ch 13 embryology

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ch 13 embryology
2010-11-14 21:36:50
dentin pulp tissues

ch 13 embryology
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  1. dentin is derived from:
    • ectomesenchyme-MESODERM
    • (enamel is from ectoderm)
  2. mature dentin is only _____ calcified with calcium ____________
    • 70%
    • calcium hydroxyapatite
    • (enamel 98%)
  3. what tooth structure makes up the bulk of the tooth?
  4. what does dentin protect?
    the pulp
  5. is dentin smoother or rougher than enamel?
  6. can dentin be removed with instrumentation?
  7. dentin is __________ so it gets its nutrients from the _____
    • avascular
    • pulp
  8. the outer cells of the dental papilla form _________
  9. what do ondontoblasts lay down?
  10. ondontoblasts leave one long ___________ ___________ (tail) in the dentin
    cytoplasmic extension
  11. can apposition of dentin keep going? why?
    yes because ondontoblasts live in the pulp
  12. what are the two steps of maturation of dentin?
    • primary mineralization phase
    • secondary mineralization
  13. (watercolor wash) as globules calcify, they expand and fuse together creating globular dentin
    primary mineralization phase (dentin)
  14. (watercolor blobs) as globules calcify, they expand but do not fuse completely. creates interglobular dentin that is less mineralized
    secondary mineralization (dentin)
  15. what is interglobular dentin?
    the "space between the paint"
  16. what are the five components of mature dentin?
    • ondontoblastic process
    • dentinal fluid
    • afferent axon
    • primary curvature
    • secondary curvature
  17. extend from the DEJ to the outer wall of the pulp
    dentinal tubules
  18. the tail end of the ondontoblast (cell within the tubule)
    ondontoblastic process
  19. the tissue fluid surrounding the cell membrane of the ondontoblast (detects temp changes)
    dentinal fluid
  20. the nerve that receives sensation for the tooth, the nerve cell body is located in the pulp of the tooth
    afferent axon
  21. what two parts are left in the pulp?
    nerve cell bodies and ondontoblasts
  22. does the direction of the tubule reflect the pathway the ondontoblast took?
  23. overall tubule course which resembles a large S
    primary curvature
  24. small delicate curves showing the daily changes in ondontoblast direction during apposition (organic-living)
    secondary curvature
  25. what are the four types of dentin?
    • peritubular dentin
    • intertubular dentin
    • mantle dentin
    • circumpulpal dentin
  26. the dentin that creates the dentinal tubule (walls of the "cave")
    peritubular dentin
  27. found between each of the tubules
    intertubular dentin
  28. first to form, closest to the DEJ (outside layer of the dentin)
    mantle dentin
  29. surrounds the pulp chamber
    circumpulpal dentin
  30. formed before the completion of the apical foramen. normal alignment of tubules and more calcified than secondary
    primary dentin (virgin)
  31. formed after the completion of the apical foramen. Less calcified than primary dentin. Formed to protect the pulp i.e. when an injury occurs, close to being a rct
    secondary dentin
  32. formed in response to trauma. irregular alignment of tubules because it is laid quickly. formed to protect the outer layer of dentin i.e. scaling too hard
    tertiary dentin
  33. because of trauma or age, the ondontoblastic process die and leave the tubule. the tubule is then filled with more dentin.
    sclerotic dentin (part of tertiary dentin)
  34. just like the incremental lines of retzius (dentin laid down cyclically)
    inbrication lines of Von Ebner
  35. darkened areas that show some sort of disturbance in apposition. the most pronounced is the _______ ____
    • contour lines of owen
    • neonatal line (most pronounced)
  36. types of dentin are defined by _________ or ________ of formation
    • location
    • time
  37. diameter of the tubules start to narrow as more dentin is laid and seals off the communication between the dentin and pulp. this is caused from:
    age changes in dentin
  38. what are the two clinical considerations with dentin?
    • the caries chute
    • hypersensitivity
  39. since dentin is less calcifed, it is more prone to ________
  40. bacteria have been seen using the dentinal tubules as _______ towards the _____
    • chutes
    • pulp
  41. why can a small cavity in the enamel be monitored, but once it has gotten to the dentin, it must be repaired asap?
    because enamel is more calcified. once the bacteria gets to the dentin, it can use the dentinal tubules as a chute straight to the pulp
  42. afferent axons are in the ________ _________
    dentinal tubules
  43. T/F afferent axons can differentiate between hot, cold, pressure, or dehydration?
    false! they just translate all stimuli as PAIN
  44. what is an active ingredient in sensodyne that can help diminish hypersensitivity?
    potassium nitrate (blocks tubules by occluding)
  45. tubules can be occluded with ________, laser treatments, and ________ ________.
    • fluoride
    • composite fillings (which sometimes secrete fluoride)