I have TMJ and Sjogrens Syndrome. Medication also dries my mouth out besides the Sjogrens.

Also if you have really dry mouth you end up with lots of plaque on your teeth

I clench mine with stress and they get bad as I put a lot of strain on them, so much so they wobble and I have had them break too. I now have an anti bite reizor ( gum shield) that helps take the pressure off and I use it every now and again overnight and it does help x

Have you been tested for Sjogrens Syndrome?
Pronounced Show-grins
A blood test will show up if you do

Clenching , grinding and I bite myself a lot. A hard nip on my lip or inside of my left cheek all of a sudden .... chomp! My bite is way off, my gums have very much receded. etc, etc.
Yes, it affects teeth very much. I've heard of teeth shattering even.