Dental Materials

Card Set Information

Author:
cassiedh
ID:
75094
Filename:
Dental Materials
Updated:
2011-03-24 22:26:12
Tags:
ch10
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Description:
casting metals, solders, and wrought metal alloys
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  1. pure gold=___% and ____% = _____ fine and _____ fine=___ karate
    • 100
    • 100
    • 1000
    • 1000
    • 24
  2. how many karates is 500 fine or 50% gold?
    12 karat
  3. what are the classifications for casting alloys? 3
    • high noble metal
    • noble metal
    • base metal
  4. t/f noble metals have no gold requirement
    true
  5. what are three examples of noble metals?
    • gold
    • platinum
    • palladium
  6. what is the most corrosive resistant nobal metal?
    gold
  7. what % of gold is 14K?
    • 58.333333333333333%
    • if 24K is 100% and 12K is 50% (12/24=.5...hence 50%) SOOOO 14/24=.5833333333333333 and there you have it!
  8. _____ is a dental alloy that is not used much
    platinum
  9. what noble metal is a good corrosive resistance, increases hardness of alloy and is less expensive than gold
    palladium
  10. palladium dental alloy is _____ corrosive resistance, ______ hardness of alloy and _____ expensive than gold
    • good
    • increases
    • less
  11. why is silver not a noble metal?
    because of high tarnish and corrosion
  12. what base metal is the highest incidence of allergic response
    nickel
  13. how is a nickel allergy shown?
    blackness around gumline
  14. what reduces the oxidation of alloy during casting of a base metal?
    zinc
  15. what is added to gold to incrase hardness?
    copper and silver
  16. why is zinc added to gold?
    to reduce oxidation of cast alloy
  17. what is added to gold based alloys to keep crystals from growing too large?
    iridium or ruthenium
  18. what is added to form oxides on the metal to bond porcelain? 4
    indium, iron, gallium and tin
  19. the substructre of porcelain is heated at high temperatures to form what on the surface?
    oxides
  20. how does the porcelain fuse to the oxide layer
    chemically
  21. how thick is coping metal?
    .3-.5mm
  22. how much does the tooth have to be reduced for a PFM?
    2 mm
  23. what is responsible for allergic responses?
    corrosion products
  24. what has the highest incidence of allergenicity?
    Nickel
  25. who is more likely to have a nickel allergy?
    WOMEN 10:1 over men
  26. why are women more likely to be allergic to nickel?
    jewelry (topically applied-worst kind of allergy)
  27. where in the mouth is the most common site for nickel allergy?
    corwns around free gingival tissues
  28. t/f some responses to nickel in the mouth cause skin reaction
    true
  29. _____ fineness number of gold solder, the _____ the gold content the _____ the melting point of the solder
    • HIGHER
    • HIGHER
    • LOWER
  30. what is added to both gold and silver solders to lower the melting range?
    TIN
  31. solders can be gold or silver what is an example of a silver solder?
    • ortho fixed space maintainer
    • solder wire components together
  32. t/f wrought metal alloys may be annealed (what does that mean)
    true-heat modified
  33. what is an example of a wrought wire?
    clasps for removable prothesis
  34. arch wire held to ortho bracket by ____ wire or ____
    • ligature
    • elastics
  35. what is held to the ortho bracket by ligature wire or elastics?
    arch wire
  36. t/f reamers have more twists than files
    • false
    • FEWER TWISTS
  37. what cuts faster reamers or files?
    reamers
  38. what is the canal sealed with so bacteria can't grow in the space
    gutta percha
  39. what is gutta percha used for?
    to seal the canal so bacteria cannot grow in the space
  40. what is the purpose of a endodontic post?
    retain core buildup
  41. t/f the endo post is in the canal perpendicular
    false PARALLEL
  42. why is the endo post parallel?
    to transmist less stress to the root than tapered

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