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Cariology > DM > Flashcards

DM Flashcards

1
Q

Materials Categories

A

Metals
Ceramics
Polymers
Composites

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2
Q

Polymer-Ceramic

A

Composite resin Glass-ionomer

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3
Q

Metal-Ceramics

A

Metal-Ceramic Crowns

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4
Q

Dental Materials characterize the______ of the material

A

Structure

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5
Q

Dental materials ______ and ______ the Properties

A

Measure

Evaluate

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6
Q

Dental materials some have…..

A

Many requirements for a given material

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7
Q

Suboptimal Materials

A

Metals such as copper tin bronze and gold were used in the 3rd century

Egyptians used lead and papyrus for catheter devices

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8
Q

What are Biomaterials

A

Materials used to construct artificial organs, rehabilitation devices, or prostheses and replace natural body tissues. Without causing ANY harm or negative reactions.

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9
Q

Synthetic Biomaterials

A

Composites

Silicon impression materials

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10
Q

Natural Biomaterials

A

Alginates

Hydrocolloids

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11
Q

Tissues Engineered Biomaterials

A

Stem Cells

Replacement tissue —growing tissue

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12
Q

Material Structure

A

Atomic Arrangments
Bonding
Composition
Defects

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13
Q

Material Properties

A 
Mechanical
Physical
Chemical
Degradation
Biologic
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14
Q

Mechanical Concepts: Metals

A

Hard
Ductile-tough
Strong

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15
Q

General Mechanical Concepts: Ceramics

A

Hard
Brittle
Strong

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16
Q

General Mechanical Concepts: Polymers

A

Soft
Ductile -Tough
Weak

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17
Q

_______ and ______ have high processing temperatures

A

Metals and ceramics

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18
Q

________tend to have lower processing temperatures

A

Polymers

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19
Q

________ tend to be used as direct processing materials

A

Polymers

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20
Q

Metallic elements

A

Have 1,2,3 electrons in their outer shell

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21
Q

Electrons in metals

A

Are key to metallic bonds

Loosely bound to nucleus

Have free mobility

  • thermal and electrical conductivity
  • ductility-bend without breaking
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22
Q

Crystallization of Metal upon cooling

A

1) Molten-equally spaced
2) Nuclei begin grouping
3) crystal growth begins with more grouping
4) Formation of grains

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23
Q

Metal Alloys

A

Mixture of 2 or more metals

  • Cast metals for crowns
  • Amalgams

Stronger less ductile

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24
Q

Ductile

A

Atoms can slide

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25
Q

Strengthening Noble Metals

A

Must be made to resist deformation
Modified to impede dislocations

Au, Ag, Pd, Pt

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26
Q

Ceramic Bonds

A

Ionic and Covalent

Both stronger than metallic

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27
Q

Ionic Bonds

A

Electron donor and electron acceptor

Na+ Cl-

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28
Q

Covalent Bonds

A

Equally shared electrons

Si-O

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29
Q

Covalent___Ionic

A

>

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30
Q

3 Most common Ceramics in Dentistry

A

3 Metallic Oxides
SiO2
Al2O3
K2O

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31
Q

Microstructure of Ceramics

A

Mixture of Metallic and non-metallic elements

SiO4 (tetrahedron) is the building block

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32
Q

SiO4

A

Tetrahedron is the building block of ceramics

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33
Q

Most dental material ceramics are

A

Semicrystalline or polycrystalline

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34
Q

Crystalline

A

Long range order

Crystalline silicate quartz or crystobilite

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35
Q

Noncrystalline

A

Short range order no long ranger

Amorphous silicate glass

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36
Q

Dental Porcelain

A

SiO4 building block

Primarily a glass with some crystalline residuals

Processed by sintering or melting at high temps

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37
Q

Dental porcelain crystalline structure

A

Noncrystaline or amorphous silicate glass
Crystalline Silicates
-quartz or crystobilite
-Leucite (NOT lucite)

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38
Q

Polymer Bond Characteristics

A 
Covalent Bonds
High molecular weight
Long molecules composed principally of nonmetallic elecments (CONH)
Polymers are entangled long chains
“Cooked spaghetti”
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39
Q

Where do polymer bonds derive strength and properties?

