Comparative stability of two removable die systems

The comparative stability of two removable die systems was evaluated. Under controlled conditions, ten casts, each with two removable dies, were constructed for each system for a total of 20 casts and 40 removable dies. Base-line pre- and postsectioning measurements to within 0.0001 inch in horizontal and vertical planes were recorded and differences calculated. Each die was removed and re-placed 30 times prior to any postsectioning measurement. The results indicated small inconsistent horizontal deviations and consistent vertical deviations for both systems. The Pindex system deviations were slightly less than those of the Di-Lok system, although t test values preclude any conclusion of significance. The results of this investigation indicate the need for dentists and dental laboratory technicians to exercise care in the utilization of any removable die system so as to obtain optimum accuracy and stability in the relationships of the components of that system.