Zurich Open Repository andArchiveUniversity of ZurichMain LibraryStrickhofstrasse 39CH-8057 Zurichwww.zora.uzh.ch

Year: 2016

Implant-prosthetic rehabilitation after radiation treatment in head and neckcancer patients: a case-series report of outcome

Cotic, Jasna ; Jamsek, Jure ; Kuhar, Milan ; Hren, Natasa Ihan ; Kansky, Andrej ; Özcan, Mutlu ;Jevnikar, Peter

DOI: https://doi.org/10.1515/raon-2016-0005

Posted at the Zurich Open Repository and Archive, University of ZurichZORA URL: https://doi.org/10.5167/uzh-135081Journal ArticleAccepted Version

Originally published at:Cotic, Jasna; Jamsek, Jure; Kuhar, Milan; Hren, Natasa Ihan; Kansky, Andrej; Özcan, Mutlu; Jevnikar,Peter (2016). Implant-prosthetic rehabilitation after radiation treatment in head and neck cancer patients:a case-series report of outcome. Radiology and Oncology:1-7.DOI: https://doi.org/10.1515/raon-2016-0005

1

Implant-prostheticrehabilitationafterradiationtreatmentinheadandneckcancerpatients:

acase-seriesreportofoutcome

JasnaCotič1,JureJamšek1,MilanKuhar1,2,NatašaIhanHren3,4,MutluÖzcan5,Peter

Jevnikar1,2

1DepartmentofProsthodontics,FacultyofMedicine,UniversityofLjubljana,Slovenia

2DepartmentofProsthodontics,UniversityMedicalCentreLjubljana,Slovenia

3DepartmentofMaxillofacialandOralSurgery,FacultyofMedicine,UniversityofLjubljana,

Slovenia

4DepartmentofMaxillofacialandOralSurgery,UniversityMedicalCentreLjubljana,Slovenia

5UniversityofZürich,DentalMaterialsUnit,CenterforDentalandOralMedicine,Clinicfor

FixedandRemovableProsthodonticsandDentalMaterialsScience,Switzerland

Correspondenceto:

PeterJevnikar,DepartmentofProsthodontics,Hrvatskitrg6,1000Ljubljana,Slovenia.

Phone:015224242;E-mail:peter.jevnikar@mf.uni-lj.si

2

ABSTRACT

Introduction

Sloveniahasahighburdenofheadandneckcancer.Patientsaremostlytreatedwith

surgeryfollowedbyradiationtherapy.Advancedsurgicalandprosthodontictechniqueshave

expandedtherehabilitationoptions.Theaimofthestudywastoreviewtheoutcomeof

implant-prosthetictreatmentafterradiationtherapy.

Materialsandmethods:

20irradiatedheadandneckcancerpatientswhoreceivedaremovableimplant-supported

dentureattheUniversityMedicalCentreLjubljanawereincludedinthestudy.Kaplan-Meier

survivalanalysis,Coxproportionalhazardmodelsandlogisticregressionwereusedtoassess

theimplantsurvivalandsuccessrate.

Results:

20patientshad100implantsinserted.Theestimatedsurvivalratewas96%after1yearand

87%after5years.Failuresweremostlyobservedbeforeloading(91.2%).Implantsinserted

inthetransplantedboneweresignificantlymorelikelytofail.Outof89implantssupporting

thedentures,79implants(88.7%)weresuccessful,meaningthattheywerefunctionally

loadedandexhibitednopain,radiolucencyorprogressiveboneloss.Prosthetictreatment

wassignificanlylesssuccessfulinolderpatients.Theattachmentsystemandthenumberof

thedenturedidnothaveastatisticallysignificantinfluenceonthesuccessrate.

Conclusions:

Implant-supporteddenturesprovedtobeareliabletreatmentmodalityafterheadandneck

cancersurgeryandradiationtherapy.Possibleearlyfailuresshouldbecommunicatedwith

thepatients.

3

KEYWORDS

headandneckcancer,radiationtherapy,dentalimplants,implant-supporteddentures

4

Izidimplantatno-protetičnerehabilitacijepoobsevanjuzaradirakaglaveinvratu

POVZETEK

Uvod:

VSlovenijijevisokapojavnostrakaglaveinvratu.Zdravljenjenajpogostejevključuje

kombinacijokirurškeobravnaveinobsevanja.Možnostikasnejšeprotetičnerehabilitacijeso

izboljšaneobuporabisodobnihkirurškihtehnikinzobnihvsadkov.Namenprispevkaje

prikazatiizidimplantatno-protetičneoskrbeobsevanihpacientovnaUniverzitetnem

kliničnemcentruLjubljana.

