The influence of impression techniques on dimensional accuracy of implant's master cast

Due to the great influence of impression techniques on dimensional accuracy of implant master casts and existence of controversy about the best impression technic, this study aimed to evaluate the influence of four impression techniques on dimensional accuracy of implant’s master cast. Methods & Materials: In this experimental study, five implant’s analogues on laboratory models was used to transfer the positions of implants with four impression techniques. For each impression technique, 4 master casts was made. Impression techniques used included: 1 – non splinted + perforated tray, 2- non splinted + open tray, 3- splinted + open tray, 4- splinted + perforated tray. Dimensional accuracy of master casts fabricated with different impression techniques, was evaluated with comparison of distance of indicated points on the implant’s analogues between laboratory model and master casts. The distance between points was calculated on 3 axis (X, Y, Z) and special position of points was also calculated. This evaluation was calculated with micrometer in precision of 1 micron. Data were evaluated with SPSS software and Repeated Measure analysis. Significant difference was not found between the influences of four impression techniques on dimensional accuracy of implant’s master casts. None of the four impression techniques didn’t transfer precisely the location of indicated points of laboratory model to master casts on X, Y, Z axes or spatial position of them. Acrylic resin splinting didn’t show significant influence to augment the dimensional accuracy of master casts, so the non splinted technique is advisable because of simplicity and economic. Although more investigations is needed in this issues to augment the dimensional accuracy of master casts and approach to oral situation for increasing the clinical relevance.