John just got his fluoride trays and his understanding was that he's to wear them (w/the fluoride paste) all night. I don't see that mentioned by anyone here in the postings. The instructions on the paste say to keep it three minutes, I believe, then rub the stuff around w/one's tongue, then spit it out and rinse off the trays. Maybe it's different if one's using the fluoride b/c of cancer treatment...Anyone else here been told to use them all night?