Metodeinmateriali:

Vštudijismopreveriliizidzdravljenja20pacientovpokirurškioskrbiinobsevanjuzaradi

rakaglaveinvratu,kismojihoskrbelizimplantatnopodprtimiprotezami.Preživetjein

uspešnostzobnihvsadkovsmostatističnoovrednotilizmetodoKaplan-Meier,Coxovimi

modelisorazmernihtveganjinlogističnoregresijo.

Rezultati:

20pacientovjeskupnoprejelo100zobnihvsadkov.Ocenjenastopnjapreživetjavsadkovje

bila96%po1letuin87%po5letih.Doodpovedivsadkovjevečinomaprišlopred

obremenitvijo(91.2%).Vsadkivpresajenikostisoimelistatističnoznačilnoslabšepreživetje.

Izmed89obremenjenihvsadkovjihjebilo79(88.7%)uspešnih,karjepomenilo

funkcionalnouporaboprotezinodsotnostbolečinalinapredujočeizgubekostnine.Opazili

smostatističnoznačilnoslabšanjeuspehaznapredujočostarostjo,medtemkoizbor

protetičnegasidrainštevilovsadkovpodprotezoinnauspehrehabilitacijenistaimela

statističnoznačilnegavpliva.

Zaključki:

5

Implantatnopodprteprotezesozanesljivnačinprotetičneoskrbepoobsevanjuzaradiraka

glaveinvratu.Pacientejepotrebnoseznanitizmožnostjozgodnjeodpovedivsadkov.

6

INTRODUCTION

Sloveniaisamongthecountrieswiththehighestincidenceoforalandoropharyngealcancer

(deCamargoCancela,2010and2012).Inapopulatonof2millionpeople,approximately450

casesarediagnosedperyear(CancerinSlovenia2011,2015).Mosttumorsareregionally

advancedandthepatientsaretreatedwithradicalresectionandreconstructionfollowedby

radiationtreatment(CancerinSlovenia2011,2015).Afterwards,patientsexperience

profoundchangesintheoralanatomy,functionandfacialappearance.Radiationtreatment

causesirreversibledamagetobothhardandsofttissuesbycreatingahypoxic,hypocellular

andhypovascularenvironmentwhichimpedeswoundhealingandcreatesariskfor

osteoradionecrosis(Marx,1983).Aprotocolinvolvinghyperbaricoxygentreatment(HBO)

wasproposedasamethodtoenhancewoundhealingbyincreasingthetissueoxygenation

(Larsen,1997).

Followingtheradicalprocedurestoeradicatecancer,thegreatestproblemsperceivedby

irradiatedpatientsareswallowing,mouthopening,xerostomiaandcompromisedaeshetics

(Fierz,2013).Prosthodontictreatmentisadvocatedtoregainlostoralfunctions,enhance

thephysicalappearanceandenablethepatienttotakepartinnormaldailyactivitieswith

greaterconfidence.However,comprehensiveprosthetictreatmentafterheadandneck

cancerischallenging,time-consumingandcostly.Therefore,only40%ofsuchpatientsare

treatedfollowingthepostsurgicalprostheticprotocol.Amongthem,70%receivedentures

supportedbytheresidualteethandboneand30%receiveimplant-supporteddentures

(Brauner,2010).Edentulouspatientswithheadandneckcancerafterradiationtherapyare

anespeciallyvulnerablesubgroup.Radiationtreatmentsequelaepersistthroughoutthe

patient’slifetimeandinthepast,radiationtherapyusedtobeanabsolutecontraindication

7

toplacingofdentalimplants(Carini,2012).Treatmentoptionshavethereforebeenlimited

toconventionalcompletedenturesornoprostheticrehabilitationatall.

