Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pres/Res > Midterm - Biomaterials > Flashcards

Midterm - Biomaterials Flashcards

(71 cards)

Start Studying
1
Q

Polymer Structure

A

many parts, may have amorphous or crystalline regions

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

Homopolymer

A

one type of building unit (can be linear or branched)

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

Copolymer

A

two or more building units (can be randomly arranged, in block formation, or grafted)

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

Croos-linked

A

contains “bridges” between linear molecules forming a 3-D network

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

Molecular Weight

A

polymers reported with average MW
increase MW/chain length - increased rigidity, strength, melting temps
increase cross links - changes MW, alters physical properties, increased rigidity, resistance to solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Elastic Deformation of Polymers

A

crystalline regions and cross-links help prevent plastic deformation and allow full recoil from the elastic formation
-after stretching with force, returns to original shape

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

Plastic Deformation of Polymers

A

permanent deformation, one chain slides over another and becomes relocated

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

Viscoelastic

A

time dependent recovery of elastic strain, length of deformation determines if it will return to original conformation or not, could be partially changed

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

Thermoplastic

A

soften by heating and solidify when cooling

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

Thermosetting

A

solidify during fabrication but do not soften by heating

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

Solvation Properties of Polymers

A

dependent on MW and cross linking

  • longer chain, higher MW dissolve slower
  • solvents break chains and take up space between them
  • crosslinking retards dissolution (makes it harder to dissolve)
  • swelling can effect fit, eventually shrinks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Polymerization

A

chemical linking of monomers to form high MW molecules

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

Types of Polymerization Reactions

A

Condensation

Addition

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

Condensation

A

step growth, components all become reactive simultaneously while producing low MW by products such as water (ex. impression materials)

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

Addition

A

addition of monomers sequentially in a chain that begins as an active venter via free-radical polymerization

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

Steps of Free-Radical Polymerization

A

induction (activation, initiation)
propagation
chain transfer
termination

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

Poly(Methyl Methacrylate) PMMA

A

used for denture base

thermosetting material example

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

Gutta Percha

A

used for filling canal space after root canals
natural polymer
classified as rubber (trans-isoprene)
thermoplastic material example

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

Polyurethane

A

used for orthodontic ligatures, modules, chains

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

Polycarbonate

A

plastic orthodontic brackets

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

Polyether, Polysulfide, Polyvinyl Siloxane

A

impression materials

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

Composite

A

a mixture of two classes of materials

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

Dental Composite

A

mixture of polymer (resin matrix) and ceramic (glass particle, fillers)