A

From the entanglement of “cooked spaghetti”

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40
Q

Polymerization Process (4 steps)

A

1 Light activation of initiator
2 Initiation of monomer
3 Propagation of Free Radical
4 Termination of Free Radical

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41
Q

4 Stages of Chain Reaction Polymerization

A 
Activation
-free radical initiation
Initiation
-Free radical combination with monomer unit
-Double bond opening
Propagation
-Chain growth
-Volume decrease
-Shrinkage
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42
Q

Monomer Functional Groups

A

Monomethacrylates

Dimethacrylates

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43
Q

Monomethacrylates

A

Linear Chains

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44
Q

Dimetharcylates

A

Branched and cross linked

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45
Q

Poylermization Reaction

A

Once reaction starts it can be very fast and generate lots of heat

MMA—

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46
Q

Why is Polymerization Important

A

Allows for in vivo processing-Direct placement

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47
Q

Direct Placement

A 
Flowable material
Stable material
Trigger for setting
Rapid setting
Room temp setting reaction
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48
Q

Direct Vs Indirect Placement

A

Direct: Less prep, one visit. Don’t last

Indirect: Longevity of restorative. Multiple visits, expensive

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49
Q

Comparison of 3 Materials

A

Metals: Indirect
High processing temps
Except amalgam

Ceramics: Indirect
High processing temps
Except cements

Polymers: Direct
Low processing temps
Except Indirect composites

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50
Q

Uses of Polymers in Dentistry

A

Provisionals-Temporary Crowns-Linear

Adhesives-Crosslinked

Restorative-Crosslinked

Registration Materials-Impression Materials

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51
Q

Composites

A

Physical mixtures of metals ceramics and or polymers

Goal is to achieve some intermediate properties between the 2 material types. Rules of mixtures: dentin and enamel

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52
Q

Rules of MIxture

A

By knowing the phases present in the structure of any material and interfacial interactions. It is possible to predict the overall Properties fairly well

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53
Q

Dispersed phase

A

Glass Fillers

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54
Q

Matrix phase

A

Monomer resin

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55
Q

Dental Composite

A

Dispersed phase
Matrix phase

Fillers are chemically bonded to resin phase to improve properties

Photinitiators

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56
Q

Increase Filler Volume

A

Increases strenght modulus and viscosity

Decreases shrinkage

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57
Q

Increase filler size

A

Increase surface roughness

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58
Q

Filler Types

A 
Silicate glass (1-100 um)
Colloidal silica (.05 um)

75-80% wt

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59
Q

Material Properties

A

Physical (environment)
Chemical (bonding affected)
Biologic (Living tissue)
Mechanical(forces)

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60
Q

Materials Structure

A 
Atomic Arrangement
-Crystalline (grains) vs non crystalline (glassy)
Bonding
-Primary(metallic, ionic, covalent)
-Secondary (hydrogen, van der Waals)
Composition 
-Elements and phases
Defects
-Macroscopic (pores)
-Atomic Scale (microflaws)
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61
Q

Reversible Interactions with the Environment

A 
Mass Properties
Thermal Properties
Electrical Properties
Optical Properties
Surface Properties
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62
Q

Density

A

= weight/ unit volume

Metals 6-18 g/cm3
Ceramics 2-6 g/cm3
Polymers .8-1.2 g/cm3

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63
Q

Specific Gravity

A

=relative density=density of material/density of water

Density of water = 1 g/cm3
Material with specific gravity of 1.2 has a density of 1.2 g/cm3

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64
Q

Thermal Expansion

A

Most things expand when heated contract when cooled

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65
Q

Heat Flow

A

Teeth are insulators due to high mineral content

Pulp can withstand small temp changes for short times. restricted circulation of pulp cannot dissipate heat and carry it away

