pulp Flashcards
embryonic origin of pulp
ectoderm > neural crest ectomesenchyme > dental papilla
constituents of the pulp
- cells and cellular elements
- blood and lymphatic vessels
- extracellular matrix
functions of pulp in the mature tooth
- hydrates dentin
- protective: sensory, barrier
- defensive: immune
- reparative: formation of new dentin and pulp
developmental precursors of the pulp have an ____ role; odontogenic ectomesenchymal cells secrete a number of signaling or growth factors that act on the epithelial cells of the ____to trigger the transition to the ____ stage
inductive; bud; cap
odontoblasts secrete ____ of dentin and participate in _____
organic matrix; mineralization
binds to collagen in forming dentin matrix; attracts Ca2+ ions to initiate mineralization
dentin phosphoprotein (DPP)
DPP is highly ____ and high in ____
phosphorylated; serine/aspartic acid
DPP is ___ and ____ charged
acidic; negatively (anionic)
dentinogenesis (crown) begins during the ____ stage
bell
3 things that are present just prior to dentinogenesis
- all 4 layers of the enamel organ
- an enamel knot
- the outline of the crown
just prior to dentinogenesis, there are no ____ or ____
odontoblasts (in the papilla); ameloblasts (in the enamel organ)
____ and _____ are present at the future DEJ, prior to dentinogenesis
inner enamel epithelial cells (in the enamel organ); undifferentiated mesenchymal cells (in the dental papilla)
dentinogenesis occurs from ____ to ____ and from ___ to ____
from cusp tips to cervix
AND from periphery to pulp center
inductive signal for odontoblast differentiation is secreted molecules from ____- most likely the ____ (epithelial-mesenchymal interaction)
enamel organ; enamel knot
2 prominent/best documented signaling/growth factors for odontogenesis
BMPs (bone morphogenetic protein)
Wnts
____ expression immediately precedes the “wave” of odontoblast differentiation
Wnt10a
Wnt10a is 1st expressed in ____, then ____ at the cusp tip, then more cervical parts of the tooth
enamel knot(s) pre-odontoblasts
modifying the wnt receptor complex to amplify effects of wnt binding increases production of ____ and ____ in animal models
reparative dentin; dentin proteins
wnt signaling important in adult pulp- pulp cells release wnt after injury in adults
pulp in the crown is the ____ or ____
pulp chamber; coronal pulp
coronal pulp includes extensions into each cusp called ____
pulp horns
pulp in the roots constitutes the ____ or ____ which is continuous with the periodontium at the ____
root canal; radicular pulp; apical foramen
spherical calcified masses, most common in the pulp chamber
pulp stones (denticles)
irregular areas of calcification, usually surrounding blood vessels or collagen fiber bundles, often in the root
diffuse calcifications
located central to the odontogenic zone and contains fibroblasts and trunks of larger branches of both nerves and blood vessels
pulp core
cells confined to the pulp that secrete extracellular matrix (ECM)
fibroblasts
have a role in cell adhesion to ECM
glycoproteins (e.g. fibronectin)
function as a matrix for diffusion, collagen fibrillogenesis, and water retention
proteoglycans (PGs) and glycosaminoglycans (GAGs)
Collagen I and III are both ____ collagens that function in _____
fibrillar; tensile strength
mature pulp does not contain ____
DSPP
stem cells have a high capacity for ____ and they can generate multiple cell types, which means they are called ____
self-renewal (they can replicate themselves); plastic
dental pulp stem cells can be induced to form a number of cell types, not only odontoblasts, but also ____ and ____ in vitro
adipocyte and glial-like cells
named for its function in transforming leukocyte precursors into granulocytes (neutrophils)
G-CSF (granulocyte colony stimulating factor)
DPSCs are ____, providing raw material for new pulp tissues
multipotent
DPSCs are ____ and secrete trophic factors promoting _____ and ____
anti-inflammatory; angiogenesis; neurogenesis
cells unique to the pulp; 2nd most numerous cell type in the pulp
odontoblasts
functions of odontoblasts
- dentinogenesis
- nutrients to dentin
- immune
“sticky” junctions between odontoblasts; maintain position and polarity
desmosomes (contain intermediate filaments) adherens junctions (contain actin filaments)
channels between odontoblasts that coordinate dentinogenesis
gap junctions (contain connexins)
apical “weld” membranes
tight junctions
depending on the exact form of the proteins and their extent, tight junctions can form an _____
inter-cellular barrier
some smaller MW substances can pass between adjacent odontoblasts, but tight junctions inhibit passage of ____ and probably ____
larger molecules; bacteria
the presence of ____ and ____ distinguish pulp from other tooth tissues
blood; lymphatic vessels
the autonomic component of pulpal blood flow control is mainly ____, via ____ and _____ receptors
sympathetic; norepinephrine; alpha adrenergic
the sympathetic nervous system causes vasculature in the dental pulp to ____
constrict
types of nerve fibers that innervate the dentin and pulp
A delta- sensory pain fibers
C- some are sensory pain fibers, others are sympathetic
B beta- sensory pain fibers
innervation begins at the ____ stage
bell
how far do nerve fibers extend into dentin?
