1Yonsei Research Institute of Dental Materials, College of Dentistry, Yonsei University, Seoul 120-752, Korea.
This study examined how temperature changes affect the dimensional stability of five silicone dental impression materials. The researchers found that cooling from body to room temperature caused shrinkage in all materials. The anterior region of the impression showed more shrinkage than the posterior region. The materials varied in their thermal expansion coefficients, with some showing significantly different behavior. These findings suggest that material and anatomical location both influence thermal stability. The study provides data that could help guide material selection in clinical settings.
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Area of Science:
Background:
Dental impression materials are essential in prosthodontic treatment. These materials must accurately replicate oral tissues and remain dimensionally stable. Prior research has shown that thermal changes affect the dimensional accuracy of these materials. However, the extent of thermal effects on different types of impression materials remains unclear. No prior work had resolved how specific regions of an impression, such as anterior versus posterior, respond differently to thermal shifts. This gap motivated the current study to investigate how temperature changes influence the dimensional stability of various silicone impression materials. The study aimed to address uncertainties in how these materials perform under realistic clinical conditions. Understanding thermal behavior is crucial for ensuring the precision of dental impressions. This research builds on existing knowledge by focusing on material-specific and region-specific thermal responses.
Purpose Of The Study:
The main outcome is that thermal changes cause dimensional shrinkage in silicone impression materials, with the anterior region showing more change than the posterior region.
Five light-body addition-reaction silicone impression materials were tested: Contrast (CT), Examix (EM), Extrude (EX), Imprint II (IM), and Perfect (PF).
The anterior region is more sensitive to thermal changes than the posterior region, according to the study results.
Thermal expansion was measured using a thermomechanical analyzer between 23 and 37 degrees Celsius.
The purpose of this study was to evaluate how thermal changes affect the dimensional stability of five different light-body addition-reaction silicone impression materials. The researchers sought to determine whether these materials shrink differently when cooled from body to room temperature. They also aimed to compare the thermal expansion coefficients of each material. Another objective was to assess whether the anterior and posterior regions of an impression experience different levels of dimensional change. The study aimed to provide data that could guide material selection in clinical settings. The motivation for this work was to improve the accuracy of dental impressions in prosthodontic applications. The researchers proposed that thermal expansion varies across materials and anatomical regions. This study contributes to the understanding of how temperature affects impression material performance.
Main Methods:
The researchers selected five light-body addition-reaction silicone impression materials for testing. Cylindrical specimens were fabricated with a diameter of 6 mm and a height of 12 mm. A thermomechanical analyzer measured thermal expansion between 23 and 37 degrees Celsius. The Mann-Whitney Usage Test analyzed the data to compare thermal expansion across materials. To simulate clinical conditions, tooth and tray shapes were modeled to measure linear shrinkage in anterior and posterior regions. The study used a controlled temperature range to mimic mouth and room temperatures. The materials were tested for dimensional changes during cooling. The anterior and posterior regions were evaluated separately to assess regional differences.
Main Results:
The thermal expansion of the materials decreased in the following order: CT ≥ PF ≥ EM ≥ EX ≥ IM (p < 0.05). The anterior region showed greater dimensional changes than the posterior region for all materials. The dimensional changes in the anterior region averaged more than 40 micrometers. The posterior region changes were consistently less than 40 micrometers. The thermal expansion coefficients varied significantly among the tested materials. Some materials exhibited statistically significant differences in thermal behavior. The anterior region experienced more shrinkage than the posterior region. These findings suggest that material and anatomical location both influence thermal stability.
Conclusions:
The authors concluded that thermal changes significantly affect the dimensional stability of silicone impression materials. The anterior region showed greater dimensional changes than the posterior region. The thermal expansion coefficients varied among the tested materials. The study supports the idea that material selection should consider thermal behavior. The researchers proposed that these findings could influence clinical material choices. The anterior region is more sensitive to thermal changes than the posterior region. These results align with the hypothesis that temperature affects material performance. The study provides evidence that thermal stability varies across materials and anatomical regions.
The dimensional changes in the anterior region averaged more than 40 micrometers for all materials tested.
The authors suggest that material selection in prosthodontic treatment should consider thermal behavior differences between anterior and posterior regions.