Advancedsurgicalsurgicalandprosthodontictechniques,suchas3Dplanningandguided

implantsurgery,haveexpandedthetreatmentoptions(Schiegnitz,2014).Inadditionto

conventionalball-andbar-retaineddentures,newattachmentshavebeenintroducedto

clinicalpractice.Locatorattachmentiscommonlyusedinremovableimplant

prosthodontics.Itisaself-aligningsystemwithrelativelysimplemaintenancerequirements

(Andreiotelli,2010).Locatoris,however,anon-rigidtypeofattachmentanddoesnot

completelyrelievethestressfromtheunderlyingmucosa.Toaddressthisissue,technically

moreadvancedsystemofprefabricateddoublecrownsonimplantshasbeenintroduced

(May,2002).TheSynConesystem(Dentsply,Germany)isindicatedinunfavourable

resectionareas,wherecompletelyrigidconstructionsarenecessaryduetotheanatomical

constraints.BothLocatorandSynconesystemsarecommonlyusedattheUniversityMedical

CentreLjubljana,Slovenia.Theseattachmentsystemshaveexpandedthetreatment

possibilitiesfortherehabilitationofheadandneckcancerpatients,whichisalwaysa

collaborativeworkbetweenoralsurgeonsandprosthodontists.

Theaimofthestudywastoreviewtheoutcomeoftheimplant-prostheticrehabilitationof

irradiatedpatientsperformedattheUniversityMedicalCentreLjubljana.

8

MATERIALSANDMETHODS

Aretrospectivechartreviewwasperformedforthepatientswhoweretreatedjointlybythe

DepartmentoforalandmaxillofacialsurgeryandtheDepartmentofprosthodonticsatthe

UniversityMedicalCentreLjubljanainthetimeperiodfrom2008to2014.Onlypatientswho

underwentresectionofmalignanttumourswithasubsequentradiationtreatmentand

receivedremovableimplant-supporteddentureswereincludedinthestudy.Therecorded

dataincludedpatientgenderanddateofbirth,smokingstatusatthetimeofprosthetic

rehabilitation,cancertype,surgicalmanagement,dateanddoseofradiationtreatment,

administrationofhyperbaricoxygentreatment(HBO),timingtoimplantsurgeryandto

functionalloading,treatedjaw,typeofimplantbed,numberofimplantssupportingthe

dentures,implantsystemandthedentureattachmentsystemused.AtUniversityMedical

CentreLjubljana,HBOisprovidedaccordingtotheprotocolsuggestedbyMarxandLarsen

(Marx1983,Larsen1997).Patientsarescheduledfor20sessionsbeforeand10sessions

aftertheimplantinsertion,respectively.Each90-minutesessionconsistsofexposureto

100%oxygenon2.5ATA(1.5bar)withthreebreaksduringwhichpatientsbreathenormal

air.

Theimplantswereassessedforsurvivalandsuccessusingtheguidelinesproposedbyvan

Steenbergheetal(1997).Thesurvivalcriteriaincludedosseointegrationandpresenceinthe

mouth.Tobeconsideredsuccessful,theimplanthadtobefunctionallyloaded,immobile,

withoutpersistentpainorinflammationoftheperiimplanttissueandwithoutprogressive

bonelossevidentfromradiographsandprobingdepthatyearlyrecall.

Thesurvivaltimewasmeasuredfromthedateoftheimplantinsertiontothedateofthe

implantfailureorthelastcontroloftheimplant.

9

Thepresentseriesconsistedof20patients(11menand9women)withamedianageof57.6

years(range46.7to77.2years)atthetimeoftheimplantinsertion.17patients(85%)hada

historyofsquamouscellcarcinoma.Mucoepidermoid,adenoidcysticandorigoignota

metastaticcancerwerediagnosedin1patienteach.Themostcommonsitesofprimary

cancerwerethetongueandthefloorofthemouth(6patientseach),followedbypharynx

andmaxilla(2patientseach).Mandible,tonsilla,larynxandorigoignotametastasesin

lymphnodeswereencounteredinonepatienteach.Asegmentalresectionofthemandible

wasperformedin8patients.Inonepatient,thetumorresectioninthemaxillaresultedinan

oronasalcommunication.Aftersurgery,allpatientsweresubjectedtotheradiationtherapy,

withreporteddosesrangingfrom54to66Gy.

Reconstructionwithboneandsofttissuegraftswasaccomplishedin3patients.Intwocases

thefibulargraftwasusedtoreconstructthemandible.Inonepatientthemaxillawas

reconstructedwiththeiliaccrestbonegraft.

