Upper central incisors with periapical lesions treated with two integrated endodontic systems: A six-month randomized controlled trial

ORIGINAL

ARTICLE/ARTICOLO

ORIGINALE

Upper

central

incisors

with

periapical

lesions

treated

with

two

integrated

endodontic

systems:

a

six-month

randomized

controlled

trial

Incisivi

centrali

superiori

con

lesione

periapicale

trattati

con

due

sistemi

endodontici

integrati:

trial

clinico

controllato

randomizzato

a

sei

mesi

Daniele

Angerame

*

,

Matteo

De

Biasi

,

Vittorio

Franco

,

Lorenzo

Bevilacqua

,

Attilio

Castaldo

a

DentalClinic,UniversityClinicDepartmentofMedical,SurgicalandHealthSciences,UniversityofTrieste, Trieste,Italy

b

GraduateSchoolofNanotechnology,UniversityofTrieste,Trieste,Italy

c_{PrivatePractice,Rome,Italy}

Received23February2016;accepted4April2016 Availableonline29April2016

KEYWORDS

Periapicallesion; Integratedendodontic techniques;

Carrierbasedsystems; Healing.

Abstract

Aim: Toassesspreliminarilythesuccessrateoftherootcanaltreatmentwithtwointegrated shapingandfillingsystemsofuppercentralincisorswithchronicperiapicalpathosis.

Methodology: Sixty adult subjectswith an untreated maxillary central incisor presenting a chronicperiapicallesionsmallerthan5mmindiameterwererecruitedforthepresentstudy.The patients were randomly divided into two treatment groups: G1 (n=30), Revo-S/One Step Obturator;G2(n=30)GTX/GTXObturator.Allrootcanaltreatmentswereperformedinasingle sessionbythesameoperator.Sensitivitytopalpationandpercussionwasregisteredatbaseline

PeerreviewunderresponsibilityofSocieta` ItalianadiEndodonzia.

* Correspondingauthorat:UniversityClinicalDepartmentofMedical,SurgicalandHealthSciences,PiazzaOspedale1,I-34125Trieste,Italy. Tel.:+390403992761;fax:+390403992665.

E-mail:d.angerame@fmc.units.it(D.Angerame).

Availableonlineatwww.sciencedirect.com

ScienceDirect

jo u rn al ho m e p ag e: ww w. el s ev i e r.c o m /l o ca t e/ gi e

http://dx.doi.org/10.1016/j.gien.2016.04.001

Introduction

Remnantsofnecroticpulpandmicrobialinfectioninsidethe endodonticspaceareknowncausesofcommoninflammatory odontogeniclesions,themostfrequentbeingtheperiapical periodontitisandradicularcyst.Fortherootcanaltreatment tobesuccessfulinrestoringtheperiapicalhealth,the clin-ician should maximize his effort to chemo-mechanically removetheinfectedendodonticcontent andsealtheroot canalwithaneffectivethree-dimensionalfilling.

Duringthelastyearsamoderntrendofsimplificationof bothshapingandfillingtechniqueshasariseninendodontics. Severalmanufacturersareintroducingonthemarketshaping

systemswithrotaryfilesthatrequirefewerstepsthanolder systems.1Similarly,carrier-basedsystemsallowfora single-steprootcanalfillingwithoutrenouncingtothe thermoplas-ticisationofthegutta-percha.Itisknownthatthelikelihood to introduce operative errors in the filling procedure increases with the number of steps,because micro-tomo-graphicdataattestthatinexperiencedoperatorscanobtain betterresultswith carrier-basedtechniques incomparison with thecontinuous waveof condensation.2 _{Moreover, the}

correspondenceinshapeandsizebetweentheshapingand the fillinginstruments, which canbe proposedas an inte-grated system, facilitates the clinician’s tasks during the differentphasesoftheendodontictreatment.Examplesof

PAROLECHIAVE Lesioneperiapicale; Tecnicheendodontiche integrate; Sistemicarrier-based; Guarigione.

andatthesix-monthrecall.Radiographichealingwasscoredbytwoblindexaminersaccordingto apreviously described scale. The absence ofstatistically significantdifferences in termsof baselineclinicalparametersbetweenthetwogroupswasassessedbymeansofaMann—Whitney test(age,apicalgauging)andx2test(sensitivitytopercussionandpalpation).Theradiographic scoresattributedtothetwogroupswerecomparedwithaMann—Whitneytest,whileax2test servedtocomparetheclinicaldatagatheredaftersixmonths(p<0.05).

