This study evaluated five types of vinyl polysiloxane impression materials for how much they changed in size over time after an impression was made. Researchers measured the final dies and compared them to a master model to determine accuracy. One material consistently produced slightly larger dies, while another regularly made undersized ones. Three materials showed random deviations, but all were within a 0.3% range. The study found no consistent pattern of change over time, with dies made at 168 hours being as accurate as those made at 10 minutes. The authors suggest that material choice is more important than timing when it comes to dimensional accuracy.
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Area of Science:
Background:
Dental impressions require materials that maintain dimensional stability over time. Prior research has shown that vinyl polysiloxane materials are commonly used for this purpose. However, uncertainty remains about how dimensional changes evolve after the impression is made. Some studies suggest that time influences accuracy, but results are inconsistent. This gap motivated the need for a detailed evaluation of dimensional changes in different materials. No prior work had resolved whether all materials behave similarly or if some are more stable. The accuracy of dies depends on the material's ability to retain shape. Understanding this behavior helps in selecting the best materials for clinical use.
Purpose Of The Study:
This study aimed to assess how five vinyl polysiloxane impression materials change dimensionally over time. The goal was to determine if any material consistently produced more accurate dies. Researchers wanted to evaluate if time affected the dimensional accuracy of the impressions. They focused on comparing the final die size to a master model. The motivation was to identify materials that minimize deviation from the original. No prior work had directly compared these materials under the same conditions. The study sought to clarify whether time played a role in accuracy. The findings could guide clinicians in material selection.
The main outcome is that dimensional changes are minimal, with the largest deviation being 0.3% for Permagum putty-wash material.
Permagum putty-wash material consistently produced undersized dies with a maximum deviation of 0.3%.
The master model served as a reference to measure and compare the dimensional accuracy of the dies produced from the impressions.
Time did not significantly affect dimensional accuracy; dies made at 168 hours were as accurate as those made at 10 minutes.
Main Methods:
Researchers selected five vinyl polysiloxane impression materials for testing. Impressions were made and poured into dies at different time intervals. The dies were then measured and compared to a master model. The master model served as a reference for dimensional accuracy. Linear dimensional changes were calculated for each material. The study evaluated results at 10 minutes and 168 hours after pouring. Statistical analysis compared the deviations across all materials. The approach aimed to identify any consistent patterns in dimensional changes.
Main Results:
One material consistently produced slightly oversized dies, with a maximum deviation of 0.1%. Permagum putty-wash material regularly resulted in undersized dies, with a maximum deviation of 0.3%. Three other materials showed random deviations, ranging from -0.08% to +0.07%. No consistent trend of increasing or decreasing size over time was observed. Dies made at 168 hours were as accurate as those made at 10 minutes. The smallest deviation recorded was 0.07% for the largest die. The largest deviation was 0.3% for the smallest die from Permagum. These results suggest that time does not significantly affect dimensional accuracy.
Conclusions:
The authors propose that dimensional changes in these materials are minimal and do not follow a predictable pattern over time. They suggest that some materials may consistently produce more accurate results than others. The findings indicate that waiting up to 168 hours does not compromise accuracy. The study supports the use of these materials for dental impressions. The authors suggest that clinicians should consider material choice based on deviation patterns. No prior work had demonstrated that time does not affect accuracy. The results suggest that material selection is more important than timing. The authors propose that these findings may inform future material development.
The smallest deviation recorded was 0.07% for the largest die produced by one of the three randomly varying materials.
The authors suggest that clinicians should consider material choice based on deviation patterns rather than timing.