Here are some tips for common dental problems:

Broken or chipped tooth: Save the tooth parts and see your dentist.
Abscessed tooth or gum: Take a pain reliever and see your dentist.
Toothache or lost filling: Take a pain reliever and see your dentist.
Broken crown: Save the pieces of the crown and see your dentist.
Broken wire on braces: Cover the end of the wire with wax or gauze and see your orthodontist or dentist.
Knocked-out tooth: Pick up the tooth by the crown, not the root. Rinse the tooth lightly with water or saline solution (e.g. contact lens solution) and try to replace the tooth. For best chance of survival, the tooth should be replaced within 20 minutes of being knocked out. If you cannot replant the tooth, store it in saline or milk or hold it in your mouth. Whether or not you are able to replant the tooth, see a dentist as soon as possible.
Bleeding gums: May be a sign of gum disease. See your dentist.
Fractured jaw: Immobilize the jaw and go immediately to your dentist or hospital emergency room.