There are two things that determine the ease of replanting a tooth- that the tooth is kept in an ideal environment (one that is most like the gums), and the vitality of the cells remaining in the gums. In most situations, it can be reconnected to the socket by means of the periodontal ligament (a group of specialized connective tissue fibers that attach a tooth to the alveolar bone). It use to be thought that the best place to keep a tooth was in the mouth or milk, but an emergency tooth preserving system, such as Save-A-Tooth has proven to be the most reliable method. Most emergency tooth preserving systems lift the odds of being able to reattach a tooth after a delayed wait 10% to 90%, assuming ideal conditions.
This is a real dental emergency, as you can imagine, and is best treated after 20-40 minutes of an injury.
Biologic basis for success of replantation following dental avulsion
The reason the tooth can be reattached is because of the ligament. The ligament is the means that a tooth gets its resources, when it is knock out, it is stretched out and ripped in half. If you successfully reattach the two ligaments, then it can continue to get blood and resources, and is the kept alive through the body’s own curative process. If this seems unlikely, the tooth must be artificially maintained until they can reverse the damage done. The damage that is done is often call cell crushing. The crushing occurs when the sensitive areas of a tooth receive pressure, crushing cells in the tooth and ligament that could prevent re-bonding the ligaments in the future.