Dental Materials Ch. 3 Flashcards Preview

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Flashcards in Dental Materials Ch. 3 Deck (16)
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1

a drop of water on a popsicle is an example of

(a) Poor wetting (low contact angle)

(b) Good wetting (high contact angle)

(c) Good wetting (low contact angle)

(d) Poor wetting (high contact angle)

(c) Good wetting (low contact angle)

2

the tightening of a guitar string is an example of which of the following stresses

(a) Compression

(b) Torsion

(c) Shear

(d) Tension

(d) Tension

3

the modulus of elasticity is an indication of what property of a material

(a) Resilience

(b) Strength

(c) Stiffness

(d) Tension

(c) Stiffness

4

cooled materials will contract, and heated materials will expand. a measurement of this change in volume in relation to change in temperature is called the coefficient of thermal expansion

(a) The first statement is true; the second statement is false.

(b) The first statement is false; the second statement is true.

(c) Both statements are true.

(d) Both statements are false.

(c) Both statements are true.

5

when a stress is induced in a material that is greater than the material's yield strength, the stress is ______ proportional to the strain, and the material does not return to its original shape

(a) Always

(b) No longer

(c) Equally

(d) None of the above

(b) No longer

6

which formula defines the modulus of elasticity

(a) stress/strain

(b) stress2/strain

(c) strain/stress

(d) 2 × stress/strain

(a) stress/strain

7

an example of a physical property is

(a) Density

(b) Strength

(c) Stiffness

(d) Setting reaction

(a) Density

8

a twisting force is termed

(a) Compression

(b) Shear

(c) Tension

(d) Torsion

(e) Bending

(d) Torsion

9

the ability of a material to dissolve in liquid is termed

(a) Viscosity

(b) Water sorption

(c) Solubility

(d) Wetting

(c) Solubility

10

elasticity is an example of which of the following properties

(a) Physical

(b) Mechanical

(c) Chemical

(d) Biologic

(b) Mechanical

11

the rate of heat flow through a material is referred to as

(a) Heat of fusion

(b) Coefficient of thermal expansion

(c) Heat capacity

(d) Thermal conductivity

(d) Thermal conductivity

12

Jennifer is a practicing dental hygienist who goes to a nearby restaurant each day for lunch. she often orders a cola with ice and a bowl of homemade soup. as she eats and drinks her composite restorations (tooth colored) and tooth structure are expanding and contracting at different rates. this change in volume or length of these materials due to the hot food and cold drink is referred to as

(a) Heat of fusion

(b) Coefficient of thermal expansion

(c) Heat capacity

(d) Thermal conductivity

(b) Coefficient of thermal expansion

13

fingernail polish remover has solvent properties as it will remove the polish from our fingernails. another property polish remover has is its tendency to evaporate. fingernail polish remover can be said to have

(a) A high vapor pressure

(b) A low vapor pressure

(c) No vapor pressure

(d) An intermittent vapor pressure

(a) A high vapor pressure
 

14

_______ is the force used to condense an amalgam in a
preparation.

(a) Solubility

(b) Compression

(c) Stress concentration

(d) Viscosity

(b) Compression

15

A hardened cement having "low" ______________ can firmly hold a patient's gold crown in place for years in a wet envi-
ronment.

(a) Solubility

(b) Compression

(c) Stress concentration

(d) Viscosity

(a) Solubility

16

________ is the term given to the increase of stress around defects within an object.

(a) Solubility

(b) Compression

(c) Stress concentration

(d) Viscosity

(c) Stress concentration