4.3 Dental Trauma
Key Takeaways
- IADT 2020 classifies avulsed permanent teeth by periodontal ligament cell viability: viable if replanted immediately or within ~15 min, compromised if stored in milk/HBSS/saliva with extra-oral dry time under 60 min, and non-viable if dry time exceeds 60 min
- Replant an avulsed permanent tooth at the accident site if possible; ideal replantation is within 60 minutes, followed by a passive flexible splint for 2 weeks (4 weeks if an alveolar fracture coexists)
- Splinting durations from IADT 2020: subluxation up to 2 weeks (optional), extrusive luxation 2 weeks, lateral luxation 4 weeks, intrusive luxation 4 weeks if surgically repositioned; concussion requires no splint
- Primary teeth should generally NOT be replanted after avulsion to avoid damaging the developing permanent successor
- Inflammatory root resorption is driven by infected necrotic pulp and arrests after root canal treatment; replacement resorption (ankylosis) is irreversible and has no reliable treatment
IADT 2020 Guidelines Overview
The International Association of Dental Traumatology (IADT) 2020 guidelines are the current international standard, published across three papers in Dental Traumatology (2020;36:309-342) and endorsed by the AAPD. They are freely available at iadt-dentaltrauma.org and the Dental Trauma Guide. Key principles: minimise extra-oral dry time, use short-term passive flexible splints, and base endodontic management on apex maturity and time to replantation.
Classification of Traumatic Injuries
Hard Tissue Fractures
| Injury | Definition |
|---|---|
| Enamel infraction | Incomplete fracture of enamel without loss of substance |
| Enamel fracture | Loss of enamel only |
| Enamel-dentine fracture | Loss of enamel and dentine, no pulp exposure |
| Enamel-dentine-pulp fracture (complicated crown) | Pulp exposed |
| Crown-root fracture | Fracture involves enamel, dentine, and cementum; pulp may or may not be exposed |
| Root fracture | Fracture confined to the root; coronal fragment may be mobile |
| Alveolar fracture | Fracture of the alveolar socket wall or process |
Luxation Injuries
| Injury | Features | Splinting |
|---|---|---|
| Concussion | Tender to percussion, no mobility or displacement | None |
| Subluxation | Abnormal mobility, bleeding from crevice, no displacement | Up to 2 weeks (optional) |
| Extrusive luxation | Tooth displaced axially out of socket; appears elongated | 2 weeks |
| Lateral luxation | Displaced laterally, often "locked" with alveolar bone fracture; high metallic percussion note | 4 weeks |
| Intrusive luxation | Displaced apically into bone; immobile, metallic percussion note | 4 weeks if surgically repositioned |
| Avulsion | Complete displacement from socket | 2 weeks (4 weeks if alveolar fracture) |
Avulsion Management
PDL Cell Viability Categories (IADT 2020)
- PDL cells most likely viable — tooth replanted immediately or kept in storage medium with extra-oral dry time under ~15 minutes at the accident site.
- PDL cells viable but compromised — total extra-oral dry time under 60 minutes, stored in a physiologic medium (milk, Hank's Balanced Salt Solution (HBSS), saliva, saline).
- PDL cells likely non-viable — total extra-oral dry time over 60 minutes, regardless of storage medium.
PDL cell survival falls steeply once dry time exceeds about 30 minutes, and IADT treats 60 minutes of dry time as the point beyond which the cells are considered non-viable. The goal is replantation within 60 minutes to maximise PDL survival.
Storage Media
Preferred storage media, in approximate order of desirability: HBSS (balanced cell culture medium) > milk (cold, long-life preferred) > saliva (in the vestibule) > saline. Water is hypotonic and causes rapid PDL cell lysis and should be avoided.
Replantation Protocol
- If the tooth is permanently avulsed and the apex is closed, rinse the root gently with saline (do not scrub or remove attached PDL), irrigate the socket, and replant immediately.
- Flexible splint (wire up to 0.4 mm / 0.016" or nylon fishing line) for 2 weeks (4 weeks if an alveolar fracture coexists).
- Tetanus prophylaxis if the wound is contaminated.
- Systemic antibiotics (e.g. doxycycline or amoxicillin) — IADT 2020 no longer recommends topical antibiotics on the root surface, as human studies failed to show improved outcomes.
- Endodontic management:
- Closed apex: initiate root canal treatment within 2 weeks (coinciding with splint removal); calcium hydroxide intracanal medicament for 2-4 weeks before obturation.
- Open apex: aim for pulp revascularisation; root canal treatment only if pulp necrosis or infection is identified at follow-up.