Metals have high thermal conductivity so they need thermal insulator like base composites do not

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66
Q

Electrical Properites

A

Metallic restorations conduct electicity
Composites and ceramics are electrical insulators

Significance:
Corrosion of metal
Galvanic reactions

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67
Q

Optical Properites

A

Color
Translucency
Gloss
Surface texture

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68
Q

Color Has 3 Dimensions

A

Hue
Value
Chroma

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69
Q

Hue

A

wavelength

Color ROY G BIV

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70
Q

Value

A

Intensity

Brightness

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71
Q

Chroma

A

Purity

Density or concentration

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72
Q

Metamerism

A

2 objects that appear the same color under one light source and different under another light source

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73
Q

Goals of Dental Material

A

Patient satisfaction

  • Esthetics
  • Functions
  • Longevity
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74
Q

Limitations

A

All Models have limitations

  • Cannot know everything about a given material or system
  • Have to choose parameters
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75
Q

Contact Angle

A

Measures how a liquid interacts with a solid

Good wetting close to 0
Poor wetting close to 180

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76
Q

Good Wetting

A

Low contact angle close to 0

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77
Q

Poor wetting

A

High contact angle close to 180

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78
Q

Hydrophilic vs. Hydrophobic

A

Can help determine the wetting properties of a material

Molecules can have both components

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79
Q

Hydrophilic primers

A

Allow penetration into areas with with water

Have low viscosity

Allow for attachment to composite

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80
Q

Sealants

A

Unrolled diluted resins
Self or light cured
Clear or opaque
Radio Plaque

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81
Q

Wetting can be anticipated on the basis of______?

A

Hydrophobicity and hydrophilicty

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82
Q

Hydrophilic Primers are usually mixed with

A

A solvent usually alcohol or acetone

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83
Q

Hydrophilic chemicals will Wet _________surfaces

A

Hydrophilic

Like associates with like

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84
Q

Surface Wetting

A

Important anytime two different materials come into contact

Important in impression materials

Important in adhesives

Important in bacterial adhesion

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85
Q

Chemical Properties

A

Chemical properties of a material are those that involve changes in the primary and secondary bonding of the material

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86
Q

Primary bonding

A

Generally affected by chemical and electrochemical reactions

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87
Q

Secondary Bonding

A

Generally affected by processes such as adsorption and absorption

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88
Q

Corrosion

A

The spontaneous destructive oxidation of metals

All metals corroded in our atmosphere spontaneously except

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89
Q

All metals corroded in our atmosphere spontaneously except

A

Gold
Platinum
Palladium

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90
Q

Amalgam filling turn

A

Black over time

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91
Q

____ alloys designed to minimize corrosion

A

Gold

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92
Q

Metal Corrosion: Active

A

Lead to destruction

Gamma 2

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93
Q

Metal Corrosion: Passive

A

Produce corrosion film that prevents further corrosion (titanium implants)

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94
Q

Metal Corrosion: Immune

A

Noble metals (gold)

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95
Q

Electrochemical Corrosion

A

Active

An anode-Corroding Metal

Cathode-Different metal

A conducting environment for ionic movement

An electrical connection between anode and cathode for the flow of electron current

In amalgam anode and cathode are the 2 phases

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96
Q

Types of Corrosion

A

Galvanic
crevice
Structure selective
Stress

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97
Q

Chemical Dissolution

A

Normally occurs through dissolution of oxides created by hydrogen bonding effects of water in local areas of high acidity

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98
Q

Absorption of water into polymers

A

Secondary bonds

Dimensional changes

99
Q

Hydrologic degration and relapses of componenents (polymers)

A

Water enzymes bacterial byproducts

Contributes to wear problem with composites

100
Q

Biological properties

A

Are interrelated with degradation properties, polymerization process, and are dynamic

101
Q

Mechanical Properites

A

Describe how a material responds to loads (forces)

102
Q

Single Dimension Force

A

Compression
Tension
Shear

103
Q

Combination forces

A

Torsion
Flexion
Diametric compression

104
Q

Mechanical Events are

A

Time and temperature dependent

105
Q

Hardness

A

Relative measure of plastic deformation.

