Dentine-Pulp Complex Flashcards
what does the dental pulp form?
the connective tissue ‘core’ of the tooth
what cells can be found within the pulp?
- fibroblasts
- odontoblasts
- defence cells
what is the function of odontoblasts within the pulp?
to produce dentine
what is the function of defence cells within the pulp?
to protect the tooth from infection
what are the extracellular components of the pulp?
- fibres
- matrix
what are examples of fibres found in the pulp & what is the function of fibres?
- collagen, oxytalan
- fibres form the backbone of the connective tissue
what makes up the matrix of the pulp & what is its function?
- proteoglycans, chondroitin, SO4
- the viscous elastic component
what type of nerves are found within the pulp?
- sensory
- autonomic
what is non-mineralised dentine known as?
pre-dentine
histologically, what are the dark lines seen in the dentine?
the dentinal tubules
what are some functions of the dental pulp?
- nutritive
- dentine growth
- dentine repair
- defence
- neural functions
how does the pulp provide a nutritive function?
- the vascular bed provides nutrients and removes waste
- essential for the pulp to allow dentine growth
what type of dentine is formed during normal growth of dentine?
- primary
- secondary
what type of dentine is formed during repair of dentine?
- tertiary
- occurs when there is aggression to the tissue
where is both the pulp and dentine derived from during dental development?
the dental papilla
where are odontoblasts found within the pulp?
at the periphery of the tissue
what close links can be found between the dentine and pulp?
- developmental
- structural
- functional
what is the most predominant extracellular matrix component in the pulp?
collagen
what structural links occur between the dentine and the pulp?
pulpal elements extend into dentine:
- odontoblast processes
- nerve terminals
- immune cells
- dentinal fluid
what do odontoblasts continue to do throughout life?
lay down secondary dentine
what type of cell is a fully differentiated odontoblast?
polarised columnar cell
- long cell process that extends into the pre-dentine and dentine within a dentinal tubule
what acts as a controlled barrier between pulp and dentine?
the odontoblast layer
what is regulated by haemodynamics?
fluid leaking from pulp capillaries —> interstitial space
what structure makes the pulp interesting in relation to inflammation?
it is a CLOSED ENVIRONMENT, therefore when it becomes inflamed… pressure builds up
how can fluid drain from the pulp?
- leaking from pulp capillaries to the interstitial space
- via lymphatics
- via the dentinal tubules
what is the fluid that drains through the dental tubules called?
dentinal fluid
what is flow of fluid in the dental tubules proportional to?
the pressure inside the pulp
what are the types of tertiary dentine formed called?
- reactionary dentine
- reparative dentine
what is tertiary reactionary dentine?
the dentine produced by the original odontoblasts faced with aggression (caused in response to mild and stimulus)
what is tertiary reparative dentine?
when aggression is too powerful, dominant non-differentiated stem cells are recruited to differentiate into odontoblasts & form dentine
what are some ways that tooth wear can occur?
- ABRASION caused by masticatory function
- functional damage caused by ATTRITION in BRUXISM
- ABFRACTION caused by occlusal overload & can cause fractures of the enamel and cervical lesions
- DIET
- CARIES
- OPERATIVE PROCEDURES
what materials travel from the pulp to dentine?
- nutrients, molecules, ions to sustain cells
- anything essential for formation/mineralisation of secondary & tertiary dentine
- (e.g calcium, phosphate, mineralising proteins)
what materials travel from dentine to the pulp?
- medicaments applied to dentine
- components from filling material s
- diffusion of toxins from bacteria in caries
what is the 1st aspect of the anatomy of pulp nerves?
branches of alveolar nerves (from the maxillary and mandibular trigeminal branches) enter the pulp via the apical foramen
what is the 2nd aspect of the anatomy of pulp nerves?
they pass along root canal in the centre of pulp towards the coronal pulp chamber
what is the 3rd aspect of the anatomy of pulp nerves?
branches fan out towards the sub-odontoblastic layer and form Raschow’s Plexus
what is the 4th aspect of the anatomy of pulp nerves?
terminal branches enter odontoblast layer & some nerves enter dentinal tubules
go through the stages of the hydrodynamic mechanism:
- stimulus (thermal, mechanical, evaporate, chemical)
- exposed dentine (open tubules)
- increased rate of dentinal flow
- generation of action potentials in intradental nerves
- action potentials pass to brain to cause PAIN
what stimuli can bypass the hydrodynamic mechanism?
- intense heating
- intense cooling
- electrical current
- pain producing chemicals
what nerve fibres make up the “intradental nerves”?
- A beta fibres
- A delta fibres
- C fibres
what is the different between the Aß/A 𝛿 fibres and the C fibres?
- C fibres and UNMYELINATED
- Abeta/Adelta are MYELINATED
how are the A beta and A delta fibres activated?
by hydrodynamic stimuli applied to dentine
what are C fibres activated by?
directly by stimuli, rather than the hydrodynamic mechanism (e.g pulp inflammation)
where does the blood supply to the teeth originate from?
branches of the MAXILLARY ARTERY
what controls pulp blood flow?
- local factors
- nerves
- circulating hormones
- drugs
what does sympathetic stimulation of the pulp nerves generate?
vasoconstriction of the blood vessels
what is the function of pulpal sensory nerves?
mediating pain
what are the functions of pulp nerves?
- sensory
- control of pulp blood vessels
- promotion of neurogenic inflammation
- promote dentine formation
how can vasodilation be stimulated in the pulp via nerves?
- afferent sensorial fibres are stimulated by changes in dentinal fluid flow
- this triggers an ‘axon reflex’
- this is the release of vasoactive & immune active peptides
- these peptides promote vasodilation and also increase vascular permeability which will increase pulp tissue pressure
what are examples of neuropeptides?
substance P and CGRP
what is the immediate dentine-pulp response to injury?
- nociceptor activation (PAIN)
what is the dentine-pulp response to injury after approx. one minute?
- early inflammation response
- kinins, prostaglandins & neuropeptides released which cause vasodilation
what is the dentine-pulp response to injury after approx. 10 minutes?
- nociceptor sensitisation (their excitability is increased)
- extravasion of fluid and oedema
- polymorph migration (neutrophils, eosinophils & basophils
what is the dentine-pulp response to injury after approx. 100 mins?
- enzyme activation (initial phase of dentinogenesis & presence of nerve growth factor)
- monocytes presence
what is the dentine-pulp response to injury after approx 1 day?
- nerve sprouting (in response to NGF)
- increased atonal transport
- altered excitability of CNS synapses
what is pulpitis?
acute inflammation in the dental pulp
