Pulpal Dental Pain . oral physio lec 2
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Transcript of Pulpal Dental Pain . oral physio lec 2
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PULPAL & DENTALPULPAL & DENTAL
PAINPAIN
Oral physiologyOral physiology
Dent 207Dent 207
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Dental pulpDental pulp
Specialized connective tissueSpecialized connective tissue
Contained within the toothContained within the tooth
Enclosed by dentineEnclosed by dentine
Continuous with the periodontal ligament through:Continuous with the periodontal ligament through:
Apical foramenApical foramen
NarrowNarrow only allows for passage of the neurovascularonly allows for passage of the neurovascularbundlebundle
Small volumeSmall volume
Total volume in all teeth is 0.40 mlTotal volume in all teeth is 0.40 ml
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Pulpodentine complexPulpodentine complex
Functions of pulp & dentine are interlinkedFunctions of pulp & dentine are interlinked
Functions of the pulpFunctions of the pulp
Maintain dentinal health by supplying nutrientsMaintain dentinal health by supplying nutrients Provide a pathway for sensory impulses fromProvide a pathway for sensory impulses from
dentinedentine
Initiate & govern repair of dentine in injuryInitiate & govern repair of dentine in injury
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Pulp nervesPulp nerves
Sensory fibersSensory fibers
AA & C fibers& C fibers
Plexus of Raschkow (subodontoblastic plexus)Plexus of Raschkow (subodontoblastic plexus) Individual axons divide into many branches in theIndividual axons divide into many branches in the
plexusplexus
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Pulp nerves during tooth formationPulp nerves during tooth formation
Fibers near base of dental papillaFibers near base of dental papilla
At cap stageAt cap stage Fibers form a plexusFibers form a plexus -- to dental follicleto dental follicle to dental papillato dental papilla
At bell stageAt bell stage unmyelinatedunmyelinated
At eruptionAt eruption -- number of fibers & their average size increasenumber of fibers & their average size increase --transition towards myelinationtransition towards myelination
Continues to increase for a few years after eruptionContinues to increase for a few years after eruption
Dentine is laid downDentine is laid down pulp reduced in sizepulp reduced in size nerve plexusnerve plexusdecrease in sizedecrease in size
Ageing pulpAgeing pulp Decrease in number of axons entering pulpDecrease in number of axons entering pulp
Reduction in myelinated fiber sizeReduction in myelinated fiber size
Raschkows shows little changeRaschkows shows little change
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Pulp nerves in primary teethPulp nerves in primary teeth
Number of axons is less than that in permanentNumber of axons is less than that in permanent
Except primary canineExcept primary canine
Number of axons decrease with resorptionNumber of axons decrease with resorptionuntil the tooth is sheduntil the tooth is shed
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Neurotrophic substancesNeurotrophic substances
Nerve growth factorsNerve growth factors evidenceevidence Promote survival of neural crest cells in trigeminalPromote survival of neural crest cells in trigeminal
ganglionganglion
Produced in the maxillary process to maintain survival ofProduced in the maxillary process to maintain survival of
nerve axonsnerve axons No role in directing spread of fibersNo role in directing spread of fibers
Act on nearby nerves to govern late invasion of pulp tissueAct on nearby nerves to govern late invasion of pulp tissueby nerve fibersby nerve fibers
Allow permanent teeth to recruit their nerve supply fromAllow permanent teeth to recruit their nerve supply from
branches of axons previously supplying deciduous teethbranches of axons previously supplying deciduous teeth Odontoblastic factors promote extension of new nerveOdontoblastic factors promote extension of new nerve
fibers into the subodontoblastic layer & dentine infibers into the subodontoblastic layer & dentine inreimplanted teethreimplanted teeth
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Functions of AFunctions of A fibersfibers
MyelinatedMyelinated
Diameter: 1Diameter: 1 4 m4 m
Rapidly conducting (>2 m/s)Rapidly conducting (>2 m/s)
Mediate sharp, piercing pain sensationsMediate sharp, piercing pain sensations
Responsible for dentinal sensitivityResponsible for dentinal sensitivity
Respond to any stimuli causing fluid movement inRespond to any stimuli causing fluid movement in
dentinal tubulesdentinal tubules Drilling, drying & application of osmotic solutionsDrilling, drying & application of osmotic solutions
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Functions of C fibersFunctions of C fibers
UnmyelinatedUnmyelinated
Diameter: < 0.5 mDiameter: < 0.5 m
Slowly conducting (< 2 m/s)Slowly conducting (< 2 m/s) Polymodal: activated byPolymodal: activated by
ThermalThermal
MechanicalMechanical
Chemical stimuliChemical stimuli histamine & bradykinenhistamine & bradykinen
