Mid States Laboratories Inc.

Ear Impression Technique

The Importance of the Impression

An ear is like a fingerprint – it is one of a kind. For this reason,
we at Mid-States believe that the most critical factor in achieving a satisfactory, and hopefully better than satisfactory, hearing instrument fitting is the ear impression.

The accuracy of the impression will determine the comfort, seal, fit, and in part the function of the earmold or hearing instrument itself. Each of these factors will play a major role in the success of your fitting.

When taking an impression, and when reading through this information, remember the importance of the impression. We know we are good at what we do, but we can’t perform magic. To produce our best earmold, we need your best impression!

Thoughts and Preparation

As you begin the impression procedures outlined in this section, always keep the following thoughts in mind:

Exhibit Professionalism

  • make sure your materials are organized and ready for use
  • insure that everything meets good hygiene standards, including your hands
  • put the client at ease by explaining what you will be doing and why

Use Care and Caution

  • perform a thorough otoscopic exam prior to the impression to check placement of the block, and again after removal
  • during the otoscopic pay attention to the length, diameter, and the direction of the canal
  • also take notice of any problems (wax, discharge, inflammation, eardrum abnormalities etc.)that need to be discussed or referred for medical advice

Critically Examine the Impression

  • after completing the impression, check to determine that all areas are adequately filled
  • if you are not satisfied, now is the time to remake the impression – everyone will be happier

Before the Impression

As mentioned above, initially do an otoscopic exam of the canal and then place your block. Of critical importance is the size and placment of the foam or cotton block. Both types are available in a variety of sizes. In some cases it may be necessary to combine more than one block to achieve the necessary size. If your are working with a surgical ear, it is best to have the blocks placed by a physician. When there is a large amount of hair, it may be necessary to trim some using blunt tip scissors to reduce the possibility of injury. Once the correct size is chosen proceed as follows:

  • insert block into the canal (use an earlight or other tool of choice and be sure to brace the hand holding the tool to prevent injury should there be any sudden head movement
  • insert the block past the second bend in order for the sound direction to be determined
  • perform another visual check to insure that the block is completely occluding the canal and that it is positioned so as to provide a ‘flat’ canal tip showing the full diameter (as a precaution, be aware that foam plugs placed at an angle may be compressed ‘sideways’ by the flow of the material which can then bypass the block!)

Taking the Impression

As noted earlier, make sure the materials needed are organized and ready for use. For the specific mixing instructions, consult the section entitled “Preparation of the Impression Material”. With the canal block in place, and the material ready for injection, proceed as follows:

  • Place the end of the mixing tip or syringe into the ear canal while bracing your hand to avoid injury in case of sudden head movement.
  • Inject material into the canal steadily but not too slowly as some materials set up rapidly, and not too fast as this will leave welds and air pockets
  • Maintain pressure until the material fills the canal and begins to cover the tip
  • At this time gradually withdraw the gun/syringe still keeping the tip slightly buried in the material to obtain a full, well defined canal
  • Proceed to fill the concha, helix, anti-helix, and cover the tragus and anti-tragus areas while continuing to keep the tip slightly buried until finished
  • Allow the material to set up / cure as specified by the manufacturer. Test for firmness by pressing your fingernail gently into the material, if a mark remains, allow additional time
  • When material had set completely, break the seal by gently pushing the ear away from the impression
  • Hold the impression and release the helix area by twisting forward and continue to gently twist while bringing the impression out of the ear
  • Perform another otoscopic to insure all material has been removed and no damage or injury has occurred
  • Examine the impression to be sure that it meets your needs, if not,now is the time to retake the impression
To produce our best earmold, we need your best impression!
| 600 N. St. Francis | P.O. Box 1140 | Wichita, KS 67201 | P 316.262.7013 | Toll Free 800.247.3669