Lecture 1 Flashcards
1
Q
Were used in the
third century B.C., by the Greek physiologist,
Erasistratus, whilst the Egyptians utilized lead
and papyrus for catheter devices
A
Copper, tin, bronze and gold
2
Q
Material used to construct artificial organs,
rehabilitation devices, or prostheses and replace
natural body tissues. Without causing any harm
or negative reactions
A
Biomaterials-
3
Q
- Composites
- Silicone Impression Materials
A
Synthetic biomaterials
4
Q
- Alginates
- Hydrocolloids
A
Natural Biomaterials
5
Q
- Stem cells
- Replacement tissues
A
Tissue-engineered Biomaterials
6
Q
- Hard
- Ductile- tough
- Strong
A
Metals
7
Q
- Hard
- Brittle
- Strong
A
Ceramics
8
Q
- Soft
- Ductile-tough
- Weak
A
Polymers
9
Q
Difference between Metals and Ceramics
A
Metals are ductile, while ceramics are brittle
10
Q
Have high processing temperatures
A
Metals and Ceramics
11
Q
Have lower processing temperatures
A
Polymers
12
Q
Used as Direct Processing Materials
A
Polymers
13
Q
Reinforce broken down teeth
A
Metal-ceramic crowns
14
Q
Restore endo treated teeth
A
Post & core
15
Q
Replace missing teeth
A
Implants
16
Q
Have 1,2,3 electrons in their outer shell
A
Metallic elements
17
Q
Key to metallic bonds
A
electrons
18
Q
loosely bound to nucleus
A
electrons
19
Q
- Free mobility
- thermal and electrical conductivity
- ductility-bend without breaking
A
Electrons
20
Q
Molten metal -> nuclei of crystalization -> Crystal growth -> crystallization of metal upon cooling -> formation of grains
A
Microstructure of metals
21
Q
Single phase-single composition
A
Polycrystalline structures
22
Q
Mix of two or more metals
A
Metal alloys
23
Q
Cast metals for crowns and amalgams are
A
Metal alloys
24
Q
Atoms can slide in
A
Ductile
25
- Must be made to resist deformation
| - Modified to impede dislocations
Strengthening nobel metals
26
Bonds associated with ceramic
Ionic and covalent
27
Stronger than metallic bons
Ionic and covalent
28
Which bond is stronger ionic or covalent?
Covalent
29
Electron donor and electron acceptor
Ionic bonds
30
Equally shared elections
Covalent bonds
31
Non mobile ions
Ceramic bonds
32
Mixture of metallic and non-metallic elements
Microstructure of ceramics
33
Most common ceramics in dentistry
SiO2, Al2O3, K2O
34
Building block of microstructure of ceramics
SiO4 tetrahedron
35
Long range order- microstructure of ceramics
Crystalline
| Crystalline silicate-quartz or crystobilite
36
Short range order no long range- microstructures of ceramics
Noncrystalline
| Amorphous silicate-glass
37
Most dental ceramics are
Semicrystalline or polycrystalline
38
Building block of dental porcelain
SiO4 tetrahedron
39
Primarily a glass with some crystalline residuals
Microstructure of dental porcelain
40
How is dental procelain processed?
By Sintering or melting at high temps
41
- Covalent bonds
- High molecular weight
- Long molecules composed principally of nonmetallic elements (Organic chemistry C,O,N,H)
Polymer bonds
42
Entangled long chains
Polymers
43
Derive strength and properties from entanglement
Polymer bonds
44
- Light Activation of Initiator
- Initiation of Monomer
- Propagation of Free-Radical
- Termination of Free-Radical
Polymerization process
45
-Activation of Initiator Molecule to generate a Free-radical
-Initiation of a monomer to generate a free radical
Propagation of Free-Radical with Four Monomers
-Termination of free radical
Polymerization process
46
Polymer formation liquid
Monomers
47
Polymer formation solid
polymer
48
Polymer formation
polymerization
49
Resin matrix
Monomers
50
Hasten free radical reaction
Initiator in resin matrix
51
Four states of chain reaction polymerization
- Activation
- Initiation
- Propagation
- Termination
52
Free radical initiation
Activation
53
-Free radical combination
with monomer unit
-Double bond opening
Initiation
54
- Chain growth
- Volume decrease
- Shrinkage
Propagation
55
- Monomethacrylates
- Dimethacrylates
- Linear chains
- Branched and crosslinked
Monomer functional groups
56
What happens once a polymerization reaction starts
It can be fast and generate a lot of heat
57
Allows for in vivo processing - Direct placement
Polymerization
58
- Flowable Material
- Stable Material
- Trigger for Setting
- Rapid Setting
- Room Temperature Setting -Reaction
Direct placement of polymerization
59
Pros: Less preparation and one visit
Cons: Often do not last as long
Direct placement
60
Pros: Longevity of restorative
Cons: Multiple visits and expensive
Indirect placement
61
What are indirect restorative materials?
Metals and ceramics
62
What are direct restorative materials?
Polymers
63
High processing temps
Metal and Ceramics
64
Exception for metals
Amalgam
65
Exception for ceramics
Cemetns
66
Linear polymers
Provisionals-temporary crowns
67
Crosslinked polymers
Adhesives and restoratives
68
Physical mixtures of
metals, ceramics,
and/or polymers
Composites
69
Goal is to achieve
some intermediate
properties between the
two material types
Composites
70
Rule of mixtures
Dentin and enamel
71
What makes is possible to predict the overall properties
Knowing the phases present in the structure of any material and interfacial interactions
72
Dispersed phase of dental composits
Glass fillers
73
Matrix phase of dental composit
Monomer resin
74
What are fillers chemically bonded to
Resin phase
75
Photoinitiators
composits
76
Silicate glass
| Colloidal silic
Filler types
77
- Physical (environment)
- Chemical (bonding affected)
- Biological (living tissues)
- Mechanical (forces
Materials properties
78
Types of atomic arrangements
Crystalline (grains) vs non crystalline (glassy)
79
Types of bonding
- Primary
| - Secondary
80
Metallic, ionic, covalent
Primary bonding
81
Hydrogen, van der Waals
Secondary bonding
82
Types of composition
Elements and phases
83
Types of defects
- Macroscopic (pores)
| - Atomic scale (microflaws)`
84
Density =
Weight / unit volume
| g/cm3
85
Specific gravity -
Density of material/ density of water
aka relative density
86
Most things expand when
| heated and contract when cooled
Thermal expansion
87
teeth are insulators due to high mineral content
Heat flow
88
Measure of heat flow
Thermal conductivity
89
Have high thermal conductivity so they need
| thermal insulator like base
Metals
90
Have low thermal conductivity so they do
| not need base
Composites
91
Conducts electricity
Metallic restorations
92
Electrical insulators
Composites and ceramics
93
- Color
- Translucency
- Glass
- Surface texture
Optical properties
94
3 dimensions of color
- Hue
- Value
- Chroma
95
- Wavelength
| - Color (Roy G Biv)
Hue
96
- Intensity
| - Brightness
Value
97
- Purity
| - Density or concentration
Chroma
98
```
2 objects that appear
the same color under
one light source and
different under another
light sourse
```
Metamerism
99
Different spectral characteristics
Metamerism
