BDS11121 Impression Techniques for Implants PDF

BDS11121 Impression techniques for implants Date : / / 20 ACCURATE IMPRESSION ACCURATE MASTER CAST ACCURATE FIT OF SUPERSTRUCTUR An impression is necessary to transfer the POSITION and DESIGN of the implant or abutment to the master cast for prosthesis fabrication “TRANSFER COPING” master cast wi...

BDS11121 Impression techniques for implants Date : / / 20 ACCURATE IMPRESSION ACCURATE MASTER CAST ACCURATE FIT OF SUPERSTRUCTUR An impression is necessary to transfer the POSITION and DESIGN of the implant or abutment to the master cast for prosthesis fabrication “TRANSFER COPING” master cast with an implant/abutment replica “ANALOG” Transfer Coping Analog The component used to Something that is transfer information on analogous or similar to position and design of something else the implant or abutment Named after the portion it to the master cast represents in the master It is named after the cast portion it transfers to the Implant analog master cast Abutment analog Implant transfer coping Abutment transfer coping Impression Techniques Implant-level impression Abutment-level impression Digital impression IMPLANT LEVEL IMPRESSIONS Implant-level impressions Used to transfer: Position of the implant Depth of the implant Angulation of the implant Hex position Soft tissue contour Transfer coping screwed to the implant Placement of implant analog in the master cast Types of Implant-level Impressions Closed-tray Techniques Open-tray 1. Closed Tray (Indirect Technique) Transfer coping is screwed on to the implant and remains in the patient mouth after removal of the impression Transfer Coping Transfer coping is connected to the implant analog and reinserted in the impression Transfer coping Implant analog Components and materials needed: Closed tray Elastic impression material Transfer coping Parallel-sided or slightly tapered Flat sides Few undercuts 2. Open Tray (direct technique) Un-splinted Splinted 2. Open tray: un-splinted Technique Transfer copings are picked up during impression removal Reduced error as coping remains within impression until master cast is poured Access holes must be visible Components and materials needed: Open tray Stiff impression material Transfers are picked up with the impression Transfer coping/pins: Long Retentive undercuts Long screw Implant analog Open tray: Splinted technique Open tray: Splinted technique Implant-level impression: No abutment is placed Requires x-ray to confirm seating of transfer Abutments: Fabrication of custom abutment (eg.using UCLA abutment) Extra-oral abutment selection (in the lab) Advantages Reduces the effect of the implant angulation Reduces the deformation of the impression material. Removes the concern for replacing the coping back into its respective space in the impression. Limitations? ABUTMENT LEVEL IMPRESSIONS Abutment Level Impressions Conventional Transfer (pick-up) Conventional (Direct Impression ) Technique Transfer (pick-up) Technique Abutment transfer coping Abutment analog Transfer Technique Snap on impression cap  Transfer cap is picked up with the impression and used for positioning of the implant analog. Ball abutment analogue. Locator attachment analogue. Abutment analogues Trans mucosal abutment analogue. Straight contoured abutment analogue.  Implant overdentures Indications for abutment-level impression: abutments for screw-retention (transmucosal abutments ) abutments for cement-retained restorations – only if untouched severe implant angulations one-piece implants overdentures DIGITAL IMPRESSIONS Digital Impressions Digital impressions: 1.Intra oral scan: using intraoral scanner Scan body (no powder) Abutment (powder) 2.Lab scan (scanning of the cast): Impression with analogues  cast lab scan with ti base, abutment, or scan body conventional direct impression of prepared abutment  cast Intra-oral scan Laboratory scan Scan Bodies The scan bodies fit precisely into the dental implant fixture in the mouth to allow for accurate capture of the associated teeth and mucosa in reference to the position of the implant fixture, just as a traditional implant impression coping does. Scan bodies Scanned intraorally after being secured in place Virtual model of the scan body and surrounding structures is created and used for CADing the abutment and final restoration Scanning the abutment: Intra-oral scan Laboratory scan To Summarize There are several impression techniques that could be used in implant prosthodontics. The choice of the implant technique, components and materials depends on the number and location of the implants as well as the type of prosthetic superstructure. Impressions can either be implant level (open tray or closed tray) or abutment level (conventional or pick-up) Digital impressions can also be used for implant restorations. Reading material Students are advised to read details at: Fundamentals of implant dentistry, prosthetic principles, John Beumer III, Robert F. Faulkner, Kumar C. Shah, Peter K. Moy. ( sections II and III) Dental implant prosthetics, Carl E. Misch, chapter 2