Indent with a load and measure size of indentation

106
Q

Fracture Toughness

A

Measures a materials resistance to crack propagation

Has high clinical correlation to clinical wear data (composites)

107
Q

Creep

A

Deformation over time in response to low constant stress

108
Q

Stress Relaxation

A

Deformation over time in response to low constant strain

109
Q

Biomechanics of Tooth Structure

A

Teeth are not rigid

When teeth are subject to chewing forces they undergo subclinical movements

110
Q

what leads to microfractures

A

Cyclic tension and compression of enamel rods

111
Q

Abfractions usually associated with

A

Heavy wear facets

112
Q

Single cycle overload

A

Unexpectedly bit on cherry pit or bone rare

113
Q

Fatigue fracture

A

Cyclic loads well below breaking load

I was eating something soft-more common

114
Q

Amalgams

A

Easy to place
Excellent Clinical outcomes
Poor esthetics

115
Q

Ceramics

A

Good esthetics
Excellent clinical outcomes
More difficult to process

116
Q

Composite Resins

A

Esthetic Direct restorative
Cured by visible light
Primary benefit is the combination of esthetics and ease of placement
Moderate clinical outcomes

117
Q

Composite

A

Hybrid material of an organic phase(resin) and an inorganic (filler) phase

118
Q

Why use composites

A

Teeth are composites
And Anat ages of Both organic and inorganic components
Easily processed and handled allows for direct restorations

119
Q

Galvanic Corrosion

A

One metal acts as an anode and another acts as cathode

120
Q

Structure Selective Corrosion

A

One phase of an amalgam and another phase

121
Q

Crevice Corrosion

A

The tip of a crack in a preparation; surface of prep

122
Q

Stress corrosion

A

Stressed portion; unstressed regions

123
Q

Ceramics Hydrolysis

A

Via Chemical dissolution-normally occurs through dissolution of oxides

Ex. Acid dissolves HA

124
Q

Polymer Hydrolysis

A

Via absorption of water into polymers

Via Hydrolysic degradation and release of polymer components

125
Q

Stress Strain Curve

A

(Know different regions of curve)

Elastic Region

Plastic Region

Ultimate Strenght

126
Q

Elastic Region

A

Straight region of the curve

Strain is reversible

127
Q

Plastic Region

A

Line starts to curve strain is permanent

128
Q

Ultimate Strength Region

A

Highest point of the curve; point at which the material fail

129
Q

Stiff and Brittle Curve

A

High modulus (steep slope)

Small plastic region
Small area under curve-absorbs a relatively small amount of energy

130
Q

Stiff and Ductile

A

High modulus (steep slope)

Larger plastic region-can handle a fair amount of permanent deformation before failing

Large area under Curve-can absorb a fair amount of energy

131
Q

Flexible and Ductile

A

Low modulus

Plastic Region that continues past ultimate strength pint-can deform past point of failure before failing completely

Large area under curve-can absorb a fair amount of energy

132
Q

Modulus and toughness

A

Slope of the straight position of the modulus of elasticity

Steeper=stiffer
Gradual=more elastic

133
Q

Reduce a materials modulus of elasticity; decreases_______ and increases __________

A

Stiffness

Flexibility

134
Q

Fatigue

A

The weakening of a material caused by repeat early applied loads

135
Q

Fracture Toughness

A

Measures a materials resistance to crack propagation

136
Q

Abfractions

A

Non-curious tooth tissue loss around the gingival margin

137
Q

Buccal-Lingual Stability

A

Want to prep tooth such that Buccal-Lingual cusps can all withstand required biting/chewing forces

