Impression Techniques & Molding Flashcards

Which mold material offers the highest heat resistance and is preferred when processing heat-vulcanized silicone prostheses?

Answer: High-expansion dental stone or epoxy resin molds

High-expansion stone or epoxy molds withstand the elevated temperatures and pressures required for heat-vulcanized silicone without warping or fracture.

A patient presents with a contracted auricular defect scar. The anaplastologist uses a tissue conditioner before impression-making primarily to:

Answer: Temporarily displace and record the tissue in a more relaxed anatomical position

Tissue conditioners record peri-defect tissue in a functionally relaxed position, improving the eventual prosthesis fit and edge seal.

The 'open-mouth' versus 'closed-mouth' impression technique for a nasal prosthesis is selected based on:

Answer: How lip and cheek movement affect the defect margins and prosthesis border seal

Dynamic tissue movement during speech and expression can unseat prosthesis margins; functional impressions record the defect borders in the positions most relevant to daily use.

When pouring an epoxy resin mold from a VPS impression, the anaplastologist should:

Answer: Apply a compatible mold release to the impression surface before pouring to facilitate clean separation

Although VPS is generally non-adhesive, a mold release ensures clean separation and protects fine surface details when demolding cured epoxy.

Which factor most directly affects the final margin thickness and feathering of a silicone nasal prosthesis during mold fabrication?

Answer: The design and position of the mold parting line in relation to the prosthesis border

Parting line placement determines how thinly the prosthesis margin can feather; poor positioning results in thick, visible edges that compromise esthetics.

Why is undercut blockout performed before constructing the matrix portion of a two-part mold?

Answer: To prevent mechanical lock between mold sections that would prevent separation

Filling undercut areas with wax or clay before pouring the matrix ensures the two mold halves can be separated without fracture or damage to the model.

A CCA candidate is asked to compare hydrophilic versus hydrophobic impression materials. Which statement is most accurate?

Answer: Hydrophilic materials (e.g., some VPS formulations) better wet moist tissue surfaces, improving detail reproduction in wet fields

Hydrophilic impression materials spread over moist tissue rather than beading, ensuring intimate contact and superior detail capture in wet clinical environments.