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The purpose of this study was to determine the accuracy of 3 implant impression methods by using strain gauge. The models used for this study were partially edentulous mandibular acrylic resin casts Model A, with two abutment analogs in #46,47 extraction site, represented two implant parallel to to the adjacent natural tooth. Model B represent an anterior implant parallel to the adjacene natural tooth and a posterior implant exhibiting a 15-degree lingual inclination. Master framework were fabricated on the master model, and 3 strain gauges were attached to a master framwork to determine the passivity of fit of the framework to sample casts made by the three impression techniques. The master framework was attached to each sample cast with gold screws,which were tightened with the torque driver to ensure a consistent toque application of 10 N㎝. Universal Digital Measuring System UCAM-5BT was used for strain measuring. Impression techniques studid were : 1. unsplinted tapered impression coping, polyvinyl siloxane, stock tray 2. unsplinted squared impression coping, polyether, custom tray 3. squared impression coping splinted with Duralay resin, polyether, custom tray. Through analysis on data from this study, the following conclusions were obtained. 1. There were no statistically significant differences between the mean strain recorded from the sample casts made with the tree impression. But only strain values of model A (parallel group) Y-axis was signifcantly differed between Technique 1 and 3 (P>0.05). 2. There was no statistically significant difference between model A (parallel group) and model B(15-degree divergent group).
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