TMJ disorders are linked to tinnitus because of the nerves that run near it. In my case, if I force an underbite I can make both of my ears ring but I don't have any TMJ issues.

There are some physical therapists (also dentists) that focus on maxillofacial dysfunction and TMJ disorders, so that's an avenue to go down as well.

The other two common reasons for tinnitus:

* Hearing damage (gunshots, explosions, etc.) and those are not reversible as of yet

* Ototoxic drugs. When I last did research on it it years ago, like hearing damage from gunshots, was also irreversible.

When you say clench, do you mean clench the muscles (i.e. as if biting down), or do you mean jutting your jaw forward?

There is a well known phenomenon among people with (at least some types of) tinnitus that moving the jaw forward increases the sound, but that this also makes the tinnitus go away for a bit. The way my ENT explained it, it has to do with how your brain calibrates sound. Pushing the jaw forward makes the sound louder, which also causes your brain to adjust your hearing to be less sensitive. Or something like this.

With some types of tinnitus, there is a specific connection to the temporomandibular joint. My understanding is that the causes tinnitus are poorly understood, however. There are many hypotheses, but little solid evidence.

Biting down.