Accuracy of six elastic impression materials used for complete-arch fixed partial dentures

Area of Science:

• Dental materials science
• Prosthodontics
• Biomaterials engineering

Background:

• Complete-arch fixed partial dentures require high accuracy in fabrication.
• Impression materials play a critical role in the precision of dental prosthetics.
• Evaluating the dimensional stability and accuracy of impression materials is essential for clinical success.

Purpose of the Study:

• To assess the accuracy of four impression materials for complete-arch fixed partial denture fabrication.
• To determine the suitability of these materials for single-cast versus multi-cast fabrication techniques.
• To identify sources of inaccuracy in the fabrication process of fixed partial dentures.

Main Methods:

• Visual comparison and indirect measurement techniques were employed.
• Four types of impression materials were tested for complete-arch impressions.
• Fabrication of a master fixed partial denture was performed, with modifications to address inaccuracies.

Main Results:

• None of the tested impression materials provided sufficient accuracy for finishing a complete-arch fixed partial denture on a single master cast.
• All tested materials can be used if a second impression is made with fitted castings in place.
• Inaccurate soldering was identified as a significant source of error, mitigated by using epoxy glue in this study.

Conclusions:

• Current impression materials necessitate a multi-cast approach for accurate complete-arch fixed partial denture fabrication.
• Fabrication errors, particularly from soldering, must be carefully managed to ensure prosthetic accuracy.
• Making a new impression with fitted castings and performing assembly/soldering on a second cast improves overall accuracy.