Week 4 - Dental Pulp Flashcards
What is the cap stage characterized by?
Dental papilla development
What is the bell stage characterized by?
Primitive pulp
When is capillary development?
During the bell stage
What zones make up mature dental pulp?
Dentin
Predentin
Odontoblast layer
Cell rich zone
Pulpal core
What cells make up the pulpal core?
Dendritic cells
What kind of tissue does dental pulp consist of and what is it derived from?
Consists of loose connective tissue derived from neural crest cells
What two compartments is mature dental pulp divided into?
Odontogenic zone
Pulpal core
What makes up the odontogenic zone?
- Odontoblast cell layer
- Cell-free zone of Weil
- Cell-rich zone
- Parietal plexus of nerves (Raschkow’s plexus)
What makes up the pulpal core?
- Fibroblasts
- Type I and III collagen
- Extracellular matrix
- Blood vessels
- Nerve tissue
What are the functions of dental pulp?
- Embryonic induction (stimulates enamel organ)
- Formative
- Protective
- Reparative
What do cell populations in pulpal tissue include?
- Odontoblasts
- Fibroblasts (MOST AMOUNT)
- Undifferentiated mesenchymal cells (ready to mature and become whatever)
- Macrophages
- Dendritic cells
- Blood vessel-related cells (e.g., endothelial &
pericytes) - Neural-related cells (e.g., Schwann cells)
- Lymphocytes (for immune response)
What is extracellular matrix of pulpal tissue made of?
Collagen types I, III, IV, and V (via odontoblasts)
- III is most numerous
What are non-collagenous matrix components?
- Proteoglycans
- Glycosaminoglycans
- Phosphoproteins
- Glycoproteins
- γ- carboxyglutamate-containing proteins
What are examples of γ- carboxyglutamate-containing proteins?
- BMP-2, 4, and 7
- Fibroblast Growth Factor (FGF)
- Epidermal Growth Factor (EGF)
- Dentin Matrix Protein (DMP)
What do γ- carboxyglutamate-containing proteins do?
Stimulate growth maturation of ameloblasts and odontoblasts
What nerve axons does pulpal innervation include?
Myelinated and nonmyelinated
Where do nerve axons branch?
They progressively
branch, passing through the subodontoblastic layer
as the parietal neural plexus (Rashchow’s plexus), on
to the odontoblastic cell layer and some fibers enter
into dentinal tubules.
What are most nerve endings in the pulp for?
pain (free nerve
endings as sensory afferents from CNV) with a few concerned with vasodilatation or constriction
What nerve do sensory afferents come from?
Trigeminal CNV
What are sensory afferents that the trigeminal nerve brings?
- Pain
- Mechanical (pressure)
- Thermal (heat)
- Tactile (touch)
Sympathetic branches from the superior
cervical ganglion are primarily?
vasomotor
fibers to pulpal blood vessels, concerned
for the most part, with vasoconstriction
The majority of myelinated pulpal nerve axons are
A-δ (A-delta):
* Fast conducting
* Diameter in range of 1-6 µm
1% of myelinated nerve fibers are classified as
A-β
(A-beta) fibers:
* 6-12 µm diameter
Nonmyelinated fibers are designated as
“C” fibers
and have small diameters, ranging from 0.4 to 1.2 µm
A-δ fibers are associated with what kind of pain?
Sharp, localized pain
“C” fibers are associated with what kind of pain?
Dull, diffuse pain
Neuropeptides and neurotransmitters identified in
dental pulp include
Calcitonin gene-related peptide (CGRP)
* Vasodilatation, stimulates fibroblast cell division
Substance P
* Vasodilatation, stimulates fibroblast cell division
Epinephrine
* Vasoconstrictive via arteriole smooth muscles
Norepinephrine
* Sympathetic vasoconstrictor
Dopamine
* Vasoactive or a precursor of epinephrine
Endorphin
* silencer of nociceptors (silencer of pain)
Each nerve fiber of dental pulp contributes to?
8 branches to
Raschkow’s plexus
Where do most nerve fibers terminate?
Most terminate in the
plexus as free, nonmyelinated nerve endings
What makes myelin sheath?
Schwann cells
What location has the highest branching of nerve axons? Lowest?
Highest: pulp horns
Lowest: root
What is larger - arterioles or venules?
Venules
Where do terminal capillaries anastomose?
Deep to the odontoblastic layer
Where are capillary loops dense? less dense?
dense in the coronal and pulp horns and significantly less dense in the radicular pulp
What capillaries and vessels are found in pulp?
Continuous and fenestrated capillaries and lymph vessels are found in pulp
What happens to blood vessels in pulp with aging?
exhibit changes such as cholesterol plaques (atherosclerosis). If progressive and severe, atherosclerotic plaques can result in pulpal hypoxia due to vessel strangulation
What do fenestrated capillaries leak?
Serum that becomes a component of the “tissue fluid”
What do fenestrated capillaries contribute to?
Swelling and edema
due to significant leakage of serum in states of inflammation
- swelling due to more blood to area and leaking to surrounding areas
When does a pulpal fibrosis occur?
Shrinkage of the pulp
with increasing age or persistent low-grade injury, e.g., multiple restorations in a single tooth, chronic bruxism, repeated
thermal insult, etc.
What are diffuse calcifications?
Irregular calcified deposits along collagen fiber bundles or within blood vessels resulting from chronic low-grade inflammation
What do true pulp stones contain?
Dentinal tubules
What do false pulp stones feature?
concentric layers of
calcified tissue but are void of dentinal tubules
What are pulp stones classified as?
either free, attached or embedded calcifications
- no pain or issues unless need a root canal
What is an abscess?
a dense aggregation of
neutrophils and macrophages and other inflammatory
cells within connective tissue undergoing liquefactive
necrosis (tissue is liquified)
Due to the inability of pulpal tissue to swell, the
increasing edema and inflammatory cell infiltration
will eventually lead to
Pulpal necrosis - clinically by persistent pain and periapical necrosis of the PDL and associated alveolar bone
The periapical necrosis is seen on dental radiographs
as
a radiolucent area associated with the apex of the involved tooth
What is diffuse cellulitis?
Could be a result from periapical abscess, the abscess enlarges so much to where it’s involving airways
- spread to muscle and possibly airways
What is treatment for periapical abscess?
Incision and drainage
Possible root canal
