Evaluation of the Paper Point Technique for Locating the Root Canal Apical Exit JoseLuisMarcos-Arenal AthesissubmittedtothefacultyoftheUniversityofNorthCarolinaatChapelHillinpartialfulfillmentofthe requirementsforthedegreeofMasterofScienceintheSchoolofDentistry(Endodontics) ChapelHill 2007 Approvedby: DrMartinTrope DrEricMRivera DrDanielJCaplan ABSTRACT JoseLuisMarcos-Arenal: EvaluationofthePaperPointTechniqueforLocatingtheRootCanalApicalExit (underthedirectionofDrsMartinTrope,EricMRiveraandDanielJCaplan) Anewmethodfordeterminingrootcanalworkinglength(WL),thepaperpointtechnique(PPT),hasbeen claimedtobeaccurateandreproducible,buthasnotbeenformallyevaluated. Hypothesis:WLdeterminationismoreaccuratewhentheElectronicApexLocatorTechnique(EALT)is supplementedwithPPTcomparedtoEALTalone. Thelengthsof84rootcanalsofunsalvageablehumanteethweremeasuredfirstusingEALT,thenPPT. EndodonticfileswerecementedtothepositionindicatedbyPPT.TheteethwereextractedandmicroCT- scanned.In71canalsthatprovidedadequatereadingsforbothEALTandPPT,theRCAEtofiletipdistance wasmeasuredto20µmresolution. Bothtechniquesshowed(1)moderateagreementand(2)excellentrepeatabilities.Therewas(3)asignificantly greateraccuracyinlocatingtheRCAEwhenPPTwasusedcomparedtoEALTalone(p(cid:1)0.0051). Conclusion:ItmaybeadvisabletosupplementtheEALTmeasurementwithPPT. ii dedicatedtothedentistsoftheFuture iii ACKNOWLEDGEMENTS DrTrope,DrRiveraandDrCaplan,yousupportedmethroughoutthisprojectandwerepatientwithmy innumerablequestions. Everyoneofthepatientpatientswhoparticipatedinthestudy. AndthestudentsandAdmissionsDeskstaff(Shirley†,Cynthia,MontyandJean)whoreferredthemtous. WallaceAmbrosetaughtmehowtousethemicro-CTmachine. Hyunsoon,LinandDrGKochfromtheUNCBiometricConsultingLaboratoryanalyzedourdataexpecting nothinginreturn. TheUNCDepartmentofEndodonticprovidedfundsandpremisesforthisproject. Thank you.Iwillneverforgetit. JLMA iv TABLEOFCONTENTS LISTOFTABLES.........................................................................................................................................viii LISTOFILLUSTRATIONS.............................................................................................................................ix LISTOFABBREVIATIONS.............................................................................................................................x CHAPTER1: INTRODUCTION................................................................................................................1 CHAPTER2: REVIEWOFTHELITERATURE........................................................................................3 2.1 APICALTHIRDOFAROOT.......................................................................................................3 2.1.1 AnatomyandHistology..................................................................................................3 2.1.1.1 Ofthetoothhardtissues........................................................................................3 2.1.1.2 Ofthetoothsofttissues:thedentalpulp...............................................................6 2.1.1.3 Oftheperiodontaltissuesurroundingtherootcanalexit.......................................7 2.1.2 Physiology&Pathology.................................................................................................7 2.2 WORKINGLENGTHDETERMINATIONINENDODONTICS.....................................................8 2.2.1 Definition........................................................................................................................8 2.2.2 TheimportanceofacorrectWLdetermination..............................................................8 2.2.2.1 Biologicalreasons.................................................................................................8 2.2.2.2 PhilosophicalReasons..........................................................................................9 2.2.3 TheapicalreferencepointinWLdetermination............................................................9 2.2.4 MethodstodetermineWL:description,degreeofaccuracyandshortcomings...........11 2.2.4.1 Periodontalsensitivity/Patientresponse..............................................................11 2.2.4.2 TactileMethod.....................................................................................................12 2.2.4.3 Radiographic.......................................................................................................12 2.2.4.4 Electronic.............................................................................................................16 2.2.4.5 CombineduseofEALandradiographs...............................................................20 2.2.4.6 