IADR Abstract Archives
A New Side-by-side Initial Hydrophilicity of Impression Materials Technique
Objectives: To test the validity of directly comparing the hydrophilic properties of impression materials in the unset state using newly developed 2-material-side-by-side interface setup and examining how a drop of water placed on this interface behaves.
Methods: Two polyether impression materials and one experimental medium-bodied VPS impression material (n=5/group) were tested against themselves. Each test sample was made by: mixing each material using Pentamix™-3 (3M-ESPE) with standard mixing times; creating a 0.2mm thick interface of each sample material separately on microscope slides, placing the slides containing samples to be compared side-by-side; placing a 5µl drop of water on the interface by a DropShape Analysis System (DSA-30, Krüss) within 60s after the start of mixing. Avi video files of the water drop encountering the interface were recorded and converted to Bitmap images at selected time frames. At a drop age of 2s, the horizontal spreading radius of water in pixels on each material from the center of the water dropper was recorded using Bitmap files and measurement tools using Microsoft® Paint, and a standardized ratio was calculated. A conversion between pixels and millimeters is available through DSA-30. One-sample T-tests were conducted to determine the statistical significance using Minitab® version-16. Because compared samples were of the same material, the expected results had a ratio=1.
Results: All ratios of mean horizontal water spread fall within the greatest one standard of deviation found (0.12), ranging 0.89-1.12. In all one-sample T-tests performed, p>0.05, ranging from p=0.37-1.00 (Table 1).
Conclusions: The three impression materials tested failed to reject the expected horizontal water spread ratio of 1 (one-sample T-test, p>0.05). The new technique used was proven to be effective and can be used to compare hydrophilicity of different impression materials at different setting stages in the future. The clinical relevance of hydrophilicity in the unset stage has yet to be tested.
Methods: Two polyether impression materials and one experimental medium-bodied VPS impression material (n=5/group) were tested against themselves. Each test sample was made by: mixing each material using Pentamix™-3 (3M-ESPE) with standard mixing times; creating a 0.2mm thick interface of each sample material separately on microscope slides, placing the slides containing samples to be compared side-by-side; placing a 5µl drop of water on the interface by a DropShape Analysis System (DSA-30, Krüss) within 60s after the start of mixing. Avi video files of the water drop encountering the interface were recorded and converted to Bitmap images at selected time frames. At a drop age of 2s, the horizontal spreading radius of water in pixels on each material from the center of the water dropper was recorded using Bitmap files and measurement tools using Microsoft® Paint, and a standardized ratio was calculated. A conversion between pixels and millimeters is available through DSA-30. One-sample T-tests were conducted to determine the statistical significance using Minitab® version-16. Because compared samples were of the same material, the expected results had a ratio=1.
Results: All ratios of mean horizontal water spread fall within the greatest one standard of deviation found (0.12), ranging 0.89-1.12. In all one-sample T-tests performed, p>0.05, ranging from p=0.37-1.00 (Table 1).
Conclusions: The three impression materials tested failed to reject the expected horizontal water spread ratio of 1 (one-sample T-test, p>0.05). The new technique used was proven to be effective and can be used to compare hydrophilicity of different impression materials at different setting stages in the future. The clinical relevance of hydrophilicity in the unset stage has yet to be tested.
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