Three-dimensional evaluation of alginate impressions depending on the mixing method
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Studenckie Koło Naukowe, Katedra Protetyki Stomatologicznej, Warszawski Uniwersytet Medyczny Students’ Research Group, Department of Prosthetic Dentistry, Medical University of Warsaw
Katedra Protetyki Stomatologicznej, Warszawski Uniwersytet Medyczny Department of Prosthetic Dentistry, Medical University of Warsaw
Acceptance date: 2024-06-17
Publication date: 2024-06-20
Prosthodontics 2024;74(2):107-115
The basic impression materials used in dental offices are alginate materials. Mixing methods, manual and automated, differ in manipulation time, which translates into the setting time of the mass and potentially the quality of the connection of soluble alginic acid salts with distilled water, which may affect the dimensions of the impression. Due to the devices available on the market that enable automation of the processes of combining powder and liquid, the impact of the mixing method on changing the dimensions of alginate impressions remains a current subject.

Aim of the study:
The aim of the study was a three-dimensional assessment of impressions taken with alginate material depending on the mixing method.

Material and methods:
42 identical impressions of a dental training model were made using three alginate materials with different application characteristics, mixed manually or with an automatic mixer. The tested material was divided according to the alginate mass used and the method of preparing the mass. Using a laboratory scanner, a series of scans were performed immediately after taking the impression and after 168 hours of storage. The obtained three-dimensional images were exported as DICOM and STL files. Using the superimposition option of the graphic software, deviations were calculated 7 days after the impression was made. The quantitative data obtained in this way was subjected to statistical analysis.

The average dimensional change of all impressions after 7 days of storage was 0.04 mm with a standard deviation of 0.13 mm. Hydrogum 5 was characterized by the lowest dimensional stability: median = 0.06 (min/max: -0.23/0.76) mixed by hand. Orthoprint mass mixed manually was characterized by the highest dimensional stability: median = 0.01 (min/max: -0.04/0.03). The differences between the 6 groups were statistically significant (ANOVA Kruskall- Wallis p=0.007107).

The automatic mixer significantly speeds up clinical work without affecting the volume of the alginate mass, regardless of its type.

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