Dental Pulp and its Responses

Question 1

List some features and functions of dental pulp:

Answer 1

• connective tissue
• essentially a matured dental papilla
• dentine if the calcified tissue of pulp

Pulp functions:

• dentine formation
• defence and repair
• sensory

Question 2

Similarities of pulp vs connective tissue:

Answer 2

• cells: many fibroblasts
• extracellular matrix, fibrous collagen, non-fibrous
• blood vessels and nerves
• 75% water, 25% organic

Question 3

Differences of pulp vs connective tissue

Answer 3

• specialised connective tissue
• contained within a rigid chamber
• no fat cells or oxytalin fibres
• blood vessels - wide lumen, narrow wall
• densely innervated

Question 4

Answer 4

Question 6

What are the layers of the pulp, from outer to inner:

Answer 6

• odontoblast layer
• cell-free zone of weil
• cell rich zone
• pulp core

Question 7

Name the pulpal cells:

Answer 7

• odontoblasts
• fibroblasts
• stem cells
• defence cells

Question 8

What are odontoblasts?

Answer 8

• specialised ectomensenchymal cells
• columnar cells
• odontoblast process in dentine
• layers appear pseudostratified
• organelle content reflects activity eg. active (many organelles)

Question 9

List some features of dental pulp stem cells:

Defence cells:

Answer 9

• retain embryonic potential
• decrease with age
• can form fibroblasts or odontoblasts

Defence cells

• macrophages
• T-lymphocytes

Question 10

What are some fibres of the pulp? Are there any fibres in the pulp which are not needed and why?

Answer 10

• Collagen
• type I - 60%
• type 2 - 40%
• also type V and VI
• No oxytalin fibres (elastic) as pulp is contained within a rigid chamber

Question 11

How are pulpal blood vessels controlled?

Answer 11

• efferent autonomic nerves from CNS out to periphery
• afferent nerves - stimuli to dentine results in pain –> increased blood flow
• axon reflex –> vasodilation and increased capillary permeability and sensitivity
• local factors e.g. bradykinin
• constant volume problem

Question 12

What is dentinal fluid?

Answer 12

• contains: proteins, glycoprotein, polysaccharides
• fluid flows outwards in opened tubules
• intrapulpal pressure 10mmHg
• dentinal fluid flow velocity of 1-2 microns per second
• fluid flow changes with pulpal pressure: inflammation, vasoconstrictors

Question 13

List some key facts regarding pulpal innervation:

Answer 13

• rich innervation - around 2500 axons enter a premolar
• mainly sensory i.e. afferent
• also efferent post-ganglionic sympathetic
• likely no parasympathetic
• 70-80% non-myelinated
• Plexus of Raschkow - classically in the cell free zone
• marginal plexus - around odontoblasts (where nerves end)

Question 14

How does the pulp change with age?

Answer 14

• decreases in volume
• decrease cells by 50%
• odontoblasts become less responsive
• less vascular
• number of nerves decrease –> less sensitive
• calcifications - pathological or age change