Results: Baselineclinicalparametersregisteredinthetwogroupswerefoundtobecomparable. Allpatientsattendedthesix-monthrecallandalltheteethwerereferredtobenegativeto sensitivity,withtheexemptionoftwosubjectspergroup.Theperiapicallesionswerescoredas totallyhealed,partiallyhealedandnothealedin43.4%,53.3%and3.3%ofcasesinG1andin 43.3%,50.0%and6.7%ofcasesinG2.Thedifferencesbetweenthegroupswerenotsignificant. Conclusions: Tough cases scored as incomplete healing should be further followed up, the presentstudyatteststhatthetwo testedintegratedshapingand fillingsystemsare capable ofhighandcomparablesix-monthsuccessrateinuppercentralincisorswithperiapicalpathosis. ß2016Societa` ItalianadiEndodonzia.ProductionandhostingbyElsevierB.V.Thisisanopen accessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Riassunto

Obiettivi: Valutarepreliminarmenteiltassodisuccessodeltrattamentoendodonticodiincisivi centralisuperioriconlesioneperiapicaleeseguitoconduesistemiintegratidistrumentazionee otturazione.

Materialiemetodi: Sonostatireclutati60soggettiadulticonunincisivomascellarecentralenon trattatoaffettodaunalesioneperiapicaleinferiorea5mmindiametro.Ipazientisonostati divisicasualmenteinduegruppiditrattamento:G1(n=30),Revo-S/OneStepObturator;G2 (n=30)GTX/GTXObturator.Tuttiitrattamentiendodonticisonostatieseguitiinsingolaseduta dalmedesimooperatore.Ladolorabilita` allapalpazioneeallapercussionee` stataregistrataal baselineealcontrolloaseimesi.Allaguarigioneradiograficae` statoattribuitounpunteggioda dueesaminatoriestraneiallasperimentazionesullabasediunascaladescrittainprecedenza. L’assenzadidifferenzesignificativedeiparametridipartenzatraiduegruppie` statavalutatacon testMann-Whitney(eta`,gaugingapicale)ex2(sensibilita` apalpazioneepercussione).Ipunteggi radiograficiattribuitiaiduegruppisonostaticonfrontaticonuntestdiMann-Whitney,mentrei daticlinicicontestx2(p<0,05).

Risultati: Iparametriclinicialbaselineregistratineiduegruppisonorisultatiparagonabili.Tutti ipazientisisonopresentatiaicontrolliaseimesi,senzalamentaredolorabilita` aidentitrattati, conl’eccezionediduesoggettipergruppo.Lelesioniperiapicalisonostateclassificatecome guarite,ridotteindimensionienonguariterispettivamentenel43,4%,53,3%e3,3%deicasiinG1 enel43,3%,50,0%and6,7%deicasiinG2.Ledifferenzetraigruppinoneranostatisticamente significative.

Conclusioni: Sebbeneicasiclassificaticomeguarigioneparzialedebbanoessereulteriormente seguitineltempo,ilpresentestudiodimostracheiduesistemiintegratidistrumentazionee otturazione sonocapaci ditassi disuccessoelevatietralorosimiliperiltrattamento della patologiaperiapicalediincisivicentralisuperioria6mesi.

such systems are given by Revo-S (Micro-Mega, Besanc¸on, France)andGTXrotaryfiles(DentsplyTulsaDental Special-ties, Tulsa, OK,USA), which have dedicated carrier-based obturators,towit,theOne-StepObturator(CMSDentalApS, Copenhagen,Denmark)and GTXObturator(Dentsply Tulsa DentalSpecialties).Thereisalreadysomeevidenceattesting thesealing ability,3 aswellas theclinicaleffectiveness of thesesystemsondifferenttoothtypes1_{asavalidalternative}

totraditionalmulti-steptechniques.

Theendodonticanatomyofthemaxillarycentralincisoris known to seldom aberratefrom themost frequent config-urationofagenerallywideandstraightsinglecanal.Evenif upperanterior teeth with internalanatomy that markedly differsfromthenormexist,4,5thealmostinvariable predo-minantformofthecentralincisor—i.e.asinglerootwitha singlecanal—posesnopeculiardifficultyforthetreatment ofthistypeoftoothinabsenceofcase-specifichindrances. However, theapical diameter ofthese teeth isfrequently widesothattheapicalthirdoftherootcanalisnotalways easytocleanthoroughlyandthensealtightly.