Mediate dull, longer standing & less wellMediate dull, longer standing & less well--localizedlocalized
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Neurotransmitters in dental pulpNeurotransmitters in dental pulp
Calcitonin geneCalcitonin gene--related peptide (CGRP)related peptide (CGRP)
Substance PSubstance P
Neurokinin ANeurokinin A
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Autonomic nerve supply in the pulpAutonomic nerve supply in the pulp
SympatheticSympathetic
ParasympatheticParasympathetic
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SympatheticSympathetic
Majority of autonomicMajority of autonomic
Some are cholinergicSome are cholinergic Removal of superior cervical ganglionRemoval of superior cervical ganglion some decrease insome decrease in
cholinesterase staining in the pulpcholinesterase staining in the pulp
In mouseIn mouse in pulp horn in pulp horn
1/3 in pulp chamber1/3 in pulp chamber
Rest in root canalRest in root canal
FunctionsFunctions
Control pulp blood flowControl pulp blood flow Regulation of odontogenesisRegulation of odontogenesis
Afferent transmission of impulses associated with pain sensationAfferent transmission of impulses associated with pain sensation
Evidences of functionsEvidences of functions Anatomical: near blood vessels & odontoblastsAnatomical: near blood vessels & odontoblasts
SympathectomySympathectomy vasodilatation & changed in dentine appositionvasodilatation & changed in dentine apposition
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ParasympatheticParasympathetic
Majority are cholinergicMajority are cholinergic
Resection of inferior alveolar nerveResection of inferior alveolar nerve
Abolish cholinesterase stainingAbolish cholinesterase staining
Increased rate f tooth eruption (increased intrapulpalIncreased rate f tooth eruption (increased intrapulpal
pressure)pressure)
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Nociceptive responseNociceptive response substance Psubstance P
Pulp reacts initially to stimulating dentinePulp reacts initially to stimulating dentine
ElectricallyElectrically
MechanicallyMechanically
ChemicallyChemically C fibers stimulatedC fibers stimulated --
Retrograde impulse in C branchesRetrograde impulse in C branches
Release of substance P at terminalsRelease of substance P at terminals
VasodilatationVasodilatation tissue edematissue edema
Release of histamineRelease of histamine increase capillary permeability &increase capillary permeability &fluid extravasationfluid extravasation
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Nociceptive responseNociceptive response -- bradykininbradykinin
Noxious stimulation of the pulpNoxious stimulation of the pulp
Bradykinin formationBradykinin formation
Contribute to vasodilatationContribute to vasodilatation May stimulate release of encephalins from pulpalMay stimulate release of encephalins from pulpal
cellscells
EncephalinsEncephalins antianti--inflammatoryinflammatory inhibitinhibit
bradykinin releasebradykinin release protectiveprotective ve feedbackve feedback
mechanismmechanism
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Nociceptive responceNociceptive responce ecosanoidecosanoid
groupgroup Are metabolites of arachidonic aidAre metabolites of arachidonic aid
ProstaglandinsProstaglandins
LeucotrienesLeucotrienes
PG I2 produced by endothelial cellsPG I2 produced by endothelial cells
Inhibit platelet aggregationInhibit platelet aggregation
VasodilatorVasodilator
Thromboxane A2 produced by platelets & fibroblastsThromboxane A2 produced by platelets & fibroblasts
Stimulate platelet aggregationStimulate platelet aggregation
In the pulpIn the pulp PGPG II22, PG, PG FF22 , PG, PG EE22 ThromboxaneThromboxane AA22 Leucotrience 12Leucotrience 12--HETE, LTCHETE, LTC44
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Nociceptive responseNociceptive response prostaglandinsprostaglandins
Bacterial/mechanical/chemical irritationBacterial/mechanical/chemical irritation
Increase in prostaglandinIncrease in prostaglandin FF22 && EE22 (found in high(found in high
conc. In inflamed pulp)conc. In inflamed pulp) VasodilatationVasodilatation
Increase painIncrease pain--producing properties ofproducing properties of
HistamineHistamine
BradykininBradykinin
SerotoninSerotonin
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Pain relieving drugsPain relieving drugs
AspirinAspirin inhibitor of cycloinhibitor of cyclo--oxygenaseoxygenase
inhibition of PG synthesisinhibition of PG synthesis
Root canal medicamentsRoot canal medicaments Phenol, pPhenol, p--Chlorophenol, cresol, thymol, guaiacolChlorophenol, cresol, thymol, guaiacol
Inhibit synthesis of PG & leucotrienesInhibit synthesis of PG & leucotrienes
Have antibacterial activityHave antibacterial activity
EugenolEugenol more effective than phenols inmore effective than phenols in
inhibition of prostaglandin synthesisinhibition of prostaglandin synthesis
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Pulpitis & pulp necrosisPulpitis & pulp necrosis
Injury to dentine (cavity prep.)Injury to dentine (cavity prep.)