TheKaplan-Meiermethodwasutilizedtoestimatetheimplantsurvivalrate.Theassociation

betweenthesurvivalandthepotentialprognosticfactorswasanalyzedbyfittingunivariate

Coxproportionalhazardsmodels.Theassociationbetweenthepotentialprognosticfactors

andimplantsuccesswasanalyzedwithunivariatelogisticregressionmodels.TheHolm-

Bonferronimethodwasusedtoaccountformultiplecomparisonsandthelevelof

significancewassettoα=0.05.Statisticalanalyseswereconductedwiththestatistical

softwarepackageR[R].

10

RESULTS

AspresentedinTable1,100implantsof3differentimplantsystemswereincludedinthe

study:18AstraTechimplants(Dentsply,Mannheim,Germany),22Straumannimplants

(InstitutStraumannAG,Basel,Switzerland)and60Ankylosimplants(Dentsply,Mannheim,

Germany).28implantswereinsertedinthemaxillaand72inthemandible.92implants

wereinsertedinnativeboneand8intransplantedbone.Themediantimebetweentheend

oftheradiationtherapyandtheimplantsurgerywas3.8years(range1.1to38.1years).

ProphylacticantibiotictherapywasprescribedtoallpatientsandHBOwasadministeredto

16patients.Osteoradionecrosiswasnotobservedinthisstudy.Allimplantswereinsertedin

edentulousjaws,with5patientsreceivingimplantsinbothjaws,14onlyinthemandible

and1onlyinthemaxilla.12patientswerenon-smokersand8patientsweresmokersatthe

timeoftheprostheticrehabilitation.Atwo-stageimplantinsertionprotocolwasusedinall

cases.Themedianhealingperiodbetweentheimplantinsertionandfunctionalloadingwas

15.1months(range4.3to54.3months).AsshowninTable2,threedifferentattachment

systemsforimplant-supporteddentureswereused:39Locatorattachments(ZestAnchors,

Escondido,USA)(Figure1),40prefabricatedconicalcrowns(SynCone,DentsplyFriadent,

Mannheim,Germany)(Figure2),and10customdesignedbar-clipsystems.

Medianfollowupafterimplantinsertionwas61.9months(range1.4to90.2months).

TheKaplan-Meierestimated1-and5-yearcumulativeimplantsurvivalrateswere96%(95%

confidenceinterval:92.2%-99.9%)and87.0%(95%confidenceinterval:80.4-94.2%).The

survivalcurveisshownonFigure3.Duringtheexaminationperiod,threepatientsdied.Time

ofthese14implants'serviceinthemouthwas,aswithotherimplants,registeredfromthe

dateoftheimplantinsertiontothedateofthelastfollow-upexamination.

Themediantimeoffailurewas19.1months(range1.4to48.5months)afterimplantation.

11

Thecrudesurvivalrateinoursamplewas88%,as12implantsin5patientsfailed.Datafor

alltheimplantsandforthesubgroupsofsurvivedandfailedimplantsaredescribedinTable

1.Primaryimplantfailureduringthehealingperiodbeforefunctionalloadingwasrecorded

in11implants(91.2%).Thecausesofimplantremovalinoursamplewereincomplete

osseointegration(4),persistentpain(4),andperiimplantitiswithrecurrentsofttissue

hyperplasia(3).Theonlyimplantthatwaslostafterfunctionalloading(secondaryimplant

failure)wasincludedinabar-supporteddentureandhadtoberemovedbecauseof

periimplantitis.

ResultsoftheanalysiswiththeCoxregressionmodelsispresentedinTable2.Thesurvived

andfailedimplantswerecomparableconsideringthepatient’sgender,ageandsmoking

status,thetimeelapsedbetweentheradiationtherapyandtheimplantsurgery,thejawof

theimplantinsertionandtheadministrationofHBO.Theresultsforthebonetypeindicated

thattheimplantsinsertedinthetransplantedbonewerestatisticallysignificantlymorelikely

tofailthanthoseinsertedinthenativebone.Theinfluenceoftheimplantsystemonthe

survivalcouldnotbeanalyzedbecauseoftheinsufficientnumberoffailureeventsamong

thethreegroups.

