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Updated: Jun 2, 2026
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Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision
Published on: April 29, 2014
Pilot study on accuracy and dimensional stability of impression materials using industrial CT technology
Stefanie Steinhäuser-Andresen1, Andreas Detterbeck, Christoph Funk
1Department of Orthodontics, University of Erlangen-Nuremberg, Erlangen, Germany. Stefanie.Steinhaeuser@uk-erlangen.de
Summary
This study evaluated dental impression materials for accuracy and stability using computed tomography (CT). Polyether impressions demonstrated superior dimensional stability compared to alginate, though alginates remain suitable for orthodontic use.
Area of Science:
- Dental materials science
- Digital dentistry
- Biomaterials engineering
Background:
- Computed tomography (CT) enables virtual data capture of dental impressions.
- Evaluating impression materials' accuracy and dimensional stability is crucial for digital workflows.
Purpose of the Study:
- To assess the accuracy and dimensional stability of alginate and polyether impression materials.
- To investigate the influence of different impression trays on the accuracy of dental impressions.
Main Methods:
- Two alginate (Zhermack Hydrogum®5, Kaniedenta Tetrachrom®) and one polyether (3MEspe Impregum™) impression materials were tested.
- Materials were combined with two acrylic trays (3M Espe Position Tray™, Profimed Opti-Tray) and scanned using CT.
- Dimensional stability was assessed by repeated scanning at 0, 2, and 6 days; accuracy was compared to a high-resolution micro-CT scanned model.
Main Results:
- Polyether impressions exhibited better dimensional stability (73 µm deviation) than alginates.
- Alginate impressions showed acceptable accuracy (Hydrogum®5: 0.129 ± 0.021 mm; Tetrachrom®: 0.137 ± 0.002 mm).
- Tray type had minimal impact on alginate accuracy but influenced polyether impression accuracy.
Conclusions:
- Alginate impression accuracy is sufficient for clinical orthodontics, yielding acceptable results for up to 2 days with proper storage.
- Polyether materials offer superior dimensional stability over alginates.
- The 3M Espe Position Tray™ provided better retention than the Profimed Opti-Tray.
