ch 6 dental materials

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ch 6 dental materials
2011-03-23 22:03:15
dental materials

ch 6 dental materials
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  1. what is the most common type of composite resin used in a private practice?
    light cured
  2. what are 2 advantages of of the dual cure (2-paste system) polymerization?
    • curing light initiates setting reaction
    • chemical setting rxn continues in areas where light cannot be reached
  3. light cured composite resin is preferred because:
    • there is no mixing needed
    • cured when the operator is ready
  4. is macrofilled composite used today? what um is it? is it easy or hard to polish? does it get rougher with age and function?
    • macrofilled is NOT used today
    • 10-100um
    • hard to polish
    • rougher with age and function
  5. t/f microfilled composites make for large surface area (many small vs few large)
  6. what is the filler volume of microfilled composites? are they weaker or stronger? more or less wear resistant
    • 35-50% (others are 70-85)
    • weaker
    • less wear resistant
  7. t/f large particle composites are replaced by hybrid composites for posterior restorations
    FALSE. small
  8. hybrid composites consist of ____ and ____ fillers
    micro and macro
  9. hybrid composites are ____ and _____ well
    strong and polish well
  10. what is the filler content of hybrid composites?
    75-85% by weight
  11. what is the particle size of microhybrid? filler content?
    • .5-3 um
    • 70%
  12. what have a particle size of .005-.02 um, shrinkage reduced from 3% to 1%, strong, and high shine?
  13. flowable composites have ___ viscosity
    low (how low can ya flow)
  14. particle size of flowable composite is ___-___um and has ___ adaptation to tooth walls
    • .07-1um
    • good
  15. t/f flowable composites are not used in conservative dentistry
    false! great in conservative dentistry
  16. what is a preventative resin, used for sealants, class V non carious lesion, and as a liner?
    flowable composites
  17. what has higher shrinkage, more wear, and weaker than a hybrid?
    flowable composite
  18. t/f flowable composite is an excellent choice for areas of high occlusal function or high wear
    false i say! not bloody likely!
  19. can fillers be high to low in sealant material?
    why yes
  20. highly viscous resins contain high volume filler particles in _______ composites
  21. what are stronger and more wear resistant than hybrids, and shrink less on polymerization (more filler/less resin)?
    packable composites
  22. what is a smart composite?
    • good for poor oral hygiene patient
    • remineralizes the tooth
    • there is no clinical study to confirm effectiveness....just a nice idea
  23. smart composites release: (3)
    • fl2
    • calcium
    • hydroxyl ions
  24. core-build up composites can be: (3) what type of cured?
    light, self, or dual
  25. what are the advantages of composite provisional restorations vs acrylic? (4)
    • wear less
    • shrink less
    • less heat as cured
    • repaired easily with flowable composite
  26. what are three disadvantages of a composite restoration vs an acrylic restoration?
    • more expensive
    • more brittle
    • break more easily in longer span bridges
  27. chemicals released from new deep composite resins can enter dental tubules and into pulp.. what is this called?
  28. which composite is able to be used for anterior and posterior restorations?
  29. which is more wear resistant, a sealant or flowable composite? why?
    • flowable composite
    • it has more filler particle content
  30. t/f the lower the elastic modulus, the more flexible the material. the higher the elastic modulus, the stiffer the material
  31. which shrink more when polymerized? hybrid or flowable?
    flowable about 5 to 7%
  32. t/f chemicals released from new deep composite resins can enter dentinal tubules into the pulp and cause an inflammatory rxn
  33. t/f when the tubules are sealed by a dentin bonding agent or protected with a base or liner, there is no chemical entering the dentinal tubules
  34. can someone be allergic to a certain composite resin material?
    yes, anything is possible, just put your mind to it and you can do it
  35. larger filler particles = stronger, tension, compression. is this correct?
    probably....the answer is yes and i am tired
  36. are microfills weaker than macrofills?
  37. does composite or amalgam wear faster?
  38. what affects the wear rate of composite?
    filler content
  39. does more filler = better wear?
    yes, more is better for shizzle
  40. t/f microfills and flowables wear faster
  41. with a chemical cure, where does it shrink?
    toward the center of the bulk of the composite
  42. does light cure shrink toward the center of the bulk of composite like chemical cure?
  43. t/f light cured resin shrinks towards the light
    false! towards the center of the bulk of the composite
  44. t/f with smaller increments there is less polymerization shrinkage
  45. post insertion sensitivity= ______ increments (leakage)
  46. larger increments of composite placement results in what ?
    • leakage
    • tension on cusps
    • greater shrinkage (bigger is not always better)
  47. thermal conductivity of composite should be close to _____ ______ _______
    natural tooth structure
  48. composite material should be _______ protective for the dental ______
    • biologically
    • pulp
  49. the greater the filler content, the _____ the CTE or the greater the resin content, the _______ the CTE
    • lower
    • higher
    • (CTE=coefficient of thermal expansion)
  50. what type of content is the greater filler content = lower cte?
  51. what type of composite is the greater resin content= greater cte
  52. _______ and _______ have higher CTE than hybrid or packable
    flowable or microfilled
  53. what is the young's modulus (elastic modulus) of composite? what is it determined by?
    the stiffness which is determined by the amount of filler
  54. the greater the volume of filler, the ______ the elastic modulus and more wear resistant the restoration
  55. t/f the elastic modulus is an important consideration for selection of the type of composite
  56. microfilled and flowable composites have fewer ________ and more ______
    • fewer particles
    • more resin
    • (better for non-stress bearing restorations)
  57. for a CLV restoration, what type of material is needed. stiff or flexible?
    FLEXIBLE for all the flexion (esp because abfraction occurs due to the forces of the tooth flexion)
  58. t/f resin matrix absorbes water over time
  59. if there is a greater resin content, then more OR less water will be absorbed?
  60. t/f microfills and flowables absorbe more water