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Dental Materials > Resin Composites > Flashcards

Resin Composites Flashcards

1
Q

What are the four components of composites?

A
  1. Matrix made of ORGANIC polymers
  2. Fillers made of inorganic particles such as glass or cermaics
  3. Coupling agents: Inorganic compound that bonds matrix and filler
  4. Initiator-Accelerator Systems
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2
Q

Ceramic have very ______ while polymers have very ______.

This makes resin composites fall ________ in terms of mechanical strength.

A

very high mechanical properties

Very low mechanical properties

Resin composites fall right between ceramic and polymers

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3
Q

What are the two most common resins?

Both of these are ________ and _________liquids.

A

Dimethacrylate (Bis-GMA)

Urethane dimethacrylate (UDMA)

Oligomers and viscous liquids

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4
Q

How do we reduce viscosity of __________ and ____________ ?

A

Bis-GMA ,UDMA

Add low molecular weight dimethacrylates such as TEGDMA and Bis-EMA6

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5
Q

Why is it important to reduce viscosity of resin composites?

A

To facilitate manipulation

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6
Q

What is the advantage of acrylic resins?

A

Lower polymerization shrinkage

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7
Q

Fillers can make up _________ to _____ in weight of the composite.

They control the ________ such as _______ and are usually particles of _______.

A

30-70% in weight of the composite

properties of the composite such as mechanical, water sorption, shrinkage

Particles of Glass

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8
Q

What glass is used in fillers?

A

Ceramics such as quartz, lithium aluminum silicate

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9
Q

What controls the properties of the composite?

A

Fillers

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10
Q

Radiopaque fillers include

A

barium
strontium
zinc
borosilicates
aluminosilicates

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11
Q

Fillers can reduce _________.

A

Shrinkage

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12
Q

What are the three categories of filler size?

A

Fine : 0.2 ro 3 micrometers/microns

Microfine : 0.04 microns

Nanofine: 1-100 NANOmeters

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13
Q

________ which are about _________ in size can agglomerate and form a ________

A

Nanofine, 1-100 NANOmeters, nanocluster

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13
Q

______ nanometers = _______ micrometer/micron

A

1000 = 1

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14
Q

The size-distribution of fillers can be split into _______ and _______.

A

Hybrids: Different Sizes

Filled: Similar sizes

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15
Q

What are two other options of fillers?

A
  1. Fiber-reinforced

Glass Fibers or Polyethylene or Aramid

  1. Nano-tubes

Carbon
Halloysite
Ceramics, Carbides, Zinc Oxide ..

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16
Q

Fiber-reinforced fillers include ______, ______ and ________.

_________ are ______ cost and have good adhesion

______ have __________ and poor adhesion

A

glass fibers, polyethylene fibers and aramid fibers

Glass , low cost, good adhesion

Polyethylene Fibers , enhanced mechanical properties, poor adhesion

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17
Q

Macrofill

A

10-50 micrometer sized particles

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18
Q

Microfill

A

40-50 NANOmeter sized particles that agglomerate

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19
Q

Hybrid

A

Some Macrofill (10-50 microns)
Some Microfill (40-50 nm)

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20
Q

Midifill

A

1-10 microns

40 nanometer

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21
Q

Minifill

A

0.6-1 microns

40 nanometer

22
Q

Nanofill

A

5-100 NANOmeters

23
Q

We can classify composites by consistency

________ composites have better ________/______. It reduces _________ but also reduces __________.

_________ allows formation of ____________ and has modified ___________ or other types of ________.

A

Flowable, adaptation/dispensing

Filler content but also reduces mechanical properties

Packable , tight interproximal contacts

filler size distribution or other types of fillers

24
Q

What are bioactive fillers/monomers?

A

They prevent secondary caries and regenerate tissue?

25
Q

What are the 3 types of bioactive monomers?

