New Invisalign tray doesn't fit perfectly

Good Question.  Make sure you have worn your last tray the full amount of time prescribed by your dentist, usually 22 hours/day for 2 weeks.  If you skipped even a few hours it helps to add a full week to allow the teeth to fully complete the movement needed, so they are ready for the next tray.  If after the extra week wear the new tray for 2-3 days to see if it settles in.   Sometimes toward the end of an Invisalign case you will start to enter a phase of over correction where the trays look and feel different.  I often have patients that I start increasing their time in each tray to 3 even 4 weeks at end stage trays.  Bottom line, if a new tray doesn't feel right after a few days, go back to your old tray and ask your dentist advice, they can check your stage and give you a better idea what you should expect.  

Hi gemma1984,Thank you for posting your question.  If aligner #19 does not fit well then you may need help to seat it more. You can chew on cotton rolls to help seat it down further so it is flush with your teeth.  If after a few days the aligner is still not fully seated then you should see your dentist prior to placing the next one.  Sometimes these types of situations do resolve with wear.  You may also consider calling your dentist and hear what he has to say. Hope this helps.  Good Luck!