Knocked Out Permanent Tooth
From:Tips for Dealing with Dental Emergencies

Hold the tooth by the crown and rinse off the root of the tooth in water if it’s dirty. Do not scrub it or remove any attached tissue fragments. If possible, gently insert and hold the tooth in its socket. If that isn’t possible, put the tooth in a cup of milk and get to the dentist as quickly as possible. Remember to take the tooth with you!