138
Q

BisGMA-TEGDMA

A

Most common system

Allow for relative ease of processing-flows well when unpolymerized

139
Q

BisGMA

A

Methacrylate

Structural component-provides physical properties for polymer

140
Q

TEGDMA

A

Dimethacrylate

Dilute the-used in 30-50% wt
Forms cross links between chains

141
Q

Composite Fillers

A

Silica or zirconia based inorganics

142
Q

Different composite filler sizes

A

Higher, Smaller, Micron, nano, Nano in polymer matrix

143
Q

High Filler

A

Loading results in a higher modulus

144
Q

Smaller Filler

A

Better

Matches tooth structure
Have better wear properties
Allow for better polishing and finishing
Better mechanical properties

145
Q

Nano Filler

A

Microfine

Has a lower modulus but increased surface area results in better wear resistance

146
Q

Nano filler in polymer matrix

A

Microfine fillers polymerized in matrix

Poorer filler to matrix bonding-no coupling agent

147
Q

Coupling Agent

A

Adds methacrylate groups that can bond with polymer chains

Forms very strong bonds between filler and resin

148
Q

Resin helps ______ and_____

A

Processing and handling

149
Q

Filler helps______ and ______

A

Modulus and wear resistance

150
Q

More filler will result in:

A

Increased Strenght & resistance

Reduce Shrinkage during curing

But will increase viscosity and brittleness

151
Q

More resin will:

A

Increase toughness flow ability and improve processing

Decrease strength and wear resistance

152
Q

What does Curing do?

A

Induces polymerization of resin

153
Q

Visible Light Cure

A

Ease of use of resins. Allows for a longer working time

154
Q

Cross linking

A

Formation of bonds between polymer chains within a resin

155
Q

How crosslinking controls properties

A

Improves Strenght of material

More crosslinking leads to more resilient material

156
Q

3 types of curing

A

Chemical Mixing
Heat
Light Cure

157
Q

Chemical mixing cure

A

Working time is operator dependent

Can be done chair side

158
Q

Heat Curing

A

Consistent high temperature

Not good in vivo

159
Q

Light Cure

A

Cure ion command

Good in vivo

160
Q

What portion of composite will shrink upon polymerization?

A

Resin matrix portion

161
Q

Consequences of shrinkage

A

Stress on tooth structure

Can cause micro leaks and lead to secondary caries

162
Q

Acidic polymer in aqueous solution

A

Poly acrylic acids

163
Q

Basic glass (powder)

A

Aluminaflurosilicate glass

164
Q

Glass ionomer curing reaction

A

Cured by acid base reaction

Not all glass is consumed by reaction

Salt bridges form crosslinage and are made from polyacid and glass

165
Q

Water based restorative

A

Good adhesion to tooth structure (hydophilicyt)

Primarily bonds to tooth structure chemically

Bonds better with enamel than with dentin

166
Q

Process of Application\

A

Place liner on dentin to clean the smear layer and leave smear plugs
Apply GI mix
Polyacid matrix dissolve periphery of glass
Glass release calcium alummninum fluroide

167
Q

Resin modified glass ionomer

A

Hybrid of GI and composite resin
Both VLC and acid base curing
Increased mechanical properties of GI

168
Q

Composite Initiation

A

Free Radicals initiate methacrylate polymerization

-visble light initiator

169
Q

Adhesives are based on the composite resin chemistry

A

Contains acidic groups to promote bonding

Dimethacrylate are visible light cured

170
Q

_______ promote bonding

A

Hydrophilic modifiers

171
Q

_______ and ______ are needed for bonding

A

Hydrophilic and hydrophobic Properites

172
Q

Tooth structure are________, composites are________ and adhesive layers are both

A

Hydrophilic

Hydrophobic

173
Q

Adhesive Failure

A

Failure between composite and adhesive

174
Q

Cohesive Failure

A

Failure in the adhesive section only

175
Q

Structural failure

A

Failure in the Dentin portion only

176
Q

Smear Layer

A

Consisted of ground collagen and HA

177
Q

Sealants

A

Designed to flow well and seal Noncavitated tooth surface to prevent decay

178
Q

Etching

A

Necessary to create micro racks in the enamel to add surfaced area

179
Q

Sealants have fillers

A

0-10%

180
Q

Oxygen inhibition layer

A

Atmospheric layer of sealant does not solidify well due to oxygen

181
Q

Impression Molds

A

Used to make a negative mold of dental structures

182
Q

Hydrocolloid

A

Alginate
Agar-agar

Bot are hydrophilic and wets the tooth structure and gypsum

Immediate pouring of impression in stone should occur due to ability of hydrocolloids to gain or lose water