Theaimofthepresentstudyistotestthenullhypothesis thatthesix-monthsuccessrateoftherootcanaltreatmentof uppercentralincisorswithchronicperiapicalpathosisdoes not differ when performed with two shaping and filling integratedsystems.

Materials

and

methodology

This randomised controlled trial with two parallel groups design was preparedand reported followingthe CONSORT guidelines6_{andinagreementwiththeprinciplesofthelast}

updateoftheHelsinkiDeclaration.Afterbeinginformedon theobjective andthedesignofthestudy, allthepatients

assessedforeligibilitygavetheirconsentfortheinvolvement inthestudybysigningadedicatedform.

Eligibilitycriteria

Consecutivemaleandfemalesubjectswhopresentedatthe DentalClinicoftheUniversityofTriestebetweenAugust2014 andFebruary2015wererecruitedforvoluntaryparticipation inthestudy.Theinclusioncriterionwasthepresenceofan untreatedmaxillary centralincisor with chronicperiapical lesions smaller than 5mm in diameter (measured on the periapical radiograph). The teeth were scheduled for sin-gle-sessionrootcanaltreatment. Patientswith physicalor psychological disabilities, inability to understand instruc-tions, severe systemic disorders (i.e. non-controlled dia-betes, immunologic diseases, malignant neoplastic processes) were excluded from the trial. From a total of 70subjectsassessedforeligibility,60patientswereenrolled in the present study. The phases of the trial (enrolment, allocation,follow-up,andanalysis)areportrayedinFig.1. Anindependentoperator,blindtothecharacteristicsofthe trialotherthanitsdesign,generatedtherandomsequence bystratified blockedrandomizationusingafreesimulation software.7Thepatientswereunawareoftheexperimental groupofassignment.

Interventions

Theanamnesticdataconcerningthegeneralandoralhealth werecollectedbyinterviewingthepatients.Asingle opera-torexaminedtheincludedpatientswearing4magnifying loupes. The preoperative clinical signs were recorded,

includingtendernesstopercussionorpalpationofthebuccal sulcusintheapicalarea.

A single experienced operator treated all enrolled patients.Beforestartingtherootcanaltreatment,arubber damwaspositionedontothedesignedtoothtoobtainfield isolation.Ifneeded,acompositeresinbuild-uprestoration was madeto achieveoptimal marginalseal of therubber dam.Coronalandapicalpatencywasverifiedwithasize10K file(DentsplyMaillefer,Ballaigues,Switzerland),whichwas connectedtoanelectronicapexlocator(RootZX,MoritaCo., Tokyo,Japan)forthedeterminationoftheelectronic work-inglength.Alltheotheroperativeproceduresotherthanthe shapingandfillingprotocolswereidenticalinthetwogroups. Duringinstrumentationthecanalswereirrigatedaftereach instrumentwithanendodonticsyringefilledwith2.5mlof 5.25%sodiumhypochlorite(Niclor5,Ogna,Muggio`,Italy).

Forcanalshaping,therotaryinstrumentsweremounted onanendodontichandpiececonnectedtoadedicatedmotor (TecnikaVisionS,ATR,Pistoia,Italy)thatwassetin accor-dancewiththeindicationssuggestedbythemanufacturers. Thecanalshaping/fillingprotocolswereasfollows: Group1 (G1,n=30): the rootcanalwas shaped making

useofthestandardsequenceofrotaryRevo-Sinstruments (Micro-Mega):SC1(25/.06),SC2(25/.04),andSU(25/.06). Afterwards, theapex was gaugedwith manual Ni-Tifiles (MityTurbo,JSDental,Ridgefield,CT,USA)andaccordingly enlargedwithfinishingfilesAS30(30/.06),AS35(35/.06)or AS40(40/.06).Manualrefinementwasperformedif neces-sary.Therootcanal wasdriedwith paperpointsandthe canal walls were smeared with eugenol-free endodontic sealer(Sicura-Seal,Dentalica,Milano,Italy)usingasterile drypaperpoint.Acarrier-basedobturatoroftheOne-Step Obturatorsystem(CMSDentalApS,Copenhagen,Denmark) chosentomatchtheapicalpreparationsizewasinsertedinto theOne-StepObturatorOven(CMSDentalApS)tosoftenthe outergutta-perchaandthenintroducedintotherootcanal 1mmshorteroftheworkinglength.After10s,thehandleof theobturatorwascutattheorificelevelwithadedicated burmountedonahighspeedhandpiece.

