Among the many things wrong with fluoride use, one of them is the potential to act as a cholinesterase inhibitor. Mestinon is a cholinesterase inhibitor.

I don't have the energy right now to do all of the research on this topic. Simply search "fluoride acetylcholine."

It's very hard to find a toothpaste without fluoride in it, and, if you do, it'll probably have equally as toxic substances in it. Tom's brand might have one without fluoride, if I recall correctly.

Simply try brushing without it once, and see if you're mouth is still weak. If it is, it's do to the use of muscles while brushing. If that's the case, you might use that as a clue to your MG becoming worse (to some degree).

Annie