Dental pulp Flashcards
what is the Dental Pulp
A soft connective tissue to support the dentin
how is the dental pulp unique
vascular
Not calcified
Embyronic origin of the dental pulp
Ectoderm (neural crest ectomesenchyme)- dental papilla
what makes up the dental pulp
Cells and cellular elements
Blood and lymphatic vessels
Extracellular matrix
Functions of the Pulp in the mature tooth
Hydrates Dentin
Protective: sensory, barrier
Defensive: Immune
Reparative: formation of new dentin & pulp
why are the pulps sensative
Keeps person from using that side of the mouth on the side of an injury
what is the inductive roll of the Pulp
Induces the bud to go to a cap
Formative Function of the Pulp
Dentinogenesis (odontoblasts)
Roll of odonotoblasts
Secrete organic amtrix of dentin
Participate in mineralization
what is the major component of dentin
Collagen as a scaffold
Roll of Odonotoblasts in mineralization
Transport Ca ions that make the HAP cystals
secreted proteins for controllling mineralization
protein important for mineralization for dnetin
Dentin phosphoprotein (DSPP gene)
how specific is Dentin Phosphoprotein
RElatively specific to dentin
How prominant is Dentin Phosphoprotein
Greater than 50% of the Non-collagenous proteins
How is DEntin Phosphoprotein made
Binding sites for Collagen
Highly phosphorylated
High in serine/aspartic acid
Acidic/anionic
Action of Dentin Phosphoprotein
Binds to collagen in forming dentin matrix
Attracts Ca ions to initiate mineralization
what protein initiates dentin mineralization
Dentin Phosphoportein
when does Dentinogenesis begin
At the bell stage
What exists right before dentinogenesis
4 layers of the dental organ present
Crown outline is present
No odontoblasts or ameloblasts
what happens in the Late bell stage
Inner enamel epithelial cells (ameloblasts)
Undiffferentiated mesenchymal cells/dental papilla: odontoblasts
Dentin secreted
Enamel secreted
How does Dentinogenesis travel through the tooth
Cusp tips to cervix
Periphery to pulp center
when does Odontoblast differentiation begin
when the cells in the outer layer of the papilla stop dividing near the DEJ
How do Odontoblasts differentiate
Odonotoblasts stop devidining elongate nucleus moves to the periphery processes elongate to the DEJ and begin to Deposite predentin grow down to the pulp
what induces odontoblast differentiation
Secreted moleucles from the enamel organs from the inner enamel organs/ secondary enamel knows
(epithelial-mesenchymal interactions)
what are the signals that induces odontoblast differentiation
BMP’s (bone morphogeneitc portein)
Wnt’s
How did we detect the role of Wnt10a in odontoblast differentation
Stained for Wnt10a and Dentin sialophosphoprotein (a sign of odontoblast differentiation)
expressed first at enamel knots
Then pre-odonotoblasts
then successively more cervical parts of teeth
what immediately precedes the wave of odonotblasts differentiation
Wnt10a
what does Wnt10a bind to
binds to GSK to inactivate it (GSK is an inhibitory effect on transcption)
Beta Catenin released and travels to nucleus and initiates transcription
How did we figure out the importance of GSK inhibitor
compared how fast dentin repared using a collagen sponge alone, mta with sponge, and GSK inhibiots and sponge. The gsk showed the greatest amount of repearative dentin
Gross parts of the pulp
Pulp horns Pulp chamber/coronal pulp Root canal/radicular pulp accessory lateral foramina Apical foramen
as you age how does the pulp chagne
less cells and more collagen
what type of dentin buldes into the pulp
Tertiary dentin
pulp calcifactions
Pulp stones (Chamber) Diffuse calcifactions (cannals)
How common are pulp calcifications
They are common
do we know what causes pulp stones
Not really sure
what are the zones of the pulp
Odontogenic zone
central core
Zones of the odontogenic zone from outside to inside
Odontoblast layer
Cell free zone
Cell rich zone
what makes up the pulp core
Fibroblasts (mainly)
Capillaries/blood vessles
Nerves (perineural sheaths)
Cells of the pulp
Odontoblasts
Fibroblasts
Immune system cells
stem cells
roll of fibroblasts in the pulp
confined to the pulp to secrete ecm
resident immune system cells of the pulp
Macrophage T lmphocytes eosinophils Dendritic cells pmn's
Inflammation cells of the pulp
B lymphocytes
Plasma cells
Mast cells
roll of stem cells in the pulp