Group2(G2,n=30):therootcanalwasshapedwith GT SeriesXrotary files(DentsplyTulsaDentalSpecialties)in the order: 20/.04, 20/.06, 30/.04, 30/.06. The apical gaugingwas carriedoutasdescribedinG1andtheapex wasfinishedwith.06or0.8taperedGTSeriesXfiles.Canals weredriedandtheirwallssmearedwithaeugenol-based sealer(PulpCanalSealer,SybronEndo,Orange,CA,USA). ThefillingprocedureresembledthatofG1andwasdone withGTSeriesXObturatorsandaThermaprepoven (Dents-plyTulsaDentalSpecialties).

Radiographiccenteringandexamination

CustomizedRinnXCPdevices(RinnCorp.,Elgin,IL,USA)and adigitalX-ray system(VistascanDental Perio,Du¨rrDental AG,Bietigheim,Germany)wereusedthroughoutthestudy with a paralleling technique and a X-ray device (2200 IntraoralX Ray System, Kodak Dental Systems, Rochester, NY,USA) set at 70kVp, 10mA, and 0.20s exposure time; the images were registered in ‘‘Endo’’ mode to enhance readability.8 Radiographs were taken immediately after theconclusion of the rootcanal treatment (baseline) and atthesix-monthrecall.

Two blind examiners with 19 and 23 years of clinical experience inendodontics extraneousto involvedpatients andstudydesignwerecalibratedaccordingtoapreviously describedscaledevelopedtoscorethehealingofperiapical lesions.9Accordingtosuchscale,thefollow-upradiographs wereattributedtooneoffourcategories(Fig.2):

1.Healing:normaltrabecularboneandphysiological period-ontalligamentwidth.

2.Improvement:decreaseofthelesionsize.

3.Failure:increaseoflesionsizeorabsenceofchangesfrom theinitialstatus.

4.Unreadableradiograph.

Eachfollow-upradiographwasscoredinthecourseoftwo sessionsofradiographicevaluationthattookplace immedi-atelyafterthecollectionoftheradiologicalimagesandafter onemonth.10

Statistical analysis

Both the sensitivity to percussion and palpation and the radiographicscorewereconsideredmainoutcomemeasures of the present trial. The Statistical Package for Social Sciences v. 15 (SPSS Inc., Chicago, IL, USA) was used for statistical analysisof gathered data. The comparability of baselineparametersofthetwogroupswastestedbymeans of a Mann—Whitney (age, apical diameter) and a x2 test (sensitivity to percussion and palpation). The differences between the groups in terms of radiographic score and clinicalexaminationparameters(percussionandpalpation) wereassessedwiththeMann—Whitneyandx2test, respec-tively.The levelofintra- andinter-observeragreement of theratingofradiographichealingwasevaluatedwithkappa statistics with quadratic weighting. The imputed relative distances between the ordinal categories served as basis for weighting: healing-improvement, 1; improvement-fail-ure,2.

Results

Table1summarizesthebaselinevariables,thesensitivityto

Both the intra- and inter-observer agreement rates of radiographichealingscoreswereexcellent.Thekappavalues of intra-observer reliability ranged from 87% CI [68; 100] (observerA)to92%CI[76;100](observerB),thoseof inter-observerreliabilityfrom89%CI[70;100](secondsession)to 91%CI[74;100](firstsession). Discordanceconcernedonly differencesinclassificationbetweentotalandpartialhealing, whereastheevaluationofthecasesconsideredradiological failureswasconsistentintimeandbetweenobservers.

