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Dmat4

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olola's version from 2016-09-19 02:23

Section

Question Answer
The term "____ _____" is used to refer to a broad category of compounds derived from the basic structure of acrylic acid. Their structure is that of a vinyl group with an ester group substituting for the R-group.Acrylic Resins
Substitution of the hydrogen atom with a methyl group on the double-bonded carbon having the ester leads to a class of compounds termed the _______Methacrylates
when is a vinyl material preferred over an acrylic and why.When an allergy may be a concern
When reference is made to acrylic resins in dentistry, it most often refers to ________-based monomers.Methacrylate
What is the boiling point of methyl methacrylate monomer?100.3 deg celsius
Methyl Methacrylate penetrates ____ gloves easily... so only ____ gloves should be wornLatex; Rubber
State the light wavelength which is able to polymerize pure methyl methacrylate without activator or initiator presentUV light, between 280-320 nm (harsh UV).
T/F: Methyl Methacrylate should be kept in dark brown vials to filter out UV lightTrue
T/F: Methyl Methacrylate can undergo spontaneous polymerizationTrue (random molecular collision, one C=C may have sufficient kinetic energy that the C=C will break apart, forming a free radical) (spontaneous free radical formation)
State three mechanisms used to create free radicals from benzoyl peroxideHeat, UV light, Tertiary amine (will result in the generation of a high number of free radicals)
If the non-reacted end of the crosslinker does not react, but remains as a permanent part of the polymer, it is referred to as a ______ methacrylate groupPENDANT
State the amount of polymerization shrinkage expected per mole of methacrylate group converted from monomer into polymer23 cc per mole ("Every mole of methacrylate groups converting from double bonds to single bonds during polymerization, there is approximately 23 cc of volumetric shrinkage.")
state how monomer size affects polymerization shrinkageless shrinkage should occur is to make the monomer molecules very large
______ is an extremely viscous fluid that is unusable by itself. It has the consistency of honey that has been subjected to a very cold temperature.Bis-GMA
This is commonly added to Bis-GMA (as a diluent) and lowers the viscosity of Bis-GMATEGDMA
This monomer does not have the (-OH) groups as found in Bis-GMA. Thus, it is much less hydrophilic, and the resulting polymer would not be as susceptible to water sorption.Ethoxylated BIS-GMA
These monomers were originally used because of their potential for enhanced photopolymerization with ultraviolet (UV) energy: the first generation of photo-cured restorative resins were UV-activated, not blue-light activated.Urethanes
Some research has indicated that ______ absorb more water than do other resins.Urethanes
identify the components added to increase the storage life of resinsInhibitors
2 examples of a common inhibitorMEHQ (methylether of hydroquinone) and BHT ((Butylated hydroxy Toluene)
Storage of monomers at ____ temperatures greatly decreases the rate at which spontaneous radicals form, and thus prolongs the useful life of the materialLow Temp
Compounds termed "_____" may also be added to commercial products to intentionally delay the onset of polymerization, providing working time.Retarders
Compounds termed "______" are added to monomer systems to quench any spontaneously formed free radicals and to keep them from initiating a polymerization reaction, thus prolonging the shelf life of a monomer-based product.Inhibitors
Eugenol interferes with free radical formation and restorative base materials because it has a structure similar to ______MEHQ (inhibitor)
Because free radicals are 30,000 times more likely to react with oxygen and form a stable structure... the _____ _____ layer is formedOxygen inhibited layer
Addition of "____"greatly increases viscosity and effectively limits the depth to which oxygen can diffuse and offset the polymerization reaction.Filler
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