It does seem to help to a degree, however even using the shortest bands apparently supplied by clear guard, my lower jaw is not extended as far as when I used my last device made by a dentist - and I can tell if doesn't work as well due to this. (Confirmed using my overnight pulse ox). By my estimation, if they had a band 1/2 to 3/4 size of smallest it would do the trick. Mine has also cracked only after a few weeks.