I chipped a tiny corner of one of my front teeth this afternoon. I have no idea how it happened. I was sitting at my desk when my tongue felt something sharp. I checked in the mirror and found that I had chipped a tooth. I had not been eating anything, chewing anything, grinding or clenching my teeth.
I find this particularly disturbing because I have frequent dream in which my teeth break off in pieces. They feel dry and porous, like pumus rock, and when I run my tongue over them small pieces come off until eventually I have half a molar missing.
Not quite déjà vu, but definitely disconcerting.