CPO CPO Materials Science & Technology

Question 1

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

Accepted Answer

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

Answer

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.

Question 2

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

Accepted Answer

Provide higher stiffness-to-weight ratio

Answer

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

Question 3

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?

Accepted Answer

Conformability and ease of molding for precise total contact

Answer

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

Question 4

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?

Accepted Answer

Resilience / Elasticity

Answer

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.

Question 5

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

Accepted Answer

Pin-lock or lanyard engagement with the socket

Answer

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

(CPO) Certified Prosthetist Orthotist Practice Test

(CPO) Certified Prosthetist Orthotist Practice Test

CPO CPO Materials Science & Technology