The success rate for replantation of permanent teeth is highest when the tooth is replanted within _____ of the avulsion.

• A. 5 minutes
• B. 30 minutes
• C. 2 hours
• D. 24 hours

Answer: (B)

Preserving periodontal ligament cell viability on the root surface is the key for a favorable replantation outcome. When a permanent tooth is avulsed, these cells can die quickly if the tooth dries out. Replanting as soon as possible keeps more PDL cells alive and able to reattach in the socket, guiding normal healing rather than leading to complications like ankylosis or resorption.

Within about 30 minutes, a larger portion of PDL cells remains viable, which is why this window yields the highest chance of success. If replantation is delayed beyond that, cell death increases and the prognosis worsens; times like 2 hours or 24 hours are far less favorable due to extensive tissue damage and poorer healing.

If immediate replantation isn’t possible, storing the tooth in an appropriate medium (such as milk or a balanced solution) and seeking dental care right away helps preserve viability until replantation.