First and foremost stay calm, since your child will probably be hysterical. If it's a baby tooth, there's no need to run right to the dentist or ER (baby teeth aren't as deeply rooted as permanent teeth and are much more prone to being knocked out). Don't worry about finding the tooth unless you want to save it for the scrapbook, because your dentist probably won't reattach it. Just have your child rinse his mouth with water and then apply a cold compress (like a clean washcloth) to keep the swelling down and stop any bleeding. Be sure to let the dentist know what happened, though. If the underlying permanent tooth will not be coming in for a while, your child may need a false tooth to keep the neighboring teeth from crowding into the newly vacant space and ensure that his permanent tooth grows in normally. Any early trauma could also affect the enamel on the developing permanent tooth, making it more vulnerable to decay later on.
Knocking out a permanent tooth, however, is an emergency, but there's a good chance it can be successfully reattached if you get it taken care of immediately. Rinse the tooth gently with water, but don't scrub the roots or use soap. Have your child hold the tooth in place if she's old enough, if not, put it in a clean container of milk, which has a similar pH level to saliva, and head to your dentist or the ER. --Richard Laliberte
Copyright © 2001. Reprinted with permission from the September 2001 issue of Parents magazine. Updated 2009