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1、UnitThirtyTheSurgicalPrinciplesofOsseointegrationRagnarAdellOsseointegration;processanddefinition.Thepossibilityofpermanentlyretainingtitaniumfixtureinvitalremodelingbonewithacapacityofconsiderableloadbearingdependsonanadequatecomprehensionoftheosseointegrationprocess.ProfessorPcr-lngvarBranemarkcoi
2、nedOsscointigrationasatermintheearly1970s.Itscurrentdefinition-adirectcontactbetweenliving,haversianboneandtheloadedimplantsurface-isbasedonhistologicalandultrastructuralobservationsbutisnotyetfullydefined.However,itiswellsupportedbylong-termradiographicandclinicalstudiesdemonstratingpcrifixturalbon
3、eadaptionandremodelingaswellaslong-termfixturestabilityandload-bearingcapacity.Thereisnoinstantosseointegration.Itsgradualandslowdevelopmentmustbefullyunderstoodinorderforasuccessfulclinicaloulcomelobeachieved.AchievingosseointegationThemereuseoftitaniumasanimplantmaterialisbynomeansanyguaranteeofac
4、hievingosseointegration.Managingthehostorganismandtissuesshouldattractatleastasmuchinterestasthepropertiesandhandlingoftheimplant.PreoperativehostfactorsGeneralpatientconditionsNoinvestigationssofarhavebeenundertakensystematicallytoevaluatetheinfluenceofdiseases,medications,anddrugsthatmaytheoretica
5、llyaffectwoundhcaling-cspcciallybonehealingandremodeling-afterinstallationoftitaniumfixtures.Severalsuchpatientpreconditionscouldbeconsidered:1. Age2. Sex(duetopostmenopausalosteoporosis)3. Malabsorptionsyndromes(eg,ulcerativecolitis)Bonemetabolicdiseases(eg,osteoporosis,osteomalacia,gyperparathyroi
6、dism,Pagetsdisease)4. Rheumaticdiseases(eg,rheumatoidarthritis,Sjogrenssyndrome,systemiclupuserythematosus)5. Hormonaldiseases(eg,diabetes,Cushingssyndrome,gyperparathyroidisrn)6. Coagulationdisordersandanticoagulationmedications7. Systemictreatmentwithglucocorticoidcs8. Alcoholabuse9. Tobaccosmokin
7、gStudieshaveinitiallyindicatedthatahigherchronologicalpatientagealoneisnotadeterminingfactorfortheoutcomeoftreatmentwithfixtures,whereastobaccosmokingmaybe.Sofar,thereisinsufficientevidencetosupporttheinstallationoffixturesingrowingjaws.Experimentalstudiesandafewclinicaltrialsindicatethatthefixtures
8、maynotmovewithLosingmseointegrationAclinicallymobilefixture,beitduetoaneverestablishedoseointegrationorlatertototallylostosseointegration,hasneverbeenobservedtobecomestable/osseointegratedagain.Theonlyconditionthatmaymimictruemobilitywithafibroussleevearoundthefixtureiswhenthesupportingboneismostlyc
9、ancellousandnotyetsufficientlyremodeled.Aminuteelasticitymaythenbeexperiencedandpossiblymisinterpreted.Fixturessupportedinthismannerareofcourseatgreatriskandcould,moreover,transmitpressuretoadjacentnerves.AfewcasesofunpleasantsensationsfollowingloadingofsuchfixtureshavebeenaUributedtothesecircumstan
10、ces.Apartiallossofosseointegration(ie,lossofmarginalbonesupport)isdifficulttohandleifitalsoentailsexposureofthreadstowardmobileoralmucosa.Grindingorfillingthethreadsisoflimitedornovalue.Thereisalwaysdifficultyinkeeping(hedepthofthethreadclosesttothebonemarginfreefrombacterialplaque.Infact,thissituat
11、ionmaybetheonlyonethatcouldultimatelyrequireremovalofastablefixturebymeansofatrephinebur.Guidedtissueregenerationhasnotbeentestedforthisindicationandmaynotworkwellwhenthetitaniumsurfacehasalreadybeencontaminated.Thesameappliescorecoveringthefixturewithafreshperiostealflapwithorwithoutaninterposedbon
12、egraft.TherecommendationsbyLckhomctalonhowtomanagemobilefixturesandotherclinicalsurgicalcomplicationsstillholdtrue.MaintainingosseointegrationTwofactorsinfluencingthefixture-supportingbonemustbecontrolledfbr(helifespanofthefixture,namely,loadingandtheperiabutmentconditions.LoadingAsemphasizedearlier
13、inthischapter,theperifixturalboneadaptstotheloadapplied.Itsfullstrengthisseldomreacheduntilafterayearofadequateload.Overloadingevenafterseveralyears(eg,bybruxism,changeoftheopposingbitetoporcelaincrowns,orbyachangeofextensionorfitofthesuprastructurc)couldcauseperifixturalmicrofracturcs,whichthenmayh
14、ealwithnon-mineralizedconnectivescartissue.Asaresult,thefixtureswillbecomemobile.Ontheotherhand,ifadequatelyloaded,fixturesmaycontributetothepreservationofmandibularboneheight.PeriabutmentandperifixturalconditionsAnyinflammationintheperiabutmentsofttissuescausedbytraumaand/ormicrobiologicalagentscou
15、ldcausemarginalboneresorptionandshouldconsequentlybeavoided.Whenthemarginaloralsofttissuearchealthy,thereisonlyminutemarginalboneresorptionofapproximately1mmthroughthefirstyear,andthenonly0.1mmannuallyforthefollowingyears.Individualvariationscould,however,beconsiderableandtheirreasonsarenotwellknown
16、.Thepreoperativehostfactorcouldinfluencethemarginalbonesupportandwellasthepostoperativeconditions.Forexample,whetherbasaljawboneforfixturesupporthasagreaterresistancetolossofmarginalboneheightthanthealveolarprocessproperhasnotbeeninvestigated.SummaryWhendueattentionispaidtotheindividualprcopcrativchostconditions,whentreatmentiscarriedoutwithprecisionaccordinglorecommendedguidelines,andwhentheabovefactorsformaintenancearecontrol