Newmethod:thePaperPointTechnique............................................................20 2.3 MICROCOMPUTEDTOMOGRAPHY(CT)INEXPERIMENTALENDODONTICS..................22 2.3.1 Introduction..................................................................................................................22 2.3.2 Resolutionofmicro-CT(formeasurementofteethlength)..........................................22 2.3.3 Limitationsofmicro-CT................................................................................................23 v CHAPTER3: MANUSCRIPT..................................................................................................................25 3.1 INTRODUCTION,LITERATUREREVIEWandRATIONALEforthisPROJECT......................25 3.2 HYPOTHESIS............................................................................................................................27 3.3 PURPOSEandSPECIFICAIMS...............................................................................................27 3.4 MATERIALSandMETHODS.....................................................................................................28 3.4.1 Overviewofdesign......................................................................................................28 3.4.2 SubjectsandTeeth......................................................................................................28 3.4.2.1 Inclusion/exclusioncriteria...................................................................................28 3.4.2.2 Collecteddata......................................................................................................29 3.4.2.3 Samplesizecalculation:......................................................................................29 3.4.3 Invivopartofthestudy:...............................................................................................30 3.4.3.1 Assessmentofpatientsandteeth........................................................................30 3.4.3.2 Anesthesia,operatingfieldisolationandtoothdecoronation...............................30 3.4.3.3 ObtainingtheEAL-length.....................................................................................31 3.4.3.4 ObtainingthePPT-length....................................................................................32 3.4.3.5 CementinganendodonticinstrumenttoPPT-length...........................................35 3.4.3.6 Toothextraction...................................................................................................35 3.4.4 Exvivopartofthestudy..............................................................................................35 3.4.4.1 Specimenpreparationandstorage......................................................................35 3.4.4.2 Micro-CTimageacquisition.................................................................................36 3.4.4.3 Volumetricreconstructionofthetoothapex.........................................................38 3.4.4.4 Analysisofreconstructedapices:measuringthefile-tiptoRCAEdistance.........38 3.4.4.5 ObservationsandMeasurements........................................................................39 3.4.5 DataAnalysis...............................................................................................................40 3.4.5.1 DefinitionofVariables..........................................................................................40 3.4.5.2 Analysisofthedata.............................................................................................40 3.4.5.3 ReliabilityoftheImageAnalysis..........................................................................41 3.5 RESULTS..................................................................................................................................42 3.5.1 Accuracy(n=71):.........................................................................................................43 3.5.2 Repeatability(n=9):.....................................................................................................46 3.5.3 Agreement(n=71):.......................................................................................................47 vi 3.6 DISCUSSION............................................................................................................................49 3.6.1 RegardingtheMaterialsandMethods.........................................................................49 3.6.2 RegardingtheResults.................................................................................................53 3.6.3 Researchquestionsforfutureprojects........................................................................61 3.6.4 