UnitThirtyTheSurgicalPrinciplesofOsseointegrationRagnarAdellOsseointegration;processanddefinition.Thepossibilityofpermanentlyretainingtitaniumfixtureinvitalremodelingbonewithacapacityofconsiderableloadbearingdependsonanadequatecomprehensionoftheosseointegrationprocess.ProfessorPcr-lngvarBranemarkcoinedOsscointigrationasatermintheearly1970s.Itscurrentdefinition-adirectcontactbetweenliving,haversianboneandtheloadedimplantsurface-isbasedonhistologicalandultrastructuralobservationsbutisnotyetfullydefined.However,itiswellsupportedbylong-termradiographicandclinicalstudiesdemonstratingpcrifixturalboneadaptionandremodelingaswellaslong-termfixturestabilityandload-bearingcapacity.Thereisnoinstantosseointegration.Itsgradualandslowdevelopmentmustbefullyunderstoodinorderforasuccessfulclinicaloulcomelobeachieved.AchievingosseointegationThemereuseoftitaniumasanimplantmaterialisbynomeansanyguaranteeofachievingosseointegration.Managingthehostorganismandtissuesshouldattractatleastasmuchinterestasthepropertiesandhandlingoftheimplant.PreoperativehostfactorsGeneralpatientconditionsNoinvestigationssofarhavebeenundertakensystematicallytoevaluatetheinfluenceofdiseases,medications,anddrugsthatmaytheoreticallyaffectwoundhcaling-cspcciallybonehealingandremodeling-afterinstallationoftitaniumfixtures.Severalsuchpatientpreconditionscouldbeconsidered:1. Age2. Sex(duetopostmenopausalosteoporosis)3. Malabsorptionsyndromes(eg,ulcerativecolitis)Bonemetabolicdiseases(eg,osteoporosis,osteomalacia,gyperparathyroidism,Pagetsdisease)4. Rheumaticdiseases(eg,rheumatoidarthritis,Sjogrenssyndrome,systemiclupuserythematosus)5. Hormonaldiseases(eg,diabetes,Cushingssyndrome,gyperparathyroidisrn)6. Coagulationdisordersandanticoagulationmedications7. Systemictreatmentwithglucocorticoidcs8. Alcoholabuse9. TobaccosmokingStudieshaveinitiallyindicatedthatahigherchronologicalpatientagealoneisnotadeterminingfactorfortheoutcomeoftreatmentwithfixtures,whereastobaccosmokingmaybe.Sofar,thereisinsufficientevidencetosupporttheinstallationoffixturesingrowingjaws.ExperimentalstudiesandafewclinicaltrialsindicatethatthefixturesmaynotmovewithLosingmseointegrationAclinicallymobilefixture,beitduetoaneverestablishedoseointegrationorlatertototallylostosseointegration,hasneverbeenobservedtobecomestable/osseointegratedagain.Theonlyconditionthatmaymimictruemobilitywithafibroussleevearoundthefixtureiswhenthesupportingboneismostlycancellousandnotyetsufficientlyremodeled.Aminuteelasticitymaythenbeexperiencedandpossiblymisinterpreted.Fixturessupportedinthismannerareofcourseatgreatriskandcould,moreover,transmitpressuretoadjacentnerves.AfewcasesofunpleasantsensationsfollowingloadingofsuchfixtureshavebeenaUributedtothesecircumstances.Apartiallossofosseointegration(ie,lossofmarginalbonesupport)isdifficulttohandleifitalsoentailsexposureofthreadstowardmobileoralmucosa.Grindingorfillingthethreadsisoflimitedornovalue.Thereisalwaysdifficultyinkeeping(hedepthofthethreadclosesttothebonemarginfreefrombacterialplaque.Infact,thissituationmaybetheonlyonethatcouldultimatelyrequireremovalofastablefixturebymeansofatrephinebur.Guidedtissueregenerationhasnotbeentestedforthisindicationandmaynotworkwellwhenthetitaniumsurfacehasalreadybeencontaminated.Thesameappliescorecoveringthefixturewithafreshperiostealflapwithorwithoutaninterposedbonegraft.TherecommendationsbyLckhomctalonhowtomanagemobilefixturesandotherclinicalsurgicalcomplicationsstillholdtrue.MaintainingosseointegrationTwofactorsinfluencingthefixture-supportingbonemustbecontrolledfbr(helifespanofthefixture,namely,loadingandtheperiabutmentconditions.LoadingAsemphasizedearlierinthischapter,theperifixturalboneadaptstotheloadapplied.Itsfullstrengthisseldomreacheduntilafterayearofadequateload.Overloadingevenafterseveralyears(eg,bybruxism,changeoftheopposingbitetoporcelaincrowns,orbyachangeofextensionorfitofthesuprastructurc)couldcauseperifixturalmicrofracturcs,whichthenmayhealwithnon-mineralizedconnectivescartissue.Asaresult,thefixtureswillbecomemobile.Ontheotherhand,ifadequatelyloaded,fixturesmaycontributetothepreservationofmandibularboneheight.PeriabutmentandperifixturalconditionsAnyinflammationintheperiabutmentsofttissuescausedbytraumaand/ormicrobiologicalagentscouldcausemarginalboneresorptionandshouldconsequentlybeavoided.Whenthemarginaloralsofttissuearchealthy,thereisonlyminutemarginalboneresorptionofapproximately1mmthroughthefirstyear,andthenonly0.1mmannuallyforthefollowingyears.Individualvariationscould,however,beconsiderableandtheirreasonsarenotwellknown.Thepreoperativehostfactorcouldinfluencethemarginalbonesupportandwellasthepostoperativeconditions.Forexample,whetherbasaljawboneforfixturesupporthasagreaterresistancetolossofmarginalboneheightthanthealveolarprocessproperhasnotbeeninvestigated.SummaryWhendueattentionispaidtotheindividualprcopcrativchostconditions,whentreatmentiscarriedoutwithprecisionaccordinglorecommendedguidelines,andwhentheabovefactorsformaintenancearecontrol