Time-dependent accuracy of elastomer impression materials. Part I: Condensation silicones

Area of Science:

• Dental Materials Science
• Polymer Chemistry

Background:

• Condensation silicone elastomers are widely used for dental impressions.
• Dimensional stability of successive pours from a single impression is crucial for accurate dental restorations.

Purpose of the Study:

• To evaluate the dimensional accuracy of dental dies produced from successive pours of different silicone impression materials.
• To compare the behavior of putty/wash systems versus custom-tray/adhesive/wash systems.
• To assess the influence of pouring time on the dimensional stability of silicone dies.

Main Methods:

• Multiple dies were poured from single impressions using various condensation silicone elastomers (putty/wash and light-body wash systems).
• Dimensional changes (diameter and eccentricity) of the dies were measured over time.
• Comparison between single-wash and double-mix techniques was performed for condensation-silicone systems.

Main Results:

• Successive pours from condensation silicone elastomers can lead to dimensional changes in dies.
• Putty/wash systems showed variable dimensional behavior, with some increasing and others decreasing in diameter over time.
• Light-body wash silicone in custom trays resulted in dies with increasing diameters.
• Putty/wash systems generally exhibited greater die eccentricity than custom-tray systems.

Conclusions:

• Immediate pouring of condensation silicone impressions is recommended for maximum die accuracy.
• The choice of silicone impression material and technique significantly impacts the dimensional stability of dental dies.
• Understanding material-specific behavior is essential for predictable outcomes in dental prosthetics.