I don't know if this is "dental"- but didn't know where else to put it. Sometimes, during the night, or at other times, I have this waxy, lumpy, grey or white substance come out of the roof of my mouth. It's crumbly and it smells like death! It happens maybe once every couple of weeks. Does everyone get this? It started about a year ago...very strange. I've never heard of this- have you?