If an injury causes a tooth to be completely knocked out of your mouth, it is important that you are treated immediately. If this happens to you, keep the tooth moist. If possible, put it back into the socket. A tooth can be saved if it remains moist. You can even put the tooth in milk or a glass of water (add a pinch of salt.) Your endodontist may start root canal treatment based upon the stage of root development. The length of time the tooth was out of your mouth and the way the tooth was stored, may influence the type of treatment you receive.