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 a satisfactory hearing aid fitting, whether an in-the-ear, behind-the-ear, glasses or body aid, is the ear impression.

The accuracy of the impression will determine the comfort, seal and fit of the earmold or hearing aid - all factors that will play a major role in the success of your fitting.

As you read through our section on Proper Impression Technique, remember the importance of the impression - and remember our abilities.  While we are good - and we really me good - we can accomplish with a "less than perfect" impression - but, to make our job just a little bit easier, follow the steps outlined in this section and examine your impression critically.
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Ear Inspection

It is essential to inspect the ear with an otoscope before taking an ear impression.  To properly inspect the ear, grasp the pinna between your thumb and index finger and gently pull back and slightly up.  This action will straighten the canal to facilitate the placement of the otoscope into the canal.  In working with children, it is generally suggested that the pinna be pulled slightly down and back.

• Inspect for any discharging condition.  If there is any discharge in the ear, the client should be seen by an ear physician and no ear impression should be made.
• Inspect for irregularities in the canal.  This can be caused by surgery or congenital abnormalities.  It is good judgment to obtain approval of a physician prior to taking an impression on an operated ear.
• Inspect for foreign objects or excessive wax.  If there is an obstruction, the client should be referred to a physician.
• Note the following to assure a good impression:
  • size of canal to determine the size of the block necessary.
  • texture of ear and canal.  With very soft ears, it is easy to distort the impression when putting the material into the canal and ear.
  • angle and direction of canal.  It is important that the impression is a true and complete picture of the ear canal.
  • canal length.  The canal of the ear impression must be long enough to direct sound to the eardrum, this would be past the second directional turn.

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Exclusive from Mid-States - YELLOW STUFF TM and YELLOW STUFF II TM
The tip of the line, high-tech approach to impression taking,Yellow Stuff TM
products utilize a double barrel cartridge of silicone-type impression material
which is inserted into the ear with the use of an injection gun and mixing tip
system.  The material is mixed in the tip as needed.  After the impressionis
complete, the tip serves as a seal until another impression is required.

Yellow Stuff TM products offer a highly professional "no hands" approach while
providing the dispenser with a pressure less system that eliminates canal
distortion and results in a perfect replica of the ear.  The material is fluid enough
to fill the concha and canal perfectly, yet firm enough to "stay put" - no sag or
droop while the material is setting up, and no shrinkage in the finished product.

The best system ever!  Professional, perfect impressions - Yellow Stuff TM products are the choice of many of our most discriminating customers - we'd be happy to provide references!
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Ear Impression

    * For use when using Powder-Liquid Impression Material
  ** For use when using ACCU-FORM Silicone Impression Material
*** For use when using Yellow Stuff TM products
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Mid - States Powder/Liquid Impression Material
If using Powder-Liquid Impression Material, we recommend the use of our pre-measured vials of impression material to ensure accurate proportions of both ingredients.  These measurements are critical and the use of bulk material cannot be guaranteed to produce repeatedly reliable results.

The Powder-Liquid material produces an excellent impression, but one which needs care during handling.  As all Power-Liquid materials can be distorted, it is important that they be allowed to set thoroughly proper to mailing and that they be glued to the box insert for mailing.  In addition, high heat areas should be avoided when possible.   With proper use, Mid-States Pre-Measured Vials will provide you with a perfect impression!
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ACCU - FORM Silicone Impression Material
This material provides the dispenser with excellent impressions that have perfect memory and no shrinkage or distortion.  NO extra care needs to be taken in mailing as the material will not distort.  Care should be taken in making the impression to be sure that the denser material is not injected in a manner that could distend the ear.   With proper use ACCU-FORM will provide you with a perfect impression!
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Preparing the Canal

• Select a foam block or cotton block of the proper size as determined from the ear inspection.  Be sure that the thread or dental floss is securely attached to the block.
• Insert the block into the canal.  It is generally a good idea to guide the block into the canal with an ear light.  Always support the hand with the ear light to prevent any injury if there should be any rapid head movement.
• Insert the block to a sufficient depth to allow the impression to include the second directional bend in order to direct the sound to the tympanic membrane.  The ear block is essential on all impressions as it:
  • protects the eardrum from damage.
  • blocks material and allows it to expand to fill the whole canal.
  • assures a complete canal with the proper fial bend.
• In some instances it may be necessary to trim excessive hair in the canal.  Be sure to use blunt tipped scissors to reduce possibility of injury to the ear.

Making the Impression

1. Always prepare your materials in advance.
2. Follow the mixing instructions for the material in use.
3. With Powder-Liquid, mix with a spatula until a smooth creamy consistency is reached and the material has begun to congeal.  With ACCU-FORM, knead equal amounts of both components until colors are evenly blended.
4. Working rapidly, place the material in the proper syringe.  Press the plunger forward until a small amount of material is ejected.
5. With the canal block in the ear, place the nozzle tip of the syringe in the opening to the ear canal.  Be sure to support your hand to avoid any injury in the case of any rapid head movement.  Press the plunger gently, gradually withdrawing the syringe as the material fills the canal and begins to flow out into the concha and helix areas.   Be sure to fill the entire outer ear, especially the helix area, and keep the nozzle submerged in the material at all time for better filling and completeness of the total impression.
6. After the canal and outer ear are completely filled, apply only slight pressure on the outer surface of the impression to smooth for mailing purposes.
7. Allow sufficient time for the impression to set in the era.  Then minutes is the minimum time recommended.  Check by making an indention with the thumb nail.  If properly set up, no mark should remain.
8. Gently break the seal at as many points as possible to prevent distortion and reduce stress when removing the impression.
9. Grasp the pinna firmly with one hand and the impression with the other, rotate it slowly with an upward and outward motion.  The canal block should remain an integral part of the impression.
10. Re inspect the canal with an otoscope after removal to be sure the ear is clear.

(When using Yellow Stuff TM products, some variation in procedure will be necessary - consult the instructions.)
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Examining the Impression

After removal of the impression, critically evaluate all areas for accuracy.   If the impression does not represent a true picture of the ear, the best time to make a second impression is now.  In the long run it will save time in modifications and remakes.  Your client - and Mid-States - will appreciate your effort to make a perfect impression.

Handling and Mailing

1. Write the name of the client below the concha area.
2. Please mark the desired canal length.  We prefer that you NOT cut the canal, but cutting is preferable to no markings at all.
3. Glue the impression in the mailing box (glue not necessary with ACCU-FORM or Yellow Stuff TM products).
4. Place the completed order form with any special instructions in the Mid-States postage paid box.
5. To reduce possible distortion, do not place impressions in Post Office boxes for extended period of time during extreme heat.