  
  Alginate
- C.
  
  Dental impression compound
- D.
  
  Addition silicone
13.

The impression tray that is used to record the prepared tooth, a bite registration, and an impression of the opposing teeth is a:
- A.
  
  Stock tray
- B.
  
  Custom tray
- C.
  
  Triple tray
- D.
  
  Bite registration tray
14.

Which of the following impression materials set by physcial means?
- A.
  
  Agar
- B.
  
  ZOE
- C.
  
  Alginate
- D.
  
  Addition silicone
15.

The desirable strength of gympsum materials is ____ related to the amount of water used.
- A.
  
  Directly
- B.
  
  Indirectly
- C.
  
  Not
- D.
  
  Partially
16.

For gypsum products, a suitable accelerator and retarder, respectively, would be:
- A.
  
  Ethyl alcohol and oleic acid
- B.
  
  Oleic asid and glycerin
- C.
  
  Borax and potassium sulfate
- D.
  
  Potassium sulfate and borax
17.

The gypsum material known as "high strength stone" may be also referred to as:
- A.
  
  Plaster
- B.
  
  Dental stone
- C.
  
  Type III stone
- D.
  
  Improved stone
18.

The final setting time for gypsum products is typically:
- A.
  
  15-30 min
- B.
  
  30-45 min
- C.
  
  45-90 min
- D.
  
  90-120 min
19.

To make a correct mix for dental stone when using 50 g of powder, the amount of water would be approximately:
- A.
  
  10-12 ml
- B.
  
  14-15 ml
- C.
  
  28-30 ml
- D.
  
  45-50 ml
20.

Cathy and her parents will meet with an orthodontist to discuss an orthodontic treatment plan. At a previous appt, the orthodontist took impressions of Cathys maxillary and mandibular arches. The replicas made from each impression to discuss the treatment plan are termed:
- A.
  
  Casts
- B.
  
  Dies
- C.
  
  Study models
- D.
  
  Molds
21.

Decreasing the setting time of a dental material results in a products that:
- A.
  
  Takes less time to set
- B.
  
  Takes more time to set
- C.
  
  Does not affect the setting time
- D.
  
  Enhances the properties
22.

The weakest gypsum products is:
- A.
  
  Improved stone
- B.
  
  Dental stone
- C.
  
  Plaster
- D.
  
  Die stone
23.

When excess water is not present in a gypsum product, it is knwon as the:
- A.
  
  Wet strength
- B.
  
  Dry strength
- C.
  
  Initial setting time
- D.
  
  Surface strength
24.

The best way to mix gypsum products is to:
- A.
  
  "eyeball" the amount of powder added to water
- B.
  
  Add water to the powder
- C.
  
  Add powder to the water
- D.
  
  Add powder and water to the bowl simultaneously
25.

Initial and final setting times of gypsum can be determined with the use of Gilmore Needles. A practical, wasy method to determine final setting time in a dental office would be to:
- A.
  
  Set a timer for 20 min
- B.
  
  Ovserce the c hange from wet to dry strength
- C.
  
  Watch for the loss of gloss
- D.
  
  Attempt to penetrate the material with the metal spatula