When a tooth has been knocked out, the nerves, blood vessels and supporting tissues are damaged, too. The nerves and blood vessels can't be repaired. That is why all avulsed teeth will need a root canal. However, the bone can reattach to the root of the tooth once it's put back into place. The odds of saving a tooth are highest in young children, but adult teeth can be saved as well. Only permanent teeth should be re-implanted. It is important to get to the dentist as quickly as possible after a tooth has been knocked out. It is also important to avoid damaging the tooth even more.