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AU17 - Dental Materials 3 > Intro and General Properties > Flashcards

Intro and General Properties Flashcards

1
Q

What are the three material categories?

A

Ceramic
Metal
Polymer

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2
Q

Atomic arrangements, bonding, composition, and defects are all related to the material _____.

A

structure

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3
Q

What are 5 material properties?

A
  1. mechanical
  2. physical
  3. chemical
  4. degradation
  5. biological
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4
Q

What are the general properties of Metal? Ceramics? Polymers?

A

Metal: hard, ductile, strong
Ceramic: hard, brittle, strong
Polymer: soft, ductile, weak

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5
Q

T/F: Metals and ceramics have low processing temperatures.

A

False, HIGH

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6
Q

T/F: Metals and ceramics are typically used as direct restorative materials.

A

False, INDIRECT

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7
Q

An atomic arrangement is either ______ or ______.

A

crystalline or non-crystalline

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8
Q

Primary bonding is via ____, _____, and _____bonds. Order theses from strongest to weakest.

A

metallic, ionic, covalent

covalent > ionic > metallic

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9
Q

“Pores” are considered to be what kind of defect?

A

Macroscopic

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10
Q

Metallic elements have how many electrons in their outer shell?

A

1, 2, or 3

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11
Q

T/F: Electrons are key to metallic bonds.

A

True!

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12
Q

In metallic elements, electrons are loosely bound to the nucleus.

A

True, this gives them free MOBILITY and allows metals to be ductile without breaking

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13
Q

T/F: Freely moving electrons allows for thermal and electrical conductivity.

A

True

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14
Q

T/F: The crystallization of metal occurs during heating.

A

False, during cooling

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15
Q

T/F: Pure metals are single phase, single composition.

A

True, atoms are able to slide around which makes pure metals more ductile and less strong

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16
Q

What are alloys?

A

mixture of two or more metals, different sized atoms act like stoppers and prevent easy sliding of atoms = stronger and less ductile metal

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17
Q

What kind of bonds are associated with ceramics?

A

ionic and covalent

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18
Q

T/F: Ionic and covalent bonds are weaker than metallic bonds.

A

FALSE

covalent > ionic > metallic

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19
Q

____ bonds: electron donor and electron acceptor

A

Ionic

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20
Q

_____ bonds: equally share electrons

A

Covalent

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21
Q

What are the three most common ceramics in dentistry?

A

SiO2 (Silicate)
Al2O3 (Aluminum)
K2O (potassium)

“don’t SALK about ceramics”

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22
Q

What is the building block in (Si02, Al2O3, and K2O)?

A

SiO4 tetrahedron

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23
Q

Crystalline ceramics are ______ range order.

A

long (crystalLONG)

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24
Q

NonCrystalline ceramics are ____ range order

A

short (NONcrystalLONG)

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25
Q

Most dental ceramics are ____ or ____.

A

Semicrystalline or polycrystalline

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26
Q

T/F: Polymers consist of covalent bonds.

A

True

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27
Q

T/F: Polymers are high molecular weight.

A

True

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28
Q

T/F: Polymers are straight, long chains.

A

False, ENTANGLED long chains, like “cooked spaghetti”

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29
Q

T/F: Polymers derive their strength from the entanglement of molecular chains.

A

True

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30
Q

Polymers are long molecules composed primarily of _______ elements.

A 
Organic (Nonmetallic) elements 
 oxygen
nitrogen
carbon
hydrogen
31
Q

How are polymers formed?

A

free radical reaction:

  1. activation of initiator molecule
  2. initiation of monomer to form free radical
  3. propagation of free radicals with four monomers
  4. termination of free radical
32
Q

T/F: The monomer is the liquid portion of the reaction.

A

True

33
Q

T/F: Monomethacrylates and dimethacrylates are monomer functional groups.

A

True

34
Q

Why is polymerization important in dentistry?

