If you lose a tooth from trauma you should:
Rinse it very carefully with water to remove dirt.
Try not to touch the root and hold the tooth by the crown (part of the tooth that is visible and is outside the gum in your mouth)
Store the tooth in your mouth between the gum and your cheek or under your tongue. When this is not possible store it in milk.
Contact your dentist and go immediately to the office so that the tooth can be Re-Implanted as soon as possible raising the chances of success of this procedure.