If there is just a small tooth chip or fracture
without swelling or pain, this is not a dental emergency and the tooth can be repaired at your leisure. However, if there is significant fracturing, pain, swelling, or bleeding
then you should get to the dentist
as quickly as possible. This is because it is important to assess the extent of the damage and decide how to treat it. Exposed pulp inside the tooth needs to be protected to prevent infection or worsening of the injury.
You should save any tooth chips, if you can find them, as they may be able to be cemented back into place. If there is bleeding or swelling, this can be controlled with gentle pressure to the area with gauze.
If the tooth has fallen out completely, this is a serious problem that needs to be seen by a dentist immediately. If possible the tooth should be reinserted into the socket because this has the best chance of keeping the cells on the tooth root alive and maximizing chances for getting the tooth to reimplant. If that is not possible, then placing the tooth in a small plastic bag with some saliva will help.