A

it allows for direct placement

35
Q

Which metal is NOT indirect?

A

amalgam (all other metals are indirect)

36
Q

Which ceramic is NOT indirect?

A

cements (all other ceramics are indirect)

37
Q

What is the goal of composite?

A

to achieve some intermediate properties between the material types

38
Q

What is the “rule of mixtures”?

A

by knowing the phases present in the structure of any material and the interfacial interactions, it is possible to predict the overall properties fairly well

39
Q

Dental composites contain a ____ phase and a ____ phase.

A

dispersed

matrix

40
Q

T/F: The glass fillers are the dispersed phase.

A

True

41
Q

T/F: The monomer resin is the matrix phase of composite.

A

True

42
Q

T/F: Fillers are physically bonded to resin to improve properties.

A

False, chemically bonded

43
Q

T/F: Dental composites require photoinitiators.

A

True

44
Q

What is the typical filler amount in dental composite?

A

75-80% by weight

45
Q

Increased filler volume results in increased ____, _____, and ______.

A

strength, modulus, and viscosity

46
Q

Increased filler volume results in decreased ____.

A

shrinkage

47
Q

T/F: Increased filler size results in decreased surface roughness.

A

False, increased roughness

48
Q

Which filler type is larger? silicate glass or colloidal silica.

A

silicate glass (1 -100) > colloidal silica (0.05)

49
Q

T/F: There are always trade-offs involved when selecting a dental material.

A

True

50
Q

T/F: Glass Ionomer reduces secondary caries

A

True

51
Q

More filler loading = _____ modulus and wear.

A

higher

52
Q

Smaller filler size = _____ wear and translucency

A

better

53
Q

Smaller filler size = _____ viscosity

A

higher

54
Q

Enamel is a nanocomposite ____% filler

A

95

55
Q

____ molecular weight reduces shrinkage.

A

increasing

56
Q

______ molecular weight increases viscosity

A

increasing

57
Q

What is elastic modulus?

A

the relationship of elastic stress to strain

58
Q

T/F: Hardness has a high correlation to wear

A

True

59
Q

T/F: Mechanical properties are most commonly tested on a universal testing machine

A

True

60
Q

T/F: Aging tests via exposure to UV light can accurately simulate clinical use.

A

True

61
Q

___ ___ is a stress-strain relationship.

A

Tensile Strength

62
Q

T/F: Biologic properties include anything which influences or raises concerns to human health.

A

True

63
Q

T/F: Biologic properties are negative.

A

False, could be positive (anticariogenic, tissue conditioning) or negative (toxic, mutagenic)

64
Q

T/F: Two-way and Three-way interactions are the most studied and most developed in terms of predicting effects of clinical efficacy.

A

False, LEAST studied.
(two-way: physical +chemical, chemical +biologic, etc)
(three-way: chemical + physical + biologic)

65
Q

“breakdown of composite can lead to leaching of chemicals”…this is what type of interaction?

A

chemical-biological

66
Q

“polymerization shrinkage can lead to internal stresses”… this is what type of interaction?

A

chemical-mechanical

67
Q

T/F: Most chemical, physical, and biologic testing is done in vitro.

A

True

68
Q

T/F: Composite fracture toughness has a high degree of correlation to clinical longevity.

A

True

but its not a 1:1 relationship…5% increase in one does not mean a 5% increase in the other

69
Q

T/F: Minimum standards were originall set forth in order to ensure the quality of amalgam.

A

True

70
Q

Who developed minimal standards?

A

NIST and the ADA

71
Q

What is the first requirement of dental materials?

A
  1. Restoration of form and function
72
Q

General requirement #2. _____ and convenient formation for each patient

A

accurate

73
Q

T/F: Requirement #3 states that dental materials must resist the effects of the oral environment.

A

True

74
Q

T/F: Dental materials must be affordable and biocompatible.

A

True

AU17 - Dental Materials 3 (6 decks)

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