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

Dental Composite Components

A

matrix
filler
coupling agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Matrix
a plastic resin material that forms a continuous phase (matrix) that binds the filler particles dimethacrylate matrices can have varying viscosities
26
Filler
reinforcing particles and/or fibers dispersed in the matrix (50-85% of composite weight) Ceramics - silica, aluminum silicates strontium, zinc glass Increases flexure, compressive strength, hardness, reduces polymerization shrinkage, reduces coefficient to thermal expansion, increases thermal conductivity
27
Coupling Agent
bonds the filler to the matrix (increases wear, fatigue, fracture resistance) treat the filler with agent before bonding to matrix organic silicon compounds: silanes
28
Other Components of Dental Composites
initiators, activators, accelerators, inhibitors, pigments, opacifiers
29
Composite Classification
``` activation mode (light, chemical, dual cured) usage (anterior, posterior, universal) filler characteristics ```
30
Filler Characteristics
particle size - small, microfilled, hybrid, traditional (large) distribution
31
Ideal Composite
obtain the smoothness of microfilmed and the higher mechanical advantages of large particle composites
32
Hybrid Composites
(1) microfill (0.04um) | 2) second particle - small (0.1-2um), middle (0.1-10um), large (1-20um
33
Hybrid Flower Variation
- more filler = packable, used where condensation is needed | - less filler = flowable, less viscous, higher shrinkage, water sorption, thermal expansion
34
Polymerization Considerations
oxygen inhibition layer degree of conversion polymerization shrinkage contraction stress
35
Oxygen Inhibition Layer
oxygen diffuses into the resin and oxidizes the free radicals into peroxides, reduced monomer reactivity and less polymerization -susceptible to staining -reduced polymerization --> less strength 4-40um thick, uppermost layer
36
Degree of Conversion
the % of C=C converted to single bonds in addition polymerization (typically 50-70%) - residual monomer could leach if unreacted - higher % more strength
37
Polymerization Shrinkage
polymer organizes the monomers and they occupy less space, shrink - generally 2-5% -leakage, secondary caries at the margin
38
Contraction Stress
a pull on tooth structure from composite shrinkage - more conversion = more stress = higher stress - cavity configuration factor (C factor) - ratio bonded to unbonded, the higher the more stress
39
How to Lower Contraction Stress
formulation (large monomers, non-bonded fillers, adding inhibitors to slow curing, different monomer systems) liners to act as stress absorbers limit constraints and curing in increments horizontal, vertical, oblique increments of placement light cure protocols (ramp, step, pulse, concept) to slow polymerization to allow for flow before gel point
40
Do low shrink composites reduce shrinkage stress?
no, stress will still be present
41
Composite Properties: thermal expansion
higher than enamel and dentin
42
Composite Properties: water absorption
less with more filler
43
Composite Properties: wear
abrasion attrition marginal ditching corrosion
44
Composite Properties: translucency
varies, layer to achieve natural tooth look
45
Composite Properties: shade
may shift with polymerization, differs between manufacturers, should shade select prior to rubber dam placement
46
Composite Properties: finishing and polishing
smooth surface will increase longevity, reduce plaque accumulation abrasive discs, strips, cutting carbide, diamonds, stone, rubberized abrasives, pastes and powders
47
Composite Properties: failure
0-5 years: composite failure | 6-17 years: secondary caries
48
Bulk Fill Composite
placed in larger increments, less filler, thicker layers from light cure, get a composite cap at the top
49
Indirect Composite Resin
made in labs inlays, onlays, crowns, veneers, bridges cured with light cure box/machine
50
CAD/CAM
composite resin blocks used for milling in 3D scans
51
MUSOD Direct Composite Resin
``` TPH Spectra (sim lab) - universal, nano hybrid and microfiller components Synergy D6 (clinic) - universal, nano hybrid SureFil SDR (clinic eventually) ```
52
Light Cure Types
Quartz-tungsten-halogen LED (light-emitting diode) Plasma Arc (PAC) Argon Laser
53
Light Cure Types: QTH
broad wavelength distribution
54
Light Cure Types: LED
distinct, narrow wavelength distribution, or multiple distributions
55
Light Cure Types: PAC
broad wavelength distribution
56
Light Activation
Camphorquinone (CQ) - photoinitiator and amine activator | Note: the spectral emission of the light curing unit should overlap the absorption spectrum of the photo initiator
57
Light-Curing Reciprocity Law
comparable material properties will result as long as the same radiant exposure is obtained -radiant exposure=irradiancextime
58
Irradiance Variability
the light exiting light-curing units is not necessarily uniform
59
Light Attenuation
light intensity decreases with distance, cure in layers 2mm or less
60
Light Angulation
restoration perpendicular to emitted light without touching - angles reduce energy delivery
61
Light Cure Safety
need blue light filtering glasses, one second exceeds max daily exposure - cornea damage and accelerated retinal aging/degeneration -high levels cause immediate, irreversible retinal damage
62
Smear Layer
instrumentation blocks dentin tubules with debris and reduces permeability, very soluble layer that weak acids remove 0.5-5 um
63
Bonding Agent Ingredients
etchant primer adhesive
64
Etchant
conditioner, phosphorus acid solutions or gels | pH 1 to remove smear layer and mineral from around collagen fibrils in dentin
65
Primer
hydrophilic monomers in a solvent
66
Adhesives
hydrophobic, dimethacrylate TEGDMA, Bis-GMA, UDMA should be compatible with monomers used in primer and composite
67
Enamel-Resin Bond
micromechanical bond with penetration of adhesive into etched enamel by primer
68
Dentin Hybrid Layer
penetration of resin (monomers) into etched dentin around collagen fibrils -50% resin, 50% collagen matrix
69
Etch and Rinse
separate etch and rinse phase, sometimes called total etch | three step or two step
70
Self Etch
non-rinse acidic monomers | two or one step
71
MUSOD Bonding
Etch and Rinse 3 step (Optibond) | Self Etch 2 step (Clearfil)

Pres/Res (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions