Dental implants cement retention vs screw retention

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  1. 1. Dental Implants Cement retention vs screw retention John Beumer III DDS, MS Robert Faulkner DDS, MS Division of Advanced Prosthodontics, UCLA Thisprogramofinstruc1onisprotectedbycopyright.Nopor1onofthis programofinstruc1onmaybereproduced,recordedortransferredbyany meanselectronic,digital,photographic,mechanicaletc.,orbyanyinforma1on storageorretrievalsystem,withoutpriorpermission.
  2. 2. Cementvsscrewreten1on Whichmethodispreferredto retainimplantprostheses? Bothmethodscanbeemployedifusedproperly.
  3. 3. Cementretainedprostheses Advantages Simplicity Familiarity Idealizeocclusalcontacts Occlusalcontactsarenoteected bythescrewaccesschannel Esthe1cs Porcelainocclusalsurfacescanbe developed Reducesriskofporcelain chippingandfractures associatedwiththescrew accesschannel Cementretainedprosthesis Screwretainedprosthesis
  4. 4. Cementretainedprostheses Disadvantagesandconcerns Requiresprecisemarginplacement Requiresame1culoustechnique Thevolumeofcementusedmustbecarefullycontrolled CementsbecomesaOachedtothemachinedsurfaceofabutmentofthe micro-roughsurfaceoftheimplantdiculttoremove Prosthesisisnoteasilyretrieved Recurrentlossofreten1onwhenreten1onandresistanceformof theabutmentissubop1mal Residualcementmaybeimpactedsubgingivallysecondaryto incompletesea1ngofthecrownorextrusionofcementsubgingivally predisposingto: Peri-implantmucosi1s Peri-implan11s
  5. 5. MajorProblem Sub-gingivalreten1onofcement Twoissues: Impac1onofcement subgingivallyduring cementa1on Incompletesea1ng ofthecrown Thesetwophenomenonpredisposetoperi-implan**sAn inammatoryprocessaec1ngthe1ssuesaroundanosseointegrated implantinfunc1on,accompaniedbyboneloss. CourtesyDr.C.Goodacre
  6. 6. MajorProblem Sub-gingivalreten1onofcement Twoissues: Impac1onofcement subgingivallyduring cementa1on Incompletesea1ng ofthecrown Itmaytakeseveralyearsbeforetheexcesscement becomesapparent (Thomas,2009) CourtesyDr.C.Goodacre
  7. 7. MajorProblemRetainedcement Ifthemarginissub-gingival,therewillberesidualcement100%ofthe1me(Linkevicius etal,2013). Peri-implan11smayensue,leadingtolossofimplantsando`entheadjacentteeth (Wilson,2009;Wadhani,etal,2011). 80%ofcasesofperi-implan11saresecondarytosub-gingivalcementaccumula1ons (Wilson,2009)
  8. 8. Courtesy of Dr. C. Wadhwani Thesepa1entspresentedwithperi-implan11s Theimplantsares1llanchoredinbonebuttheirprognosisispoor Notecementadherenttothesurfacesoftheimplants Themethodsfordecontamina1onoftheimplantsurfacesand gra`ingthesesitehavebeenproblema1c MajorProblemRetainedcement Courtesy of Dr. G. Perri
  9. 9. Ifthecementmarginissubgingivalitisnotpossibleto removeallthecement(Linkeviciusetal,2013) Casereport Prepableabutment Animpressionwasobtainedwithanimpressioncopingandthe prepableabutmentwasaOachedtothextureanalogueimbeddedin themastercast. CourtesyDr.S.Parvispour
  10. 10. Subgingivalcementaccumula1on Prepableabutment Theabutmentwaspreparedsothatthemarginisslightlysubgingival. Themetalceramiccrownwascompletedinacustomaryfashion. Theabutmentwassecuredtotheimplantxtureandthecrownisthencemented. CourtesyDr.S.Parvispour Casereport
  11. 11. Subgingivalcementaccumula1on Prepableabutment vThepa1entwasunhappywiththeesthe1cresultandsoaholewasdrilledinto theocclusalsurfaceinordertoaccesstheabutmentscrew.Thecrownand abutmentwasthenremoved vNotetheaccumula1onofcementsubgingivally. CourtesyDr.S.Parvispour Casereport
  12. 12. Sub-gingivalcementaccumula1on ImplantSurface Bone EpitheliumSulcus Circumferen1al collagenbers Peri-implant1ssuesaremoreeasily displacedfromthesurfaceofthe implantbecauseoftheabsenceofa connec1vebersaOachedtothe implant. AsaresulttheepithelialaOachmentis easilyseveredandcementcanbe impactedtotheleveloftheboneand ontothesurfaceoftheimplant. Whyistherea greaterriskof cement accumula1onin thesulcusof implantcrowns?
  13. 13. Challengesofcementa1on Removalofcementisextremelydicult,especiallywhenitis adherenttothemicro-roughsurfaceoftheimplant. Inthispa1entitledtothefailureoftheimplantand compromisedtheperiodontalsupportfortheadjacentteeth CourtesyC.Wadhani
  14. 14. Challengesofcementa1on TPS (titanium plasma spMachined Machined c.p. Ti Acidetchedmicro-roughimplantsurface Machinedsurfaceofabutment Whencementbecomesadherenttoeitherthesurfaceofamachined ormilledabutmentorthemicro-roughsurfaceoftheimplant,itis verydicultandsome1mesimpossibleremove. Anodizedimplantsurface
  15. 15. Ifyouinsistuponcementa1on Controlthevolumeofcement Avoidtheuseofprefabricatedabutments Usecustomizedabutmentswithsupra-gingival marginsintheposteriorquadrants,especiallywhen therearesignicantundercutsandconcavi1es associatedwiththeabutment Idealizereten1onandresistanceform Avoidtheuseofprefabricatedabutments Cementretainedprostheses
  16. 16. Preparingcustom abutmentsforcementa1on Thepor1onengaging thecrownshouldnot bepolished.Itcanbe roughenedorprepared withgrooves. Thepor1onadjacent tothegingival1ssues shouldbehighly polished
  17. 17. Typesofcementsused v Polycarboxylatecementsshouldnot beusedbecausetheycontainuoride whichwillcorrodethe1tanium surfaceoftheimplantorabutment. v Resincements,containing hydroxylatedethymethacrylate, (HEMA)whichispotentcytotoxic agent,shouldbeavoided. v Zincoxideandeugenolcementsare favored.Theyarean1-bacterialand areradio-opaque. CourtesyDr.C.Goodacre
  18. 18. Typesofcementsrecommended Zincoxideandeugenolcementsarefavored Theypossessan1bacterialproper1es Theyareradio-opaque(However,excesscement onthebuccalandlabialsurfacesmaynotbeseen) CourtesyDr.C.Goodacre
  19. 19. Cementa1onRecommenda1ons Useaprovisionalcement(ZOE)suchastemp-bond unlessthereten1oniscompromisedbyashort abutment,averytaperedabutment,orthescrewaccess holeeliminatesreten1vesurface(s)
  20. 20. Cementa1onRecommenda1ons Whenreten1oniscompromisedbyimplant angula1onandtheposi1onoftheabutmentscrew orice,usezincphosphatecement CourtesyofDr.C.Goodacre
  21. 21. Cementa1onRecommenda1ons Thisimplantcrownlooseneda`er2 monthswhencementedwithZOE. CourtesyofDr.C.Goodacre
  22. 22. Poorreten1onandresistanceform secondarytoexcessivelabialinclina1on Whenreten1oniscompromised bytheangula1onofthe abutmentscrewchannel, anotherop1onistoretainthe crownwithalingualcross pinningscrew.
