Straumann impression coping8/18/2023 ![]() įor the purpose of standardization of implant insertion and positioning in all the three-testing model, surgical guides were designed using CAM software and produced through 3D printing (Formlabs Form 2 U.S). These wax models were dewaxed and processed using heat-cured acrylic resin (Lucitone-199 DENTSPLY) to form the three acrylic casts which were used as the test models. Then, silicon impressions were taken for this cast and poured in wax to form three wax modes. ![]() The test models were constructed using the following steps: stone cast simulated a partially edentulous maxillary Kennedy class III including bilaterally missed first premolar, second premolar, and first molar being obtained. Each simulated a partially edentulous maxillary Kennedy class III case. Three custom-made acrylic resin models (each model for an implant system) were made from heat-cure acrylic resin (Lucitone-199 DENTSPLY). This study aimed to evaluate the effect of various impression coping geometrical designs on accuracy, in parallel and nonparallel implants case scenarios, using open and closed implant impression techniques. This study’s clinical relevance is the identification and analysis of the influences of impression coping geometry on accuracy, which is vital in the long-term success of implant-supported prostheses. The present study hypothesizes that the highly retentive coping design for the open tray technique and the triangular cross-sectional design for the closed tray technique should produce more accurate impressions than the medium and low retentive designs and the rectangular and round cross-sectional designs in the simulated clinical scenario of parallel and nonparallel implants. Other studies confirmed that the shape and design of the impression coping affect impression accuracy more than the impression technique. In one study, the modified squared and index techniques generated more accurate casts than the squared techniques. It is postulated that the more retentive element of a square impression coping could lead to better entrapment of the impression material, resulting in less discrepancy. evaluated the accuracy of three impression coping designs and found that casts retrieved from transfer impressions with nonmodified copings and those with airborne-particle abraded adhesive-coated copings were statistically less accurate than casts from square impression copings splinted with autopolymerizing acrylic resin. However, Liou and colleagues showed that surface treatment of copings did not lead to increased accuracy. found improved precision of the impression when adhesive-coated copings were used. They may be modified by treatment with airborne-particle abrasion or impression adhesives. ![]() Several modifications have been proposed to enhance the retention of impression copings. Therefore, to produce an accurate impression, familiarity with coping designs and geometry is required. There are variations in implant impression coping shapes and designs, depending on the implant system and the components designed by the manufacturer of a particular system. Other influences include the direction of removal of the tray in relation to the implants’ axis, the number and parallelism of the implants, the degree of undercuts present, and the depth of implant position. The accuracy may be influenced by the impression material selected as well as the technique, coping design, shape, type of impression tray, implant numbers, implant angulations, and the operator’s skill. In implant prosthodontics, an accurate impression is critical in constructing a precise prosthesis. ![]()
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