Dental Materials Ch. 9 Flashcards Preview

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Flashcards in Dental Materials Ch. 9 Deck (12)
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1

the desirable strength of gypsum materials is _________ related to the amount of water used.

a) directly
b) indirectly
c) not
d) partially

a) directly

2

for gypsum products, a suitable accelerator and retarder, respectively, would be:

a) Ethyl alcohol and Oleic acid
b) Oleic acid and glycerin
c) borax and potassium sulfate
d) potassium sulfate and borax

d) potassium sulfate and borax

3

the gypsum material known as "high-strength stone" may also be referred to as:

a) Plaster
b) Dental stone
c) Type III stone
d) Improved stone

d) Improved stone

4

the final setting time for gypsum products typically is:

a) 15-30 mins
b) 30-45 mins
c) 45-90 mins
d) 90-120 mins

b) 30-45 mins

5

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

b)14-15 ml

6

Cathy and her parents will meet with an orthodontist to discuss an orthodontist treatment plan. At a previous appointment, the orthodontist took impressions of Cathy's maxillary and mandibular arches. the replicas made from watch impression to discuss the treatment plan are termed:

a) casts
b) dies
c) study models
d) molds

c) study models

7

decreasing the setting time of a dental material results in a product that:

a) will set faster
b) will set slower
c) does not affect the setting time
d) enhances the properties

a) will set faster

8

the weakest gypsum product is:

a) improved stone
b) dental stone
c) plaster
d) die stone

c) plaster

9

when excess water is not present in gypsum product, it is known as the:

a) wet strength
b) Dry strength
c) initial setting time
d) surface strength

b) Dry strength

10

the best way to mix products is to:

a) "eyeball" amount of powder added to water
b) add water to the powder
c) add powder to the water
d) add powder and water to bowl simultaniously

c) add powder to the water

11

initial and final settlement times of gypsum can be determined with the use of Gilmore needles. a practical, easy method to determine final setting time in a dental office would be to:

a) set timer for 20 mins.
b) observe the change from wet to dry strength
c) watch for the loss of gloss
d) attempt to penetrate the material with the metal spatula

d) attempt to penetrate the material with the metal spatula

12

when the setting time of a dental material is increased which of the following is true?

a) the material sets slower
b) the material sets faster
c) the setting reaction does not change
d) the setting reaction is increased

a) the material sets slower