UnitNineETIOLOGYANDCLASSIFICATIONOFPULPITISFormerlyitwasthoughtthatthepulprespondedinitiallybyacuteinflammation,followedbychronicinflammation,regardlessoftheetiologicfactor.However,Brannstr8mandLindandSeltzershowedthattheinitialresponsetocariesmightbechronicinflammationbecauseoftherelativelyslowprogressionoftheirritant.Operativeprocedures,becauseoftheirrapideffect,probablyresultinatransientacuteinflammation.Almostanyinsulttothetooth(dependingonitsseverityanddurationcansettheinflammatoryprocessinmotion.Threepathwaystothepulparcusuallydescribed:1. Directextensionthroughthedentinaltubules,asincariesorchemicalsplacedonthedentin.2. Extensionbytheprocessofanachoresis,thelocalizationofblood-bornebacteriawithinthepulp(StudieshaveshownthatorganismstendtolocateinareasthatarealreadyinflamedorpreviouslyinjuredGrossmanwasabletorecovertestorganismsinteeth(hatweretraumatized,huthewasnotabletorecoverthemfromthecirculatingbloodstream.Thismayhelptoexplainwhysomepulpsbecomenecroticwhenthereisnoapparentetiologicfactor.)3. Extensionofperiodontaldiseaseintothepulp.(Recentworkhasshownthatinjuryordiseaseintheperiodontalligamentcanhaveapulpaleffect.Langclandctal.demonstratedlocalizedareasofinflammationinthepulptobearesultofperiodontaldisease;buttheybelievetotalnecrosiswillresultonlyifthelateralcanalsorapicalforamen,orboth,areexposedtotheoralenvironment.)EtiologicfactorsTheetiologicfactorsinvolvedininflammationofthepulpcanbegroupedintofourgeneralcategories:bacterial,iatrogenic,traumatic,andidiopathic.Bacterialfactor.Bacteriaandtheirproductsarcthemostcommoncauseofendodonticdisease.Inworkonbothconventionalandgnotobioticrats,Kakehashietal.graphicallyshowedtheimpoitanceofbacteria-specificallythatexposedpulpswoulddegenerateandbecometotallynecroticwithabscessformationonlyifbacteriawerepresent.Iatrogenicfactor.Thesecondmostcommoncauseofendodonticdiseaseoccursasaresultofattempts(ocorrecttheravagesofdentaldisease.Theeffectsofoperativeproceduresresultinginexcessiveheatordrying,orboth,arewelldocumented.Pulpalchangeshavealsobeenreportedinresponsetoimpressiontechniqueswherebybacteriawereforcedthroughthedentinaitubulesinto(hepulp.Manymaterialsandchemicalsusedindentistryhavebeenfound(ocauseirritationinthepulp.NyborgandTullinreportedontheunpredictabilityof.thepathogicstatusofthepulpstuinpaftervitalextirpation.Accordingtotheseauthorsthepulpstumpcanremainvitalorbecomeinflamedornecrotic,leadingtoperiapicaldisease.Thus,inthetreatmentofdisease,furtherdiseasecanbecreated.Traumaticfactor.Theresponsetotraumaappearstobeparticularlydependentontheseverityofthe(rauma.Forexample,relativelylighttraumafromocclusionmaycauselittleornoeffect.However,heaviertraumafromocclusionmayhaveasignificantpulpaleffect.Inglereportedacaseofpulpalnecrosis,apparentlytheresultofbruxism.Theresponsetotraumafromblowsoraccidentscanbevaried.SomepulpsapparentlyhealWithnoadverseeffects,whereasothersbecomenecrotic.Thereappearstobeamiddleground(i.e.,someteethrespondtotraumabyincreasedpulpalcalcification).Thismaybesoextensivethatradiographicallytheentirecanalappearscalcified.Traumacausingacrackedorfracturedtoothsecondarilyprovidesapathwayfortheoralfloratoreachthepulp.Oncethepulpisexposedtotheoralenvironment,inflammationisapredictablecomplication.Thesecrackedteethcanresultinbizarreclinicalsymptoms,makingdiagnosisverydifficult.Idiopathicfactor.Pulpalchangesalsooccurforreasonsthatareasyetunknown(idiopathic).Acommonexampleisinternalresorption.Althoughtraumahasbeenimplicatedtoanextentin.internalresorption,thisdocsnotexplainthewholephenomenon.Theseteetharcfrequentlyasymptomaticandarediscoveredonroutinedentalradiographs.Microscopicallymacrophagesandmultinucleatedgiantcellsarefoundclosetotheresorbingdentin.Thetissuereplacingthelostdentinusuallyischronicallyinflamed.Alsoaperiapicalradiolucencymaybeassociatedwithinternalresorption,signifyingpulpalnecrosisasasequelatothereaction.ClassificationBecauseonreliableconelationhasbeendemonstratedbetweentheclinicalstatusandthehistologicstatusofthepulp,manyclassificationshavebeenbasedononeortheotherfinding.Themostdifficultaspecttoacceptisthatthereisnocorrelationbetweentheseverityofpainand(heextentofpulpalinvolvement.Thecriticaldecisionfortheclinicianiswhethertotreatthepulpendodonticallyorattemptpreventivemeasures.Once(hedecisionismadetoinstituteendodontictherapy,theprecisehistologicstateofthepulpisacademicbecausethetreatmentistotalextirpation.However,intheearlystagesofpulpalpathologythepulppassesfromareversibletoanirreversiblepulpitis.Thisdiagnosisisnotalwaysaneasyonetomakebecausethedividinglinecanbeveryobscure.Reversibleandirreversiblepulpitis.Todecidewhetherapulpitisisreversibleorirreversible.Wedependontestresults,clinicalsymptoms,andclinicaljudgment.Thepatient*shistoryofpainandthepresenceorabsenceofspontaneouspainisofcriticalimportance.Bythiswemeanpainthatisnotbroughtonbyaspecificstimulus(i.e.,heatorcold).Forexample,apatientwhohashadarestorationreplacedImonthpreviousnowappearswithacomplaintofpain.Afteraperiodofquiescence