Avulsion and Replantation
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Direct answer
An avulsed permanent tooth is one of dentistry's genuine emergencies, and the two facts that decide its fate are how long it has been dry and what it has been stored in. Best outcome comes from replantation at the scene within minutes; the 60-minute extra-oral dry time is the pivotal threshold — beyond it the periodontal ligament cells are considered non-viable. Handle the tooth by the crown, rinse the root gently with saline, never scrub or touch the root surface, and replant it immediately or transport it in Hank's balanced salt solution, cold milk, or saline. Current IADT guidance splints all replanted teeth with a passive flexible splint for two weeks, four weeks if the alveolus is fractured, and prescribes systemic antibiotics such as doxycycline or amoxicillin. Closed-apex teeth need root canal treatment within seven to ten days; open-apex teeth replanted quickly are given the chance to revascularise. Primary teeth are never replanted.
What you must remember
- The clock rules: prognosis is best with replantation within about 20-30 minutes; extra-oral dry time beyond 60 minutes means the periodontal ligament will not survive, whatever is done later.
- Handling discipline: hold the crown only, rinse the root with saline, do not scrub, scrape, disinfect, or let the root dry — every root-surface cell saved is healing potential preserved.
- Storage media, in order of preference: Hank's balanced salt solution, then cold milk, then saline; saliva is a stopgap for minutes, and tap water is avoided because its hypotonicity bursts periodontal cells.
- Replantation and splinting (IADT 2020): irrigate the socket, leave an intact clot undisturbed, replant with firm apical pressure, confirm alignment, and apply a passive flexible splint for two weeks — four weeks if the alveolus is fractured.
- Antibiotics: systemic doxycycline (age-appropriate) or amoxicillin are recommended to reduce infection-related root resorption, plus tetanus prophylaxis if the wound is contaminated.
- Endodontic timing by apex: closed apex — root canal treatment within seven to ten days, ideally at splint removal, because the pulp will necrose; open apex replanted within 60 minutes — defer, watch for revascularisation, and treat endodontically only if necrosis appears.
- Outcome vocabulary: periodontal ligament healing is the goal; its failures are inflammatory (infection-related) resorption and replacement resorption with ankylosis, which eventually loses the tooth.
- Primary teeth: never replanted — the risk of damaging the developing permanent successor outweighs any benefit.
A typical exam case: the phone call before the patient
A schoolteacher phones: a twelve-year-old has had a permanent front tooth knocked out and it sits in a handkerchief. What you say in the next sixty seconds decides the tooth. First: do not clean or scrub it — hold it by the crown. Second: replant it into the socket at the scene and bite on a handkerchief if the child can cooperate — a tooth replanted within five minutes has the best prognosis of all. Third, if replantation is impossible: milk (or saline) and come immediately; a first-aid device holding Hank's balanced salt solution is even better. On arrival: rinse tooth and socket with saline, replant with digital pressure, confirm clinically and radiographically, apply a flexible composite-and-wire splint, prescribe amoxicillin (doxycycline age-dependent per guidance) with tetanus cover if contaminated, and advise soft diet. The apex is closed, so schedule root canal treatment within seven to ten days, removing the splint at two weeks. Review for resorption at one, three and six months, then yearly. Avulsion vivas are staged as exactly this phone call.
High-yield viva angles
The examiner's staples come in a fixed order. "Best storage medium?" — Hank's balanced salt solution, then milk, because HBSS is pH- and osmolality-compatible with living periodontal cells. "Why not water?" — hypotonic water lyses the cells the procedure depends on. "Why the 60-minute dry threshold?" — periodontal fibroblasts desiccate beyond recovery in about an hour, committing the tooth to replacement resorption. "When root canal treatment, and why that week?" — seven to ten days for closed apices: after ligament reattachment, before inflammatory resorption begins. "Which teeth must not be replanted?" — primary teeth, protecting the successor follicle. A sharp external adds: "The replanted tooth is percussion-tender with a metallic sound — what is happening?" — ankylosis with replacement resorption, the diagnosis the protocol tries to avoid. The theory essay "management of an avulsed tooth" is marked as a flow: emergency instructions, transport, replantation, splinting, pharmacology, endodontics, follow-up — answer in that order.
Frequently asked questions
What is the best way to store an avulsed tooth before replantation?
Hank's balanced salt solution is ideal, with cold plain milk or saline as practical alternatives — the goal is a medium that keeps periodontal ligament cells alive, which plain water cannot.
Why must the avulsed tooth not be scrubbed or cleaned chemically?
The periodontal ligament cells clinging to the root surface are the tooth's chance of normal healing; scrubbing or chemicals destroy them and commit the root to resorption.
When should root canal treatment be done on a replanted tooth?
For a closed apex, within about seven to ten days after replantation; an open-apex tooth replanted promptly is initially left to attempt revascularisation, with endodontics if necrosis develops.
How long is a replanted tooth splinted?
About two weeks with a passive flexible splint per current IADT guidance, extended to about four weeks if there is an associated alveolar bone fracture.
Why are primary teeth never replanted?
Replantation risks injuring the developing permanent successor — including its follicle and eruption path — for a tooth that is anyway shed, so the managed outcome is space observation instead.