Accuracy of Die Systems for Conventional Fixed Prosthodontics

Newly modified die systems have been introduced in the market claim superior accuracy. The purposes of this study was to evaluated and compare the accuracy of the three removable die systems KO tray (Vident, Brea, CA), plastic base ( Dental Ventures of America Inc, Corona, CA), and Pindex system (Coltene-Whaledent, New York, NY), at their sectioned and repeated stages. Thirty-polyvinyl siloxane impressions were made utilizing custom trays from a modified maxillary model requiring three fixed partial denture prosthesis. Each impression was poured with type IV improved die stone (Vel mix, Kerr, Roumulus, MI), ten casts were made for each die system. The solid experimental casts were sectioned and repeatedly removed 30 times. A traveling microscope was used to measure the distance between abutments after sectioning and after repeated removal. Collected data were subjected to statistical analysis using two way ANOVA at (P<0.05) to evaluate any statistical significance between the systems and to master model. Thereafter, a Tukey-Kramer test was preformed to rank actual dimensional differences across the dimensions of three-tested die systems. Within the limit of this study, no statistically significant differences between the systems after sectioning at P<0.05. However, measurements after repeated removal showed a statistical significance between the system.