AspresentedinTable3,89implantswereobservedafterfunctionalloading.79ofthose

implants(88.7%)weresuccessful,meaningthattheywerefunctionallyloadedandexhibited

nopain,radiolucencyorprogressivebonelossevidentfromradiographsandprobingdepth

atyearlyrecall.Regardlessoftheappropriateosseointegration,prostheticrehabilitationof

10implants(11.2%)infourpatients(20%)didnothaveafavourableoutcome.Twopatients

with4implantsexperienceddifficultiesinadaptingtodenturesanddidnotwearthemon

regularbasis.Inaddition,twofurtherimplantswereconsideredunsuccessfulbecauseof

persistentsofttissuediscomfortreportedbythepatients.AsshowninTable3,higher

12

patientagewasastatisticallysignificantpredictorforthelackofsuccess.Gender,smoking

status,healingtimeafterimplantinsertion,thenumberofimplantssupportingthedenture,

theprostheticsystem,jaw,bonetypeandadministeredHBOdidnothaveastatistically

significanteffectonthesuccessrateofloadedimplantsinthissampleofirradiatedpatients.

13

DISCUSSION

Ithasbeenshowninthisstudythattheimplant-supporteddentureisareliabletreatment

modalityfortheheadandneckcancerpatientsthatundergoradiationtherapy.When

specialsurgicalandprosthodonticprotocolsareconductedappropriately,dentalimplants

greatlyenhancethestabilityofthedenturesandimprovethefacialcontours.Accordingto

thecurrentguidelines,veryfewabsolutecontraindicationsexistforusingdentalimplantsin

medicallycompromisedpatients(Diz,2013).Radiationtherapyintheheadandneckregion

isnolongeracontraindication,asthereisagrowingnumberofreportsthatahigh

osseointegrationrateandapredictabletreatmentoutcomecanbeexpected(Ihde,2009,

Tanaka,2013).Whenconsideringtheprosthodonticrehabilitationoptions,thesocio-

economicstatusofthepatientsshouldbeevaluatedcarefully.Asheadandneckcanceris

connectedwithsmokingandalcoholoverconsumption,similarproblemscanpersistafter

theinitialcancertreatment,jeopardizingtheimplant-prostheticrehabilitationoutcome.

Inthiscaseseriesofirradiatedpatients,theimplantfailureswererareandmostlyconfined

tothehealingperiod.Thepredominantlyearlyimplantlossisinaccordancewiththe

findingsofLinsenetal(2012).Extendedhealingtimeshouldthereforebeallowedafter

implantationandimmediateloadingprotocolsarenotadvised(Diz,2013).

TheKaplan-Meierestimated1-and5-yearcumulativeimplantsurvivalrateswere96%and

87%.ThisisinaccordancewithBuddulaetal(2012)reportingimplantsurvivalratesof98.9%

and89.9%after1and5yearsandYeritetal(2006)reportinga95%and91%survivalafter2

and5years,respectively.Duetothesmallnumberoffailedimplants,detailedstatistical

analysisofprognosticfactorsforimplantfailureisoftennotpossibleorlackspower.Itis

thereforedifficulttodrawmeaningfulconclusionsfromtheresultsofsinglestudiesalone.In

thisstudy,somelimitedinsightcouldbeobtainedregardingthesurvivalofimplants.There

14

wasastatisticallysignificanthigherfailurerateinthetransplantedbone.Thereduced

survivalofimplantsinthetransplantedbonemaybeexplainedbydifferencesinbone

quality,bonevolume,andrevascularizationcomparedtothenativebone(Schiegnitz,2014).

OurfindingsareinagreementwithYeritetal(2006),wherelowersurvivalwasalsoreported

forthetransplantedbone.Incontrast,Buddulaetal(2012)reportednodifferencebetween

implantsurvivalinthenativeandtransplantedbone.Theyalsoreportednodifferencein

survivalbetweengendersandconsideringthetimespanbetweenradiationtreatmentand

implantinsertion,whichisinaccordancewiththisstudy.Theirfindingofthestatistically

significanthigherhazardratioforimplantsintheupperjawcouldnotbeconfirmedinthis

study.Whiletheriskforimplantfailureisknowntobeslightlygreaterinsmokingpatients

(DeLuca2006),thesmokingstatuswasnotadetectablepredictorfortheimplantsurvivalin

thisstudy.ThiswasalsotrueforHBO,whichiscommonlyusedattheUniversityMedical

CentreLjubljanafortheheadandneckcancerpatientsrequiringsurgery.Generally,thereis

noagreementontheHBOefficacyandvalue(Spiegelberg,2010).

