T.K.O. Sometimes means tooth knock out! Oral injuries are common during sports activities. A properly fitted mouth guard significantly reduces the risk of oral trauma, but accidents can still occur -- such as an "avulsed" tooth. An avulsed tooth is one that has been knocked out of the socket. If this occurs it is important to get to the dentist as quickly as possible. The odds of saving a tooth are highest in young children, but adult teeth can be saved as well. Only permanent teeth should be re-implanted. It is also important to avoid damaging the tooth even more. Rinse the tooth off with water or milk, and keep the tooth moist! A tooth that has been knocked out starts to die within 15 minutes. To preserve the tooth until you're able to reach the dentist; put the the tooth in milk or carefully place it back into the socket and hold it in your mouth. Either method will help the tooth survive longer.