A new set of aligners will put pressure on your teeth that will usually cause some pain or discomfort. The pressure of the trays gradually shifts your teeth, and so this discomfort means Invisalign is working. One way to minimize the discomfort that comes with a new aligner tray is to start using it at bedtime. This allows you to sleep through those first several hours that are typically the most painful. When you wake up, your teeth may feel a bit sore, but the worst of it passed while you were dreaming about your new smile.