Follow-up Schedule
| Apex type | Schedule |
|---|---|
| Closed | 2 weeks (splint removal), 4 weeks, 3 months, 6 months, 1 year, then yearly for at least 5 years |
| Open | 2 weeks, 1, 2, 3, 6 months, 1 year, then yearly for at least 5 years (more frequent due to inflammatory resorption risk) |
Permanent vs Primary Tooth Trauma
Management differs substantially between dentitions:
| Feature | Permanent tooth | Primary tooth |
|---|---|---|
| Avulsion | Replant immediately | Do NOT replant — risk of damaging the developing permanent successor |
| Root fracture | Splint; RCT of coronal fragment if pulp necrosis | Extract if mobile or infected |
| Luxation | Reposition and splint per IADT | Often conservative; extract if displacing permanent successor |
| Intrusion | Monitor or reposition depending on apex and depth | Most re-erupt spontaneously; extract if ankylosed or impinging on successor |
Intrusive luxation of permanent teeth is managed by depth and apex maturity. Immature (open apex): allow spontaneous re-eruption whatever the depth; if there is no movement within 4 weeks, start orthodontic repositioning. Mature (closed apex): intrusion <3 mm may be left to re-erupt, but if there is no movement within 8 weeks reposition surgically or orthodontically; 3-7 mm is repositioned surgically or orthodontically; >7 mm is repositioned surgically. Root canal treatment is commenced at about 2 weeks in mature teeth because pulp necrosis is near-inevitable.
Pulp Sequelae of Trauma
Pulp Canal Obliteration (PCO)
Pulp canal obliteration — also called calcific metamorphosis — is a common response to luxation injuries, particularly in immature teeth. The pulp space narrows progressively with yellow discoloration; the tooth usually remains vital and asymptomatic. No treatment is required unless periapical pathology develops.
Root Resorption
| Type | Mechanism | Management |
|---|---|---|
| Inflammatory (external) | Stimulated by infected necrotic pulp; osteoclasts on root surface adjacent to infected dentine | Root canal treatment with calcium hydroxide; arrests once infection is controlled |
| Replacement (ankylosis-related) | PDL lost; bone resorbs root and remodels to bone; tooth becomes ankylosed (high percussion note, infrapositioned) | No reliable treatment; decoration and eventual implant placement in adults |
| Internal | Odontoclasts from within the pulp space | Root canal treatment; long-term calcium hydroxide |
Inflammatory resorption is the one form that can be arrested — it is driven by infected necrotic pulp, so root canal treatment removes the stimulus. Replacement resorption is irreversible: once the PDL is lost and the root ankylosed, no intervention reliably reverses it; infraposition over time and a high metallic percussion note are the clinical hallmarks.
Crown Fracture Management
- Enamel infraction/fracture — smooth or restore; no splint.
- Enamel-dentine fracture — restore with bonded composite; cover exposed dentine urgently to protect the pulp.
- Complicated crown fracture (pulp exposed) — Cvek pulpotomy (partial pulpotomy 1.5-2 mm) for immature teeth with a vital pulp; pulpectomy and root canal treatment for mature teeth or if the pulp is non-vital.
- Root fracture — reposition the coronal fragment, splint for 4 weeks (longer, up to 4 months, for coronal-third fractures); RCT of the coronal fragment only if pulp necrosis develops.
Key Decision Points for MFDS
- Avulsed permanent tooth, dry time 90 minutes — PDL non-viable; replantation may still be attempted for alveolar ridge preservation but ankylosis and replacement resorption are expected.
- Avulsed primary tooth — do not replant; explain to parents and arrange follow-up to monitor the permanent successor.
- Lateral luxation with alveolar fracture — disengage the locked tooth under local anaesthesia, reposition, and splint for 4 weeks (plus an additional 4 weeks if marginal bone/socket wall fracture persists).
- Intrusive luxation, open apex, any depth — allow spontaneous re-eruption; if there is no movement within 4 weeks, initiate orthodontic repositioning. (The 8-week watch-and-wait window applies to a mature tooth intruded less than 3 mm.)
A 10-year-old avulses an upper left central incisor at football. It is brought to surgery in a glass of cold milk 45 minutes later. The apex is closed. What is the PDL cell viability category and the recommended initial management?
A 9-year-old has an upper right central incisor displaced palatally with an alveolar bone fracture. The tooth is immobile and gives a high metallic percussion note. What is the diagnosis and the recommended splinting duration?
A 4-year-old falls and avulses an upper right primary central incisor. The parent brings the tooth and asks if it can be put back. What is the correct management?
Two years after avulsion and replantation, a permanent incisor has a high metallic percussion note and is infrapositioned relative to adjacent teeth. Radiographically the periodontal ligament space is lost. What is the diagnosis and its management?
A 12-year-old sustains an uncomplicated crown fracture of an upper right central incisor with enamel and dentine loss but no pulp exposure. The tooth is vital and not mobile. What is the most appropriate immediate management?