Source for replacement of odontoblasts or fibroblasts
what makes up the Extracellular matrix of the pulp
Proteoglycans and associates
Glycoproteins (fibronectin)
Collagen (I and III)
function of PG’s and associates of the EXM of the pulp
Matrix for diffusion
Collagen fibrillogenesis
Water retention
what would you want the EXm of the pulp to hold water
Pressurized the pulp to resist compressive forces
Function of glycoproteins(fibronectin) in the ECM of the pulp
Cell adhesion to ECM
function of collagen I and III in the pulp
Tensile strength
differences of collagen in the pulp and the dentin
both contain type I, but dentin has no type III(b/c it is a hard connective tissue
what protein does the mature pulp not contain that is esential to dentin
DSPP
what are two of the major components of stem cells
high capacity for self-renewal
Plastic (can generate multiple cell types)
Importance of Adult stem cells
Ready source for repair or correction of genetic defects (non-fetal, non-immunogenic)
Multipotent adult stem cells
derived from bone marrow, brain, muscles, testes, and dental pulp
what all can dental pulp stem cells differentiate into
Odontoblasts
adipocyte
Glial-like cells
what happens when dentin-like tissues are transported subcutaneously into immunocompromised mice
what looks like a tooth made of dentin and pulp forms
what successes have we had with dnetal stem cells
Creating tooth buds or reparing tooth strucutre in animal models
Treating other conditions like Multiple sclerosis or spinal cord injury
limitations of dental stem cells
Size and shape of engineered teeth poorly controlled
How to integrate an engineered tooth into the jaw
human teeth take months-years to form
what would be a practical use of Dental stem cells
Repair (regenerating pulp tissues lost to carries) - this is moden focus
what is the canine model of total pulp regeneration
Isolate stem cell from max canines for autologous impants
Remove pulp from insiors
Implanted stems cells, G-CSF in combo or separating using a collagen matrix
Performed fucntion test, removed teeth, analyzed histogy
showed that good repair took place
what is important for stem cell regeneration of dentin/pulp
The combo of stem cells and G-CSF
what is G-CSF
functions in transforming leukocyte precursors into granulocytes (netrophils)
how many tissues produce G-CSF
Lots
Functions of G-CSF
Chemotactic for many types of stem cells, including DPSCs
Promotes neurogenesis and angiogenesis
Anti-apoptotic
Can DPSC’s become many different cells
Yes, multipotent,
Function of DPSCs
PRovide raw material for new pulp tissues
anti-inflammatory
secrete trophic factors promoting angiogenesis and neurogenesis
how does G-CSF promote the processes of DPSCs
Keeps DPSC’s in the area, because DPSC’s have G-CSF receptors
Attracts other stem cells from surrounding tissues
Anti-apoptotic and proliferative effects
Use of DPSC’s to treat pulpitis
Small clinical trial, with not definitive but promising results
what is the Odontoblast unique to
Unique to the pulp
how common is the odontoblast
2nd most numerous cell type in pulp
Functions of odontoblasts
Dentinogenesis
Nuetrients to dentin
Immune
Cell body dimensions of Odontoblasts
Crown: 25-50uX5-7u
Root: more cuboid
Roll of Cytoskeletal elements in odontoblasts
PRotein transport and structural integrity
Junctions between Odontoplasts
Desmosomes and Adherens junctions
Gap Junctions
Tight junctions
roll of desmosomes and adherens
Sticky to help maintina position and polarity
Roll of Gap junctions
Channels betwen cells to coordinate dentiogeneis
what proteins are used in Adherens
Actin:Catenin:Cadherins:catenin:actin
what makes up a gap junction
Connexin
what does a desmosome connect
Intermediate filaments
Rolll of tight junctions
Apical to weld membranes
what can Tight junctions create
depending on proteins, can form an inter-cellular barrier
what can pass through a tight junction
only smaller molecular weight substances
what distinguishes the pulp from other
Highly vascularized
Lymphatic tissue/vessels
How do blood vessels enter and leave the pulp
Through the apical foramen and accessory foramina
how do blood vessels devide in the pulp
Become more diffuse and smaller as they go to the perifery and near the edge of the dentin towards the crown and lateraly
What controls the blood flow
Sympathetic
Sensory nerves