A

Antibiofilm/bacterial/fungal

Remineralizing/Regeneration

Acid Neutralizing

26
Q

___________(4) are all bioactive fillers that are have _________ properties

A

Silver
QA
ZINC

Antibiofilm/bacterial/fungal

27
Q

___________is a bioactive filler that are have _________ properties

A

Calcium Phosphate (CaP)

Remineralizing/Regeneration

28
Q

___________is a bioactive filler that are have _________ properties

A

CaP fillers

Acid neutralizing

29
Q

Calcium phosphate is a ________ that has both ________ and _______ properties.

A

Bioactive filler

Acid Neutralizing, Regenerative/Remineralizing

30
Q

Coupling agents are responsible for ___________.

They enhance _______ and minimize _______.

A

being the glue that bonds INORGANIC fillers with organic resin matrix.

Enhances mechanical properties of composite

Minimizes water absorption (hydrophobic environment)

31
Q

What is the most common agent in coupling gents?

A

Silane

32
Q

________ are often added to coupling agents.

A

INORGANIC pigments/oxides ( of iron)

Flourescent Agents for whitening effect

33
Q

There are three ways to cure composite.

What are they?

A
  1. Light
  2. Chemical Reaction
  3. Dual Initiated
34
Q

Light curing is done with ___ light at wavelength _________ in the _____ spectra.

Initiator:

Accelerator:

A

blue , 465 NANOmeters, visible light

Initiator: Camphorquinone added in 0.1-1% OR Diketone-amine

Accelerator: Organic amines such as DAEMA

35
Q

What are the two initiators of light curing?

A

Camphorquinone added in 0.1-1%

OR

Diketone-amine

36
Q

__________ is a type of curing light made of _____________.

It has _______ at ______ wavelengths and has an __________ operating temperature.

It has a life of ________.

A

Quart Tungsten Halogen

Quartz Bulb

Filtered Light - 400-500 nm

Elevated operating temperature

100 hrs

37
Q

_______is a type of curing light made of __________. It has a ____________ light spectrum and __________ generation.

Its life is __________.

A

LED

Semiconductors

narrow light spectrum and low heat

1000 hrs

38
Q

How can we calculate the power intensity for different curing lights ?

A

Total Energy = Light Irradiance x Duration

38
Q

What is light irradiance?

What is the formula?

A

How powerful the curing light is

39
Q

What is the unit for light irradiance?

A

mW/cm^2

40
Q

Light is ________ inside the composite due to _______.

The tip of the curing lamp should be within ________ of the surface.

A

Scattered

1mm

41
Q

What can measure light irradiance?

A

Radiometer

42
Q

Chemical Activation

Initiator

Accelerator

How fast does it set?

A

Organic peroxides like benzoyl peroxide that produces free radicals

3-5 minutes

43
Q

What is the result of inadequate polymerization?

A

Poor resistance to wear

Poor color stability

Secondary Caries

Adverse soft tissue/pulp reactions

Cytotoxicity

44
Q

Volumetric shrinkage during polymerization can cause ________.

A

Contraction stress

45
Q

The _______ of the composite _______ linearly with the volume fraction of ________.

The _______ is dominated by the amount of ________.

A

strength / increases linearly with volume fraction of filler

elastic modulus/stiffness is dominated by the amount of filler

46
Q

Opalescence varies by ______ and ________ of filler.

As the amount of same filler increases, translucency _________.

A

size and amount

decreases

47
Q

Water sorption causes the ________ of composite due to ___________.

This can relieve __________ and is a much ________ process than polymerization shrinkage.

After ______ , majority expansion is reached and it takes _______ to equilibrium

A

expansion, uptake of water

polymerization stress and is a much slower process

4 days, 7 days

48
Q

Water sorption is greater for _________ and evidenced as _______.

It is also higher in _________ compared to ________ filler.

A

uncured composites, color instability

microfilled than microhybrid.

49
Q

Hardness is related ___________ to the volume fraction of filler.

Strength increases _________ to the volume fraction of filler.

A

exponentially

linearly

50
Q

Higher hardness materials are more _______ to polish.

A

More difficult

51
Q

Radiopacity is proportional to the amount of __________.

A

FILLER

Dental Materials (6 decks)

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