Does this ever happen to you?
Brushing my teeth I felt something not quite right in my mouth. No surprise there. I had sort of expected an oddity, and I got it.

I spit into the sink. Out came dozens if not hundreds of tiny balls of metal which I recognized as material from old fillings. Spitting again, two teeth clattered into the basin. Rubbing my tongue around my mouth caused a couple more to loosen and tumble to the sink which was now frothy with bloodstained foam.

It was quite disconcerting.

Fortunately I awoke before calling a dentist.

I assume that my dentist appointment for the following morning triggered this dream.