Here’s what to do if your crown falls off, with Dr. Mark Burhenne of Did you know that crowns are not kept in place by glue? Crowns are kept in place by mechanical retention. Do not glue your crown back in yourself! It could fall back out again and result in you swallowing it, meaning you’ll have to pay for another one. If your crown falls out, see your dentist right away. You can put your crown in a plastic ziploc baggie so your dentist can put it back on for you.