Dentine and Pulp 2 Flashcards
what does the odontoblast layer do as a permeability barrier?
separates pulp and tubular space, regulates movement of material between pulp and tubular ECF
what material moves from pulp to dentine?
nutrients, formation of secondary and tertiary dentine
what material moves from dentine to pulp?
medicaments applied to dentine, diffusion of toxins from bacteria/filling material
what is the nerve supply of the pulp?
alveolar nerves
what nerves enter the pulp?
neurovascular bundles via the apical foramen
once in the apical foramen, where do the nerves go?
along the root canal in the centre of the pulp towards the coronal pulp chamber
when in the coronal pulp chamber what is the organisation of the nerve supply?
it branches out in the sub-odontoblastic layer called Raschow’s plexus
what do the terminal branches of the nerves do?
enter the odontoblast layer and some enters the dentinal tubules
what is the distribution of nerves in the coronal, root and pulp-predentine areas
15% in coronal, 4% in root, most in pulp-predentine
describe what happens in the dentine when a stimulus is applied to the tooth
increased dentine fluid flow, generation of AP intra-dental nerves to brain to cause PAIN
if the fluid is flowing in an outward direction what way is it going?
pulp to dentine
if the fluid is flowing in an inward direction what way is it flowing?
dentine to pulp
what stimuli causes an outward fluid flow?
cooling, drying, hypertonic solutions, decreased hydrostatic pressure
what stimuli causes an inward fluid flow?
heating, mechanical, increased hydrostatic pressure
what direction of fluid flow is more effective in activating intradental nerves and why?
outward as it is rapid and stretches the nerves
which stimuli bypass the hydrodynamic mechanism?
intense heating, intense cooling, electrical current, pain-producing chemicals
what are the Abeta and Adelta fibres activated by?
hydro-dynamic stimuli
what are C fibres activated by?
direct stimuli
where does the blood supply to the teeth come from?
branches of the maxillary artery
what controls pulp blood flow?
local factors, nerves, circulating hormones, drugs (LA)
what are the functions of the pulpal nerves?
sensory (pain mediation), control of pulp blood vessels, promotion of neurogenic inflammation, promotion of dentine formation, facilitation of immune response
what is the immediate dentine-pulp pain response?
nociceptor activation
what is dentine-pulp response after 1 minute of stimuli
early inflammatory response, kinins, prostaglandins, neuropeptides, vasodilation
what is the dentine-pulp response after 10 minutes of stimuli
nocicpetor sensitisation, extravasation of fluid = oedema, polymorph migration
how long after stimuli does tertiary dentine begin to form?
1 week
what does oedema in the pulp cause?
an increase in pulp pressure