nerve processes do reach the dentin, but extend just to the inner third
dentinal tubules are most highly innervated in the ____; nerve fibers also terminate throughout and profusely innervate the ____
crown; pulp-dentin border zone
all dentinal stimuli that cause pain cause ____ in dentinal tubules: this is the _____ theory
fluid movement; hydrodynamic
fluid movement in dentinal tubules causes deformation of _____ sensitive nerve endings close to and in the dentin
mechanically
_____ are embedded in the membranes of nerve fiber _____ of alpha delta and alpha beta fibers in the ____ region
mechanically-activated ion channels (“mechanoreceptors”)
endings
pulp/dentin border
3 things that happen when the nerve fiber endings are deformed
- ion channels open
- Na+ sodium flows into the nerve endings
- nerve endings are depolarized and give rise to action potentials
tooth pain also arises directly from stimuli in the ____
pulp
other pulp nerve fiber endings, especially ____, have receptors for ____ and ____ stimuli; these receptors are members of the ____ receptor family
C fibers; inflammatory; thermal; TRP receptor family
TRP receptors are a family of _____ receptors for thermal and inflammatory pain in many regions of the body
transmembrane
_____ receptor is activated by many inflammatory mediators such as ____ and ____
TRPA1; reactive oxygen species; prostaglandins
TRPA1 receptors are also to ____ through an indirect pathway
bradykinin
location of A delta and A beta fibers
dentinal tubules and most superficial pulp
location of C-fibers
pulp only, superficial and deep
dentinal stimuli activates ____ and ____ fibers through ____ forces; leads to ____ pain
Adelta; Abeta; hydrodynamic; sharp/piercing
infection or trauma activates ____ through inflammation; leads to ___ pain
C-fibers; dull/aching
tooth nerve sensitivity can ____/_____ under conditions of inflammation through many mechanisms
change/become hypersensitized
expression of _____ can increase during inflammation
pain receptors
pain nerve fibers in the tooth have an important ____ influence on the pulp itself
regulatory
the regulatory influence is mediated largely by the release of a class of neuromodulators called _____
neuropeptides
two prominent types of neuropeptides
substance P and CGRP (calcitonin-gene related peptide)
peptides are synthesized in the ____, which is in the ____ (outside the brain)
cell body; trigeminal ganglion
at central endings (trigeminal nucleus, CNS, specifically the brainstem), the peptides have a ____ function, binding with receptors on brain neurons to regulate _____
transmitter; pain
at peripheral endings (in the tooth), peptides have ____ function, binding with receptors on _____ for a _____ effect
local regulatory; vasculature/local cells; pro-inflammatory
inflammatory and immune functions of sensory (pain) nerves
- vasodilation (opposes sympathetic control)
- plasma extravasation
- angiogenesis
- interactions with immune cells
resident immune system cells in the pulp
macrophages
lymphocytes
eosinophils
dendritic cells
types of cells in the pulp during inflammation
plasma cells
mast cells
pmn’s
stem cells in the pulp are a source of replacement for ____ or _____
odontoblasts; fibroblasts
3 locations of stem cell probably present in mature pulp
- undifferentiated mesenchymal cells in cell-rich zone
- perivascular cells (pericytes) in the core
- other cells in the core
different stem cell populations in the pulp probably play a role in response to ____
injury
