Odontoblast cell layer Cell-free zone of Weil Cell-rich zone Parietal plexus of nerves (Raschkow’s plexus)

Fibroblasts Type I and III collagen Extracellular matrix Blood vessels Nerve tissue

Dentinal Pulp and Caries Flashcards by sophie rosen

The dental pulp consists of loose connective tissue

derived from

neural crest (ectomesenchymal) cells

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Mature dental pulp is divided into two compartments:

Odontogenic Zone

Pulpal Core

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Odontogenic Zone (4)

Odontoblast cell layer
Cell-free zone of Weil
Cell-rich zone
Parietal plexus of nerves (Raschkow’s plexus)

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Pulpal Core (5)

Fibroblasts
Type I and III collagen
Extracellular matrix
Blood vessels
Nerve tissue

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Functions of dental pulp: (4)

Embryonic induction
Formative
Protective
Reparative

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Cell populations in pulpal tissue include: (8)

  Odontoblasts 
  Fibroblasts 
  Undifferentiated mesenchymal cells 
  Macrophages 
  Dendritic cells 
  Blood vessel-related cells  (e.g., endothelial &      pericytes) 
  Neural-related cells  (e.g., Schwann cells) 
  Lymphocytes

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8% of total cell population (2)

 Macrophages

 Dendritic cells

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Extracellular matrix of pulpal tissues: (2)

 Collagen types I, III, IV, and V (via odontoblasts)

 Non-collagenous matrix components:

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 Non-collagenous matrix components: (5)

Proteoglycans
Glycosaminoglycans
Phosphoproteins
Glycoproteins
γ- carboxyglutamate-containing proteins

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• γ- carboxyglutamate-containing proteins (4)

 BMP-2, 4, and 7
 Fibroblast Growth Factor (FGF)
 Epidermal Growth Factor (EGF)
 Dentin Matrix Protein (DMP)

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Pulpal innervation includes both

myelinated and

nonmyelinated nerve axons.

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Pulpal innervation includes both myelinated and
nonmyelinated nerve axons. 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.

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Most nerve endings in pulp are for

pain (free nerve
endings as sensory afferents from C-V) with a few
concerned with vasodilatation or constriction.

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Sensory afferents from the Trigeminal (C-V): (4)

Pain
Mechanical (pressure)
Thermal (heat)
Tactile (touch)

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— branches from the superior
cervical ganglion are primarily vasomotor
fibers to pulpal blood vessels, concerned
for the most part, with —.

Sympathetic

vasoconstriction

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The majority of myelinated pulpal nerve axons are

A-δ (A-delta):
• Fast conducting
• Diameter in range of 1-6 μm

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1% of myelinated nerve fibers are classified as

A-β (A-beta) fibers:

• 6-12 μm diameter

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Nonmyelinated fibers are designated as

“C” fibers and have small diameters, ranging from 0.4 to 1.2 μm

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A-δ fibers are associated with

sharp, localized pain.

“C” fibers are associated with

dull, diffuse pain.

Neuropeptides and neurotransmitters identified in

dental pulp include: (6)

  Calcitonin gene-related peptide (CGRP)
  Substance P 
  Epinephrine 
  Norepinephrine 
  Dopamine 
  Endorphin

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 fiber contributes at least

8 branches to Raschkow’s plexus. Most terminate in the plexus as free, nonmyelinated nerve endings.

Location: pulp horns Predentin: Mineralizing Front: Denton up to 100 um:

27% 11% 8%

Location: remaining crown Predentin: Mineralizing Front: Denton up to 100 um:

14% 6% 2%

Location: root Predentin: Mineralizing Front: Denton up to 100 um:

11% 0% 0%

Venules have a diameter of

100 um to 150 um

Arterioles have a diameter of

50 um to 100 um

The terminal capillaries anastomose deep to the --- layer

odontoblastic

Capillary loops are dense in the coronal and pulp horns | and significantly less dense in the

radicular pulp

(2) capillaries and lymph vessels | are found in pulp

Continuous and fenestrated

With aging, blood vessels in pulp will exhibit changes such as

cholesterol plaques (atherosclerosis). If progressive and severe, atherosclerotic plaques can result in pulpal hypoxia due to vessel strangulation.

Fenestrated capillaries leak serum that becomes a component of the so-called “--- ---”. They also contribute to

tissue fluid | swelling and edema due to significant leakage of serum in states of inflammation.

Pulpal fibrosis occurs with

``` increasing age or persistent low-grade injury, e.g., multiple restorations in a single tooth, chronic bruxism, repeated thermal insult, etc. ```

Diffuse Calcifications:

Irregular calcified deposits along collagen fiber bundles or within blood vessels resulting from chronic low-grade inflammation.

Pulp Stones (a.k.a. Denticles):

True pulp stones contain dentinal tubules. False pulp stones feature concentric layers of calcified tissue but are void of dentinal tubules.

Pulp Stones are classified as either (3)

free, attached or embedded

An abscess is defined as a

dense aggregation of neutrophils and macrophages and other inflammatory cells within connective tissue undergoing liquefactive necrosis.

Due to the inability of pulpal tissue to swell, the increasing edema and inflammatory cell infiltration will eventually lead to

pulpal necrosis that, in turn, is expressed 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.