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How to create a good ear impression .... wot I do ....


I have been asked what I learned when preparing for my UK hearing aid dispenser exams.
This info is purely my experience and provided WITHOUT liability. You MUST check with your instructor BEFORE using any of this

I suspect that youngsters (i.e. under 50!) can work with any tools and simply overcome their limitations etc - but I need to
optimise my tools in order to do a good job.

The following work for me at age 50 - but there is NO guarantee that this will work for you - or that is safe!

After trying several sorts I now use the Phonak otoblocks. These are high quality CONICAL foam blocks and almost always line-up 100%
OK. Why bother with cylindrical foam blocks which always want to turn over?

My eyesight is poor so I use a syringe so I can be close to the patient.
The guns have long "mixing probes" which keep me too far from the patient. Their resin is also very thin.
[I did want to try a Westone electric gun - but at $400 they seem very expensive]

I have tried several sorts. The green Phonak resin is, for me, too "thick". The blue Puresil 2 is too "runny". However I find the
yellow Detax resin 100% perfect & wonderful - it flows well, but does NOT move after being injected .... it simply "smooths" itself.
[Some other Detax resins are VERY thin]. The only minor problem is that it takes about 10 minutes to set [in UK temperatures]

Make sure that you use a bright lamp especially when syringing - either a mains lamp or a "head light".

Use one hand to pull pinna back and then push otoblock in, with bright light probe, one or two smooth moves until deep enough -
don't bother with many tiny pushes. The Phonak conical shape helps greatly here. Don't be shy - make sure the block is deep enough
... but NOT too deep! Get your instructor to help you learn this.

Place the nozzle near the otoblock, syringe steadily keeping tip buried, and sort of "float" the tip out with the resin. When the
concha is mostly done, sweep round to the helix and then back to fill the rest of the concha. Make sure all the edges are covered.
This takes a bit of practice. Do NOT be random - learn a technique that works for you, and stick to it.

Follow ALL your countries safety rules - do NOT take an impression if there is wax, infection or any other problem; ALWAYS use an
otoblock; ALWAYS check the block has sealed the canal BEFORE syringing; do NOT syringe too fast or hard; follow ALL the bracing
rules; SIT do NOT stand during all this; do NOT pull the cord to remove an impression; GENTLY break any air seal whilst removing the
finished impression [I grip the bottom edge of the hardened resin and wiggle whilst pulling gently]; do CHECK the ear canal AFTER
the impression to make sure there is nothing left behind and no bleeding etc

I obtained a couple of rubber ears and did about 40 impressions with all sorts of resins, otoblocks etc. You feel very silly doing
this ... but the practice IS worthwhile! [My rubber ears wore out!]

A can of worms ... read your local rules!

I'm sure I've missed lots of things ... if anyone has additional or differing hints etc please do add your input!

I found that finding a resin brand which suited my personal style was the key issue.
The "concha-helix-concha" sequence is also very important - for me at least.

Have fun - but be safe!



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