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1、UnitNineETIOLOGYANDCLASSIFICATIONOFPULPITISFormerlyitwasthoughtthatthepulprespondedinitiallybyacuteinflammation,followedbychronicinflammation,regardlessoftheetiologicfactor.However,Brannstr8mandLindandSeltzershowedthattheinitialresponsetocariesmightbechronicinflammationbecauseoftherelativelyslowprog
2、ressionoftheirritant.Operativeprocedures,becauseoftheirrapideffect,probablyresultinatransientacuteinflammation.Almostanyinsulttothetooth(dependingonitsseverityanddurationcansettheinflammatoryprocessinmotion.Threepathwaystothepulparcusuallydescribed:1. Directextensionthroughthedentinaltubules,asincar
3、iesorchemicalsplacedonthedentin.2. Extensionbytheprocessofanachoresis,thelocalizationofblood-bornebacteriawithinthepulp(StudieshaveshownthatorganismstendtolocateinareasthatarealreadyinflamedorpreviouslyinjuredGrossmanwasabletorecovertestorganismsinteeth(hatweretraumatized,huthewasnotabletorecoverthe
4、mfromthecirculatingbloodstream.Thismayhelptoexplainwhysomepulpsbecomenecroticwhenthereisnoapparentetiologicfactor.)3. Extensionofperiodontaldiseaseintothepulp.(Recentworkhasshownthatinjuryordiseaseintheperiodontalligamentcanhaveapulpaleffect.Langclandctal.demonstratedlocalizedareasofinflammationinth
5、epulptobearesultofperiodontaldisease;buttheybelievetotalnecrosiswillresultonlyifthelateralcanalsorapicalforamen,orboth,areexposedtotheoralenvironment.)EtiologicfactorsTheetiologicfactorsinvolvedininflammationofthepulpcanbegroupedintofourgeneralcategories:bacterial,iatrogenic,traumatic,andidiopathic.
6、Bacterialfactor.Bacteriaandtheirproductsarcthemostcommoncauseofendodonticdisease.Inworkonbothconventionalandgnotobioticrats,Kakehashietal.graphicallyshowedtheimpoitanceofbacteria-specificallythatexposedpulpswoulddegenerateandbecometotallynecroticwithabscessformationonlyifbacteriawerepresent.Iatrogen
7、icfactor.Thesecondmostcommoncauseofendodonticdiseaseoccursasaresultofattempts(ocorrecttheravagesofdentaldisease.Theeffectsofoperativeproceduresresultinginexcessiveheatordrying,orboth,arewelldocumented.Pulpalchangeshavealsobeenreportedinresponsetoimpressiontechniqueswherebybacteriawereforcedthroughth
8、edentinaitubulesinto(hepulp.Manymaterialsandchemicalsusedindentistryhavebeenfound(ocauseirritationinthepulp.NyborgandTullinreportedontheunpredictabilityof.thepathogicstatusofthepulpstuinpaftervitalextirpation.Accordingtotheseauthorsthepulpstumpcanremainvitalorbecomeinflamedornecrotic,leadingtoperiap
9、icaldisease.Thus,inthetreatmentofdisease,furtherdiseasecanbecreated.Traumaticfactor.Theresponsetotraumaappearstobeparticularlydependentontheseverityofthe(rauma.Forexample,relativelylighttraumafromocclusionmaycauselittleornoeffect.However,heaviertraumafromocclusionmayhaveasignificantpulpaleffect.Ingl
10、ereportedacaseofpulpalnecrosis,apparentlytheresultofbruxism.Theresponsetotraumafromblowsoraccidentscanbevaried.SomepulpsapparentlyhealWithnoadverseeffects,whereasothersbecomenecrotic.Thereappearstobeamiddleground(i.e.,someteethrespondtotraumabyincreasedpulpalcalcification).Thismaybesoextensivethatra
11、diographicallytheentirecanalappearscalcified.Traumacausingacrackedorfracturedtoothsecondarilyprovidesapathwayfortheoralfloratoreachthepulp.Oncethepulpisexposedtotheoralenvironment,inflammationisapredictablecomplication.Thesecrackedteethcanresultinbizarreclinicalsymptoms,makingdiagnosisverydifficult.
12、Idiopathicfactor.Pulpalchangesalsooccurforreasonsthatareasyetunknown(idiopathic).Acommonexampleisinternalresorption.Althoughtraumahasbeenimplicatedtoanextentin.internalresorption,thisdocsnotexplainthewholephenomenon.Theseteetharcfrequentlyasymptomaticandarediscoveredonroutinedentalradiographs.Micros
13、copicallymacrophagesandmultinucleatedgiantcellsarefoundclosetotheresorbingdentin.Thetissuereplacingthelostdentinusuallyischronicallyinflamed.Alsoaperiapicalradiolucencymaybeassociatedwithinternalresorption,signifyingpulpalnecrosisasasequelatothereaction.ClassificationBecauseonreliableconelationhasbe
14、endemonstratedbetweentheclinicalstatusandthehistologicstatusofthepulp,manyclassificationshavebeenbasedononeortheotherfinding.Themostdifficultaspecttoacceptisthatthereisnocorrelationbetweentheseverityofpainand(heextentofpulpalinvolvement.Thecriticaldecisionfortheclinicianiswhethertotreatthepulpendodo
15、nticallyorattemptpreventivemeasures.Once(hedecisionismadetoinstituteendodontictherapy,theprecisehistologicstateofthepulpisacademicbecausethetreatmentistotalextirpation.However,intheearlystagesofpulpalpathologythepulppassesfromareversibletoanirreversiblepulpitis.Thisdiagnosisisnotalwaysaneasyonetomak
16、ebecausethedividinglinecanbeveryobscure.Reversibleandirreversiblepulpitis.Todecidewhetherapulpitisisreversibleorirreversible.Wedependontestresults,clinicalsymptoms,andclinicaljudgment.Thepatient*shistoryofpainandthepresenceorabsenceofspontaneouspainisofcriticalimportance.Bythiswemeanpainthatisnotbroughtonbyaspecificstimulus(i.e.,heatorcold).Forexample,apatientwhohashadarestorationreplacedImonthpreviousnowappearswithacomplaintofpain.Afteraperiodofquiescence