Implantosseointegrationandsurvivaldataprovidevaluableinformationaboutthesuccess

oftheimplanttherapy.Nevertheless,thefinaljudgementoftheimplant-prosthetictherapy

shouldbemadeaccordingthothedentureperformanceintheoralcavity.Successful

implantsenablethepatientstousethedenturesanddonotcauseanypersistent

discomfort.Toachieveafavorableclinicaloutcome,itiscrucialtodesignaviableprosthetic

planearlyintherehabilitationprocess.Headandneckcancerpatientspresentseverely

alteredandunfavourabletissueconditions,makingitchallengingtomodelrehabilitation

usingtheoptimaltop-downapproach.Thefragilemucosa,xerostomia,limitedmouth

openingandjawdeviationsareadditionalfactorstoconsider.Thepossiblelocations,

15

angulationsandimplantdimensionsmightnotbeidealandshouldbediscussedthoroughly

betweentheoralsurgeonandtheprosthodontist.

Theoptimalnumberofimplantsshouldbecarefullydecided.Thereisatendencytoinsertas

fewimplantsaspossibleinoncologicalpatients,tofacilitatebonehealing.Ontheother

handagreaternumberisoftenrequiredtodesignrigid,implant-borneprosthetic

constructions(Diz,2013).Moreimplantsalsoallowmoreflexibilityinprosthetictreatment

planning.Moreover,ifsomeimplantsarelost,implantdenturescanbesuccessfullyrepaired

andwornbythepatients.Itiscurrentlythoughtthatthenumberofimplantsisnotcritical

forthesuccessoftheprosthetictreatment(Roccuzzo,2012),butlong-termclinicalstudies

arelacking.Inthepresentstudythenumberofimplantssupportingthedentureswasnota

detectablefactorinthesuccessrateoftheprosthodonticrehabilitation.Similarly,neither

wasthetreatedjaworthehealingtime,whichexceeded4monthsinallimplants.

Theloadedimplantsalsoexhibitedsimilarsuccessratesregardlessofthedenture

attachmentsystemused.Whilethebar-supportingimplantsexperiencedlesssuccess,the

differencesincomparisontotheLocatorattachmentsandSynConesystemswerenot

significant.

Additionalsystemicandpatient-relatedfactorsmightplayanimportantroleinimplant

prostheticrehabilitation.Inthiscaseseriesofirradiatedpatients,advancedageshoweda

negativeprognosticvaluefortherehabilitationsuccess,butnotforimplantsurvival.Oneof

thepossiblelimitationsofthisstudywasthatthedataonsystemicdiseasesandalcohol

consumptionwhichmightnegativelyaffectimplantperformancewerenotincluded.After

completionoftheimplant-prostheticrehabilitation,itisofutmostimportancetoenrolthe

patientinanappropriatesupportiveprogram,withregularrecalls,cancerscreeningand

maintenanceoftheperi-implantconditions.Therecallprogramshouldmeettheindividual

16

needsofthepatientsaccordingtotheoverallriskprofile.Somepatientsshouldberecalled

every3months,whileothersmayneedtobecheckedonceperyear(Lang2015).

Thisstudyhasshownthatfavorablerehabilitationresultscanbeobtainedwithimplant-

prosthetictreatmentinirradiatedpatients.Withpropercollaborationbetweenexperienced

surgeonsandprosthodontists,thistreatmentmodalitycanberegardedaviableoptionfor

oralrehabilitationafterheadandneckcancer.

17

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TABLES

Table1

Summaryoftheimplantsurvivalaccordingtothefactorsofinterest.

Parameter Allimplants

(n=100)

Survivedimplants

(n=88)

Failedimplants

(n=12)

Patient’smedianageat

implantinsertioninyears

(range)

58.3

(46.7-77.2)

61.5

(46.7-77.2)

57.9

(46.7-77.2)

Mediantimeinterval

betweenradiation

treatmentandimplant

insertioninyears

(range)

3.8

(1.1-38.1)

3.2

(1.1-38.1)

5.2

(2.4-12.8)

Patient’sgender

• Female,n(%)

• Male,n(%)

40(40%)

60(60%)

32(36%)

56(64%)

8(67%)

4(33%)

Smoking

• No,n(%)

• Yes,n(%)

66(66%)

34(34%)

57(65%)

31(35%)

9(75%)

3(25%)

Implantsystem

• Astra,n(%)

• Straumann,n(%)

• Ankylos,n(%)

18(18%)

22(22%)

60(60%)

18(20%)

17(20%)

53(60%)

0(0%)

5(42%)

7(58%)

Jaw

• Lower,n(%)

• Upper,n(%)

72(72%)

28(28%)

63(72%)

25(28%)

9(75%)

3(25%)

Bone

• Native,n(%)

• Transplanted,n(%)

92(92%)

8(8%)

85(97%)

3(3%)

7(58%)

5(42%)

HBOadministred

• No,n(%)

• Yes,n(%)

19(19%)

81(81%)

14(16%)

74(84%)

5(42%)

7(58%)

21

Table2

Predictorsoftheimplantfailure.

