Impression Techniques & Molding Flashcards
7 cards from real CCA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Impression Techniques & Molding flashcards as text
Which impression technique is preferred when the anaplastologist needs to capture an auricular defect with deep concavities and significant undercuts?
Answer: Two-stage putty-wash technique using VPS
The two-stage putty-wash VPS technique records undercuts accurately while the light-body wash captures fine detail without trapping.
What is the primary function of adding a gauze mesh or burlap reinforcement within a plaster mold?
Answer: To increase mold strength and prevent cracking during processing
Fiber reinforcement embedded in the mold body resists fracture forces during clamping and demold, extending mold lifespan.
Polysulfide rubber base impression material is less commonly used in anaplastology primarily because:
Answer: It has an unpleasant odor and longer set time compared to VPS
Polysulfide materials produce sulfurous odors and require extended setting times, making patient management more difficult compared to VPS alternatives.
During impression making for a mid-facial prosthesis, a 'vent hole' in the tray is used to:
Answer: Provide an escape path for excess material and reduce hydraulic pressure
Vent holes prevent hydraulic pressure buildup that could displace soft tissue and distort the recorded anatomy.
When is a custom impression tray preferred over a stock tray for facial prosthetic impressions?
Answer: When the defect anatomy is irregular, large, or requires controlled material thickness
Custom trays ensure uniform material thickness, reduce material waste, and provide better control over border extension in complex defects.
The 'snap set' characteristic of alginate is clinically significant because it:
Answer: Reduces patient discomfort by minimizing the set wait period
Alginate's rapid, abrupt gelation minimizes the time patients must remain motionless, which is especially important for patients with limited cooperation.
A mold seam line appearing on the finished silicone prosthesis most directly results from:
Answer: Misalignment or incomplete closure of the two mold halves
Poor mold registration or incomplete seating creates a gap where excess silicone flashes, leaving a visible seam on the prosthesis surface.