Biotene makes a gel that works pretty good for me. I keep it by my bed and squeeze a drop or two on the back of my hand then put it in my mouth and swish it around making sure it coats all my teeth.

I've seen something new at the drug store, but I haven't tried it. It's some kind of disc that naturally sticks to the roof of your mouth while you sleep. The problem is, I'm so sensitive to ingredients, that I'm kind of scared to anything new right now.