Tooth Knocked Out
If a tooth is knocked out, pick it up by the chewing end to prevent further damage to the nerves. The sooner the tooth can be reinserted, the better the chance of saving it. First try to return the tooth to the socket and bite down lightly to keep it in place.
Otherwise, put the tooth in a closed container of cool fresh milk (or water). Put a sterile dressing in the socket and bite down to stop the bleeding. See your dentist or emergency room doctor as soon as possible.
Emergency Orthodontic Appointment
As a general rule, an emergency appointment may be made when there is severe pain, a loose band, a broken wire or something sticking out that you can't take care of. It's important to know the names of the parts of your appliances. It will help, when you phone the office, to be able to identify what part is broken or out of place. For braces, refer to this diagram:

1: Band; 2: Bracket; 3: Tie wire; 4: Archwire; 5: Elastic ligature; 6: Elastic; 7: Headgear tube; 8: Buccal tube