Impression materials.. and electrodeposits. Part I: Impression materials

Area of Science:

• Materials Science
• Dental Materials Science

Background:

• Accurate dental impressions are crucial for prosthodontic restorations.
• Understanding the dimensional stability of impression materials is vital for predictable outcomes.

Purpose of the Study:

• To evaluate the dimensional stability of two dental impression materials (President and Polyjel) after polymerization.
• To assess the impact of polymerization temperature and environmental exposure on material dimensions.

Main Methods:

• Specimens of President and Polyjel were polymerized under different temperature conditions.
• Dimensional changes were measured after polymerization and during a 3-week bench set.
• Material stability was tested during immersion in acid and alkaline electroplating baths.

Main Results:

• All impression materials showed shrinkage between 0.07% and 0.23% compared to the master die.
• Room temperature polymerization resulted in slight initial shrinkage, followed by stability.
• Higher temperature polymerization led to significant initial dimensional changes upon cooling, then stability.
• President demonstrated minimal change in an acid electroplating bath.
• Polyjel exhibited expansion in both acid and alkaline electroplating baths.

Conclusions:

• Dental impression materials undergo measurable shrinkage, influencing subsequent fabrication processes like electrodeposition.
• Polymerization temperature significantly impacts the initial dimensional stability of impression materials.
• Polyjel shows dimensional instability when exposed to electroplating baths, potentially affecting electrodeposit accuracy.