Nerve fibers & odontoblastic processes pulled byNerve fibers & odontoblastic processes pulled by
hydrodynamic forcehydrodynamic force
Separated from pulpal tissueSeparated from pulpal tissue
Damaging nerve fibers & killing of odontoblastsDamaging nerve fibers & killing of odontoblasts
Pain in dentinePain in dentine
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Small injury to dental pulpSmall injury to dental pulp
In small damaged areas / odontoblastic layerIn small damaged areas / odontoblastic layer
damage is slightdamage is slight
Reparative dentine may seal off small damagedReparative dentine may seal off small damagedareasareas
Blocks reBlocks re--innervationinnervation
Innervation of adjacent areas is increasedInnervation of adjacent areas is increased
CGRP from reactive axons promote growth of newCGRP from reactive axons promote growth of newfibersfibers
When the lesion healsWhen the lesion heals -- new fibers disappearnew fibers disappear
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PulpitisPulpitis
Cavity or caries reach the pulpCavity or caries reach the pulp Odontoblastic layer destroyedOdontoblastic layer destroyed
Inflammation occurs locallyInflammation occurs locally
In small lesions, dentine bridge formsIn small lesions, dentine bridge forms inflammationinflammationresolves & pulp heals (reversible pulpitis)resolves & pulp heals (reversible pulpitis) Inflammation area demarcated by fibrous tissueInflammation area demarcated by fibrous tissue
More severe stimuli / larger lesionsMore severe stimuli / larger lesions irreversible pulpitisirreversible pulpitis Severe inflammationSevere inflammation --inflammation area demarcated by fibrousinflammation area demarcated by fibrous
tissuetissue
Lack of pain at a later stage of pulpitisLack of pain at a later stage of pulpitis CGRPCGRP--mediated growth of nerve fibers outsidemediated growth of nerve fibers outside
inflammation areainflammation area Hypersensitivity in early pulpitisHypersensitivity in early pulpitis
Difficulty in achieving anesthesia a tooth with an inflamed pulpDifficulty in achieving anesthesia a tooth with an inflamed pulp
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Pulp necrosisPulp necrosis
More severe pulpal exposureMore severe pulpal exposure
Irreversible pulpitisIrreversible pulpitis -- necrosis occursnecrosis occurs
Necrosis area demarcated by fibrous tissueNecrosis area demarcated by fibrous tissue CGRPCGRP--mediated growth of nerve fibers outsidemediated growth of nerve fibers outside
necrosis areanecrosis area
Lesion extends to root apexLesion extends to root apex
Nerve growth in periapical tissueNerve growth in periapical tissue
New fibers appear to be involved in pain sensationNew fibers appear to be involved in pain sensation
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Pain of dental originPain of dental origin
Exposed dentineExposed dentine sensitivitysensitivity -- painpain Dental caries or cavity prep.Dental caries or cavity prep.
Cemental layer wears awayCemental layer wears away
Any sensation through dentineAny sensation through dentine painpain
Heat / cold may be perceived as separate sensations?Heat / cold may be perceived as separate sensations? Most sensitive areas in dentine as atMost sensitive areas in dentine as at
EDJEDJ
Exposed dentine in cervical root areasExposed dentine in cervical root areas
Nerve fibers to dentine are limited to coronal dentineNerve fibers to dentine are limited to coronal dentine
Nerve fibers numerous under cuspsNerve fibers numerous under cusps Nerve fibers extend for a short distance within dentineNerve fibers extend for a short distance within dentine
Odontoblastic processes vary in extension through dentineOdontoblastic processes vary in extension through dentine Function as receptorsFunction as receptors
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Three theories of dentinalThree theories of dentinal
hypersensitivityhypersensitivity
Odontoblastic processes as receptorsOdontoblastic processes as receptors
Odontoblasts are neural crest in originOdontoblasts are neural crest in origin
Nerve fibers extend through dentineNerve fibers extend through dentine
Direct stimulationDirect stimulation Deformation of odontoblasts by fluid movement promotesDeformation of odontoblasts by fluid movement promotes
potassium releasepotassium release action potential in neighboring nerveaction potential in neighboring nervefibersfibers
Hydrodynamic theoryHydrodynamic theory Movement of fluids through dentinal tubules inward &Movement of fluids through dentinal tubules inward &outwardoutward
Distortion of nerve endings in Raschkows plexusDistortion of nerve endings in Raschkows plexus
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Referred painReferred pain
Sensation of pain resulting from a deep organSensation of pain resulting from a deep organ
peripherally in areas derived from the sameperipherally in areas derived from the same
somitesomite
Pain of cardiac origin may be perceived in the armPain of cardiac origin may be perceived in the arm
Convergence of somatic & visceral sensoryConvergence of somatic & visceral sensory
impulses at one or more of 3 levelsimpulses at one or more of 3 levels
PrespinalPrespinal
SpinalSpinal
SupraspinalSupraspinal
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Referred orofacial painReferred orofacial pain
In trigeminal, levels areIn trigeminal, levels are PrepontinePrepontine
PontomedullaryPontomedullary
SuprapontineSuprapontine
No convergence within brainNo convergence within brain
Pain within the oral cavity is referredPain within the oral cavity is referred
Within the distribution of the specific divisions of the trigeminal nerveWithin the distribution of the specific divisions of the trigeminal nerve
Doesnt cross midline except in ramifications of nerve terminalsDoesnt cross midline except in ramifications of nerve terminals(incisor region)(incisor region)
Migrainous headache may be due to dental conditionsMigrainous headache may be due to dental conditions Not referred painNot referred pain
Because it is vascular in originBecause it is vascular in origin