Yes, certainly.
The ones which you heat in boiling water can be shaped quite well to cover much of the roof of the mouth. Also if you keep reheating and reforming, you can get them quite thin and tight fitting.
I did have one and once it was formed to shape, I carefully cut away the front 4 teeth so it did not show in normal use but the plate part and the sides were still there, almost like part of twin blocks.
Not like the real thing though.