I have a recurring nightmare. It always involves one of my teeth cracking and falling out in bits. In my dream, I have that sort of large gritty sensation from it in my mouth, like when you've gotten too much plaque build-up or (if you ever had braces) when they're scraping the remains of cement off your teeth. It's always realistic enough that when I finally managed to wake myself up, I end up checking all my teeth to make sure they're still there, after which I like, heart-pounding, in bed waiting to calm down enough to go back to sleep.
Most times in my nightmare, it happens when I'm chewing gum and it sticks to my teeth, and they come out in my hands as I try to pull the gum out. Last night's dream was a little different. I was in a parking lot, like the one were the Caldor's used to be in Crosstown Plaza, with a group of girls, and suddenly I felt my tooth crack for no reason, my right incisor, and could feel the pieces and the blood floating in my mouth. I spit into my hand, little bits of hard white with the blood, and reached into my mouth to pull out the remainder of my tooth, its root rotted to nothingness, from the top of my mouth and just stood looking at the pieces in my hand, tongue probing the empty spot in my gums. Then I woke up. I could still taste the blood in my mouth.