Dental Materials

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Dental Materials
2011-01-21 00:44:35
Chapter two part two

week one
Show Answers:

  1. Acceptable dental materials need to expand and contract _______ with the ______
    • Consistent
    • tooth
  2. Excessive expansion may lead to What?
    fractured cusps
  3. Excessive contraction may lead to what?
    leakage of fluids and bacteria into the open gaps, producing sensitivity
  4. Measurements of expansion and contraction=what?
    Coefficient of Thermal Expansion (CTE)
  5. Large difference between CTE and tooth structure causes __________; and ___________ may occur
    • percolation
    • leakage
  6. CTE = 11
    Thermal conductivity = 2.0
  7. CTE = 8
    Thermal conductivity = 1.30
  8. CTE = 20-28
    Thermal conductivity = 54
  9. CTE = 15
    Thermal conductivity = 350
  10. CTE = 15
    Thermal conductivity = 2.5
  11. CTE = 26-40
    Thermal conductivity = 2.60
  12. ________ material may reduce thermal conductivity
  13. nonmetals such as ceramics, resins, cements, enamel, and dentin are very poor conductors, and poor conductors can be used as what?
  14. ________ is a natural insulator
  15. What is one of the best thermal conductors?
  16. When there is a large difference between the CTE and the restorative material as for amalgam and tooth structure, the percolation will be __________
  17. The reactions of some components when they are mixed may result in the production of heat
    exothermic reaction
  18. Name 4 'other' factors in material selection
    • retention
    • mikroleakage
    • biocompatibility
    • esthetics
  19. the ability of a material to maintain its position without displacement when under stress
  20. What might help secure retention of a material?
    mechanical chemical adhesion or bonding
  21. What type of retention uses undercuts?
  22. Dental cements retain restorations by __________ and/or __________ connecting the two surfaces
    • mechanically
    • chemically
  23. ___________ of materials occurs when the tooth surface is prepared through the use of an acid-etch technique to create microscopic pores in enamel and dentin.
  24. What kind of retention is using etch material?
    when the fluid fills the poors created by the etch it is mechanical; then the restorative materials on top of that chemically adhere to that material
  25. What are 6 factors that can affect the bond strength or the success of a material as an adhesive?
    • wetting
    • viscosity
    • film thickness
    • surface characteristics of the tooth
    • restoration
    • adhesive
  26. When liquids bead up on a surface, the surface has ______ surface energy
  27. Lliquids generally wet or spread over high surface energy surfaces better such as what? (3)
    • metals
    • ceramics
    • enamel
  28. What happens if the interface of a resoration is not sealed?
    fluids and microorganisms can penetrate between tooth structure and restorative material
  29. What is responsible for much of the recurrent decay, marginal staining, and postoperative sensitivity?
  30. Tubule fluid flow causes what?
  31. not adversely affecting living tissue
  32. Nickel and acrylic hypersensitivity are caused from what factor?
  33. It has been reported that a significant percentage of people have skin allergies or hypersensitivity to some metals in particular what 2?
    nickel and acrylics
  34. What are the 3 components that describe the resultant color?
    • hue
    • chroma
    • value
  35. intensity or strength of color
  36. describes how light or dark the color is
  37. the dominant color of the wavelength detected
  38. colors look different under different light sources
  39. Why is the detection of restorative material critical in dental hygiene?
    so we can recognize what is a restoration or tooth and not damage it
  40. What are 4 sources that can have adverse affects on restorations that are used in dental hygiene?
    • scaling
    • sonic and ultrasonic scaling
    • air and polishing
    • fluoride
  41. What are 3 ways to detect different restorative materials?
    • x-rays
    • explorer (tactile)
    • visual, light, air, magnification
  42. What is the most reliable way of detecting a restorative restoration with tooth colored fillings?
    explorer/tactile senses
  43. What is an example of galvanism?
    amalgam contacting gold
  44. An excessive film thickness may cause what?
    improper seating of restoration
  45. microleakage may be responsible for what?
    • marginal staining
    • postoperative sensitivity
    • recurrent decay