三次元測定による全顎歯列の印象および模型の寸法精度

ラバー系印象材の種類とトレー形態の影響

抄録

The purpose of this study was to investigate and compare the accuracy of complete dental arch impressions and stone casts made from two kinds of impression materials (addition type silicone and polysulfide rubber) and trays (custom tray andmodified custom tray).
In addition, the effect of quantity of gypsum was examined. Impressions were made from a metallic model of a simplified maxillary dentition. Impressions and stone casts were measured respectively using the three-dimensional measuring microscope.
The results were as follows:
1. Distortion of impressions was so small that the reproducibility of impressions was superior three-dimensionally.
2. These kinds of impressions and trays did not influence the accuracy of impressions but had an effect on the accuracy of the stone casts.
3. Generally, the setting expansion of gypsum in the impression occurred in all directions.
4. Arch widths and lengths on the stone casts tended to increase in number.
5. Stone casts made from an addition/type siliconeimpression material and a custom tray were the most accurate because the combination of the impression material and tray effectively suppressed the setting expansion of gypsum.
6. By controlling the quantity of gypsum, the accuracy of stone casts could be improved.