Intentional replantation of a permanent tooth can be successful, if the dry time (how long the root of the tooth spent OUTSIDE the bony socket) is less than 20 minutes.
The longer the dry time, the more likely it will be for the cells lining the external root surface that form the attachment structures to the bone (periodontal ligament) will die. When these cells are no longer viable, the root of the tooth cannot integrate with the bone. This means that the root of the tooth may become either:
1) Ankylosed
The root of the tooth becomes fused to and progressively replaced by bone in a process called ankylosis. This can result in the tooth seeming to sink in relation to the adjacent teeth. Ultimately, the tooth may be lost.
2) Externally resorbed
Inflammatory cells from within the bone eat away at the tooth root causing external root resorption. This causes pain and inflammation in the gum, the tooth may loosen and extrude out of the gum.
Confirming a diagnosis of ankylosis or external resorption is done using xrays. Both diagnoses mean that the replantation has failed and that the tooth will need to be extracted.
The replanted tooth should be splinted (with a flexible splint) to stabilize its position for 2 weeks while initial healing occurs.
If replantation is successful, there should be new bone and periodontal ligament formation on xray within 6-8 weeks.
If replantation of a living mature tooth (with a vital nerve/pulp) was done, then root canal treatment must be started within 7-10 days to prevent another type of root resorption (internal root resorption) from occurring.
Clinical and radiographic (xray) monitoring of the healing and long term stability is essential.