Discussion

Ourresultsshowthatsixmonthscanbeasufficientfollow-up timetoobservecompleteradiographichealingof endodon-tically treated maxillary central incisors with a periapical lesionsmallerthan5mmindiameter.Therearefewstudies thatfollowupendodonticallytreatedteethwithperiapical

pathosistomonitortheirradiographichealing.Murphyetal. hadalreadyreportedcompletehealingratessimilartothat ofthepresentstudyafterthreemonths,presentingalso six-month successrates around 60%.11 Conversely,Peters and Wesselinkobserved markedly inferiorhealing rates in the samefollow-upperiods.12Suchavarietyoffindingsmaybe explained by the differences in terms of type of study, operators, techniques and characteristics of the lesions. For instance, Murphy analysed conventionalfilm radiogra-phies, which are known to be less sensitive than filtered digitalradiographies.8Furthermore,thelatterauthorsmade useof2%sodiumhypochloriteasrootcanalirrigating solu-tion,12whenitisknownthatmoreconcentratedsolutionsare neededfor improve the irrigant antibacterial activity and dissolutionpower.13Thefactremainsthatthefindingsofthe presentstudyare promising,since mostof thelesionsnot totallyhealed aftersixmonths werefound to bepartially resorbed.It isconceivable thatacomplete healing ofthe

majority of these lesions will occur in the following six months.

The success rate of the endodontic treatment has been matter of study of a host of primary andsecondary research, but its values are characterized by pronounced variability.14—18The rootcanaltreatmentisreportedto be successful in a percentage of cases that ranges between 75%and97%.14,16,19 However,another sourceofvariability isconstitutedbythedifferenceofthetypesofstudies,and, mostimportantly,bythekindofpatientsbeingrecruitedand treated.In fact, somestudies do notdistinguish between teeth with a healthy periapical status and those with a periodontallesion.Thisfactconsiderablyafflictsthe relia-bilityoftheinformationthatcanbedrawnfromthereviews thatdonotdistinguishsuchpublications.20Inagreementwith thisstatement,awell-designedstudydemonstratedthatthe successrateofendodontictreatmentscarriedoutwithNi-Ti rotaryfilesandThermafilobturationmaydropfrom94%to 48%incaseofperiapicallesion.21Accordingly,asystematic review14 reported thatthe presenceof periapical radiolu-cencycanworsentheprognosisoftherootcanaltreatment byloweringthesuccessrateasmuchas8—13%.

Thescalethathasmostfrequentlybeenusedfor deter-minationofsuccessisprobablytheperiapicalindex(PAI)22; nonetheless,thisindexhasbeencriticizedinthepast.The appropriatenessofageneraluseofPAIforallteethhasbeen questioned,asitwasdevelopedonradiographicand histo-logicalfindings of maxillary incisors.20 Thepresenceof a thickcorticalplateoranunfavourablepositionoftheroot tipinrelationtothecortexmightlimitthereliabilityofa radiographicassessmentusingPAI.20In thepresentstudy, thea posteriori outcomeofthe kappa statistics attested thatadoptingthescaledescribedbyKatebzadeh9wasagood choiceforthe effective stagingof the healingprocess of periapical lesions. Unlike PAI, which contemplates several classes with interpretable distinction, this scale wasspecificallyformulatedtoclassifyanexistingperiapical lesion as disappeared, reduced in size, or unchanged/ increased. These classes are easily understandable and clearly defined. Supported by the intrinsic simplicity of the scale, the radiographic assessment of the periapical changesofcentralmaxillaryincisorswasarelativelyeasy taskfortheevaluators,almostfreefromthepossibilityof mistakesderivingfromanatomicalnoiseorother interfer-ences.Inthistypeofteeth,thecustomizationofthefilm

holder with a simple putty silicone registration assures sufficientrepeatability ofthe radiographicimage charac-teristicsatdifferenttimepoints.Thisapproachallowsfora reliableassessment ofthe changes insize of aperiapical lesion, even without making use of more complex and time-consumingtechniques,likedigitalsubtraction radio-graphy.1

System-specificpredefined operativeprotocols are sug-gestedbythemanufacturersinordertosimplifytheclinical practiceandtoreducetheinfluenceoftheoperator.Thetwo testedsystemswerechosenbecausetheyaremodern tech-niques proposed as integratedcombinationof shapingand fillinginstruments.Specifically,thetwoseriesofNi-Tirotary files are manufacturedby followingpresent-day principles andthecarrier-basedobturatorsaresimilarinconceptand materialsto theThermafil system,whosesealing abilityis well-established.23,24 GT series X files are the improved generationoftheformerGT.Accordingtothemanufacturer, the new M-Wire alloy that constitutes these new files enhances their mechanical properties. The manufacturer alsoclaimsthatthenewcross-sectiondesign,togetherwith thecoilangulationandvariableradialplanes,provides bet-ter cutting ability. These theoretical advantages are still discussed in literature. According to the findings of some studies, the new instruments are not characterized by improvedresistancetocyclicfatigue25andtorsionalstress.26 On the contrary, other studies reported significant advan-tages associated with GTseries X files, such as increased resistance to flection,27 resistance to torsion28 and cyclic fatigue.29

