PULPAL MICROVASCULAR RESPONSE IN INFLAMMATION

By Max Hutchins, Ph.D., Department of Basic Sciences; John Suchina, D.D.S., M.S., Department of Stomatology, The University of Texas Health Science Center at Houston, Dental Branch and Jim Patten, D.D.S., Ph.D., Private Practice limited to Endodontics, El Paso, Texas.

SELF-ASSESSMENT EXAMINATION

This examination will evaluate your ability to read and comprehend the basic information related to the PULPAL MICROVASCULAR RESPONSE TO ACUTE DENTINAL EXPOSURE.

The format for the following self-assessment  exam is commonly used in multiple choice questions; a stem followed by statements or items which may be TRUE or FALSE.

EXAMPLES

TRUE___ Exchange of fluid across the subodontoblastic capillaries should be equal. (filtration =reabsorption)

FALSE__ Relaxation (vasodilation) of the precapillary sphincter increases the resistance to blood flow (resistance a 1/vessel radius 4 )

TRUE___ Interstitial edema of dental pulp within the low compliant tooth could compress the low pressure venules and reduce blood flow.

  1. Subodontoblastic Capillaries:
    1.         Blood flows from the low pressure TA into the high pressure PCV
    2.         The subodontoblastic capillaries (SC) form loops around the basal region of the odontoblast.
    3.         The resistance to blood flow through SC occurs by controlling the radius of the TA and PC vessels.
    4.         Diffusion of O2 and CO2 between SC and the odontoblast increases with edema in the interstitial space.

  2. Fluid movement:
    1.         Filtration is determined by the magnitude of the Capillary Hydrostatic pressure (Chp) plus the tissue oncotic pressure (Top)
    2.         An increase in permeability of the capillary endothelium to albumin would increase the tissue  oncotic pressure.
    3.         Reabsorption of interstitial fluid is determined by the Plasma Oncotic pressure (Pop) plus  the tissue hydrostatic pressure (Thp).
    4.         Localized vasodilation would decrease capillary filtration and reduce the reabsorption of  interstitial fluid.

  3. Localized odontoblast degeneration:
    1.         Pulpal interstitial fluid edema would elevate the tissue hydrostatic pressure.
    2.         Localized dental pulp inflammation would produce a microvascular response in this order;  collapse of venules, vasodilation, degeneration of odontoblasts, and an  increase in capillary  permeability
    3.         An increase in tissue hydrostatic pressure could collapse the postcapillary venules.
    4.         Localized dead tract dentin occurs as the odontoblast degenerate and become necrotic.


  4. Protective mechanisms of the adjacent non-inflamed pulp tissue
    1.         The elevated tissue hydrostatic pressure promotes absorption of fluid into the non-collapsed  adjacent venules.
    2.         Albumin is absorbed from the inflamed pulpal interstitial tissue by the adjacent lymphatic channels.
    3.         As pulpal inflammation progresses the arteriovenous anastomosis deliver more blood to the inflamed site.

E-mail answer to Dr. Hutchins.

     


Content questions should be directed to: Dr. Max Hutchins
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