ThePaperPointTechniqueinclinicalcontext.............................................................62 3.6.4.1 ImplementingthePPT.........................................................................................62 3.6.4.2 ExcessivelyshortPPTreadings..........................................................................63 3.7 CONCLUSIONS.........................................................................................................................64 APPENDIX A: RAWDATAoftheSTUDY...............................................................................................65 REFERENCES .........................................................................................................................................66 vii LISTOFTABLES Table1 (cid:1)InclusionCriteria 28 Table2 (cid:1)VariablesDataCollection 29 Table3 (cid:1)Sample 42 Table4 (cid:1)ContinuousAccuracyofEALTandEALT/PPT 43 Table5 (cid:1)CategoricalAccuracyofEALTandEALT/PPT(allintervalsobserved) 43 Table6 (cid:1)CategoricalAccuracyofEALTandEALT/PPT(RCAEascut-offpoint) 44 Table7 (cid:1)CategoricalAccuracyofEALTagainstEALT/PPT 44 Table8 (cid:1)CategoricalAccuracyofEALTandPPT(clinically-relevantranges) 45 Table9 (cid:1)Repeatedreadingsin9cases(rawdata). 46 Table10 (cid:1)Between-methoddisagreementwithinspecificranges 47 Table11 (cid:1) Criteriaforselectingtheapicallandmark 50 Table12 (cid:1)Criteriaforselectingatechniqueforanalyzingthespecimens’apices 53 Table13 (cid:1)Potentialerror-sourcestepsinEALTandPPT 60 Table14 (cid:1)TworootcanaltherapysequencesincorporatingthePPT 62 viii LISTOFILLUSTRATIONS Figure1.Rootapex:(A)horizontalcross-section.(B)longitudinalsection.Ppulp,Ddentin,Ccementum,AF apicalperiodontalfibers,ABalveolarbone,Eepithelium,GRANgranulomatoustissue.FromSeltzer.........4 Figure2.Canalsforaminararelyareattherootapex.FromGutierrezandAguayo......................................7 Figure3.EndometricProbe.FromDummerandLewis................................................................................16 Figure4.PaperpointsshowingtheangleoftheRCAEtothelongaxisofthecanal.(A)FromRosenberg.(B) FromWWatsonJr........................................................................................................................................20 Figure5.Studyteeth:isolatedanddecoronated..........................................................................................31 Figure6:Kerrabsorbentpaperpoints..........................................................................................................33 Figure7.Representationofapaperpointrightat(A)andpast(B)theRCAE.............................................34 Figure8.TOP:Lengthofthelongestpaperpointreturningcompletelydry..................................................34 Figure9.Teethlabeledandstoredinformalhaldehyde................................................................................36 Figure10.Specimenswereplacedinplasticvialspriortomicro-CTscanningprocess...............................37 Figure11.A:SkyScanmicro-CTunitusedinthisproject. B:Plasticvialcontainingspecimen,positionedon rotatingstand................................................................................................................................................37 Figure12.Analysisofcross-sections:(A)theonetoshowthelastevidenceofthefiletip,(B)thelastoneto showtherootcanalasafulloval..................................................................................................................39 Figure13.Parametricanalysisofbetween-methodagreement:pairedmeanreadinglengthsagainstpaired differenceofreadings...................................................................................................................................48 Figure14.RepeatabilityanalysisoftheEALTandPPT(in9cases): meanagainststandarddeviation.....55 ix LISTOFABBREVIATIONS 3D (cid:1) threedimensional 2D (cid:1) twodimensional AC (cid:1) ApicalConstriction AF (cid:1) ApicalForamen CDJ (cid:1) CementoDentinalJunction CT (cid:1) ComputedTomography (cid:2) (cid:1) Meanpairederrordifferenceofthemeasurements EAL (cid:1) ElectronicApexLocator EALT (cid:1) ElectronicApexLocatorTechnique EALT-accuracy (cid:1) distancefromEALT-lengthtotheRCAE EALT-length (cid:1) lengthofthecanalaccordingtotheEALT IRB (cid:1) InstitutionalReviewBoard(alsoEthicalReviewBoard) PPT (cid:1) PaperPointTechnique PPT-accuracy (cid:1) distancefromPPT-lengthtotheRCAE PPT-length (cid:1) lengthofthecanalaccordingtothePPT RA (cid:1) RadiographicApex(oftherootofatooth) RCAE (cid:1) RootCanalApicalExit S (cid:1) within-subjectstandarddeviationofeachparticulartechnique w S (cid:1) standarddeviationofthebetween-methodpaireddifferences d UNC-CH (cid:1) UniversityofNorthCarolinaatChapelHill WL (cid:1) WorkingLength x