Yes, my teeth shifted. I had 2 lower molars pulled before radiation (one on either side). Then my dental fluoride trays were fitted, fitted, fitted and fitted. 3 times after the rads. (Long story) Whenever I wore them, my bite was uncomfortable after.
So I stopped wearing the trays and brushed with fluoride 2 times a day instead.

Then 2 of my front teeth moved - one back and one forward. The dental clinic told me that although brushing was fine, the trays act as a retainer, so I had to choose between my front teeth moving and being able to eat comfortably.

They said it was a result of the extractions combined with radiation.

It can all be fixed by a Prosthodontist, I just have to win the lottery first!