2/1: Intro to Biomaterials-Amalgam & Class I and Class V Restoration Flashcards

1
Q

What are the 4 major classes of dental materials?

A
  1. Metals and alloys
  2. Porcelains and ceramics
  3. Polymers
  4. Composites
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2
Q

What are the two different types of polymers?

A

Elastomer (impression materials)
Plastics (denture base, sealants)

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3
Q

What are composites?

A

Polymers with fillers

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4
Q

How many specifications for dental materials, instruments, and equipment?

A

More than 10

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5
Q

What are restorative material specifications: related to material properties that should reflect clinical function?

A

In vitro (in glass)- tested in lab
In vivo (in the living beaing)
*Exploration of in vitro data to in vivo conditions should be done with caution

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6
Q

What two things does the food and drug administration focus on?

A

Safety, efficacy

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7
Q

What is the FDA’s goal?

A

Protect the public from hazardous or ineffective medical materials and devices

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8
Q

What class has the lowest risk?

A

Class I

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9
Q

What class has the highest risk?

A

Class III

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10
Q

Performance of all dental materials depends on ________

A

Atomic structure

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11
Q

What does atomic structure determine?

A

Mechanical and physical properties of materials

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12
Q

What are the two types of interatomic bonds?

A

Primary and secondary

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13
Q

What are primary interatomic bonds?

A

Ionic, covalent, metallic

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14
Q

What are secondary bonds?

A

Hydrogen bonds, Van der Waals forces

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15
Q

What are ionic bonds?

A

Electrostatic attraction of positive and negative charges

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16
Q

What do ionic bonds involve?

A

Electron transfer between ions (one becomes positive, one becomes negative ex: NaF)

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17
Q

What are properties of ionic bonds?

A

Non-directional, strong bonds
100-200kcal/mole
No free electrons, good thermal and electrical insulators

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18
Q

what are examples of ionic bonds?

A

Ceramics, gypsum

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19
Q

What are covalent bonds?

A

2 atoms share an electron

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20
Q

What are properties of covalent bonds?

A

Directional bonds
50-100kcal/mole
Low electrical and thermal conductivity
Water insoluble

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21
Q

What are examples of covalent bonds?

A

Water, glass, polymers, composite

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22
Q

What are metallic bonds?

A

Cluster of positive metal ions surrounded by a gas of electrons

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23
Q

What are properties of metallic bonds?

A
  • non directional bonds (100 kcal/mole)
  • high electrical and thermal conductivity
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24
Q

What are examples of metallic bonds?

A

Amalgam and gold alloys

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25
Q

What are biological classifications of material properties?

A

The biological response to a material when in contact with the human body

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26
Q

What is an example of a biological material?

A

Gingivitis from plaque

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27
Q

What is the surface classification of material properties?

A

The unique properties of a material associated with its surface

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28
Q

What is an example of a surface material?

A

Denture retention, adhesive bonding

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29
Q

What is the physical classification of material properties?

A

Depend on the type of atoms and the bonding present in material

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30
Q

What has NO EFFECT on physical classification of material properties?

A

Size or shape

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31
Q

What classification is structure insensitive?

A

Physical

32
Q

What is an example of a physical classification of material property?

A

Optic (color, glass), thermal (conductive)

33
Q

What is the mechanical classification of material properties?

A

Reaction of a material to the application of an external force

33
Q

What AFFECT mechanical properties?

A

Size and shape of specimen

34
Q

What material property is structure sensitive?

A

Mechanical classification

35
Q

What is an applied force referred to?

A

Load

36
Q

When load (force) applied to material, ______ develops in response

A

Stress

37
Q

What is stress?

A

Load per unit area
measured in psi, MPa, kg/cm^2

38
Q

What is fracture strength?

A

how much stress a material can withstand before it breaks

39
Q

How is type of strength measured dependent on?

A

Type of force applied

40
Q

What are the 5 types of force?

A

Compressive - pushing
Tensile - puling
shear - sliding
Torsion - twisting
Flexure - bending

41
Q

What is the highest strength measure for most materials?

A

Compressive strength

42
Q

What is compressive strength?

A

Measure of the stress necessary to fracture a material by 2 opposing forces directed toward each other

43
Q

What pushes atoms and structure closer?

A

Compression
- usually require higher loads to cause failure

44
Q

What is tensile strength?

A

Pulling force

45
Q

What is the lowest strength for most materials?

A

Tensile strength

46
Q

What does tensile strength measure?

A

the stress necessary to fracture a material by 2 opposing forces directed away from each other

47
Q

What pulls atoms and structures apart?

A

Tension
- failure occurs at lower loads

48
Q

What is shear strength?

A

Sliding force

49
Q

What is an intermediate strength between compressive and tensile?

A

Shear strength

50
Q

What is shear strength?

A

Stress necessary to rupture a material by 2 opposing parallel forces directed toward each other but not in the same plane

51
Q

What is a clincial situation with shear force/shear strength?

A

Implant-bone interface

52
Q

What is torsion strength?

A

Twisting force

53
Q

What is torsion strength not relevant to?

A

Direct or indirect dental restorations

54
Q

What torsion tool is used to place dental implants?

A

Torque wrench (torsion)

55
Q

What is torsion a test of in the clinical setting?

A

experimental dental implant-bone interface stability/strength of osseointegration

56
Q

What is torsional fatigue?

A

Endodontic rotary files

57
Q

What is flexural strength?

A

Bending force

58
Q

What is flexural strength a measure of?

A

Stress to cause failure in bending

59
Q

What does the 3-point bend test measure?

A

Compressive load
Combination of compression and tensile stress

60
Q

What is flexural strength vital due to?

A

Occlusal load
- on direct restorations (amalgam and composite)
- also indirect/removable/etc (everything that gets chewed on)

60
Q

What are the two types of dental stress?

A

Protrusive movement
Posterior occlusion

60
Q

What is protrusive movement?

A

Anterior teeth
Flexure load on incisors

61
Q

What is posterior occlusion?

A

Chewing = compressive load
At marginal ridge contact areas
At fossa areas

62
Q

What is occlusal stress equal to?

A

Occlusal load (Force)/occlusal contact area

63
Q

What do tripodized occlusal contacts allow for?

A

Distribution of occlusal load across maximum area = minimized stress

64
Q

What does premature contact result in?

A

Decreased AREA
- patient’s occlusal force stays the same BUT occlusal stress is INCREASED

65
Q

What can premature contact result in?

A

Potential restoration failure
Potential pain/discomfort for patient on biting

66
Q

What is strain?

A

The DEFORMATION that occurs in a material when force is applied to the material

67
Q

What is strain equal to?

A

change in length (deformation)/unit original length

68
Q

_____ and ______ are interrelated?

A

Stress & strain
- if you have one, you will have the other

69
Q

On a stress strain diagram, what is elastic strain?

A

Temporary distortion of material by applied force

70
Q

In elastic strain, strain is _______ the elastic limit

A

Below
- when force is removed, materials reverts to original form
ex: rubber band

71
Q

What is plastic strain?

A

PERMANENT distortion of a material

72
Q

In plastic strain, strain is _______ the elastic limit

A

BEYOND
- elastic portion of strain recovered
- plastic portion of strain NOT recovered

73
Q

In plastic strain, when force is removed, shape is ________

A

Remains changed
ex: bending a paper clip