implanthistoryanddevelopment口腔种植.pptx

History and Development of Dental implantlPrevious non-integrating forms of implants may have been anchored to bone by means of a surrounding sheath of pseudoperiodontal ligament,but this fibrous sheath was a poorly differentiated layer of scar tissue.l In most cases,loading and gradual widening of this led to loosening of the implant and subsequent implant failure.ImplantslImplants consist of three main parts.lThe three components include Implant,abutment and superstructure.Implants lMost contemporary dental implants are made of commercially pure titanium,which has been shown to have excellent biocompatibility.lTitanium is a light metal.ImplantslWhen exposed to air,a surface oxide is rapidly formed.lThis layer of oxide determines the biological response.l Commercially pure titanium is also highly resistant to corrosion.ImplantslOther metals have been used for osseointegration,including zirconium,gold and titanium-aluminium-vanadium alloys.lThese alloys may strengthen the implant but have been shown to have relatively poor bone-to-implant contact.ImplantslImplant design has a great influence on the stability and subsequent function of the implant in bone.lThe main parameters are implant shape,implant length,implant diameter and surface characteristics.ImplantslRoot-form implants,such as screws and cylinders,are the dominating implant designs todays.lScrew implants are considered to be superior to cylindrical ones in terms of initial stability and resistance to compression and tension stresses under loading.AbutmentlA dental abutment is typically a machined or custom-made component that connects the final prosthesis to the implant.The abutment may be made from a variety of materials.AbutmentlA machined abutment is typically manufactured from titanium,gold or ceramic.lThe advantages are that it is simple to use,requires minimal chairside and laboratory time and has a predictable precision fit and good retention.AbutmentlA customised abutment may be prepable,custom-made in the laboratory or computer-aided design-computer-aided manufacture(CAD-CAM)designed.l A prepable abutment is generally supplied by the manufacture as a blank in titanium or ceramic to be modified by the clinician at the chairside or by the dental technician on the master model.AbutmentlCustomisation in the laboratory typically involves waxing to the required design and casting.lA CAD-CAM-designed abutment is produced with specialised computer software and a milling machine.AbutmentlThe selection and use of an abutment is determined by a number of factors,including implant angulation and orientation,depth of soft tissue from implant body to gingival cuff,aesthetic demands,interocclusal space and preference for a cement or screw-retained prosthesis.SuperstructurelA final prosthesis lIt may be connected to the implant lThere are several ways to connect the final prosthesis to the implant:screw retained direct to the implant;Screw retained to the abutment;Lateral/horizontal screw retained to abutment;Cement retained to abutment