how does the sympathetic system control the blood flow in the pulp
constricts via norepinepthrine and alpha adrenergic receptors
what is the roll of the lymphatic vessels in the pulp
Healing by draining proteins accumulated during inflammation
what fibers innervate the pulp
Small A delta and C fibers
A beta fibers
what is the roll of A delta nerve fibers
Sensory pain fibers
what is the roll of c fibers
Sensory painn fibers
also smypathetic
roll of A beta fibers
Sensory pain fibers
what is the main sensation arising from activating nerve fibers innervating the pulp and dentin
PAIN
when does tooth innervation begin
At the bell stage
For how long does sensory innervation increase
increases until eruption and then slows until a few years after
when does Innervation of the tooth decrease
with aging
what dentintion is innervated
Primary and seconday
where do nerves travel in the pulp
enter through the apical foramen and terminate in pulp dentin border zone and dentin
how far do nerve processes extend into the dentin
Only up to about the inner 1/3
how did we figure out that Nerve processes only go 1/3 up into the dentin
Used a fluorescent dye that was lipophilic and was then taken up by the nerves to show it only went like 1/3 in
Do odonotblasts reach the outer dentin
Yes, due to dentinogenesis, but then seem to retract
what dentinal tubules are most highly innervated
Those in the crown
where is Rashhow’s plexus
at the border of the cell free zone and the cell rich zone
most likely in the pulp horns
what zone do nerve fibers profusely innervate
The pulp-dentin border zone
How does the Hydrodynamic theory of dental pain work
Mechanically activated ion channels in the nerve fibers ends of A delta and A belta fibers in the pulp/dentin border regeion
upon deformation, ion channels open
Na+ flows in
Depolarization and AP
what are the mechanoreceptors used for Hydrodynamic theory of dentin
PIEZO2 (stretch sensitive ion channels used for touch and proprioception throughout the body
why is there not direct stimulation of dental pain
Nerve endings don’t reach that far
why is there not a synapse on odontogenesis for pain
Does not form that synapse for pain
does the Odonotblast do nothing for dental pain
Yes, due to crowding and proximity in tubule, so it affects the fluid dynamic around the nerve process
is hydrodynamic motion the only way of getting pain
Direct stimuli of the pulp(hydrodynamic fluid flow not required)
What nerve fibers are responsible for pain due to direct stimulation of the pulp
C fibers(other recetpors on them)
what receptor type is neccessary for pulp sensitivity to inflammation and thermal stimuli
TRP receptors
what are TRP receptors
Famility of transmembrane receptors for thermal and inflammatory pain throughout the body
what can activate TRPA1 rectpors
reactive oxygen species
Prostaglandings
Bradykinin
How to tell a difference between Hydrodynamic pain or inflammation
Hydrodynamic: sharp pain (responds to hot, cold, electric pulp tests)
Inflammation: dull pain (less response)
what fibers are used for the Hydrodynamic theory
A beta and A delta fibers
what fibers are responsible for inflammation pain
C fibers (pulp only, superficial and deep)
what make cause inflammatio in the pulp
Cytokines
Prostaglandins
Bradykinin
INcreased pressure
how can tooth sensitivity change
can be hypersensitized under conditions of inflammation because more pain receptors are expressed when inflammed
Roll of nerve fibers aside for sensation
Protective role by limiting use (sensation)
release of neuropetides
what neuropetides are realsed by the pulp nerves
Substance P and CGRP (calcitonin-gene related peptide)
location of cell body for the tooth
Trigeminal ganglion
where are nueropeptides released
Released at both the Peripheral ending (tooth)
and Central ending in the CNS
why are nueropeptides relased
painful stimulase
Brain: neurotransmitter for pain
Pulp: bind w receptors on vasculature/local cells for a pro-inflammation response
Important part of the skull for pain in the tooth
Meckel’s cave
what are the Inflammatory runction of the nerve
VAsodilation (oposite of sympa)
plasma extravasation
Angiogenesis
Interaction with immune cells
how does Inglamation of nerve is pulp interact with the immune cells
Stimulate cytokine production by macrophages
Chemotactic effects on immune cell migration
