dentine pulp complex

Question 1

dentine pulp

contents?

role?

Answer 1

• 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

Question 2

label

Answer 2

Question 3

roles of pulpal organ :

Answer 3

• 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.

Question 4

dental pulp organisation at dentine-pulp interface

Answer 4

Question 5

how do interactions with the odontoblast cells and pulp tissues occur?

Answer 5

through tight and intermediated junctions

Question 6

what is the role of gap junctions in odontoblasts??

Answer 6

cell-cell communication

• between adjacent odontoblasts
• between pulp tissue and odontoblasts
  
  • maintains structural orientation and regulates odontoblast function

Question 7

how does the structure of odontoblasts change with age??

Answer 7

cell size and organelle content reduce with age

Question 8

what is the organisation of organelles in the odontoblasts?

Answer 8

At forefront

• Organelles involved in translation, secretion of proteins

At periphery

• Mitochondria and nucleus

Question 9

what cells of pulp are there??

Answer 9

• fibroblasts
• undifferentiated mesenchymal stem cells
• defence cells

Question 10

how does the morphology of young and aged pulp fibroblasts differ?

Answer 10

• Young pulp fibroblasts more rounded and plump.
• Aged pulp cells adopt flattened spindle shape with dense nuclei.

Question 11

where are pulpal fibroblasts most abundant?

Answer 11

cell-rich zone and pulpal core

Question 12

where are undifferentiated mesenchymal stem cells found?

Answer 12

In Cell-rich zone, central pulp & surrounding blood vessels.

Question 13

role of undifferentiated mesenchymal stem cells in pulpal tissue?

Answer 13

• Respond to cytokines & growth factors to form new fibroblasts & odontoblasts.
  
  • During trauma / disease
• Those surrounding BV -
  
  • new endothelial cells

Question 14

roles of pulpal fibroblasts

Answer 14

• 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.

Question 15

fibrous matrix components in pulp tissue?

Answer 15

• 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

Question 16

non-fibrous matrix components

Answer 16

• Proteoglycans:
  
  • DS-decorin, DS-biglycan, versican, syndecan.
    
    • DS - dermatan sulphate substituted forms
  • Cell signalling, matrix assembly, cell migration & proliferation.
  • Inhibition of mineralisation.
• Glycoproteins:
  
  • fibronectin, laminin, tenasin.
  • Matrix formation, cell attachment, migration.

Question 17

which defence cells are present in pulpal tissue?

Answer 17

dendritic cells

T lymphocytes

Macrophages

Question 18

role of dendritic cells in pulpal tissue

Answer 18

• 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

Question 19

when are T lymphocytes present in the pulp?

Answer 19

• always present in small numbers
• but when injury or trauma = increased numbers

Question 20

how are macrophages distributed

role?

Answer 20

• widely distributed
  
  • mostly around blood vessels and odontoblast layer
• removal of dead / damaged cells and bacteria

Question 21

describe the vascular and lymphatic supply to the pulp

Answer 21

• 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.

Question 22

describe the lymphatics in the pulp

Answer 22

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.

Question 23

What is the plexus of nerves beneath the odontoblasts?

Answer 23

plexus of Raschkow

Question 24

What is the plexus of Raschkow

Answer 24

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

Question 25

changes to pulp with age:

Answer 25

• 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