Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pulse - Dental Materials > Physical Properties > Flashcards

Physical Properties Flashcards

1
Q

Latent heat of vaporization

A

The amount of energy needed for transformation of a boiling liquid into vapour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Latent heat of fusion

A

The amount of energy released when a liquid freezes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Melting temperature

A

The amount of energy required for the transformation of solids into a liquid state.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Sublimation

A

The process in which some solids transform directly into a gas phase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Different types of bonds

A
  1. Ionic bond (Gypsum, phosphate cements)
  2. Covalent bond (Dental resins)
  3. Metallic bond (Pure gold)
  4. Hydrogen bond (Water)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Glass transition temperature

A

The temperature at which there is an abrupt increase in the thermal expansion coefficient, indicating increased molecular mobility.

It is characteristic of a particular glassy structure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cohesion

A

Force of attraction between like molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Adhesion

A

Force of attraction between unlike molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Adhesive

A

Material or film added to produce adhesion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Adherend

A

The material to which an adhesive is applied.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What property of a material affects adhesion most?

A

Surface energy of the material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Relation of surface energy of restorative materials to tooth

A

Materials have greater surface energy than tooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does difference in surface energy of materials and that of tooth affect behaviour of restorations?

A

There is a greater tendency for the surface and margins of the restoration to accumulate debris with resultant high incidence of marginal caries.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hue

A

The specific COLOUR produced by a specific wavelength of light. Describes the dominant colour of the object, eg. Red, green or blue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Value, aka

A

Brilliance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Value

A

The lightness or darkness of an object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

High value =

A

light shade.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Saturation, aka

A

Chroma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Chroma

A

The amount of colour per unit area of an object (degree of saturation of a certain hue).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Translucency

A

The property of an object that permits the passage of light through it but does not give any distinguishable image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Metamerism

A

The tendency of objects that appear to be colour matched under one type of light to appear different under another light source.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Fluorescence

A

The energy that a tooth absorbs is converted into light with longer wavelengths, and becomes a light source.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What properties of teeth does fluorescence affect?

A
  1. Brightness

2. Vital appearance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Benzold-brucke effect

A

Change in colour due to change in brightness.

25
Q

Rheology

A

The study of matter flow characteristics. (Viscosity)

26
Q

Viscosity

A

Resistance to motion

27
Q

Newtonian fluid

A

Ideal fluid with constant viscosity that demonstrates a shear stress that is proportional to the strain rate. (Straight line graph) |/_

28
Q

Pseudoplastic

A

A material whose viscosity decreases with increasing shear rate.

29
Q

Dilatant

A

Liquids that become more rigid with increasing shear rate - as the rate of deformation increases, these liquids become more viscous.

30
Q

Thixotropic

A

A liquid that becomes less viscous and more fluid under pressure.

31
Q

Examples of thixotropic materials.

A
  1. Dental prophylaxis pastes
  2. Plaster
  3. Resin cements
  4. Some impression materials.
32
Q

Water contact angle of hydrophobic materials

A

95 degrees

Polysulphide, addition and condensation silicones

33
Q

Water contact angle of hydrophilic materials

A

30-35 degrees

Alginate, agar, polyether

34
Q

Stress (definition)

A

Stress is the force per unit area

35
Q

Stress (explanation)

A

It is the internal reaction to external force

36
Q

Tensile stress

A

It tends to stretch or elongate a body.

37
Q

Compressive stress

A

Tends to compress a body

38
Q

Shear stress

A

Resists the sliding or twisting of one portion of a body over another.

39
Q

Strain

A

The change in length per unit length of body when a stress is applied.

40
Q

Poisson’s ratio

A

When an object is subjected to a tensile or compressive stress, there is simultaneous axial and lateral strain.

Within the elastic range, the ratio of lateral to the axial strain is called poisson’s ratio.

41
Q

Ideal Poisson’s ratio

A

For an ideal isotropic material of constant volume - 0.5.

42
Q

Elastic limit

A

The maximum stress that a material can withstand without permanent deformation.

43
Q

Proportional limit

A

It is the greatest stress that may be produced in a material such that the stress is directly proportional to the strain.

44
Q

What are the conditions required to be met for a material to satisfy Hooke’s law?

A

The elastic stress should be proportional to the elastic strain

45
Q

Young’s Modulus

A

It describes the relative stiffness or rigidity of a material.

46
Q

How do you calculate Modulus of elasticity?

A

It is the ratio of stresses to strain within the proportional limit.

Elastic modulus
= tensile stress/tensile strain
= compressive stress/compressive strain

47
Q

Unit of modulus of elasticity

A

Giga Pascal

48
Q

Shear modulus

A

38% of elastic modulus

49
Q

Yield strength

A

The strength at which a material begins to function in a plastic manner.

50
Q

Yield strength (definition)

A

The stress at which a material exhibits a limiting deviation from proportionality of stress to strain.

51
Q

Resilience

A

The amount of energy absorbed by a structure when it is stressed, not to exceed its proportional limit.

52
Q

Lateral strain as expressed in dental terms

A

Axial strain

53
Q

Toughness

A

The amount of energy required to fracture a material. It is a measure of a material’s resistance to fracture.

54
Q

Factors that affect toughness of a material.

A
  1. Strength

2. Ductility

55
Q

Brittleness

A

The inability of a material to sustain plastic deformation before a fracture occurs.

56
Q

Ductility

A

The ability of a material to withstand permanent deformation under a tensile load without rupture.

57
Q

Malleability

A

The ability of a material to withstand permanent deformation under a compressive load without rupture.

58
Q

Flexibility

A

The strain that occurs when the material is stressed to its proportional limit.

Pulse - Dental Materials (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions