Should your new trays fit your teeth perfectly or will you have retainer space at the bottom of the teeth
When You Get a New Set of Trays Are They Supposed to Fit Well?
Doctor Answers 2
New aligners should fit tight
New aligners (trays) should fit tight at the beginning.
There should be no retainer space.
New Invisalign® trays should be tight
Each new tray is set up to where the teeth should move TOWARD, not how they are currently. There may be some space, but it shouldn't be much. After a few days of wearing them, the teeth should have moved into place. If not, return to the dentist and see what they say. It is likely going to take care of itself.