CTO Orthotic Materials & Fabrication Techniques 3

Question 1

Which solvent is most commonly used to bond Barge cement layers when attaching leather to thermoplastic orthotic components?

Accepted Answer

Contact cement thinner (MEK)

Answer

MEK (methyl ethyl ketone) is the standard thinner for Barge and contact cements, maintaining proper viscosity for strong adhesion.

Question 2

A patient requires a supramalleolar orthosis (SMO) with medial longitudinal arch support. Which material combination is most appropriate for the shell?

Accepted Answer

1.5–2mm polypropylene with closed-cell foam liner

Answer

A 1.5–2mm polypropylene shell with closed-cell foam liner provides the necessary rigidity and cushioning for an SMO in a pediatric or adult population.

Question 3

During grinding and finishing of a thermoplastic AFO, which personal protective equipment (PPE) is essential to prevent respiratory hazard?

Accepted Answer

N95 or P100 respirator and safety goggles

Answer

Grinding thermoplastics generates fine particulate dust that is a respiratory hazard, requiring an N95 or P100 respirator along with eye protection.

Question 4

What does 'drop-lock' refer to in orthotic metal joint fabrication?

Accepted Answer

A ring that drops over the joint to lock it in extension, which can be unlocked for sitting

Answer

A drop-lock (ring lock) is a metal ring that slides down over the knee joint to lock it in extension, enabling stance stability while allowing removal for sitting.

Question 5

Which method is used to determine the appropriate trim line placement on an AFO to allow dorsiflexion assist while maintaining mediolateral stability?

Accepted Answer

Trimming anterior to the malleoli for flexibility and posterior for rigidity

Answer

Trim lines placed anterior to the malleoli reduce stiffness and allow dorsiflexion assist, while posterior trim lines increase rigidity.

(CTO) Certified Orthotic Technician Practice Test

(CTO) Certified Orthotic Technician Practice Test

CTO Orthotic Materials & Fabrication Techniques 3