Impression taking

Make a good impression

To ensure successful patient fittings, accurate ear impressions are vital. The right fit means more comfort for your patient. And good acoustic seal and retention helps to prevent feedback – leading to a better hearing experience. It also results in less return appointments and time savings for the dispenser or audiologist.

Make sure you store impression materials at a temperature ranging from 15 - 28°C and never use them after the date shown on the packaging.


Which technique?

The ‘Open Jaw’ technique has been well researched and is widely promoted amongst industry experts.

Downward movement of the jaw causes the facial muscles and the ears cartilaginous tissues to move forward, leading to an increase in the diameter of the ear canal. Jaw movement has been known to create a break in the acoustic seal around earmoulds produced from closed jaw impressions, resulting in problems such as loose fit or intermittent oscillation as the ear canal diameter increases.

Taking the impression of the ear whilst holding the jaw in an open position with the use of a mouth prop, enables the impression to reflect the maximum increase in the ear canal diameter. The resulting earmould is more able to provide the required acoustic seal, comfort and retention to perfectly compliment the fitting. It allows for regular jaw movements such as eating, talking and yawning without losing retention and reduces the problem of the fit loosening.


Impression checklist

When the impression is complete, use the following checklist to make sure the impression is ready to be sent to us for production:

  • Is the impression a uniform colour?
  • Are the helix and antihelix complete?
  • Does the impression have a smooth finish?
  • Are there any air bubbles or voids?
  • Is the canal length sufficient to define the second bend of the ear canal?
  • Is the impression material itself unusually oily?
  • Is the tragus portion of the ear clearly defined?
  • Is the concha complete?

Ensure there are no folds or voids in the finished impression (these can be caused by the impression material drying too quickly).

Too much canal length on an impression is never a problem for our production team. Too little is!

Often the acoustic seal of an earmould occurs at the opening of the canal, not deep within the canal. Too much canal length on a mould may be uncomfortable for the wearer and can make it difficult to insert and remove. Correct canal length depends entirely on the requirements of the individual patient. Our technicians need to have impressions with good definitions of the ear canal, including the second bend. This helps them make moulds that don’t feedback due to the sound outlet being occluded by the ear canal wall.

The use of more viscous impression materials, long canal lengths, and the noting of excessive jaw movement are critical factors in producing impressions that work.


Professional courses

Mary Hare offer BSA Certificate in Otoscopy and Impression Taking and Earmoulds and Impression-Taking Refresher Courses. These can be delivered on their site in Newbury, or depending on the number of candidates, they can come to you. To find out more visit the Mary Hare website.


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