Dental Materials

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Dental Materials
2011-03-23 14:31:06

dental amalgam (thru amalgam strength)
Show Answers:

  1. what is the most widely used material in restorative and corrective dentistry?
  2. amalgam has had a reduced usage by _____% in the last ____ years
    • 40
    • 15
  3. t/f testing has not show amalgam to be safe or harmful to humans, it is still undergoing testing.
    FALSE, testing shows amalgam is safe
  4. some disadvantages of amalgam is the lack of _____ and the fear of ______ safety
    • estehetics
    • mercury
  5. what are the 7 metals contained in amalgam (four big ones in "red")
    • SILVER
    • COPPER
    • TIN
    • zinc
    • palladium
    • indium
  6. the addition of _____ in amalgam composition causes a reaction called ______
    • mercury
    • amalgamation
  7. adding what metal to amalgam causes amalgamation?
  8. what is the chemical reaction called that mercury causes in amalgam
  9. how are amalgams classified?
    shape of particles (irregular, admixed, spherical)
  10. what are the composition of MODERN amalgam (5)
    • copper
    • silver
    • tin
    • mercury
    • zinc
  11. what % of MODERN amalgam is copper?
  12. what % of MODERN amalgam is silver
  13. what % of MODERN amalgam is tin
  14. what % of MODERN amalgam is mercury? and how is it measured?
    • 43-50
    • by weight
  15. t/f mercury is measured for modern amalgam by particle size
    FALSE-by weight
  16. what % of MODERN amalgam is zinc
  17. what are two advantages to shperical alloys?
    • less mercury
    • set faster
  18. t/f spherical alloys set faster than lateh cut
  19. t/f with spherical alloys more mercury is required to bring all materials together (amalgumation)
    FALSE, less mercury required GOT IT!
  20. zinc in amalgam inhibits _______ by reducing ______ of other metals
    • corrosion
    • oxidation
  21. in _____ copper amalgam, when moisture is present during placement, the zinc is responsible for gradual _____ of amalgam over time
    • low
    • expansion
  22. how many hours does it take for amalgam to COMPLETELY set?
    24 hours
  23. t/f when the alloy in powder form is mixed with liquid mercury a chemical reaction occurs
  24. The chemical reaction that occurs when alloy and mercury are mixed has ____ phases, what are they?
    • THREE phases
    • Gamma phase
    • Gamma-1 phase
    • Gamma-2 phase
  25. what type of amalgam does not have a gamma-2 phase? what is the benefit of this?
    • High Copper amalgams
    • superior in their clinical performance, reduced corrosion, higher strength and margins that hold up better
  26. what is the strongest chemical reaction phase?
    gamma phase
  27. what is the weakest chemical reaction phase?
    gamma-2 phase
  28. what is used to control the rate of set of amalgam?
  29. copper reacts with ____ so its not available to act in with the mercury (gamma-2 phase)
  30. what is tarnish a result from?
    contact with oxygen, chlorides and sulfides in mouth
  31. what results from contact with oxygen, chlorides and sulfides in the mouth?
  32. t/f the rougher the surface the more tarnish
  33. ______ can occur from a chemical reaction between the amalgam and substacnes in saliva and food
  34. corrosion is an _____ of amalgam becuse of ______ reaction between amalgam and substances in _____ or _____
    • oxidation
    • chemical
    • saliva
    • food
  35. t/f corrosion can occur when two dissimilar metals interact in a solution containing electrolytes
  36. if galvanism occurs one of the metals ______ causing corrosion
  37. ______ takes place within the amalgam through interactions of its metal components, it ____ the amalgam over time, ____ tooth structure and lead to ______ of margins
    • corrosion
    • weakens
    • stains
    • deterioration
  38. most amalgams are ____ copper alloys
  39. high copper alloys ______ gamma 2 reaction, are more _____, have less _______ of ______ and less _____
    • eliminate
    • durable
    • deterioration
    • margins
    • corrosion
  40. gradual change in shape of the restoration from compression by the opposing dentition during chewing or by pressure from adjacent teeth
    CREEP..jeepers creepers where'd you get them peepers
  41. t/f creep occurs more now that amalgams are high copper
    FALSE-occurs LESS!
  42. creep is a phenomenon associated with what chemical phase of alloy and mercury being mixed?
    gamma -2 (found in low copper amalgam alloys not high remember.....pause pause pause for dramatic effect okay now you can move on)
  43. what happens if an amalgam contracts excessively?
    opens gaps at the margins=leakage!
  44. too much contraction of an amalgam results in open ____ causing ____ _____ and what would that cause (I am going to make you think)
    • gaps
    • marginal leakage
  45. what happens if there is too much expantion of an amalgam
    puts pressure on the cusps causing pain when biting and could result in a fracture
  46. where does expantion of an amalgam put pressure?
    on the cusps
  47. if there is pain upon biting down what is that an indication of?
    poss perio ligament, abcess, high filling
  48. what is is pain upon releasing of pressure an indication of?
    fracture of tooth
  49. amalgams are strongre in compression than _____ or ____ _____
    • composites
    • glass ionomers
  50. t/f amalgams are weak in tension and shear and therefore require adequate bulk to resist breaking
    true (I can't word somethint that nicely and make it false duh!)
  51. what does amalgam need to resist breaking?
  52. high copper amalgams have a high _____ ______ strength
    EARLY compressive strength
  53. what type of amalgam has a high early compressive strength
    high copper amalgams
  54. what is the time frame to be considered an early compression vs late compressive strength
    LESS than 24 hours for early...24 hours would be LATE