Dentine-Pulp Complex Flashcards
ILO 8.5b: have knowledge of the form and function of teeth and associated structures, and the oral environment, in health and disease
what cells are present in the pulp?
3
odontoblasts, fibroblasts, defence cells
what are the extracellular components in pulp?
2
fibres: collagen, oxytalan
matrix: proteoglycans, chondroitin SO4, dermatan SO4
what kind of nerves does the pulp have?
2
sensory, autonomic (sympathetic)
what are the functions of the pulp?
5
nutrition - blood vessels
dentine growth - odontoblasts
dentine repair - odontoblasts
defence - immune cells
neural - sensory pain
what are the developmental links between the dentine and pulp?
both develop from the dental papilla
what are the structural links between the dentine and pulp?
4
pulpal elements extend in to dentine:
* odontoblast process
* nerve terminals
* immune cells
* dentinal fluid
what are the functional links between the dentine and pulp?
3
formation of secondary dentine
formation of tertiary dentine
regulate exchange of material between dentine and pulp
what occurs at the odontoblast layer?
4
fluid leaks from pulp capillaries into interstitial space
some drains by lymphatic system
some passes along dental tubules
flow is proportional to pulp pressure
what are the causes of tooth wear?
6
mastication (abrasion)
bruxism (attrition)
abfraction
erosion
caries
operative procedures
what are the different types of tertiary dentine and when are they produced?
2
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
how is the odontoblast layer a permeability layer?
2
separates pulp and tubular space
regulates movement of material between pulp and tubular ECF
movement may be in either direction
what is exchanged from pulp to dentine?
3
nutrients
formation of secondary and tertiary dentine
function of tubular nerves
what is exchanged from dentine to pulp?
2
medicaments from filling materials
toxins from bacteria from caries
what is the anatomy of pulp nerves?
5
where did they arise, enter, pass along, branch out
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
describe the innervation of dentine in cusps, roots and coronal portions
3
cusps: 40%
coronal portions: 15%
roots: 4%
how does the hydrodynamic mechanism theory work?
5
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
does outward or inward fluid flow cause greater stimuli?
rapid outer flow stretches the nerves and causes greater stimuli
more effective in activating intradental nerves
which stimuli bypass the hydrodynamic mechanism?
4
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
how do high fillings cause pain associated with dentinal fluid changes in flow?
inlays and onlays will be distorted by occlusal forces and generate pressure to alter the flow of fluids
* force distorts the dentine and alters tubular fluid flow
what are the types of intradental nerves and what are their properties?
3
properties, activated by, mediate
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
how is the pulp blood flow controlled?
4
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
describe the blood supply to the teeth
3
arises from branches of maxillary artery
pulp vascular bed is very rich
blood vessels stop short and away from dentine
what is the funtion of pulp nerves?
4
sensory - mediating pain
control of pulp vessels
promote neurogenic inflammation
promote dentine formation
sympathetic - vasoconstriction, somatic - vasodilation of pulp vessels
describe the stages of neurogenic inflammation
5
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
what occurs immediately after the dentine-pulp complex is injured?
1
nociceptor activation - pain
what occurs around 1 minute after the dentine-pulp complex is injured?
3
early imflammatory response
kinins, prostaglandins, neuropeptides present
vasodilation
what occurs around 10 minutes after the dentine-pulp complex is injured?
3
nociceptor sensitisation
extravasation of fluid and oedema
polymorph migration
polymorphs - neutrophils, eosinophils and basophils
what occurs around 100 minutes after the dentine-pulp complex is injured?
2
enzyme activation and nerve growth factor (NGF) present
monocytes present = cell mediated immunity
what occures around 1 day after the dentine-pulp complex is injured?
3
nerve sprouting in response to NGF
increased axonal transport
altered excitability of CNS synapses
what occurs around 1 week after the dentine-pulp complex is injured?
1
repair and tertiary dentine formation = dentinogenesis
what is pulpitis?
acute inflammation of teh dental pulp
what occurs during pulpitis?
3
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
