Dentin Pulp Complex II Flashcards
What is the living, highly cellular core of the tooth?
Dental pulp
What is the primary cell type of the Dental pulp?
Fibroblasts followed by odontoblasts
What is the embryonic origin of the dental pulp?
Arises from the dental papilla, ectomesenchymal tissue
What are the support structures for the mineralized components of the tooth found in the dental pulp?
- Blood vessels
- Enervation
- Fibroblasts
- Pool of immune cells
- Pool of pregenitor cells for replacement and repair
What are the 4 histological zones of dental pulp from outer to inner?
- Odontoblast layer
- Cell free zone of Weil
- Cell rich (cell dense zone)
- Pulp core
The Extracellular matrix of the dental pulp contains which types of collagen?
- Mostly Collagen III
- Also some Collagen I
The Dental pulp ECM is a soft ______ matrix
connective tissue
T/F The dental pulp ECM contains numerous non collagenous proteoglycans and glycoproteins
TRUE
What happens to the make up of the pulp ECM with age?
- Collagen content increases
- Fibrils aggregate into larger bundles
*Greatest concentration apically
The ground substance of the pulp will contain what?
- Proteoglycans (GAG chains)
- Glycoproteins
- Water (physiological fluid)
List the 5 common proteoglycans found in the pulp
- Chondroitin-6-sulfate
- Chondroitin-4-sulfate
- Heparin Sulfate
- Dermatan sulfate
- Keratan sulfate
What is the key dentin-pulp complex cell type?
Odontoblasts
Odontoblasts are _______ cells which have their ______ toward the pulpal side of the cell and their _______ towards the dentinal side
- Polarized
- Elongated nucleus
- Secretory components (Golgi Bodies)
Where would Odontoblasts be larger and more columnar?
In the crown
Where would odontoblasts be more cuboidal?
Toward the root
Odontoblasts form a discrete layer of cells held together by ________
Junctional complexes
*Adherans junctions not zonular
T/F Odontoblasts can form gap junctions with pulpal fibroblasts
TRUE
Because of the way they are held together, Odontoblasts cell layers may have a degree of ________ through which _______ may pass
- permeability
2. serum proteins
Odontoblasts function to create and maintain _____ and are supported by __________
- Dentin
2. The rest of the pulp
Odontoblasts produce and secrete what kinds of proteins?
Collagen and Non-collagenous
T/F Odontoblasts produce and sequester key growth factors in dentin matrix
TRUE
Give 4 examples of key growth factors that come from odontoblasts
- VEGF
- TGF-beta-1
- BMP-2
At what location on the cell do odontoblasts release secretory vesicles?
Primarily found in the OD process
The release of secretory vesicles from OD process continues throughout the lifespan of the OD, forming _________
Peritubular dentin
What are some distinct characteristics of aged odontoblasts?
- Fewer organelles
- Less secretory activity
- Nucleus somewhat more central
Describe OD turnover
- Assumed to be long lived
- Can be replaced from mesenchymal progenitor pool
OD turnover is key to what?
Responsiveness of tooth and capacity for self repair
Odontoblasts communicate with what other cells?
- Fibroblasts
- Nerve cells
- Immune cells of the pulp
How far do the OD processes extend?
- Not agreed upon
- Possibly all the way to the DEJ
- Prehaps only around 1/3 of the way into the dentin
Sequestered GFs in the dentin matrix play a role in what?
Recruitment of new OD
What is the predominant cell type found in dentin-pulp complex?
Fibroblasts
Where do you find fibroblasts in the dentin-pulp complex?
Found in the pulp core and cell rich zone
What do Fibroblasts do for the dentin-pulp complex?
Produce and maintain the supportive matrix of the pulpal tissue
The pulpal tissue matrix that is supported by the fibroblasts supports what?
- Progenitor cells
- Immune cells
- Vasculature
- Lymph
- Nervous tissues
T/F Fibroblasts may have a role in facilitating mesenchymal progenitor cell recruitment and differentiation
TRUE
Mesenchymal progenitor cells are present where?
in dental pulp
In response to ______, mesenchymal progenitor cells are recruited to form ________
- Damage
2. New Ondontoblast-like cells
Dental pulp progenitor cells are involved in ________
Reparative dentin formation
As far as immune cells go, _______ are present in the dental pulp as part of innate immunity
Macrophages
Healthy pulp has a key role in ________
cell turnover and clearance
Healthy pulp has involvement in __________
Immune response to infection
*IL-1B, TNF-a
Concerning Adaptive immunity, what type of cells can be found in the pulp?
