dentine pulp complex Flashcards
dentine pulp
contents?
role?
- Contains cells, loose connective tissue, nerves & vascular supply.
- Contains various types of cell embedded in surrounding extracellular matrix
- Contains all blood vessels and nerves for the tooth
- The only tissue within the tooth which is non-mineralised
- Maintains the vitality of dentine.
- Through provision of nutrients, removal of waste and pain sensation to the tooth
label
roles of pulpal organ :
- Support, maintenance & continued formation of dentine.
- Nutrition:
- blood supply to pulp & dentine.
- Sensory:
- extremes in temperature, pressure, or chemical insult to the dentine or pulp is perceived as pain.
- Defensive:
- immuno-inflammatory response.
- Protective:
- formation of reparative tertiary dentine.
dental pulp organisation at dentine-pulp interface
how do interactions with the odontoblast cells and pulp tissues occur?
through tight and intermediated junctions
what is the role of gap junctions in odontoblasts??
cell-cell communication
- between adjacent odontoblasts
- between pulp tissue and odontoblasts
- maintains structural orientation and regulates odontoblast function
how does the structure of odontoblasts change with age??
cell size and organelle content reduce with age
what is the organisation of organelles in the odontoblasts?
At forefront
- Organelles involved in translation, secretion of proteins
At periphery
- Mitochondria and nucleus
what cells of pulp are there??
- fibroblasts
- undifferentiated mesenchymal stem cells
- defence cells
how does the morphology of young and aged pulp fibroblasts differ?
- Young pulp fibroblasts more rounded and plump.
- Aged pulp cells adopt flattened spindle shape with dense nuclei.
where are pulpal fibroblasts most abundant?
cell-rich zone and pulpal core
where are undifferentiated mesenchymal stem cells found?
In Cell-rich zone, central pulp & surrounding blood vessels.
role of undifferentiated mesenchymal stem cells in pulpal tissue?
- Respond to cytokines & growth factors to form new fibroblasts & odontoblasts.
- During trauma / disease
- Those surrounding BV -
- new endothelial cells
roles of pulpal fibroblasts
- Responsible for matrix synthesis, remodelling & repair.
- Remove old or damaged matrix components from the within the pulp
- Replace with newly synthesised matrix components
- Heterogeneity in cell phenotypes contribute to complex structure?
- Respond to cytokines, growth factors & inflammatory mediators - trauma & injury.
- Stimulation of reactionary & reparative dentine formation.
- Reduced repair capacity with age.
fibrous matrix components in pulp tissue?
- type 1 collagen
- mostly
- run parallel to predentine surface
- protection and strength to pulp
- confers some rigidity and maintenance of vessels
- type 3 collagen
- present in large amount
- type V and VI collagen
- in small amounts
- elastin in walls of blood vessels
- oxytalan fibrils
non-fibrous matrix components
- Proteoglycans:
- DS-decorin, DS-biglycan, versican, syndecan.
- DS - dermatan sulphate substituted forms
- Cell signalling, matrix assembly, cell migration & proliferation.
- Inhibition of mineralisation.
- DS-decorin, DS-biglycan, versican, syndecan.
- Glycoproteins:
- fibronectin, laminin, tenasin.
- Matrix formation, cell attachment, migration.
which defence cells are present in pulpal tissue?
dendritic cells
T lymphocytes
Macrophages
role of dendritic cells in pulpal tissue
- distributed around odontoblast and central blood vessels
- capture and present foreign antigens to T-cells
- initial detection
- initiate primary immune response
- increased number in carious teeth
- early detection of trauma within pulp
- project processes into dentine tubules
when are T lymphocytes present in the pulp?
- always present in small numbers
- but when injury or trauma = increased numbers
how are macrophages distributed
role?
- widely distributed
- mostly around blood vessels and odontoblast layer
- removal of dead / damaged cells and bacteria
describe the vascular and lymphatic supply to the pulp
- Superior & inferior alveolar arteries & veins.
- High blood flow & pressure in pulp.
- Enter through apical foramina & lateral canals as neuro-vascular bundles.
- Arterioles, venules & capillaries.
- Branch diffusely in coronal pulp.
- Arterioles branch & divide in sub-odontoblast area, form extensive capillary network.
- Exit through accessory foramina.
describe the lymphatics in the pulp
Small, thin walled capillaries.
Start as blind opening near zone of Weil / odontoblast layer.
Coalesce to form larger vessels & run along blood vessels.
Waste removal.
What is the plexus of nerves beneath the odontoblasts?
plexus of Raschkow
What is the plexus of Raschkow
pronounced plexus of nerves beneath the odontoblasts:
- branches from the plecus pass into odontoblast layers and form marginal plexus
- other branches continue into dentine to accompany odontoblast processes in the dentinal tubules
changes to pulp with age:
- pulp volume decreases with age
- due to deposition of secondary dentine
- less cellular, less vascular, less innervated
- narrowing of apical foramen can lead to pulp necrosis
- increased pulp mineralisation with age
- response to trauma
- pulp stones
