Abstract
The purpose of this study was to investigate the accuracy of working casts made from two types of model, aparallel type and an angled type. Athree-dimensional measuring microscope was used to measure reference points on the master model and working casts.
The master model was made from metal, and standard points A, B and C were located on the base of the master model. Reference points were provided on the occlusal surface and on the measuring jigs for implants.Impressions were taken using a custom tray and additional type silicone impression material, and working casts were made. Then the working casts were measured and compared to the master model.
The results were as follows:
1. In the implant area the distance between the two implants was greater than that of the master model for both types of working casts.
2. Clockwise rotation of the implants was observed in both types of working casts.
3. For the angled type working casts, reference points of the remaining teeth moved to a lower position.