Withregardto thesecondtestedfilesystem,the trian-gular section of Revo-S files is asymmetric and has three cuttingedgesthatcorrespondtothethreedifferentradiiof thecross-section.Oncetheinstrumenthasstartedrotating inside the canal, its particular shape would determine a vibratingsnake-likemotion,whichistheoreticallybeneficial tothetransportationofdentinedebrisoutoftherootcanal. Alimitednumber ofarticleshavebeen producedonthese instruments. Thereissomeevidence attesting thatRevo-S files tend to cause fewerdentinal microcracks thanHERO Shaper(Micro-Mega),TwistedFile(SybronEndo)andProTaper rotaryinstruments(DentsplyMaillefer).30Otherresearchers foundthat,likemanyotherNi-Tisystems,Revo-Sfilescan effectivelyshapetherootcanal,maintainingthepreparation centredtotheoriginalendodonticanatomy,evenincurved

Table1 Anamnesticvariables,operativedata,clinicalandradiographicparametersregisteredatbaselineandaftersixmonths: comparisonbetweengroups.

Age(y) Apicaldiameter (mm)

Baseline Six-monthrecall Radiographicscore(%) Vertical percussion test(%) Palpation test(%) Vertical percussion test(%) Palpation test(%) 1 2 3 4 + + + + G1n=30 46.319.4 0.380.06 6.7 93.3 6.7 93.3 6.7 93.3 6.7 93.3 43.4 53.3 3.3 0 G2n=30 50.819.6 0.390.05 3.3 96.7 10.0 90.0 3.3 96.7 6.7 93.3 43.3 50.0 6.7 0 Diff. p=0.340 p=0.313 p=0.554 p=0.640 p=0.554 p=1.000 p=0.887

canals.31 Another recent article demonstrated that they extrudealimitedamountofapicaldebris,whichwas com-parabletomanualinstrumentation.32

Oneaspectthat,tothebestofourknowledge,hasbeen nottakenintoaccountbyresearchersistheinfluenceofthe shapeofthecarrier.Inparticular,itisunknownwhethera carrierthatexactlymatchestheshapeoftherotary instru-mentsactuallybringsadvantagetotheendodonticsealand, moreimportantly,totheclinicaleffectivenessofthe treat-ment. Even if our study was not designed to address this specificissue,itpreliminarilysuggeststhattheinfluenceofa strictshapecorrespondencebetweentherotaryinstruments and the carrier might not be necessarily relevant. Since information regarding the shape of the carrier was not available, we checked the dimensions and taper of thecarriers viamicroscopicmeasurements,asportrayedin

Fig.3.WeobservedthatOneStepObturatorsdifferonlyin termsoftipdiameterandaremanufacturedwithunvarying taper(3%),whileGTXObturatorsare offeredindifferent combinationsoftaperandtipdiametertomatchtherelative

rotary finishingfile. Theseconsiderations lay the basisfor futureinvestigations.

In light of all the aforementioned advantages that characterise the twointegrated systems andof the posi-tivefindings ofthe presentstudy,it canbeaffirmed that both GTX and Revo-S instruments and their respective obturators perform well in the clinical setting, at least for the treatment of maxillary central incisors with periapicallesion.

Conclusions

Theuseoftheintegratedshapingandfillingsystemstestedin thepresenttrialledtoahighpreliminarysuccessrate,which wassimilarinthetwoexperimentalgroups.The correspon-denceinshapebetweentheinstrumentsoftheshapingand fillingtechniques—likethecaseofthetwotestedsystems— seemstobeaneffectiveandfastsolutionforthetreatment ofmaxillarycentralincisors,evenincaseofperiapicallesion.

Patientsclassifiedaspartiallyhealedaftersixmonthsshould befurtherfollowed-up.

Conflict

of

interest

Theauthorshavenoconflictofinteresttodeclare.

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