Which of the following is a type of elastomeric impression material?

• A. Polysulfide
• B. Alginate
• C. Zinc oxide eugenol
• D. Impression plaster

Answer: (A)

Elastomeric impression materials are rubber-like substances used for final impressions because they deform under pressure but return to their original shape, giving accurate details and good tear resistance during removal. Polysulfide fits this category because it cures to a flexible, elastic rubber that can capture fine anatomy and withstand removal without permanent deformation.

Alginate, by contrast, is an irreversible hydrocolloid that sets into a gel rather than a true elastic rubber, and it’s typically used for preliminary impressions rather than final, highly precise ones. Zinc oxide eugenol and impression plaster are rigid impression materials that do not exhibit the elasticity needed for reliable final impressions.