The dental pulp Flashcards
What is the soft connective tissue that supports dentin?
the dental pulp
T/F. The dental pulp is vascular and calcified.
False, the dental pulp is vascular and NOT calcified.
What is the embryonic origin of the dental pulp?
ectoderm - neural crest ectomesenchyme-dental papilla
What are the constituents of the dental pulp?
cells & cellular elements, blood and lymphatic vessels, extracellular matrix
What are the functions of the pulp?
inductive, formative, nutritive, protective (sensory, barrier) and defensive/reparative (immune, formation of new dentin and pulp)
What part of the pulp promotes the spread of infection?
accessory/lateral foramina
T/F. As one ages, the pulp chamber increases.
False, it decreases.
Over time, the dental pulp ___ its cellularity and ___ its extracellular matrix.
decreases; increases
What are the two forms of ectopic calcifications found in the pulp?
- pulp stones (in the pulp chamber)
2. diffuse calcifications (in the root)
If large and dense, pulp stones can be seen where?
radiographs
What are the three layers of the odontogenic zone?
odontoblast layer (closest to the predentin)
cell free zone
cell rich zone
Which area in the odontogenic zone has the greatest concentration of fibroblasts?
the cell rich zone
The odontoblast layer of the odontogenic ___ contains a single layer of ___ lining the ___-dentin junction.
zone; odontoblast; pulp
What structures can be found in the pulp core?
capillaries, fibroblasts and nerves
What are the four major types of cells found in the pulp?
odontoblasts
fibroblasts
immune system cells
stem cells
Which immune system cells are resident to the pulp?
macrophages
lymphocytes
eosinophils
dendritic cells
Which immune system cells are inflammatory?
plasma cells
mast cells
polymorphic neutrophils
Which cell type of the pulp is confined to the pulp and secretes the extracellular matrix?
fibroblast
What cells are the source of replacement for odontoblasts or fibroblasts?
stem cells
What are the components of the ECM of the pulp?
proteoglycans (&GAGs)
glycoproteins
collagen
What types of collagen are found in the ECM of the pulp?
type I and III
What is the function of the proteoglycans of the ECM?
they are involved in collagen fibrillogenesis and water retention
What is the function of the glycoproteins in the ECM?
role in cell adhesion to the ECM
What is the function of collagen in the ECM?
tensile strength
Which ECM structures are found in both the pulp and dentin?
proteoglycans and type I collagen
Which ECM structures are found in the pulp and not the dentin and vice versa?
pulp - type III collagen
dentin - DSPP
In vitro, dental pulp cells can be induced to form odontoblasts, ___ and ___ cells.
adipocytes; glial-like
What is the 2nd most numerous cell type found in the pulp? 1st?
2nd - odontoblasts
1st- fibroblasts
What are the functions of odontoblasts?
dentinogenesis, nutrients to dentin, immune
What shape are the cell bodies of odontoblasts near the root?
more cuboid
Odonotoblasts have ___ elements used for protein transport and structural integrity.
cytoskeletal
___ and ___ junctions between odontoblasts maintain position and polarity.
Desmosomes; Adherens
What are channels between odontoblast that coordinate dentinogenesis?
gap junctions
Which type of junction serves as a barrier for odontoblasts?
tight junctions
What are three examples of tight junctions in odontoblasts?
claudin, occludin, and JAM
If they are extensive enough, ___ ___ can form a barrier.
tight junctions
How do cavity preparations affect the cells?
it can disrupt the barrier
T/F. The dental pulp is highly vascularized but does lacks lymphatics. This distinguishes it from other tooth tissues.
False, The dental pulp is highly vascularized AND HAS lymphatics. This distinguishes it from other tooth tissues.
Branching of the pulpal vasculature occurs near what area?
the odontoblastic zone
The ___ system constricts the blood vessels in the pulp when ___ binds to alpha-adrenergic receptors.
sympathetic; NE
T/F. There is no supply from the parasympathetics to the pulp that causes vasodilation. This is accomplished by sensory input.
True.
How do the lymphatics play a role in healing of the pulp?
it drains proteins that accumulated during inflammation
___ vessels in the pulp may have a complex anatomy to overcome challenge associated with encasement in a hard tissue.
Lymphatic
What type of fibers innervate the pulp?
A-delta, C fibers and A-beta
Which fiber type is associated with no-touch sensations, included no pain, in other areas of the body?
A-beta fibers. They are sensory pain fibers in the pulp
What is the main sensation arising from activating nerve fibers innervating the pulp and surrounding dentin?
pain
Innervation begins at the ___ stage.
Bell
There is an increase in the density of innervation until when?
eruption
T/F. Both primary AND secondary dentition is innervated.
True.
Nerves enter through the ___ ___ and terminate in the ___-___ border zone and ___.
apical foramen; pulp-dentin; dentin
What lipophilic dye is taken up by nerve processes and can tell you how far it is transported into dentin?
Dye I injections (this also stains odontoblasts)
Why is Dye I used?
It shows how far nerve and odontoblast process extend into dentin
T/F. In early dentinogenesis, odontoblast processes reach the outer dentin. Later, they seem to retract.
True.
Where are dental tubules most highly innervated?
the crown
In the crown, what is the plexus of nerves that occupies the cell-free zone?
Rashkow’s plexus
If the nerve fibers don’t extend all the way to the DEJ, why is there high sensitivity to the DEJ when exposed?
Fluid movements stretch the nerve fibers and there stretch sensitive endings equate pain. This phenomenon is known as the Hydrodynamic Theory of Dentinal Pain.
T/F. The more pressure, the less pain.
False, the more pain.
What type of nerve fibers play a role in the hydrodynamic dentinal pain theory?
A-beta fibers, they have VERY LOW thresholds for mechanical stimulation in other parts of the body.
What were the two theories of dentinal pain that have been rejected? Why?
Direction stimulation, nerve fibers don’t extend that far
Odontoblast receptor, no functional connection ODB and nerve fibers found
How else can odontoblast affect dentinal sensitivity?
nerve fibers are found in close proximity to ODB. Crowding affects fluid dynamics and adhesive contacts cause ODB to “pull on” nerve fiber (non-synaptic communication).
T/F. Pain can also arise DIRECTLY from stimuli in the pulp.
True.
Which pulpal fibers have TRP receptors for inflammatory and thermal stimuli?
C fibers
___ receptor on the nerve fibers of pulp is activated by many inflammatory mediators.
TRPA1
Dentinal stimuli initiate ___ forces that signal A-___ and A-___ fibers in the dentinal tubules and most superficial pulp to perceive ___ pain.
hydrodynamic; beta; delta; sharp
Electric pulp and Hot & Cold test for pulp vitality ___ activate A-___ fibers but are less effective in activating ___ fibers.
easily; delta; C
___ or ___ causes inflammation and ___-fibers found only in the ___ (superificial and deep) are activated and perceive ___ pain.
Infection; trauma; C; dull
T/F. Expression of pain receptors can increase during inflammation.
True.
___ are found in dentinal and pulp sensory nerves.
Neuropeptides
Where are the cell bodies that synthesize neural peptides?
trigeminal ganglion
T/F. Peptides bind with receptors on brain neurons (cental endings) and lead to pain. Peptides bind with receptors on vascularture/local cells (peripheral endings) and cause pro-inflammatory responses.
True.
Sensory (pain) nerves promote ___ (opposing sympathetic control), cause plasma ___, angiogenesis and interactions with ___ cells (cytokine production by macrophages, chemotactic cell migration).
vasodilation; extravasation; immune
