Hey,
Recently, I had a dream in which my jaw was very painful :
I clenched them very hard ( not on pourpose ) and my teeth were distorted ( a lot ), it wasn’t a LD for sure and I know this dream lasted 5-10 min ( constant pain ).
Plus, this is a recurrent dream.
I don’t know how the pain is triggered off.
All I know is that I have had a dental device ( LOL I’m French, I hope you understood me ).
did you have the device at the time? it could be real life discomfort transferred to the dream. or it could be the memory of having to use one triggering these dreams.
I think you probably clench your teeth in your sleep.
No, I no longer have that device and I noticed that a couple of days ago, I clenched my jaw just before sleeping, it surprised me because it wasn’t deliberate ( I sleep on my chest and my pillow must make me clench my jaw, probably ).
This is pointless but it really embarass me and it happens to me during the night and I can’t counter-act that.
Try sticking a rock in your mouth! 
Just kidding. I have my braces still and they are a pain in the A**! What I do, is put wax on the areas that hurt. I don’t know why, it just makes you feel better.
I used to clench my teech while sleeping when younger, so dreaming about pain and loosing teech was a bit normal.
It might be your imagination only, but yourself clenching your our teech is more probable.
Some dental devices, leave the teech unstable for some days, (I’m not sure how long because I didn’t have to use them, but my sister did) and depending how you apply pressure to them, they hurt a lot.
You may wish to see about getting a mouth guard for sleeping. I too sleep on my stomach and find I clench my teeth sometimes painfully enough to transfer into dreams.
The alternative would be to start laying on your side, or stop using a pillow. Sleeping on your stomach with a pillow puts your neck at an odd angle and can cause neck pain, or you could try a memory-foam pillow as these offer better support and I found since buying one I don’t clench as much.
I hate sleepin on my back, it’s too incomfortable for me ( except the morning in holidays cause I’m tired ).
But these pains in NDs happen 2 or times a month to me ( but this is a ****ing pain ). It could make me lucid but this isn’t the appropriated topic.