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65 Cards in this Set

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What is a compound of two or more distinctly different materials such that the compound has superior (or intermediate) properties of the individual materials being combined?
composite
What is unique about the strength of a composite?
It's stronger than the individual strengths of the materials that make it up
What are two examples of naturally occurring composite?
enamel, dentin
What is the composition of enamel?
1% wt enamelin, 90-92% wt hydroxyapatite and water
What is the composition of dentin?
18% wt collagen, 75% wt hydroxyapatite and water
True or False, restorative resins are not considered synthetic composites
False, they ARE
In what decades were Acrylic resins developed?
1940s and 1950s
Acrylic resin has (high, low) polymerization shrinkage (PS) and (high, low) coefficient of thermal expansion (CTE)
high, high
What was added to acrylic resin to decrease polymerization shrinkage and coefficient of thermal expansion?
Quartz filler
What are the 6 components of a composite resin?
Resin matrix, filler particles, coupling agent, activator-initiator, inhibitor, modifiers/opacifiers/UV absorbers
In composite resin, the resin matrix is what phase? Filler particles are what phase?
continuous phase, dispersed phase
Bis-GMA is one of the most widely used ___. What does this stand for?
monomers; bisphenol A-glycidyl methacrylate
Bis-GMA is (high, low) molecular weight, (high, low) viscosity, (cross-linked, linear) multifunctional dimethacrylate resin
high, high, cross-linked
Bis-GMA has proportionately (more, less) polymerization shrinkage than methyl methacrylate
less
Bis-GMA has (5 times, 1/5th) the molecular weight and (5 times, 1/5th) the density of methacrylate double bonds
5 times, 1/5th
What does UDMA stand for?
urethane dimethacrylate
UDMA contains how many urethane groups and how many methacrylate end groups?
one or more, 2
What does TEGDMA stand for?
triethylene glycol dimethacrylate
TEGDMA is (high, low) molecular weight, permits (high, low) filler content, it (increases, decreases) polymerization shrinkage and wear of resin and forms (10-25%, 25-50%, 50-75%, almost 100%) of the resin
low, high, increase, 25-50%
True or False, in a resin with Bis-DMA and TEGDMA, more TEGDMA will cause the resin to be less viscous
True.
Of the resin monomers Bis-GMA, UDMA, and TEGDMA, which has 2 carbon rings in it?
Bis-GMA
What are three examples of inorganic filler particles? What are their size ranges in micrometers?
quartz, glass, amorphous silica; .1-100
Quartz was originally used as an inorganic filler particle but it had two downsides, what are they?
hard and abrasive
Microfillers are how big? What is the process called that makes them?
.04 micrometers, precipitation or pyrolytic process
Microfillers are added in concentrations that are (less than, equal to, greater than) 5% weight
less than
Microfillers (raise, lower) viscosity and (improve, worsen) consistency
raise, improve
What is the primary purpose of filler?
strengthen composite resin and reduct amount of matrix material
Increasing filler concentration: (increases, decreases) hardness and strength, (increases, decreases) wear, (reduces, increases) polymerization shrinkage, (reduces, increases) thermal expansion coefficient
increases, decreases, reduces, reduces
Increasing filler concentration: (increases, decreases) viscosity, (reduces, increases) water sorption, softening, and staining, (increases, decreases) radioopacity, incorporates compounds like (Ba and Sr, S and N, Se and Br)
increases, reduces, increases, Ba and Sr
Filler-matrix chemical bonding will lower polymerization shrinkage in proportion to the ___ fraction of filler
volume
Filler-matrix chemical bonding lowers coefficient of thermal expansion compared to unfilled resin, which produces (more, less) interfacial stress
less
Filler-matrix chemical bonding (improves, worsens) compression and tensile strength, stiffness and abrasion resistance
improves
Name two organosilanes
gamma-MPS, vinyl trichlorosilane
gamma-MPS and vinyl trichlorosilane coupling agents have ___ bonds between solanol groups on filler surface and coupling agent
siloxane
Coupling agents have ___ bonds between methacrylate groups on coupling agent and on resin
covalent
Coupling agents permit transfer of what from matrix to stiffer filler particles?
stresses
Coupling agents provide hydro(static, lytic, phobic) stability
hydrolytic
What are the four types of activator-initiator systems?
chemical, light, and heat activated, as well as dual-cured
Describe a chemically activated activator-inhibitor system
two paste system containing benzoyl peroxide initiator and tertiary amine activator in the other that are mixed
In a chemically activated activator-initiator system, the (initiatior, activator) is benzoyl peroxide and the (initiator, activator) is tertiary amine
initiator, activator
True or False, a chemically activated system is a one paste system and a light activated system is a two paste system
False. Chemically activated is 2, light is 1.
What is the wavelength of sensitivity of the camphoroquinone in a light activated system?
about 470nm
What is the photosensitizer molecule in the light activated system?
camphoroquinone
A dual cured system is like having the capabilities of (pick 2: heat, light, chemical) activated systems in one
light, chemical
What is added to minimize spontaneous or premature polymerization of monomers?
inhibitor
How does the inhibitor minimize spontaneous and premature polymerization?
terminates ability of free radicals to start polymerization process
What two specific compounds can be added in trace amounts to impart color and translucency/opacity?
TiO2 and Al2O3
Darker and more opaque shades are (more, less) difficult to polymerize and should be places in (thinner, thicker) layers
more, thinner
What is one issue that is common in chemically-activated resins because they are mixed?
air bubbles may inhibit polymerization due to presence of O2
What kind of control over the working time do you have in a chemically activated resin once the mixing starts?
no control
True or False, a chemically activated resin should be left alone for several minutes because messing with it can disturb polymerization
True.
You should cure a light activated resin (before, after) you contour it
after
What is the wavelength of light used for light activated resins?
400-500
What is the curing time for 2mm work of light curing resin?
40-60 sec
Light activated resins shrink (towards, away from) the light source
towards
The Quartz-Tungsten Halogen lights have a ___ bulb with a ___ filament in a ___ environment
quartz, tungsten, halogen (go figure, it's in the name)
True or False, Quartz-Tungsten Halogen lights are the most widely used
True.
Quartz-Tungsten Halogen lights emit light in what range?
400-500 (broad spectrum)
Blue Light-emitting Diode (LED) lights emit light in what range?
440-480 (narrow)
Which type of light system is the least expensive?
Quartz-Tungsten Halogen
Plasma-arc curing lights share their wavelength range with what other type of light?
Quartz-Tungsten Halogen
Plasma-arc curing lights generate very (high, low) intensity light
high
Argon-ion laser lights have a narrow wavelength spectrum at about ___nm
490
With increase in light intensity output, you (increase, decrease) depth of cure, (increase, decrease) curing time, (improve, worsen) flexural strength
increase, decrease, improve
With increase in light intensity, you have two bad things happen. You polymerization shrinkage stresses (increase, decrease) and temp. of resin by radient heat energy (increases, decreases)
increase, increases