I had my teeth pulled before radiation, and did not get my dentures for five months afterward. I had lost a lot of bone, and my denturist felt I would need adhesive. But I didn't because I could not swallow, and therefore was not eating at all. Seven months later, after several throat dilations, I began eating, and now need to use adhesive. My teeth still move some when I eat, but I think it's because they need some adjustment. There are some foods that I may never eat, due to the combination of the dentures not being as good as real teeth, and my low saliva status. But it's getting easier all the time.
I have a friend who wears dentures and uses the solid sheets for her uppers that were recommended above. She swears by them, and I suspect eventually I'll look into them. They seem like a good alternative for those of us with little mouth moisture.