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