COF Materials & Fabrication Basics 3

Question 1

What is 'creep' in the context of orthotic materials?

Accepted Answer

Gradual permanent deformation under sustained load

Answer

Creep refers to the slow, time-dependent permanent deformation that occurs when a material is subjected to a constant load over an extended period.

Question 2

When selecting leather for an orthotic interface, which property is most critical for patient comfort over long wear periods?

Accepted Answer

Moisture-wicking and breathability

Answer

Leather's natural moisture-wicking and breathability properties help manage perspiration and reduce skin maceration during extended orthosis wear.

Question 3

What is the purpose of a plaster of Paris negative cast in the custom orthosis fabrication process?

Accepted Answer

To capture an exact impression of the patient's anatomy for model creation

Answer

A plaster of Paris negative cast captures the precise shape of the patient's limb, which is then filled to create a positive model over which the orthotic material is formed.

Question 4

Which type of rivet is preferred when joining orthotic components that may need to be disassembled for adjustment?

Accepted Answer

Pop (blind) rivet

Answer

Pop rivets can be drilled out for disassembly and replacement, making them practical for orthotic joints that may require periodic adjustment or component exchange.

Question 5

What does 'Shore hardness' measure in orthotic materials?

Accepted Answer

Resistance to permanent indentation or penetration

Answer

Shore hardness quantifies how resistant a material is to surface indentation, helping clinicians select padding and liner materials with appropriate firmness for the clinical application.

(COF) Certified Orthotic Fitter Practice Test

(COF) Certified Orthotic Fitter Practice Test

COF Materials & Fabrication Basics 3