CPO Materials Science & Technology Flashcards

Which thermoplastic material is most commonly used for low-temperature custom orthotic fabrication due to its workability at approximately 60–70°C?

Answer: Low-temperature thermoplastic (e.g., Orfit, Aquaplast)

Low-temperature thermoplastics such as Orfit and Aquaplast soften at 60–70°C, allowing safe custom molding directly on or near the patient's body.

Carbon fiber composite prosthetic components offer a primary advantage over aluminum components primarily because they:

Answer: Provide higher stiffness-to-weight ratio

Carbon fiber composites provide a superior stiffness-to-weight ratio compared to aluminum, allowing stronger, lighter prosthetic components that reduce metabolic cost.

When fabricating a total contact cast (TCC) for a diabetic foot ulcer, which property of plaster of Paris makes it preferred over fiberglass in some clinical protocols?

Answer: Conformability and ease of molding for precise total contact

Plaster of Paris is more conformable than fiberglass, allowing the clinician to achieve true total contact that distributes plantar pressure more uniformly.

Which material property describes a material's ability to return to its original shape after deformation, which is critical for prosthetic socket fit under cyclic loading?

Answer: Resilience / Elasticity

Elasticity (resilience) describes a material's ability to recover its original shape after deformation, essential for socket liners and flexible inner sockets that must maintain fit under repeated loading.

Silicone suspension liners for transtibial prostheses primarily achieve suspension through which mechanism?

Answer: Pin-lock or lanyard engagement with the socket

Most silicone pin-lock liners achieve suspension via a distal metal pin that engages a ratchet lock mechanism within the prosthetic socket.

What is the primary reason polyethylene foam (Plastazote) is used as an interface material in diabetic insoles?

Answer: Closed-cell structure providing cushioning and pressure distribution

Plastazote's closed-cell foam structure provides cushioning and conforms to foot shape, distributing plantar pressure to protect insensate diabetic feet from ulceration.