183
Q

Alginate

A

Irreversible chemical reaction

Material is elastic and used in stock tray for primary impression and final impression for complete dentures

184
Q

Factors that affect alginate setting time/rxn rate

A

Temperature
Liquid/powder ratio
Particle size
Mixing rate

185
Q

Alginate is NOT used for

A

Crown and bridge impressions due to lack of accuracy

186
Q

Agar-Agar

A

Reversible physical reaction -Temp

Material is elastic and used in special stock trays to make 2ry impressions for fixed restoration (inlay onlay crown and bridges)

Low tear strenght due to high water content(will tear easier)

187
Q

Viscoelasticity

A

Upon placing impression tray with material on teeth the material will immediately strain and on removal of impression tray with material the material will be permanently strained and no recovery of original shape

188
Q

Plain Elastic

A

Would deform under stress but return to shape following removal of stress

189
Q

Plain Viscous

A

Would defor very gradually with stress and would provide resistance to initial stress and initial deformation

190
Q

When taking impressions

A
  • Let the material set
  • Don’t exert over pressure on tray after insertion
  • Use rapid snap removal of imporession with long axis of teeth to decrease unwanted deformation and prevent tearing
191
Q

Classification of Impression materials 3 types by physical condition after setting

A

Rigid

  • Zoe
  • Plaster

Plastic

  • Wax
  • Compound

Visco(elastic)

  • Hydrocolloids
  • Elastomers
192
Q

Alginate acid dissolved in ______

A

Water

193
Q

Alginates are temperature controlled______and chemically controlled_______

A

Reversible

Irreversible

194
Q

How can Alginates be manipulated

A

Water to powder ratio

195
Q

Alginate lower water to powder ratio

A

Increases strenght tear resistance and consistency

Decreases working and setting time and flexibility

196
Q

Alginates have ______ crosslinks

A

Calcium

197
Q

Advantage of Alginate

A

Surface energy- wets tooth structure and gypsum stone well
Quick setting
Easy to use

198
Q

Disadvantage of alginate

A

Poor dimensional stability
-Synereis
Imbition

199
Q

Syneresis

A

In a dry environment will lose water over time leading to shrinkage and deformation

200
Q

Imbibition

A

In wet environment will gain water and expand

201
Q

Polysulfides: impression material

A

Conform well to a prepared tooth, resulting in good surface detail and are oxidize by lead dioxide or copper hydroxide to form a polysulfide rubber with a water condensate

202
Q

Polysulfides :Low molecular weight_______ containing reactive _______groups

A

Oligmer

Metacarpan

203
Q

Advantage of Polysulfidle impression

A 
Low shrinkage
Very little expense
Good actuary and stability
Material retained well in tray well
Can add layers to old layers
204
Q

Disadvantages of Polysulfides

A

Can stain brown
Odorous
Sets slows
Must be poured within 1 hour after impression

205
Q

Polysiloxanes

A

Inherently hydrophobic
Excellent accuracy
Good chemical dimensional stability

206
Q

Polysiloxanes advantages

A 
More stable than alginate and polysulfides
Can repour
Greatly accuracy
No staining
No odor
Paste system easing mixing
Various viscosity
207
Q

Polysiloxanes disadvantages

A

Difficult for operator to vary setting time
EXPENSIVE
Can produce bubbles in final cast due to hydrogen

208
Q

Polyethers

A

Low molecular weight polyether oligomer with terminal ethylene I mine reactive ring groups will react with aromatic sulfonic ester by dual ring opening with resultant polymer being cross linked

