Resin Composites Flashcards
What are the four components of composites?
- Matrix made of ORGANIC polymers
- Fillers made of inorganic particles such as glass or cermaics
- Coupling agents: Inorganic compound that bonds matrix and filler
- Initiator-Accelerator Systems
Ceramic have very ______ while polymers have very ______.
This makes resin composites fall ________ in terms of mechanical strength.
very high mechanical properties
Very low mechanical properties
Resin composites fall right between ceramic and polymers
What are the two most common resins?
Both of these are ________ and _________liquids.
Dimethacrylate (Bis-GMA)
Urethane dimethacrylate (UDMA)
Oligomers and viscous liquids
How do we reduce viscosity of __________ and ____________ ?
Bis-GMA ,UDMA
Add low molecular weight dimethacrylates such as TEGDMA and Bis-EMA6
Why is it important to reduce viscosity of resin composites?
To facilitate manipulation
What is the advantage of acrylic resins?
Lower polymerization shrinkage
Fillers can make up _________ to _____ in weight of the composite.
They control the ________ such as _______ and are usually particles of _______.
30-70% in weight of the composite
properties of the composite such as mechanical, water sorption, shrinkage
Particles of Glass
What glass is used in fillers?
Ceramics such as quartz, lithium aluminum silicate
What controls the properties of the composite?
Fillers
Radiopaque fillers include
barium
strontium
zinc
borosilicates
aluminosilicates
Fillers can reduce _________.
Shrinkage
What are the three categories of filler size?
Fine : 0.2 ro 3 micrometers/microns
Microfine : 0.04 microns
Nanofine: 1-100 NANOmeters
________ which are about _________ in size can agglomerate and form a ________
Nanofine, 1-100 NANOmeters, nanocluster
______ nanometers = _______ micrometer/micron
1000 = 1
The size-distribution of fillers can be split into _______ and _______.
Hybrids: Different Sizes
Filled: Similar sizes
What are two other options of fillers?
- Fiber-reinforced
Glass Fibers or Polyethylene or Aramid
- Nano-tubes
Carbon
Halloysite
Ceramics, Carbides, Zinc Oxide ..
Fiber-reinforced fillers include ______, ______ and ________.
_________ are ______ cost and have good adhesion
______ have __________ and poor adhesion
glass fibers, polyethylene fibers and aramid fibers
Glass , low cost, good adhesion
Polyethylene Fibers , enhanced mechanical properties, poor adhesion
Macrofill
10-50 micrometer sized particles
Microfill
40-50 NANOmeter sized particles that agglomerate
Hybrid
Some Macrofill (10-50 microns)
Some Microfill (40-50 nm)
Midifill
1-10 microns
40 nanometer
Minifill
0.6-1 microns
40 nanometer
Nanofill
5-100 NANOmeters
We can classify composites by consistency
________ composites have better ________/______. It reduces _________ but also reduces __________.
_________ allows formation of ____________ and has modified ___________ or other types of ________.
Flowable, adaptation/dispensing
Filler content but also reduces mechanical properties
Packable , tight interproximal contacts
filler size distribution or other types of fillers
What are bioactive fillers/monomers?
They prevent secondary caries and regenerate tissue?
What are the 3 types of bioactive monomers?
Antibiofilm/bacterial/fungal
Remineralizing/Regeneration
Acid Neutralizing
___________(4) are all bioactive fillers that are have _________ properties
Silver
QA
ZINC
Antibiofilm/bacterial/fungal
___________is a bioactive filler that are have _________ properties
Calcium Phosphate (CaP)
Remineralizing/Regeneration
___________is a bioactive filler that are have _________ properties
CaP fillers
Acid neutralizing
Calcium phosphate is a ________ that has both ________ and _______ properties.
Bioactive filler
Acid Neutralizing, Regenerative/Remineralizing
Coupling agents are responsible for ___________.
They enhance _______ and minimize _______.
being the glue that bonds INORGANIC fillers with organic resin matrix.
Enhances mechanical properties of composite
Minimizes water absorption (hydrophobic environment)
What is the most common agent in coupling gents?
Silane
________ are often added to coupling agents.
INORGANIC pigments/oxides ( of iron)
Flourescent Agents for whitening effect
There are three ways to cure composite.
What are they?
- Light
- Chemical Reaction
- Dual Initiated
Light curing is done with ___ light at wavelength _________ in the _____ spectra.
Initiator:
Accelerator:
blue , 465 NANOmeters, visible light
Initiator: Camphorquinone added in 0.1-1% OR Diketone-amine
Accelerator: Organic amines such as DAEMA
What are the two initiators of light curing?
Camphorquinone added in 0.1-1%
OR
Diketone-amine
__________ is a type of curing light made of _____________.
It has _______ at ______ wavelengths and has an __________ operating temperature.
It has a life of ________.
Quart Tungsten Halogen
Quartz Bulb
Filtered Light - 400-500 nm
Elevated operating temperature
100 hrs
_______is a type of curing light made of __________. It has a ____________ light spectrum and __________ generation.
Its life is __________.
LED
Semiconductors
narrow light spectrum and low heat
1000 hrs
How can we calculate the power intensity for different curing lights ?
Total Energy = Light Irradiance x Duration
What is light irradiance?
What is the formula?
How powerful the curing light is
What is the unit for light irradiance?
mW/cm^2
Light is ________ inside the composite due to _______.
The tip of the curing lamp should be within ________ of the surface.
Scattered
1mm
What can measure light irradiance?
Radiometer
Chemical Activation
Initiator
Accelerator
How fast does it set?
Organic peroxides like benzoyl peroxide that produces free radicals
3-5 minutes
What is the result of inadequate polymerization?
Poor resistance to wear
Poor color stability
Secondary Caries
Adverse soft tissue/pulp reactions
Cytotoxicity
Volumetric shrinkage during polymerization can cause ________.
Contraction stress
The _______ of the composite _______ linearly with the volume fraction of ________.
The _______ is dominated by the amount of ________.
strength / increases linearly with volume fraction of filler
elastic modulus/stiffness is dominated by the amount of filler
Opalescence varies by ______ and ________ of filler.
As the amount of same filler increases, translucency _________.
size and amount
decreases
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
expansion, uptake of water
polymerization stress and is a much slower process
4 days, 7 days
Water sorption is greater for _________ and evidenced as _______.
It is also higher in _________ compared to ________ filler.
uncured composites, color instability
microfilled than microhybrid.
Hardness is related ___________ to the volume fraction of filler.
Strength increases _________ to the volume fraction of filler.
exponentially
linearly
Higher hardness materials are more _______ to polish.
More difficult
Radiopacity is proportional to the amount of __________.
FILLER
