The Effect of Tray Design and Impression Material Consistencies on Accuracy of Complete Arch Implant Supported Fixed Dental Prostheses Master Casts
Date of Award
Master of Science (MS)
Purpose of this Study: The purpose of this study is to determine the accuracy and precision of complete arch implant supported fixed dental prosthesis impressions made with a low viscosity PVS while supporting the splinted impression copings with heavy viscosity PVS on a reference model simulating an all-on-4 prosthesis using both stock and custom trays. Material and Methods: A model was scanned to act as the reference model. The splinting device and custom tray were printed using FormLAb printer and custom resin tray material. Four group were included in the study. Stock tray with and without support and custom tray with and without support. nine impression were made for each group and the generated casts were scanned and superimposed to the reference module using Geomagic software. RMS was calculated and 2-way anova test was utilized. Results: RMS for group I ranged from 46-100µm. RMS for group II ranged from 58-580µm. RMS for group III ranged from 36-78µm. RMS for group IV ranged from 41-67µm. There was no significant difference between groups with and without heavy body PVS support (P=0.1). The average for the no heavy body PVS supported groups was 61µm, while the average for the heavy body PVS supported groups was 110µm. However, there was a significant difference (P=0.045) between types of tray. The average for the custom tray impression group was 55 µm, while the average for stock tray impression group was 117µm. There was no interaction between groups combination (P=0.1). Conclusions: Custom tray impression groups showed better results in comparison to the stock tray impression group. There was no difference between supporting and not supporting the splinting device segments. There was no interaction between the two factors. The rigidity of the 3D splinted devices may be the most important factor in determining the accuracy of PVS impressions with stock or custom impression trays.