Dental Pulp Chapter 7 Quiz

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Dental Pulp Chapter 7 Quiz
2013-08-24 16:33:08
Dental Pulp

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  1. Which nerve fibers are the largest in the dental pulp?
    Aβ are larger than Aδ and C fibers
  2. Nerve fibers contribute to tooth survival by (3 sub 3)
    • 1. Detecting stimuli
    • 2. Dental reflexes
    • 3. Interacting w/ OD, Fibroblasts, BVs, immune

    All this to protect, maintain healthy function and repair
  3. Tooth nerves can be classified based on:
    • 1. Sensory perception (sharp, dull, prepain)
    • 2. Effective stimulus (mechanical, thermal, chemical, noxious, polymodal)
    • 3. Conductive velocity (Aβ, Aδ-fast, Aδ-slow, C and C Sympathetic)
  4. Where to terminal sympathetic fiber have their cell bodies?
    Cervical sympathetic ganglion
  5. What is the rate of transport of vesicles anterograde and retro grade of neurons?
    1-400mm/day peripheral and central anterograde (towards the cell body)

    50-100mm/day retrograde (away from cell body)
  6. The nerve fibers of the pulp are part of a somatosensory system that includes:
    Gingiva, junctional epi, PDL, Tongue, Lips, masticatory, TMJ
  7. Where do most A fibers terminate?
    Coronal OD layer, predentin, and inner
  8. Where do most C fibers have their terminals?
    Deeper in pulp along BVs
  9. Aβ fibers make large endings near:
    ODs (close) along dentin-pulp border near horn tip

    Lack receptors for NGF

    Most sensitive to hydrodynamic stimulation of dentin
  10. Majority of A fibers are _____ and ________ myelinated fibers.
    • small
    • medium
  11. What neuropeptide do A fibers contain?
    CGRP and express receptors for NGF (except Abeta)
  12. Where is most of the Aδ innervation concentrated?
    Dentin near the pulp horn tip and less freq toward cervical region, least in root dentin
  13. Two types of Aδ fibers?
    Fast conducting

    Slow conducting: sensitive to capsaicin, thin
  14. At least half of the nerve fibers in human teeth are ___________, slow-conducting __ fibers
    • unmyelinated
    • C
  15. The GDNF (glial cell line derived neurotrophic factor) dependent group of fibers have this function
  16. NGF dependent fibers have this function
    polymodal or nociceptive sensitivity, as well as paracrine signaling
  17. All fibers in the pulp continue to express this protein
    GAP-43, growth assoc protein
  18. Sympathetic fibers are located where in the pulp
    deeper pulp and along BVs
  19. How do we know that ODs do not have a primary sensory function?
    they lack synaptic and gap junctions with nerve fibers
  20. What indicates that ODs are excitable and mechanosensitive?
    Neural like ion channels and TREK-1 (mechanosensitive potassium channel)

    Attract nerve fibers

    Express neurotrophin factors and receptors
  21. How do fibers convey info about pulp status to the cell body?
    Pick up and transport local pulp factors such as NGF
  22. Type 1 Injuries
    • Least damaging
    • 1. transient change
    • 2. Reactive dentinogenesis
    • 3. sprouting of neuropeptide-rich nerve fiber endings (return to normal days-weeks)
    • 4. Little/no invasion of leukocytes

    Example: shallow cavity, scaling, strong ortho
  23. Type II injuries
    • Extensive dentinal injury
    • 1. loss of pulp tissue
    • 2. invasion of leukocyctes, local vascular resp
    • 3. reparative dentin
    • 4. ext sprouting, CGRP and subst P contents continues until walled off by scar (old folks able to as well)

    Example: deep cavity, small pulp exp, heat stimulation
  24. Type III injuries
    • Pulpal damage that cannot be repaired
    • 1. IP insues
    • 2. intense nerve sprouting, inc NFG expression

    Examples: infect pulp exp, bacterial invasion from leaked restoration, deep infected caries, failure of scar around abscess
  25. Type IV injuries
    • involve other tissues, out of the radicular structure
    • 1. PDL involved
  26. What are the typical responses to fiber sensory endings in brainstem and ganglion during inflammation?
    1. altered exp of neurotrophin receptors, neuropeptides, voltage ion channels
  27. c-Fos and tooth injuries?
    Injuries cause persistent expression, indicates altered central pain pathway functions
  28. Difference between adult and primary teeth in density of innervation?
    Coronal regionas are more innervated than radicular in both  BUT

    in primary teeth cervical third of the coronal region more dense than adult (less dentinal tubules in kids innervation)

    less CGRP, subst P, and VIP
  29. Sharp increase in sensitivity is seen when the ____ _____ of teeth _____.
    • root apices
    • close
  30. Name the neuropeptides located in the pulpal axons
    • Tachykinins
    • Neurokinin A and SP
    • CGRP
    • VIP
    • NPY
    • Cholecystokinin
    • Somatostatin
    • Galanin
    • Methionine
  31. How do CGRP and SP function in neurogenic inflammation?
    • 1. Blood flow control
    • 2. Inflammation
    • 3. Tissue repair
  32. Which neuropeptides produce vasodilation and which one vasoconstriction?

