Tooth knocked out or loosened.

 

If the tooth is chipped badly (more than 1/4 of the tooth.), see the dentist the next day.

Teeth are a common injury in children.  If knocked out completely, push a permanent tooth back into the socket in the correct direction.  
Only handle the tooth by the crown and not be the root. 
If you cannot  re-implant the tooth back into the socket, save the tooth in Saliva in the corner of your cheek and gum. 
Or in milk in a bag and put on ice.  If filthy, rinse briefly with water but only for seconds. 
Water for a long time is harmful.  There are also tooth transport media that a can be purchased.  
It is preferred to have the tooth implanted inside 2 hours so go now! 

DO NOT SAVE OR RE-IMPLANT BABY (DECIDUOUS) TEETH.  It is worse to put them back in.   Re-implant permanent teeth only.

http://www.healthychildren.org/English/tips-tools/symptom-checker/Pages/Tooth-Injury.aspx

 If tooth is traumatized and not loose, just watch it. If the corner is chipped, watch it.

If the tooth is loose but in socket and not chipped, then give liquids only and see the dentist the next day to “splint” it.

Roger Knapp MD

 (see: http://www.save-a-tooth.com/ )