Pulp Flashcards
Pulp
Soft connective tissue that supports dentin
What are some unique features of pulp?
Vascular
Not calcified
What is the embryonic origin of the pulp?
Ectoderm - neural crest ectomesenchyme - dental papilla
What are some contents of pulp?
Cells and cellular elements
Blood and lymphatic vessels
Extracellular matrix
What are the functions of pulp?
Inductive Formative Nutritive Protective Defensive/Repairative
Inductive function of pulp
Very early in development, it is involved in inducing transition from dental lamina to bud stage
Nutritive function of pulp
Helps supply the dentin with nutrients and water
What changes might an endodontically treated tooth undergo?
Dentin will become more brittle because pulp can bring nutrients
What are the protective mechanisms of the pulp?
Sensory mechanism
Barrier
Sensory mechanism of pulpal protection
Nerve fibers travel in the pulp, which inform us if the tooth is injured, causing us to use the tooth less, preventing further damage
Barrier mechanism of pulpal protection
Pulp are under positive pressure at odontoblast junctions - if there is a break, the positive pressure forces things out into the oral cavity, protecting the underlying pulp
Defensive/repairative mechanisms of pulp
Immune system
Formation of new dentin and pulp
What are the types of foramina of the pulp?
Apical foramen
Accessory foramen
What happens to pulp chambers as we age?
They get smaller - making endo more difficult with older patients
Pulp has more cells at a young age and more extracellular matrix in older ages
T/F - the pulp is never calcified
False - it is common to have ectopic calcifications
What are the types of ectopic calcifications?
Pulp stones
Diffuse calcifications
Pulp stones
Ectopic calcification commonly found in pulp chamber in crown of the tooth
Spherical or ovoid
No clear cause
Diffuse calcifications
Ectopic calcification often found near blood vessels
Are ectopic calcifications problematic?
Not likely, mostly likely just an annoyance if you’re an endodontist
What are the zones of the pulp?
Odontogenic zone
Pulp core
Odontogenic zone layers
Odontoblast layer
Cell free zone
Cell rich zone
Odontoblast layer
Most superficial layer of odontogenic zone
Single layer of odontoblasts lining the pulp dentin border
Can look like multiple layers, but its likely an artifact of how the slide was cut
Cell free zone
Cells are less prominent
Middle layer of odontogenic zone
Cell rich zone
Increase concentration of fibroblasts
Deep layer of odontogenic zone
Pulp core
Lots of fibroblasts, blood vessels, and nerves
What cells are found in the pulp?
Odontoblasts
Fibroblats
Immune system cells
Stem cells
Odontoblasts
Cells that make dentin
Has processes that go into dentinal tubules
Fibroblasts
Confined in the pulp
Secrete ECM of the pulp
-mostly collage, but other proteins as well
What are the 2 types of immune system cells in the pulp?
Resident immune cells
Inflammation cells
What are the types of Resident Immune cells
Macrophages
Lymphocytes
Eosinophils
Dendritic cells
Dendritic cells
Sit at the PD order, surveying the environment
If there’s an infection, these present the infection to the immune system
Inflammation cells
When you get a tooth infection, these cell numbers increase
Plasma cells
Mast cells
PMNs
Stem cells
Source of replacement for odontoblasts or fibroblasts
High capacity of self reneway
Mutlipotent - can generate multiple cell types
What are components of the ECM of the pulp?
Proteoglycas
Glycoproteins
Collagen
Proteoglycan function in pulp
Gelatinous matrix for diffusion of molecules through the pulp
Help control when and how much collagen is secreted
Water retention - important for keeping pulp moist and keeping positive pressure
Glycoprotein function in the pulp
Cell adhesion to the ECM
Collagen function in the pulp
Tensile strength
What types of collagen are found in the pulp?
I and III
Odontoblast function in the pulp
Dentinogenesis
Nutrients to dentin
Immune - can secrete immunity molecules when needed
What are the types of junctions between odontoblasts?
Desmosomes and adherens junction
Gap junctions
Tight junctions
Desmosomes and adherens junctions
Maintain position and polarity of odontoblasts
Gap junctions
Coorinate dentinogenesis - once one odontoblasts decides to make dentin, it signals to neighbors to do the same thing using gap juncitons
Tight juncitons
Form a barrier to prevent things from diffusing between odontoblasts
Sits at apical portion of cells
Why are the structures of tight junctions so complex?
The more complex they are, the better they are at keeping things out
T/F - Tight junctions prevent all things from getting between odontoblasts
False - small things can still potentially get through. Tight junctions are better at preventing large molecules from going through
What is the importance of lymphatic tissue in the pulp?
Healing - they drain proteins that accumulate during inflammation
Why does the lymphatic tissue have complex anatomy in the pulp?
To overcome challenges associated with encasement in a hard tissue
What are the types of nerve fibers in the pulp
A-delta fibers
C fibers
A-beta fibers
What happens to innervation during tooth eruption?
Density of innervation increases - it decreases with aging
Where do nerve fibers enter the pulp?
Apical foramen
How far do nerve fibers extend into the dentin?
We’re not sure - but it’s likely not all the way to the DEJ
Where is the dentin most highly innervated?
In the crown
Hydrodrynamic theory of dentinal pain
Air, solids, or cold can create a fluid wave in the dentinal tubule, which stretches the nerve fiber, activating pain
Does pain in the pulp follow the Hydrodynamic theory of dentinal pain?
No, just the dentin.
What type of pain receptors are associated with the pulp?
TRP receptors
TRP receptors
Family of transmembrane receptors for thermal and inflammatory pain in many regions of the body
Activated by many inflammatory mediators
Describe the path of pain associated with A fibers
Dental stimuli –>
Hydrodynamic forces –>
A-beta and A-delta fibers –>
Sharp pain
Describe the path of pain associated with C fibers
Infection or trauma –>
Inflammation –>
C fibers –>
Dull pain
What fibers can be activated by electric pulp and hot/cold testing?
A fibers
What do neuropeptides do at central endings?
They have a transmitter funciton
They bind to receptors on brain neurons and produce pain
What do neuropeptides do at peripheral endings?
They have a local regulatory function
They bing with receptors on vasculature and local cells and lead to pro-inflammatory response
