The most important thing to do when a child knocks out a permanent tooth is to remain calm. Locate the tooth and hold it by the crown. Rinse the tooth with salt water or milk to remove debris, but do not use water. Be careful to avoid contact with the root. If the root is intact, you can try to reinsert it into the socket. If you are unable to do so, place the tooth in a glass of milk and take your child to the dentist immediately. If your child knocks out a baby tooth, don’t try to reinsert it; you may damage the developing adult tooth below it. You should still take your child to see the dentist for an evaluation as soon as possible if he or she knocks out a baby tooth.