Flashcards in Tooth Morphology Deck (15)
Branches of pulpal nerves fan out into the subodontoblastic layer. What are these called?
Dentinal tubules contain nerves. Which part of dentine contains the most nerves?
dentine under cusps (40% of tubules contain nerves here)
What is the percentage of nerves found in coronal dentine and root dentine?
coronal dentine = 15% of tubules
root dentine = 4% of tubules
How may outward fluid flow be caused in dentinal tubules?
cooling, drying, evaporation, hypertonic solutions, decreased hydrostatic pressure
How may inward fluid flow be caused in dentinal tubules?
heating, mechanical, increased hydrostatic pressure
How are A beta and A delta nerve fibres activated in dentine/pulp? What do these mediate?
activated by hydrodynamic stimuli applied to dentine
probably mediate 'normal' dentinal sensitivity
How are C fibres activated in dentine/pulp? What do these mediate?
probably activated directly by stimuli, rather than hydrodynamic mechanism
they respond to most forms of intense stimulation
probably mediate pain associated with pulpal inflammation (eg caries)
Where does the blood supply for all teeth come from?
branches of maxillary artery
A cell free zone in present in dental pulp tissue beneath the odontoblast layer. What is this called?
Basal layer of Weil
Describe the immediate responses of dentine/pulp to injury.
immediate: nociceptor activation - pain
after approx. 1 min: early inflammatory response, kinins, prostaglandins, neuropeptides released, vasodilation
Describe the dentine/pulp responses to injury after approx. 10 mins.
nociceptor sensitisation (biting will now hurt the patient)
extravasation of fluid, oedema
Describe the dentine/pulp responses to injury after approx. 100 mins.
enzyme activation; nerve growth factor
Describe the dentine/pulp responses to injury after approx. 1 day.
nerve sprouting (NGF)
increased axonal transport
altered excitability of CNS synapses
Describe the dentine/pulp responses to injury after approx. 1 week.
repair; tertiary dentine formation
NB: completion of repair and recovery occurs at variable times