When is it recommended to attempt to replace a knocked out tooth in the ER for an adult or child with no significant medical history, such as a bleeding disorder, within a short time frame after the injury?

When to Attempt Tooth Replantation in the ER

An avulsed permanent tooth should be replanted immediately in the ER—the sooner the better, with the highest success when replanted within the first 15-30 minutes after avulsion. 1, 2, 3

Immediate Replantation is Always Recommended

The treatment of choice for an avulsed permanent tooth is immediate replantation, regardless of time elapsed since injury. 1, 2 The 2024 American Heart Association and American Red Cross guidelines explicitly recommend attempting to replant the tooth in the socket as an initial action after briefly rinsing visible debris for less than 10 seconds. 1

Time-Critical Nature of Replantation

• The likelihood of successful reimplantation decreases rapidly with every minute the tooth remains out of the socket, particularly as the periodontal ligament fibroblasts die or become injured. 1, 2
• Optimal outcomes occur when replantation happens within 15-30 minutes of the avulsion injury. 2, 3
• Even if the tooth has been out of the socket for longer periods, replantation should still be attempted, though prognosis worsens significantly after 60 minutes of extra-alveolar dry time. 4

Critical Pre-Replantation Steps in the ER

Confirm Tooth Type

• Verify that the avulsed tooth is a permanent tooth, not a primary tooth—primary teeth should never be replanted. 1, 2
• This is particularly important in children where tooth type may be uncertain. 1

Proper Tooth Handling

• Handle the tooth only by the crown portion, never touching the root surface, as the root is covered with fragile periodontal ligament fibroblasts essential for successful reattachment. 1, 2
• If the tooth is dirty, rinse it briefly under cold running water for less than 10 seconds only—avoid scrubbing or prolonged washing. 1, 2

Replantation Technique

• Gently reposition the tooth into the socket using digital pressure. 1
• Have the patient bite down on clean gauze or cloth to hold the tooth in position until definitive dental care. 2
• Ensure the tooth position does not interfere with occlusion by having the patient say "cheese" or the letter "e" to visualize that posterior teeth can fully interdigitate. 1

If Replantation Cannot Be Performed Immediately

Storage Medium Hierarchy (in order of preference)

1. Hanks Balanced Salt Solution (best option) 1, 2, 4
2. Oral rehydration salt solutions 1, 2
3. Propolis or rice water (if preprepared) 1, 2
4. Cling film wrap to prevent dehydration 1
5. Cold cow's milk (acceptable alternative) 1, 2, 4
6. Saliva (patient can hold tooth in buccal vestibule) 1, 4

Critical Storage Pitfall

• Never store the tooth in tap water—this causes osmotic lysis of root fibroblasts and significantly worsens prognosis. 1, 2

Post-Replantation ER Management

Immediate Stabilization

• Apply direct pressure with clean gauze to control bleeding from the socket—copious bleeding from gingival tissues and alveolar socket is expected. 2
• Arrange immediate dental referral for placement of a flexible splint, which will be needed for 7-10 days. 1, 2, 4

Antibiotic Prophylaxis

• For patients over 12 years old (including adults): prescribe doxycycline as the systemic antibiotic. 2
• For children under 12 years old: prescribe penicillin, or clindamycin if penicillin-allergic. 2

Patient Instructions

• Advise the patient that root canal therapy will likely be required within 7-10 days after replantation. 2, 4
• Prescribe chlorhexidine rinses and emphasize stringent oral hygiene while the splint is in place. 4
• Provide analgesics as needed for pain management. 4

Common Pitfalls to Avoid

• Do not delay replantation to search for optimal storage media—immediate replantation is always superior to delayed replantation even with ideal storage. 2
• Do not allow the tooth to dry out—extra-alveolar dry time is the most critical prognostic factor. 2
• Do not scrub or aggressively clean the root surface—this damages the periodontal ligament cells. 2
• Do not assume the tooth cannot be saved if significant time has elapsed—even teeth with prolonged extra-alveolar time should be replanted, though prognosis is guarded. 4