209
Q

Polyethers advantages

A

Great stability
Slightly hydrophilic
Adhesives work well
Fast setting time

210
Q

Polyethers Disadvantages

A

Extremely stiff-tough to remove from undercuts
Low tear strenght-tears easy
Slightly hydrophobic
Bad taste
Can cause hypersensitivity in some patients

211
Q

Gypsum

A

Dental plaster and stone to make casts

212
Q

Mineral gypsum is the _____ form of _______

Found in a compact mass in nature

A

Dehydrate

Calcium sulfate

213
Q

Calcination

A

Part of the water is driven off to form calcium sulfate-hemihydrate

214
Q

Water cured

A

When dental stone is mixed with water the reverse reaction takes place (calcination)

Hemihydrate coverted back to hydrate
Heat is released exothermic

215
Q

Gypsum crystals grow and interlock during setting, why?

A

Interlocking contributes to Strength and dimensional change of gypsum

Properties can be altered by manipulating growth of dehydrate crystals

216
Q

Types of Gypsum

A

Dental Plaster

Dental Stone

217
Q

Dental Plaster: Type I

A

Impression plaster

218
Q

Dental Plaster: Type II

A

Model plaster

219
Q

Dental ______ is weaker than dental _____ due to porous particles that require more water and ______

A

Plaster
Ston
Irregular crystal shape

220
Q

Dental Stone: Type III

A

Dental stone quickstone

221
Q

Dental Stone: Type IV

A

High strenght dental stone (silky rocky)

Used for inlays crowns bridges casts

222
Q

Dental Stone: Type V

A

High strenght high expansion stone
Used for polyethers or polyvinyl impressions

Composed of alpha form of hemidhyrdate crystals

223
Q

Principal difference between plaster and stone

A

Shape and form of hemihydrate crystals

224
Q

If gypsum is place in water

A

It can dissolve

225
Q

Dental stone used for models not plaster

A

High crushing strength

Better abrasion resistance

226
Q

Denture base

A

Triad

Machine is a visble light curing machine that cures the triad material. Used to make custom accurate stable trays

227
Q

Denture base need for difference in composition

A

Differences in composition provide differences in mechanical characteristics of the tray

Fillers provide hardness and rigidity to the tray

228
Q

TRIAD and TRIM and JET use same baseline material

A

Polmethylmethacrylate

229
Q

Which is strongest and why TRIAD TRIM JET

A

TRIAD due to dimethylmethylacrylate crosslinkage

230
Q

Mouthguard

A 
Designed to absorb impact
High toughness low rigidity 
Thermoplastic materials (not thermoset)
231
Q

Cements

A

Used to bind restorations or appliances to tooth structure

232
Q

Requirements for cements

A

Low viscosity but good mechanical Properites

233
Q

Water Based Cements

A

Glass ionomer
Resin modified glass ionomer
Zinc phosphate
Zinc polyarcylate

234
Q

Resin Based cements

A

Composites

Compomers

235
Q

Oil Based Cements

A

Zinc oxide eugenol

236
Q

Base and Liners functions

A

To protect pulp and minimize post op sensitivity

  • Act as thermal and chemical barrier
  • Control inflammation of pulp
  • Control fluid movement
237
Q

Bases

A

Provide thermal protection for pulp

Supplement mechanical support for the restoration by distributing local stresses

238
Q

Liners

A

Thin layer of material used to protect dentin

239
Q

Calcium Hydroxide

A

Pulp capping

  • insulator
  • Stimulates reparative dentin
  • Rleases hydroxide ions
  • At low ion concentrations - stimulates odontoblasts
240
Q

ZOE

A

Pain reduction
Dulls pulpal pain
Limits free radical formation-cannot put composite on top of ZOE because it will limits polymerization

241
Q

Waxes

A

Should melt at lower temperatures
Should be carvable
Must be able to be burned off
Must be dimensionally stable

242
Q

Hexane

A

Volatile liquid

243
Q

Candle Wax

A

Typical semi-solid Wax

244
Q

Poly-ethylene

A

Plastic

Cariology (2 decks)

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