CCA Facial Prosthetics Design & Fabrication 2 — Questions and Answers
Question 1: Which silicone characteristic is most critical when selecting material for an auricular prosthesis in a patient who lives in a high-humidity coastal environment?
- High Shore A hardness
- Excellent hydrolytic stability (Correct answer)
- Maximum pigment absorption capacity
- Rapid room-temperature cure time
Correct answer: Excellent hydrolytic stability
Hydrolytic stability ensures the silicone resists degradation when repeatedly exposed to moisture, salt air, and perspiration.
Question 2: A nasal prosthesis margin that lifts away from the skin within weeks is most likely caused by:
- Incorrect intrinsic pigmentation
- Adhesive incompatibility with the silicone formulation (Correct answer)
- Insufficient oxide catalyst in the mix
- Excessive flange thickness at the periphery
Correct answer: Adhesive incompatibility with the silicone formulation
Many silicone adhesives are formulated for specific silicone types; using an incompatible adhesive causes premature margin failure.
Question 3: When fabricating a mold for an orbital prosthesis using dental stone, which layer is applied first to capture fine surface detail?
- Reinforcement layer of burlap mesh
- Thick base coat of fast-set stone
- Thin wash of low-viscosity impression material or die stone (Correct answer)
- Separator coat of petroleum jelly
Correct answer: Thin wash of low-viscosity impression material or die stone
A thin wash of low-viscosity material captures the finest anatomical detail before bulk is added with subsequent layers.
Question 4: Intrinsic colorants in medical-grade silicone prostheses must be:
- Water-soluble dyes to allow rinsing
- Non-leaching, biocompatible pigments (Correct answer)
- Applied after final cure to avoid color shift
- Limited to primary colors for predictability
Correct answer: Non-leaching, biocompatible pigments
Colorants must be biocompatible and non-leaching to prevent skin sensitization and maintain color integrity over time.
Question 5: During wax pattern carving for a nasal prosthesis, the anaplastologist should reference the patient's:
- Lateral cephalometric radiograph exclusively
- Pre-operative photographs and contralateral anatomy (Correct answer)
- Standardized anthropometric nasal database only
- Mirror image of the existing defect margins
Correct answer: Pre-operative photographs and contralateral anatomy
Pre-operative photos and the patient's own contralateral anatomy provide the most individualized and accurate morphological reference.
Question 6: What is the primary function of a silicone thinner (diluent) added during prosthesis fabrication?
- Accelerate platinum-catalyst cure
- Reduce Shore A hardness and increase flow (Correct answer)
- Improve adhesion to the skin surface
- Enhance UV resistance of the silicone
Correct answer: Reduce Shore A hardness and increase flow
Silicone diluents lower durometer and viscosity, allowing fabrication of softer, more lifelike margins and improved movement.
Question 7: A patient presents with a mid-face maxillary defect requiring an obturator prosthesis that also restores external facial contour. This combined restoration is called a:
- Mesostructure prosthesis
- Feeding obturator
- Maxillofacial prosthesis with extraoral component (Correct answer)
- Palatal augmentation prosthesis
Correct answer: Maxillofacial prosthesis with extraoral component
A maxillofacial prosthesis with an extraoral component addresses both the intraoral void and the external soft-tissue deficiency simultaneously.
CCA Facial Prosthetics Design & Fabrication 2
Which silicone characteristic is most critical when selecting material for an auricular prosthesis in a patient who lives in a high-humidity coastal environment?