YSK that you might be grinding your own teeth while asleep without knowing it
Why YSK: it’s a common condition called bruxism and I know two guys who had it and had no idea.
Two major clues for if you have bruxism are: 1) your teeth are flattened from all the grinding, like this 2) your teeth hurt first thing in the morning and/or they feel loose.
The treatment for that as far as I know is to wear a mouth guard while asleep.