1. what is dentin derived from?
    ectomesenchyme- MESODERM
  2. mature dentin is only ______% calcified with _____ ______
    • 70
    • calcium hydroxyapatite
  3. dentin makes up the_____ of the tooth and protects the ______
    • bulk
    • pulp
  4. t/f dentin cannot be removed with instrumentation
    false-it CAN be removed with instrumentation
  5. where does dentin get its nutrition from?
    pulp (dentin is avascular)
  6. t/f dentin has its own blood supply
    false-dentin is avascular
  7. how does dentin feel compared to enamel?
  8. what is the process of apposition of dentin?
    • out cells of dental papilla form odontoblasts
    • odontoblasts lay down predentin
    • they leave one long cytoplasmic extension in the dentin (odontoblastic process)
    • keeps going throughout life because odontoblasts remain in the pulp
  9. what cells form odontoblasts?
    outer cells of the dental papilla
  10. what is the long cytopasmic extension left by odontoblasts in the dentin?
    odontoblastic process
  11. where do the odontoblasts live?
    in the pulp
  12. t/f apposition of dentin can be made all throughout life?
  13. what are the two steps of maturation of dentin?
    • primary mineralization phase
    • secondary mineralization phase
  14. what phase of maturation of dentin is described as this: as globules calcify, they expand and fuse together and create globular dentin
    primary mineralization phase
  15. what phase of maturation of dentin is when globules calcify they expand but do not fuse completely. Creates interglobular dentin that is less mineralized
    secondary mineralization
  16. what does the primary mineralization phase create?
    globular dentin
  17. what does secondary mineralization create?
    interglobular dentin
  18. what is less mineralized globular dentin or interglobular dentin?
    interglobular dentin
  19. what are 3 components of the dentinal tubules?
    • odontoblastic process
    • dentinal fluid
    • afferent axon
  20. what extends from the DEJ to the outer wall of the pulp?
    dentinal tubules
  21. what is the tail end of the odontoblast?
    odontoblastic process
  22. what is the tissue fluid surrounding the cell membrane of the odontoblast?
    dentinal fluid
  23. what is the nerve that receives sensation for the tooth and where is it located in the tooth?
    • afferent axon
    • located in the pulp
  24. the _____ of the tubule relfects the pathway the odontoblast took
  25. what is the overall tubule course called which resembles a large S
    primary curvature
  26. what resembles a large S within the dentin?
    primary curvature of the dentinal tubule
  27. what are the small delicate curves of the dentinal tubules called and what do they show?
    • secondary curvature
    • shows daily changes in the odontoblast direction during apposition
  28. what are two ways the types of dentin are described?
    location and time
  29. what are the four types of dentin by location?
    • peritubular dentin
    • intertubular dentin
    • mantle dentin
    • circumpulpal dentin
  30. what type of dentin creates the dentinal tubule?
    peritubualar dentin
  31. where is the peritublar dentin located?
    walls of dentinal tubule
  32. what type of dentin is found between each of the tubules?
    intertubular dentin
  33. where is intertubular dentin found?
    between each of the tubules
  34. what type of dentin is the first to form and is closest to the DEJ?
    mantal dentin
  35. what is mantle dentin?
    first to form and closest to the DEJ
  36. what type of dentin surrounds the pulp chamber?
    circumpulpal dentin
  37. what is circumpulpal dentin?
    dentin that surrounds the pulp chamber
  38. what are the three types of dentin by time of formation?
    • primary dentin
    • secondary dentin
    • tertiary dentin
  39. what type of dentin is formed before the completion of the apical foramen?
    primary dentin
  40. what type of dentin has normal alignment of tubules and is more calcified than secondary?
    primary dentin
  41. when does primary dentin form?
    before the completion of the apical foramen
  42. what type of dentin forms after the completion of the apical foramen
    secondary dentin
  43. t/f secondary dentin is more calcified than primary dentin and t/f is formed to protect the pulp.
    • false-secondary dentin is less calcified than primary dentin
    • true
  44. when does secondary dentin form?
    after the completion of the apical foramen
  45. what type of dentin forms in response to trauma?
    tertiary dentin
  46. t/f tertiary dentin has irregular alignment of tubules because it is laid quickly and t/f it is formed to protect the pulp.
    • true
    • false-formed to protect the outer layer of dentin
  47. what is formed because of trauma or age and involves the odontoblastic process to die and leave the tubule
    sclerotic dentin
  48. what is the tubule filled with when the odontoblastic process dies and leaves the tubule
    more dentin
  49. what is sclerotic dentin?
    formed in the tubule because of trauma or age, the odontoplatic process dies and leaves the tubule and then is filled with dentin
  50. t/f imbrication lines of von ebner are just like incremental lines of retzius
  51. how are imbrication lines of von ebner laid down?
  52. what are darkened areas that show some sort of disturbance in the apposition
    contour lines of owen
  53. what is an example of a contour lines of owen
    neonatal line
  54. what is the most pronounced line of contour lines of owen
    neonatal line
  55. t/f the contour lines of owen are any line that is darker than normal?
  56. describe the age changes of dentin
    diameter of tubules starts to narrow as more dentin is laid and seals off the communication between the dentin and the pulp
  57. t/f with age changes in dentin the diameter of the tubules start to widen
    false-tubules start to narrow as more dentin is laid
  58. t/f dentin is more calcified than enamel and is less prone to caries
    false- dentin is less calcified than enamel and is more prone to caries
  59. bacteria have been seen using the _____ ____ as chutes towards the _____
    • dentinal tubules
    • pulp
  60. why can a small cavity in the enamel be monitered but once it has gotten to the dentin it must be repaired?
    bacteria uses the dentinal tubules as chutes towards the pulp
  61. why is the dentin hypersensitive
    afferent axons are in the dentinal tubules
  62. afferent axons in your dentinal tubules translate all stimuli into what?
  63. what is the exact mechanism of the afferent axon stimuli?
  64. what can help diminish hypersensitivity?
    occluding the tubules-fluoride, laster treatments or composite fillings
  65. what is the active ingredient that helps to occlude tubules?
    potassium nitrate
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