Parameter Hazardratio

(95%confidenceinterval)

p

Patient’sageatimplant

insertioninyears

1.05

(0.99-1.12)

1.0000

Timeintervalbetween

theradiationtreatment

andtheimplant

insertioninyears

0.99

(0.92-1.07)

1.0000

Femalegender 2.74

(0.82-9.10)

1.0000

Smoker 0.72

(0.19-2.66)

1.0000

Lowerjaw 0.84

(0.23-3.09)

1.0000

Transplantedbone 12.37

(3.87-39.56)

0.0003

HBOadministered

0.31

(0.10-0.98)

0.4753

22

Table3

Summaryoftheloadedimplants’successaccordingtothefactorsofinterest.

Parameter Allloaded

implants

(n=89)

Successfulloaded

implants

(n=79)

Unsuccessful

loaded

implants

(n=10)

Medianpatient’sageat

prostheticrehabilitation

inyears

(range)

59.1

(49.3-79.2)

58.9

(49.3-67.9)

71.7

(59.1-79.2)

Medianhealingtime

aftertheimplant

insertioninmonths

(range)

15.1

(4.3-54.4)

15.2

(4.3-54.4)

13.0

(4.3-24.6)

Patient’sgender

• Female,n(%)

• Male,n(%)

33(37%)

56(63%)

25(32%)

54(68%)

8(80%)

2(20%)

Smoking

• No,n(%)

• Yes,n(%)

57(64%)

32(36%)

49(62%)

30(38%)

8(80%)

2(20%)

Mediannumberofthe

implantssupportingthe

denture

(range)

4(2-5)

4(2-5)

4

Implantdenturesystem

• Bar,n(%)

• Locator,n(%)

• SynCone,n(%)

10(11%)

39(44%)

40(45%)

6(8%)

37(47%)

36(45%)

4(40%)

2(20%)

4(40%)

Jaw

• Upper,n(%)

• Lower,n(%)

25(28%)

64(72%)

21(27%)

58(73%)

4(40%)

6(60%)

Bone

• Native,n(%)

• Transplanted,n

(%)

86(97%)

3(3%)

76(96%)

3(4%)

10(100%)

0(0%)

HBOadministred

• Yes

• No

75(84%)

14(16%)

65(82%)

14(18%)

10(100%)

0(0%)

23

Table4

Predictorsoftheloadedimplants’success.

Parameter Oddsratiofortheloadedimplants’success

(95%confidenceinterval)

p

Patient’sageatprosthetic

rehabilitation

0.66

(0.49-0.80)

0.0075

Healingtimeafterthe

implantinsertion

1.09

(0.53-2.73)

1.0000

Malegender 8.64

(1.99-60.09)

0.1456

Smoker 2.44

(0.57-16.95)

1.0000

Numberoftheimplants

supportingthedenture

0.78

(0.24-1.94)

1.0000

Dentureattachmentsystem

• Locatorvsbar

• SynConevsbar

• SynConevsLocator

12.33

(1.98-104.98)

6.00

(1.15-32.68)

0.48

(0.06-2.65)

0.1456

0.4416

1.0000

Upperjaw

0.54

(0.14-2.30)

1.0000

24

Figures

Figure1

Aclinicalsituationofapatientwiththesegmentalresectionoftheleftmandiblebodydueto

cancer,asvisibleontheradiograph(a).Thepatientreceivedanimplant-supportedlower

denture(b),wheretheretentionwasbasedontheLocatorconcept(c).

b

c

a

25

Figure2

Aclinicalsituationofapatientrehabilitatedafteroropharyngealcarcinoma.Segmental

resectionoftheleftmandiblebodyisvisibleontheradiograph(a).Thepatientreceived

implant-supportedlowerandupperdentureswithretentionbasedontheSynConedouble

crownconcept(b).

a

b

26

Figure3

TheKaplan-Meiercurveforthesurvivaloftheimplants.95%confidenceintervalsand

censoreddataareincludedontheplot.