implant-history-and-development-口腔种植VIP免费

HistoryandDevelopmentofDentalimplantPreviousnon-integratingformsofimplantsmayhavebeenanchoredtobonebymeansofasurroundingsheathofpseudoperiodontalligament,butthisfibroussheathwasapoorlydifferentiatedlayerofscartissue.Inmostcases,loadingandgradualwideningofthisledtolooseningoftheimplantandsubsequentimplantfailure.ImplantsImplantsconsistofthreemainparts.ThethreecomponentsincludeImplant,abutmentandsuperstructure.ImplantsMostcontemporarydentalimplantsaremadeofcommerciallypuretitanium,whichhasbeenshowntohaveexcellentbiocompatibility.Titaniumisalightmetal.ImplantsWhenexposedtoair,asurfaceoxideisrapidlyformed.Thislayerofoxidedeterminesthebiologicalresponse.Commerciallypuretitaniumisalsohighlyresistanttocorrosion.ImplantsOthermetalshavebeenusedforosseointegration,includingzirconium,goldandtitanium-aluminium-vanadiumalloys.Thesealloysmaystrengthentheimplantbuthavebeenshowntohaverelativelypoorbone-to-implantcontact.ImplantsImplantdesignhasagreatinfluenceonthestabilityandsubsequentfunctionoftheimplantinbone.Themainparametersareimplantshape,implantlength,implantdiameterandsurfacecharacteristics.ImplantsRoot-formimplants,suchasscrewsandcylinders,arethedominatingimplantdesignstodays.Screwimplantsareconsideredtobesuperiortocylindricalonesintermsofinitialstabilityandresistancetocompressionandtensionstressesunderloading.AbutmentAdentalabutmentistypicallyamachinedorcustom-madecomponentthatconnectsthefinalprosthesistotheimplant.Theabutmentmaybemadefromavarietyofmaterials.AbutmentAmachinedabutmentistypicallymanufacturedfromtitanium,goldorceramic.Theadvantagesarethatitissimpletouse,requiresminimalchairsideandlaboratorytimeandhasapredictableprecisionfitandgoodretention.AbutmentAcustomisedabutmentmaybeprepable,custom-madeinthelaboratoryorcomputer-aideddesign-computer-aidedmanufacture(CAD-CAM)designed.Aprepableabutmentisgenerallysuppliedbythemanufactureasablankintitaniumorceramictobemodifiedbytheclinicianatthechairsideorbythedentaltechnicianonthemastermodel.AbutmentCustomisationinthelaboratorytypicallyinvolveswaxingtotherequireddesignandcasting.ACAD-CAM-designedabutmentisproducedwithspecialisedcomputersoftwareandamillingmachine.AbutmentTheselectionanduseofanabutmentisdeterminedbyanumberoffactors,includingimplantangulationandorientation,depthofsofttissuefromimplantbodytogingivalcuff,aestheticdemands,interocclusalspaceandpreferenceforacementorscrew-retainedprosthesis.SuperstructureAfinalprosthesisItmaybeconnectedtotheimplantThereareseveralwaystoconnectthefinalprosthesistotheimplant:screwretaineddirecttotheimplant;Screwretainedtotheabutment;Lateral/horizontalscrewretainedtoabutment;Cementretainedtoabutment