Which impression material is described as flexible and is melted at approximately 209 degrees, cooled to 130-135 degrees and poured into a mold flask containing a waxed denture and cooled to a solid state?

Which impression material is described as flexible and is melted at approximately 209 degrees, cooled to 130-135 degrees and poured into a mold flask containing a waxed denture and cooled to a solid state?

• A. Wax Pot
• B. Hydrocolloid
• C. Denture Base Acrylic
• D. Reversible Hydrocolloid

Answer: (D)

The material described is thermally reversible hydrocolloid, also known as agar. Its standout property is that it can be melted, cooled to a workable temperature, and poured or formed into a mold, then later reheated and reshaped if needed. In this scenario, it’s melted to about 209°F to liquefy, cooled to around 130–135°F to handle and place into the flask with the waxed denture, and then allowed to cool and set as a flexible, detailed impression. This ability to transition between liquid and gel states with heat is what makes reversible hydrocolloid unique and suitable for denture-workflows that require a flexible impression material. Why the others don’t fit: a wax pot is used for melting wax, not as an impression material; a hydrocolloid (in general) includes irreversible types that set chemically and can’t be melted and reused; denture base acrylic is a resin used to fabricate the denture base, not an impression material.

The material described is thermally reversible hydrocolloid, also known as agar. Its standout property is that it can be melted, cooled to a workable temperature, and poured or formed into a mold, then later reheated and reshaped if needed. In this scenario, it’s melted to about 209°F to liquefy, cooled to around 130–135°F to handle and place into the flask with the waxed denture, and then allowed to cool and set as a flexible, detailed impression. This ability to transition between liquid and gel states with heat is what makes reversible hydrocolloid unique and suitable for denture-workflows that require a flexible impression material.

Why the others don’t fit: a wax pot is used for melting wax, not as an impression material; a hydrocolloid (in general) includes irreversible types that set chemically and can’t be melted and reused; denture base acrylic is a resin used to fabricate the denture base, not an impression material.