What can help stop grinding teeth that won't move and gag or choke an Alzheimer's patient?

Well, I'd already discussed it with her doctor and the Home Health agency. I'm not sure it's from anxiety, because she'll be smiling and still do it. You'll get her to laugh, and she still does it. She does it morning, noon, and night now. She usually seems to be in a good mood, as nearly as we can determine (thankfully). She does it before eating, after eating, etc., so it doesn't seem to be a hunt that she's hungry, either, I think. It's really baffling.

I'd discuss it with her doctor to see what might help. Sometimes, teeth grinding can be a result of undue anxiety. I'd explore if medication could help. Maybe, if her anxiety were reduced, the grinding would too.