Dentine and the Pulp Flashcards
What does the pulp contain?
Blood vessels
Lymphatics
Nerves (autonomic sympathetic)
What cells are present in the pulp?
Odontoblasts - produce dentine
Fibroblasts - produce extracellular matrix and collagen.
Defence cells
What is the nevre supply to the pulp?
Autonomic sympatetic nevres
What are the functions of the pulp?
Dentine growth - primary (whilst tooth is forming) and secondary dentine (once tooth formed)
Dentine repair - tertiary dentine laid down.
Nutritive function- provide blood supply to the tooth.
Defence role - Immune cells present and lymphatics.
Neural - Provides sensory function via autonomic sympathetic nerves.
Describe the types of teriary dentine.
Reactionary - laid by primary odontoblasts.
Reparative - laid by secondary odontoblasts
since the stimuli was so intense it destroyed the primary odontoblasts
What tissue does dentine and the pulp form from?
Dental papilla.
There is a close link between dentine and the pulp; what processes from the pulp etend into the dentine?
Odontoblast processes.
Nerve terminals
Dentinal fluid leaks from the pulpal capillaries into dentinal tubules.
What are the functions of the odontoblast layer?
Separates the pulp and tubular space.
Regulate exchange of materials between dentine and the pulp in either direction.
What materials are exchanged by the odontoblast layer from the PULP TO DENTINE?
Secondary and tertiary dentine.
K ions from nerve endings - used in AP’s.
Nutrients from the blood supply.
What materials are exchanged by the odontoblast layer from the DENTINE TO THE PULP?
Medications applied to the dentine.
Toxins.
Where do the pulpal nerves branch from?
The autonomic sympathetic nerves branch from the alveolar nerve.
Describe the way in which the nerves enter the pulp.
As neurovascular bundles (nerves and blood vessels joined by connective tissue)
Describe the hydrodynamic events that occur after a stimulus has been applied to the tooth.
Stimuli applied.
Increases tubular flow.
Increased flow activates the intra dental nerves via stretching.
Stretching the nerves generates AP’s
Action potentials pass to the brain causing pain.
What direction of tubular flow is the most effective in activating intradental nerves?
Outward flow.
Rapid outward flow stretches the nerves and generates pain.
What stimuli causes outwards tubular flow?
Cooling and drying.
What stimuli causes inward tubular flow?
Heating and mechanical stimuli.
What types of autonomic nerve fibres are activated in the hydrodynamic mechanism?
Abeta and Adelta fibres.
Varying degrees of myelination.
What stimuli bypasses the hydrodynamic mechanism?
Intense heating and cooling.
Electrical currents
Pain producing chemicals
When are C fibres activated within the pulp?
Intense stimuli that acts directly.
What nerve fibres mediate pain from pulpal inflammation?
C fibres
List the functions of pulpal nerves.
Control blood supply via vessel diameter.
Promote dentine formation.
Mediate pain
Produce neurogenic inflammation.
Describe the events that take place in neurogenic inflammation after a stimuli is applied.
Stimuli
Afferent neutron releases inflammatory mediators.
Inflammatory response increases vasodilation of blood vessels.
Increases pulpal pressure
Increases outward tubular fluid flow
= pain.
What factors control the blood flow to the pulp?
Sympathetic, somatic nerves.
Local metabolites.
Circulating hormone e.g. adrenaline
Drugs e.g. Local anaesthetic with vasoconstrictors.
Describe the dentine-pulp response to injury over 1 week.
Immediate repose:
Nociceptor activation.
1 minute:
Early inflammatory response = vasodilation of blood vessels.
10 minutes:
Nociceptor sensitisation and oedema.
100 minutes:
Enzyme activates nerve growth factor.
1 day:
Nerve sprouting occurs to replace the damaged axons.
1 week:
Repair via tertiary dentine.
What is pulpits and why is it so painful?
Acute inflammation of the pulp.
Swelling is restricted by the tooth crown therefore nerve excitability and blood flow is effected.