    VC: NPY (inhibits SP release by sympathetics)
  33. Which neuropeptides are anti-inflammatory?
    NPY (vasoconstrictor and inhibits SP release)

    VIP (though vasodilatory it inhibits pro-inflammatory cytokines while upregulating anti-inf IL-10)
  34. Which cytokines do CGRP and SP promote?
    TNF-alpha, IL1-beta, IL-6
  35. Upregulation of SP and CGRP receptors occurs as a gradient because expressions are _______ in pulp tissues with ________ _________ and presence of _________ to _________ ________
    • highest
    • irreversible pulpitis
    • moderate
    • severe pain
  36. Pulp expression of NPY varies in caries infected teeth how?
    Most expressed in mild to moderate caries

    Least in severe caries and even less in normal pulps
  37. The effect of most neuropeptides is controlled by which protein receptor?
    GPCR (g-protein coupled receptors)
  38. Somatostatin and NPY are linked to which g-protein pathway?
    G-alphai/o GPCR pathway

    Inhibitory pathway of nerve activity (analgesic effect wiht opoids working this way too)
  39. Which GPCRs excite nerve activity?
    • Galphas GPCR increase
    • Prostaglandins and CGRP work here
  40. Which GPCR pathways causes increased pain levels?
    Galphaq GPCR pathway

    Activated by SP, bradykinin, endothelin

    lead to Phospholipase-C and protein Kinase C activation on nociceptors

    sensitization of TRPV1 receptors
  41. What is the capsaicin receptor?

    temp activated activity (more than 43C)

    active at lower temps with inflammatory mediators
  42. What Na channels are most likely involved in in pulpal pain mechanisms?
    Na 1.7, -1.8, and -1.9
  43. What is temporal summation?
    inc of the electrical stimulation freq of low intensity changes the nonpainful (prepain) sensation to a painful one
  44. Studies indicate there is a _____ correlation between clinical ____ symptoms and the ________________ status of the pulp.
    • poor
    • pain
    • histopathologic
  45. Classification of the pulpal primary afferents as A and C fibers is based on
    their conduction velocities
  46. Slow A-delta are sensitive to ________, where as most fast A-delta fibers respond to _________ stimulation
    • capsaicin
    • hydrodynamic
  47. C fibers do not respond to dentinal __________ stimulation, the sensitivity of dentin is entirely based on the function of intradental _ fibers

  48. What is variation in pain quality attributed to?
    Activation of diff nerve fiber types and diff in the nerve firing patterns evoked by various stimuli
  49. What fiber groups are involved in the mediation of prepain?
    ABeta and Adelta fibers
  50. Basis of single-fiber recordings activation of a _____ number of pulpal afferents is needed to evoke prepain or pain. Significance?

    Produce false-positive response, even in extensive pulpal necrosis, as long as some axons are still responsive
  51. What mediates the intradental nerve activation in response to several different stimuli from all experiments taken together?
    Hydrodynamic mechanism

    Responding fibers are Adelta and ABeta
  52. Pulpal _ fibers are ___________ because they respond to several different modes of stimulation and have high thresholds for activation.
    • C
    • polymodal
  53. The ____ pain induced by pulpitis may be evoked by C-fiber activation.
  54. ________ of the dentinal tubules is required for the ____________ of exposed dentin.
    • Patency
    • sensitivity
  55. Name the six types of sensory axon
    • 3 A fibers (myelinated)
    • 1. Aβ : large, fastest (30-70m/s)
    • 2. Adeltaf: medium fast (12-30m/s)
    • 3. Adeltas: small slow (2-10m/s)

    • 3 C fibers (unmyelinated) (.5-2.5m/s)
    • 1. Cm: mechanosensitive
    • 2. Ct: thermosensitive
    • 3. Cp: polymodal
  56. It is the __________ strength of solutions and their ________ composition that elicits pain responses in human teeth.
    • Osmotic
    • chemical
  57. What are some of the changes induced by nerve fibers during pulpal inflammation?
    • 1. Growth factors released causing nerve terminal sprouting
    • 2. Reduce threshold of other nerves
    • 3. Pulpal blood flow affected
    • 4. Increase in size of receptive fields
    • 5. Increased regional sensitivity
    • 6.
  58. PDL contains these mechanreceptors.

    from trigeminal ganglion or mesencephalic ganglion
  59. What are the two major mechanism of pulpal pain?
    • 1. Dentinal sensitivity
    • 2. Pulpal inflammation
  60. What are "silent" A fibers?
    Slow conducting Adelta fibers NOT sensitive to hydrodynamic stimuli of the coronal dentin

    activated by intense heat and cold that reaches pulp proper.
  61. Injury to the pulpodentin complex causes far reaching effects via the nerve fibers, describe
    • 1. Signals go to ganglion and central pain pathways
    • 2. Terminals release neuropeptides affecting vasodilation