Dental Pulp Flashcards
What layers does the dental pulp have?
pulpal core
cell rich zone
odontoblast layer
(predentin?)
What are the layers of the odontogenic zone of dental pulp?
- Odontoblast cell layer
- Cell-free zone of Weil
- Cell-rich zone
- Parietal plexus of nerves (Raschkow’s plexus)
What is in the pulpal core?
- Fibroblasts
- Type I and III collagen
- Extracellular matrix
- Blood vessels
- Nerve tissue
What is the dental pulp derived from?
neural crest cells
What is the main component of dental pulp?
loose connective tissue
What are the four functions of dental pulp?
- Embryonic induction
- Formative
- Protective
- Reparative
What are the cells of the pulpal tissue?
- fibroblasts (most)
- odontoblasts
- undifferentiated mesenchymal cells
- macrophages/dendritic cells (8%)
- blood vessel related cells (pericytes, endothelial, etc.)
- neural related cells (schwann, etc.)
- lymphocytes
What are the collagen types in dental pulp?
Type III (most)
Type I, IV, V
What are the non-collagenous matrix components of dental pulp?
- Proteoglycans
- Glycosaminoglycans
- Phosphoproteins
- Glycoproteins
- γ- carboxyglutamate-containing proteins
- BMP-2, 4, and 7
- Fibroblast Growth Factor (FGF)
- Epidermal Growth Factor (EGF)
- Dentin Matrix Protein (DMP)
Does pulp have myelinated or nonmyelinated nerve axons?
both!
Most nerve endings in the pulp are for…
pain
Nerves of the pulp progressively branch and then follow what path?
- pass through the subodontoblastic layer as the parietal neural plexus (Rashchow’s plexus)
- then into the odontoblastic cell layer and some fibers enter into dentinal tubules.
What cranial nerve are the sensory afferents of the dental pulp from?
trigeminal (CN V)
What are the sensory afferents in dental pulp?
pain
mechanical
thermal
tactile
Sympathetic branches from the superior cervical ganglion are primarily ________ fibers to pulpal blood vessels.
vasomotor
Sympathetic branches from superior cervical ganglion do what to blood vessels?
vasoconstriction (mostly)
What ganglion are the sympathetic branches to the dental pulp from?
superior cervical ganglion
The majority of myelinated pulpal nerve axons are…
A-δ (A-delta)
What are A-δ (A-delta) nerves?
fast conducting
diameter (1-6 um)
1% of myelinated nerve fibers are classified as…
A-β (A-beta) fibers
6-12 um diameter
Nonmyelinated fibers are designated as…
“C” fibers
What are “C” fibers?
small diameters (0.4-1.2 um)
slower
What fibers are associated with sharp, localized pain?
A-δ (A-delta)
What fibers are associated with dull, diffuse pain?
“C” fibers
What are the neuropeptides/neurotransmitters in dental pulp?
- Calcitonin gene-related peptide (CGRP)
- Substance P
- Epinephrine
- Norepinephrine
-Dopamine - Endorphin
What does substance P do in dental pulp?
Vasodilatation, stimulates fibroblast cell division
What does calcitonin gene-related peptide (CGRP) do in dental pulp?
Vasodilatation, stimulates fibroblast cell division
What does epinephrine do in dental pulp?
Vasoconstrictive via arteriole smooth muscles
What does norephinephrine do in dental pulp?
Sympathetic vasoconstrictor
What does dopamine do in dental pulp?
Vasoactive or a precursor of epinephrine
What does endorphin do in dental pulp?
silencer of nociceptors (silencer of pain)
Each fiber contributes at least __ branches to Raschkow’s plexus.
8
Does the distribution of nerve axons in intratubular predentin increase or decrease from pulp horns down to the root?
decrease
- pulp horns = 27%
- remaining crown = 14%
- root = 11%
Does the distribution of nerve axons in intratubular dentin increase or decrease from predentin to dentin up to 100 um?
decrease
ex: in pulp horns
predentin = 27%
mineralizing front = 11%
dentin up to 100 um = 8%
Do venules or arterioles have a bigger diameter?
venules (100 um to 150 um)
arterioles (50 um to 100 um)
Terminal capillaries anastomose deep to what layer of dental pulp?
odontoblastic layer
Capillary loops are dense in the _________________ and significantly less dense in the radicular pulp
coronal and pulp horns
What type of capillaries are found in the pulp?
Continuous and fenestrated capillaries
If progressive and severe, atherosclerotic plaques can result in _________________ due to vessel strangulation.
pulpal hypoxia
What can fenestrated capillaries leaking serum cause?
swelling and edema that can lead to inflammation
When does pulpal fibrosis occur?
increasing age or persistent
low-grade injury, e.g., multiple
restorations in a single tooth,
chronic bruxism, repeated
thermal insult
What is pulpal fibrosis?
shrinkage of the pulp
What are diffuse calcifications?
Irregular calcified deposits along collagen fiber bundles or within blood vessels resulting from chronic low-grade inflammation
What are pulp stones (denticles)?
- True pulp stones contain dentinal tubules
- False pulp stones feature concentric layers of calcified tissue but are void of dentinal tubules
fenestrated capillaries
pulpal fibrosis
diffuse calcifications
False pulp stones (false denticles)
True pulp stones
- can be attached, embedded, or free (yellow arrow)
Pulp stones
What is a pulpal abscess?
a dense aggregation of neutrophils and macrophages and other inflammatory cells within connective tissue undergoing liquefactive necrosis
What does edema, inflammatin, and pulpal necrosis lead to clinically?
persistent pain and periapical necrosis of the PDL and associated alveolar bone
necrotic pulp (box) with periaprical abscess (arrow)
diffuse cellulitis
I and D (incision and drainage) of periapical abscess
