Several investigations have been carried out on the impact of these factors on the accuracy of impressions. There are some factors that could affect the accuracy of implant impressions, such as impression technique, splinting the impression coping, surface treatment of impression copings, the depth and angulation of implants, and the connection type and length. Making precise implant master cast necessitates precise materials and techniques for impression making and pouring. Any inaccuracy in this process will result in increased stress to the implants and their superstructures and subsequent biological and biomechanical complication will arise. Recording and transferring the 3-dimensional position of dental implants through impression taking is the first prosthetic step in achieving the passive fitness. The significance of passive framework fit to the long-term success of dental implants is a well-recognized principle. The accuracy of the closed tray coping was greater than the low retentive coping and equal to the high retentive coping. The design of the impression copings was more important than the undercuts. There was significant difference between the different designs of the impression copings ( F = 31.789, P < 0.001) but the interaction between the dependent variables was not significant ( F = 0.511, P = 0.603). There was no significant difference between the complete and partially edentulous groups ( F = 3.252, P = 0.079). Then, they were compared to the scan of the reference model, and the calculated mean errors were analyzed with a 2-way ANOVA and Tukey test. Two scan-bodies were secured on each cast, scanned by an optical scanner. Three different impression techniques were performed (open high retentive, open low retentive, closed ) for each condition. The teeth were eliminated to create an edentulous condition. The posterior teeth were inserted as tilted to simulate intra-oral undercuts. Materials and Methods:Ī reference model with 2 implants inserted in bilateral mandibular canines was fabricated. Closed tray impression coping whole formed by CT impression coping + hexagonal abutment + screw.The aim of this in vitro study was to evaluate the effect of the type and design of the impression copings on the accuracy of implant impressions in 2 different conditions.Closed tray impression coping machined in technical plastic.Long impression screw with longitudinal millings for manual tightening.Anti-rotation millings and vertical retention neck for a good fixation.
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