Dimensional accuracy of an epoxy die material using different polymerization methods

Area of Science:

• Dental materials science
• Polymerization chemistry

Background:

• Resinous die materials offer advantages like strength and abrasion resistance over traditional stone.
• However, shrinkage during setting limits their widespread clinical adoption.
• Dimensional accuracy is crucial for precise transfer of dental arch information.

Purpose of the Study:

• To evaluate if retarding polymerization and altering the base-to-catalyst ratio improve dimensional accuracy of epoxy resin die materials.
• To determine if these modifications reduce inaccuracies in transferring spatial positions from the oral cavity to the master cast.

Main Methods:

• A Blue Star Type E epoxy resin die material was tested against a metal master die.
• Forty polyether impressions were made, and ten dies were fabricated for each of four groups (S, M, N, P).
• Group S followed manufacturer instructions; groups M, N, and P involved modified setting times and base/activator ratios.

Main Results:

• Significant differences in dimensional accuracy were found between the four groups (p < 0.0001).
• No resin group precisely matched the metal master die dimensions (A, B, C).
• The P group showed statistically closer results to the metal master die for dimension C compared to the S group.

Conclusions:

• Modifying polymerization or the base/activator ratio did not enhance the dimensional accuracy of the tested epoxy resin die material.
• The material exhibited significant shrinkage variability across all tested conditions.
• This inherent shrinkage poses a challenge for accurate master cast fabrication.