  23. 23. Problem-Insucientinterocclusalspacetodesignan abutmentwithappropriateresistanceandreten1onform. Recurrentlossofreten1onisseenmosto`enwhenlackofinterocclusal spacepreventsdevelopmentofcustomabutmentswithsucientaxial walllengthstoretainthecrown. Anotheradvantagewithscrewreten1on-theemergenceproleofthe crownisidealized CourtesyG.Perri Screwreten1onfavoredwhen thereisLackofinterocclusalspace
  24. 24. Thiscustomabutmenthasanexcessivetaper. Cementa1onRecommenda1ons Customabutmentsmustbedesignedwith appropriatereten1onandresistanceform
  25. 25. Theaddi1onofgrooveswillimproveresistanceformand isrecommendedforsingletoothmolarrestora1ons. Cementa1onRecommenda1ons Customabutmentsmustbedesignedwith appropriatereten1onandresistanceform
  26. 26. Cementa1onprocedures Carefullycontrolthevolumeofcementused(Wadhwaniand Pineyro(2009) Theintagliosurfacesofthecrown/sislinedwithteontape Theimplantrestora1onisseatedrmlyontotheabutmentsand thenremoved Afastseingvinylpolysiloxanematerialisinjectedintotheintaglio surfacesofthecrown/s. Theexcessmaterialisusedasahandle.Whenthematerialhas polymerized,itisremovedfromthecrown/s.
  27. 27. Carefullycontrolthevolumeofcementused(Wadhwaniand Pineyro(2009) Theteontapeisremovedfromthecrown/s Asuitablecementispreparedandathinlayerisplacedinsidethecrown/s TheVPSabutmentanaloguesareseatedintoposi1onandtheexcess cementisremoved. Averythinlayerisaddedandthecrownisseatedintoposi1on Excesscementisremovedwithcurvedplas1cinstruments. Cementa1onprocedures
  28. 28. Challengesofcementa1on Plakormreduc1on(plakormswitching) Ifthecementbecomesimpactedbelowthemargin,its removalisproblema1c Accessisextremelydicultifnotimpossiblewithoutlayinga so`1ssueap CourtesyDr.G.Perri
  29. 29. Challengesofcementa1on Howwillyouremovethecementifit becomesimpactedbeneaththemarginsof thisimplantcrown? Morethanlikely,youwillnot,giventhe severityoftheundercutassociatedwiththe customabutment. Therefore,underthesecircumstancesitis advisabletoplacethemarginssupra-gingival.
  30. 30. Cementretainedprostheses Posteriorquadrants Itisadvisablethatmarginsof customabutmentsbedesignedto beslightlysupra-gingivalinorder tofacilitateremovalthecement
  31. 31. Cementretainedprostheses Ven1ngisnoteec1ve Ven1ngmakesiteasiertoseatthecrowns,especially amul1-unitimplantbornprosthesis,butdoesnot preventimpac1onofcementsub-gingivally.
  32. 32. Cementretainedprostheses Packingretrac1oncordisineec1vein preven1ngsubgingivalcementaccumula1ons ThereisriskofdetachingtheepithelialaOachmentwhenpacking thecord Sub-gingivalcementaccumula1onisnotpreventedbypacking gingivalretrac1oncordpriortocementa1on Cementhasbeenshowntoextrudeapicaltotheretrac1oncord (Wadhwanietal,2011).
  33. 33. Avoidtheuseof preformednon-prepableabutments Issuesofconcern vPosi1onofthecementmarginin rela1ontothegingivalmargin vPar1cularlysignicantintheanterior region vImpac1onofcementintothe gingivalsulcusishighlylikely vDicultyinsea1ngthecrown becauseofhydraulicpressure
  34. 34. Preformedabutmentsare problema1c vThemarginbetweenthecrownandtheabutmentdoes notfollowthegingivalmargin. vThereissignicantriskoftrappingcementbeneaththe gingival1ssuesuponcementa1onintheproximalareas. CourtesyDr.A.Pozzi
  35. 35. Preformednonprepableabutments This implant crown was retained by a prefabricated abutment. Note the inflammation associated with the peri-implant gingiva 2 1/2 years post insertion. Radiograph revealed significant bone loss. DxPeri-implan11s
  36. 36. Preformed nonpreparableabutments Thispa1entpresentedwithperi-implantmuc