Dentine-Pulp Complex

Question 1

what cells are present in the pulp?

3

Answer 1

odontoblasts, fibroblasts, defence cells

Question 2

what are the extracellular components in pulp?

2

Answer 2

fibres: collagen, oxytalan
matrix: proteoglycans, chondroitin SO4, dermatan SO4

Question 3

what kind of nerves does the pulp have?

2

Answer 3

sensory, autonomic (sympathetic)

Question 4

what are the functions of the pulp?

5

Answer 4

nutrition - blood vessels
dentine growth - odontoblasts
dentine repair - odontoblasts
defence - immune cells
neural - sensory pain

Question 5

what are the developmental links between the dentine and pulp?

Answer 5

both develop from the dental papilla

Question 6

what are the structural links between the dentine and pulp?

4

Answer 6

pulpal elements extend in to dentine:
odontoblast process
nerve terminals
immune cells
dentinal fluid

Question 7

what are the functional links between the dentine and pulp?

3

Answer 7

formation of secondary dentine
formation of tertiary dentine
regulate exchange of material between dentine and pulp

Question 8

what occurs at the odontoblast layer?

4

Answer 8

fluid leaks from pulp capillaries into interstitial space
some drains by lymphatic system
some passes along dental tubules
flow is proportional to pulp pressure

Question 9

what are the causes of tooth wear?

6

Answer 9

mastication (abrasion)
bruxism (attrition)
abfraction
erosion
caries
operative procedures

Question 10

what are the different types of tertiary dentine and when are they produced?

2

Answer 10

reactionary dentine - response to mild stimulus, laid down by primary odontoblasts
reparative dentine - response to intense stimulus, laid down by secondary odontoblasts if primary are destroyed

Question 11

how is the odontoblast layer a permeability layer?

2

Answer 11

separates pulp and tubular space
regulates movement of material between pulp and tubular ECF

movement may be in either direction

Question 12

what is exchanged from pulp to dentine?

3

Answer 12

nutrients
formation of secondary and tertiary dentine
function of tubular nerves

Question 13

what is exchanged from dentine to pulp?

2

Answer 13

medicaments from filling materials
toxins from bacteria from caries

Question 14

what is the anatomy of pulp nerves?

5

where did they arise, enter, pass along, branch out

Answer 14

branches from alveolar nerves
neurovascular bundles enter pulp via apical foramen
pass along root canal to coronal pulp chamber
branches out in sub-odontoblastic layer to form plexus of Raschow
terminal branches enter odontoblast layer and some enter dentinal tubules

Question 15

describe the innervation of dentine in cusps, roots and coronal portions

3

Answer 15

cusps: 40%
coronal portions: 15%
roots: 4%

Question 16

how does the hydrodynamic mechanism theory work?

5

Answer 16

stimulus - thermal, evaporative, mechanical, chemical
acts on exposed open dentine tubules
increases rate of flow of dentinal fluid flow
generates action potentials in intra-dental nerves
action potentials pass to brain to cause pain

Question 17

does outward or inward fluid flow cause greater stimuli?

Answer 17

rapid outer flow stretches the nerves and causes greater stimuli
more effective in activating intradental nerves

Question 18

which stimuli bypass the hydrodynamic mechanism?

4

Answer 18

intense heating
intense cooling
electrical current
pain-producing chemicals

all act directly on intradental nerves, not all stimuli is due to movement of dentinal fluid

Question 19

how do high fillings cause pain associated with dentinal fluid changes in flow?

Answer 19

inlays and onlays will be distorted by occlusal forces and generate pressure to alter the flow of fluids

Question 20

what are the types of intradental nerves and what are their properties?

3

properties, activated by, mediate

Answer 20

Aβ and Aδ(large and small myelinated)
* activated by hydrodynamic stimuli applied to dentine
* mediate normal dentinal sensitivity
C fibres (unmyelinated)
* activated by stimuli directly (intense)
* mediate pain associated with pulp inflammation

Question 21

how is the pulp blood flow controlled?

4

Answer 21

local factors (e.g. metabolites)
nerves - sympathetic and somatic afferents peptidergic
circulating hormones (e.g. adrenaline)
drugs (e.g. LA)

sympathetic - vasoconstriction, somatic - releases peptides to vasodilate

Question 22

describe the blood supply to the teeth

3

Answer 22

arises from branches of maxillary artery
pulp vascular bed is very rich
blood vessels stop short and away from dentine

Question 23

what is the funtion of pulp nerves?

4

Answer 23

sensory - mediating pain
control of pulp vessels
promote neurogenic inflammation
promote dentine formation

sympathetic - vasoconstriction, somatic - vasodilation of pulp vessels

Question 24

describe the stages of neurogenic inflammation

5

Answer 24

afferent sensorial fibres stimulated by changes in dentinal fluid flow
triggers an axon reflex which releases vasoactive peptides
peptides promote vasodilation and increases vascular permeability
increases pulp tissue pressure
increases tubular fluid flow

Question 25

what occurs immediately after the dentine-pulp complex is injured?

1

Answer 25

nociceptor activation - pain

Question 26

what occurs around 1 minute after the dentine-pulp complex is injured?

3

Answer 26

early imflammatory response
kinins, prostaglandins, neuropeptides present
vasodilation

Question 27

what occurs around 10 minutes after the dentine-pulp complex is injured?

3

Answer 27

nociceptor sensitisation
extravasation of fluid and oedema
polymorph migration

polymorphs - neutrophils, eosinophils and basophils

Question 28

what occurs around 100 minutes after the dentine-pulp complex is injured?

2

Answer 28

enzyme activation and nerve growth factor (NGF) present
monocytes present = cell mediated immunity

Question 29

what occures around 1 day after the dentine-pulp complex is injured?

3

Answer 29

nerve sprouting in response to NGF
increased axonal transport
altered excitability of CNS synapses

Question 30

what occurs around 1 week after the dentine-pulp complex is injured?

1

Answer 30

repair and tertiary dentine formation = dentinogenesis

Question 31

what is pulpitis?

Answer 31

acute inflammation of teh dental pulp

Question 32

what occurs during pulpitis?

3

Answer 32

pulp is inflammed but cannot swell as it is confined within the pulp chamber
oedema causes an increase in pulp pressure
has variable effects on blood flow and nerve excitability