When I attempted to put in tray # 11, the bottom tray fit fine, but the upper tray did not. The attachment on one tooth did not line up with the hole on the tray. I wore tray 10 for another week or so. Finally, the dentist made a new impression for the upper teeth and said I would have to do mid-course refinement. How long does it take for the refinement trays to come back? It was about a month before I got the original trays.