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40 Cards in this Set
- Front
- Back
what bacteria cause demineraliation?
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streptococcus mutans and lactobacillus
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if plaque is left for several days what happens
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it begins to leach Ca++ ions out of solution and solidify into calculus
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what does lactic acid do?
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brings down the oral pH and causes demineralization of teeth
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saliva contains what that helps rebuilds the tooth that lost from acid?
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calcium and phosphate
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what color does decay go from?
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chalky, white spots, to dark and soft, then cavitates
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any invasion of the enamel can be fixed by:
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Any materials such as a composite, amalgam.. etc
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any invasion into living tissue can be fixed by
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extraction of tooth
removal of pulp tissue by RCT |
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mixture of 2 more metals
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alloy
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when is Hg mercury liquid?
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room temperature
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what classes can amalgam be used?
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1,2,6
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why is amalgam not used in class V?
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moisture control questions, hard to keep in, pt selection
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after RCT, much of coronal portion is missing either due to previous rest that were removed for RCT, caries, prep for the RCT or all of the above. what can we use when this occurs?
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we can use a build up to build up what was lost and place a full crown on it
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when root canals fail and need to be retreated what are the 2 options?
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do a second routine RC on tooth
or do RCT surgery by flapping the gum and sealing the canal space at the apex w amalgam or super EBA cement |
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rct surgery by flapping gum and sealing the canal space at apex w/ amalgam or super EBA cement is called what?
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retrofill
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what is percentage of silver in low copper amalgam?
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70%
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amount of tin in low copper amalgam
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27%
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amount of copper in low copper amalgam
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5%
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amount of silver i high copper amalgam
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46-60%
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amount of tin in high copper amalgam
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27%
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amount of copper in high copper amalgam
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13-30%
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what is antiquated method of making the powders
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shaving silver coins
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ingot of AgSn is cut on lathe producing small, irregular particles
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lathe cut alloy
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ingot of AgSn melted down and sprayed thru a nozzle creating a very small, uniform spheres of alloy
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spherical alloy
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mix of lathe cut and spherical alloys
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admixed alloy
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what type of reaction is the low copper amalgam?
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precipitation rxn
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beta/ gamma =
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unconsumed alloy particles
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gamma 1=
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ag2Hg3
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sn7hg=
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gamma 2
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strongest componet of set amalgam in low copper products?
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original and unreacted particles
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weakest componet of low copper?
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gamma 2 phase
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what are the problems with gamma 2?
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corrodes faster,
subject to fracture |
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what makes high copper amalgam better
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the tin ions react with the copper and prevent formation of gamma 2 making a stronger and longer lasting rest
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what does more Hg in mix do?
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increases plasticity and set time
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what does properly trituated product look like?
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plastic shiny and holds together
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what does overmix cause
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hotter, drier, sticky mass with short working time and quicker set
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if proper mixing what happens upon set?
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dimensional change occurs and slight contraction of set mass
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is corrosion good with amalgam?
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yes!
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dimensional change of a material under constant stress
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creep
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what happens to zinc when it gets weT?
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EXPANDS
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what does bulk amalgam provide
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strength
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