CREATING THE PERFECT IMPRESSION
An accurate ear impression is fundamental to achieving a successful patient fitting. The correct fit results in patient comfort, helps prevent feedback through good acoustic seal and retention and ultimately provides a better hearing experience. It also results in less return appointments and time savings for the dispenser or audiologist.
Impression materials must be stored between an ideal temperature range of 15 - 28°C and used within the use by date indicated on packaging.
The Open Jaw Technique
‘Open Jaw’, is a technique well researched and 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, yawning without losing retention and reduces the problem of the fit loosening.
Impression Checklist
When the impression has been completed, the following points provide a useful checklist to ensure the impression is ready to be sent to the earmould laboratory for production:
- Is the impression a uniform colour?
- Are the helix and antihelix complete?
- Does the impression have a smooth finish?
- Ensure there are no air bubbles or voids
- Is the canal length sufficient to define the second bend of the ear canal?
- The impression material itself is not 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 (caused by the impression material drying too quickly)
Too much canal length on an impression is never a problem for the production team. Too little is!
Often the acoustic seal of an earmould occurs at the aperture 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. However it is necessary for the laboratory technicians to have impressions with good definitions of the ear canal including the second bend. This helps them make moulds that do not feedback due to the sound outlet being occluded by the ear canal wall.
The use of more viscous impression materials, long canal lengths, and where excessive jaw movement noted, open-jaw impressions are critical factors in producing impressions that work.
Starkey run a number of refresher courses on impression taking, combining technical seminars with the latest product innovations and industry advice. To learn more about our courses, please contact Customer Service.
Impression Taking Material
Otoform AK X
Ideal for all types of impressions.
- Pink
- 3 minutes 15 seconds curing time
- Available in 250ml or 500ml Tubs
| PRODUCT CODE | PRODUCT DESCRIPTION |
|---|---|
| 43050-000 | Otoform AK X - 2 x 250ml Pots |
| 43051-000 | Otoform AK X - 2 x 500ml Pots |
Otoform A Soft
Product of choice for those who prefer the auto canular approach.
- Yellow
- 3 minutes 15 seconds curing time
- Convenience of gun injector system
| PRODUCT CODE | PRODUCT DESCRIPTION |
|---|---|
| 43048-000 | Otoform A Soft - 8 x 50ml Cartridges |
| ENG65-058 | Injector Gun |
| 43049-000 | Otoform A Soft - 40 x Canulas (pink) |
Otoform KC
- White impression material / Red hardener
- 4 minutes curing time
| PRODUCT CODE | PRODUCT DESCRIPTION |
|---|---|
| 43052-000 | Otoform KC - 800g tub (includes 20ml tube of hardener) |
| 43053-000 | Otoform KC Hardener - 20g Tube |