Dendritic cells
Where are the dendritic cells found in the pulp?
Under the odontoblast layer
T/F T and B lymphocytes are also in the pulp
TRUE
*especially in infected pulp
Dendritic cells are especially closely related with what components of the pulp?
Neuronal and vascular
**has to do with coordinated tissue responses
Where does pulp vascular supply arise from?
External carotid arteries and superior/inferior alveolar arteries
_______ arterioles per root access the pulp through the _______ and spreads upward into the coronal pulp
- 4-8
2. Apical foramen
What is the progression of blood supply in the pulp?
- Arterioles
- Capillaries
- Venules
As arterioles proceed into the pulp, _________ increases, _________ decreases
- Caliber
2. Vessel wall
Capillaries network is present where?
In the cell free zone
*during dentin formation present in the odontoblast layer
Venules leave the apical foramen and connect to ______ and drain ultimately into _______
- Superior and inferior alveolar veins
2. Internal jugular vein
What does it mean for the lymphatic supply to be in a steady state in the pulp?
Lymph flow is equal to arterial interstitial flow
Describe the lymphatic vessels in the pulp
Thinner walls, epithelial lining and smooth muscle layer
What do lymph vessels do for the pulp?
Drain vascular exudate, interstitial fluid out of the pulp
Nerve fibers branch out through the coronal pulp forming what?
The plexus of Raschkow
T/F Plexus of Raschkow are most present in root pulp
FALSE They don’t exist in root pulp, only branches of nerve fibers
Afferent nerve fibers to the pulp come from where?
Trigeminal
Sympathetic branches in the pulp come from where?
Cervical Ganglion
What does the innervation of the pulp function to do?
- Control blood flow
- Nociception
- Maybe immune response
The nerves in the pulp run in close contact with ______
Blood vessels
Nerve bundles in the pulp consist of which type of axons?
- Myelinated (Adelta)
- Unmyelinated (C)
Myelination decreases as fibers proceed towards the ________
Coronal pulp
Some unmyelinated nerve axons pass into __________ and are closely associated with ________
- Dentinal tubules
2. Odontoblasts
What is the role of the nerve axons that run up into the dentinal tubules?
No clear understanding of their role
What are the 3 proposed models of dentin sensitivity?
- Direct innervation
- Odontoblast nociception
- Tubule fluid conductance (hydrodynamic)
What is the thought behind Direct innervation for dentin sensitivity?
There are nerves in some tubules, but a minority
What is the thought behind Odontoblast nociception causeing dentin sensitivity?
Odontoblasts are neural crest cerived buta natomically do not synapse extensively with pulpal nerves; gap junctions exist however
What is the though behind Tubule fluid conductance in dentin sensitivity?
Local anesthetics applied to exposed dentin ineffective, changes in fluid levels can cause sensitivity
What is a pulp stone?
Mineralized tissue formed inappropriately in the pulp
What is a “free” pulp stone?
Surrounded by soft pulp tissue
What is an “attached” pulp stone?
Bound to dentin or embedded in secondary dentin
What is a “true” pulp stone?
-Containing tubules and associated wit odontoblast-like cells (rare)
What is a “false” pulp stone?
- Consisting of atubular mineralized tissue, sometimes with necrotic tissue at the center
- these are more common
T/F Pulp Stones can grow large enough to compress pulp and make debridement difficult
TRUE
Where do pulp stones occur?
Around collagen fibers, dead cell aggregates to thrombi
Pulp stones are more prevalent after how many years of life?
50
As you age, what causes recession of the pulp?/
Secondary dentin formation
*reduction in cell number (pulp cells I think)
What happens to the cell response to stimuli as you age?
It decreases
What happens to pulp permeability as you age?
It decreases
-Peritubular occlusion
-leads to more brittle teeth
In aged pulp there is a loss of _______ which leads to a decrease in _________
- Nerve axons
2. Sensitivity
What happens in the central pulp as you age?
Dystrophic Calcification
