Earmold and Impression Techniques Flashcards

Which impression material property is most critical when taking an impression on a patient with a very narrow ear canal?

Answer: Low viscosity to flow into tight spaces without excessive pressure

Low-viscosity material flows into narrow canals without requiring excessive injection force that could cause discomfort or a distorted impression.

What is the primary purpose of placing an otoblock (dam) before taking an ear impression?

Answer: To protect the tympanic membrane from impression material

The otoblock acts as a physical barrier to prevent impression material from contacting or damaging the tympanic membrane.

A patient with an open jaw impression shows a significant gap between the impression and the tragus area when the mouth is closed. This most likely indicates:

Answer: The temporomandibular joint movement was not adequately captured

TMJ movement changes the shape of the ear canal, and a gap at the tragus suggests the open-jaw technique did not fully account for this dynamic change.

Which earmold style is most appropriate for a patient with severe-to-profound hearing loss who needs maximum low-frequency amplification?

Answer: Full-shell earmold with no vent or a minimal vent

A full-shell earmold with minimal or no venting provides the best acoustic seal to prevent feedback and retain low-frequency energy needed for severe-to-profound loss.

What does the term 'shrinkage' refer to in the context of earmold laboratory processing?

Answer: Dimensional change of the earmold material as it cures or cools

Shrinkage is the dimensional reduction that occurs as acrylic or silicone materials polymerize or cool, which can affect the final fit of the earmold.

When inspecting a completed ear impression, an air bubble or void in the canal portion indicates:

Answer: A potential fit problem and the impression should be retaken

Voids in the canal portion of an impression will translate to bumps or gaps in the finished earmold, causing a poor fit and possible feedback.

Which of the following best describes a 'canal lock' feature on an earmold?

Answer: A protrusion that fits into the second bend of the canal to improve retention

A canal lock is a small protrusion molded onto the canal portion that engages the second bend of the ear canal, significantly improving earmold retention.