Originally Posted by JeffS
I'm planning on getting impressions soon for new custom tips. Last time my audiologist had me just relax my jaw and my fit was not really good. When I had them refit he had me hold my mouth open as wide as I could for the entire time. Obviously holding my mouth open does not relax the jaw and I wonder if that makes a difference in fit. It was good but I wonder now if it could have been better.
What kind of difference does the bite block make, and how lager is is a large bite block? You seem to have some experience in this area so I'd appreciate your thoughts.
Hi, yes, I had several re-fits with my custom and had some discussions with the chief of operations of the custom company as well as with the audiologist (who was very experienced and a musician himself). The basic idea is that your ear canals change shape as the muscles in your jaw clench/relax and the mandible (jaw bone) moves. The ear canal opens when the jaw opens and it opens when you relax your jaw muscles. So, even if you're not a musician, you might just smile, yawn or eat some food or drink something while wearing the customs. You want a mold that properly reflects the dimensions of the ear canal during use. Now, there sadly isn't just one answer to this and custom iem companies have changed their recommendations over the years. However, what makes the most sense for most people who have working mouths is to use a bite block and also relax your jaw.
My first set of impressions used a usual size bite block and the impressions didn't work so well. After a few attempts at re-fits, I needed new ear-molds. We went with a larger bite block because when I opened my mouth, the seal was lost with the first mold. My audiologist actually did a free second set with a closed mouth just to give the techs at the custom company more to work with. I ended up with a very good fitting set.