Sometimes in an accident , you could knock out our permanent teeth , like with Isiah Thomas:
WATCH: Isaiah Thomas catches elbow, loses tooth in Game 1 of Wizards-Celtics

The most common ones to get knocked out are the permanent front teeth. Wearing a mouth guard helps reduces the risk , though there is no realistic way to prevent it .

In some cases , if the entire root is intact , the knocked out tooth ( avulsed tooth ) can be re-implanted into its socket . The chances of that succeeding are increased when the tooth can be put back ( re-implanted ) into its socket within one hour.

If you do knock out your tooth and it falls on the ground , pick it up from the crown part ( do not touch the root ). If there is soil on it – gently pour some water or milk on it. DO NOT SCRUB IT DOWN. Place the tooth either in the mouth next to the cheek ( do not make children do that – they might swallow it accidentally ). Alternatively , you could place the tooth in a cup of milk or covered by salva completely. Take it to your dentist as soon as possible.

We can , in certain cases , place the tooth back in the socket and splint it to adjacent teeth to immobilize it for a couple of weeks. Root Canal Treatment may need to be done on the teeth and there should be a follow up every 6 months to assess the condition of teeth.

Read more at: knocked out teeth