Comparative evaluation of dimensional accuracy of casts generated from multiple mix impression technique, matrix impression system and dual arch impression technique – An in vitro study

For a successful fixed partial prosthodontics, obtaining an accurate impression for making an accurate cast is of prime importance.In the present study the three fixed prosthodontic impression procedures, multiple mix impression technique, matrix impression system and dual arch impression technique; have been compared in terms of dimensional accuracy. An articulated acrylic resin typodont prepared with reference points was used as a master model. Addition silicon impression materials in various consistencies were used for making impressions. The coordinate measurement machine (Lloyd, Germany) was used for three dimensional measurement of master model and stone casts with an accuracy of 0.0001 mm.As per statistical analysis, all the impressions had a tendency to be oversized in horizontal dimensions and undersized in vertical dimensions. Dual arch impression technique used with flexible disposable plastic tray has found to be less dimensionally accurate as compared to multiple mix impression technique and matrix impression system whereas the other two techniques were comparable to each other.