Dental Trauma: Classification and Emergency Management

Traumatic dental injuries (TDIs) represent one of the few true emergencies in dentistry—where the timeliness and quality of initial management directly determine the long-term prognosis of the injured tooth. TDIs occur with peak incidence in two age groups: preschool children (1-3 years), when falls during early ambulation predominate, and school-age children and adolescents (7-15 years), when sports injuries, playground accidents, and bicycle falls are the leading mechanisms. The maxillary central incisors are the most frequently injured teeth, accounting for approximately 80% of all TDIs, followed by the maxillary lateral incisors and the mandibular incisors. This article provides a systematic review of the Andreasen classification of traumatic dental injuries and evidence-based emergency management protocols.

The Andreasen Classification System

The classification of traumatic dental injuries, developed and refined by Jens Ove Andreasen and colleagues at the University Hospital of Copenhagen, is the international standard adopted by the World Health Organization and the International Association of Dental Traumatology (IADT). The system categorizes injuries based on the tissues affected—enamel, dentin, pulp, periodontal ligament, and alveolar bone—and the nature of the injury. The classification is hierarchical: injuries to the hard dental tissues and pulp, injuries to the periodontal tissues, and injuries to the supporting bone.

Injuries to Hard Dental Tissues and Pulp

Injuries to Periodontal Tissues

Injuries to Supporting Bone

Emergency Management Protocols

Crown Fractures

Enamel infraction: No active treatment is required beyond sealing the crack with unfilled resin to prevent staining. Monitor pulp vitality at 6-8 weeks and 1 year.

Uncomplicated crown fracture (enamel only): Smooth the sharp edge or restore with composite resin. No urgency; the tooth can be restored electively.

Uncomplicated crown fracture (enamel-dentin): The exposed dentin must be covered as soon as possible—ideally within 24-48 hours—to protect the pulp from bacterial ingress through dentinal tubules and to manage dentin sensitivity. If immediate restoration is not possible, cover the exposed dentin with a glass ionomer or calcium hydroxide interim dressing. Definitive restoration uses acid-etch composite resin; if the fracture is extensive and the patient is near growth completion, a full-coverage ceramic restoration may be indicated.

Complicated crown fracture (pulp exposure): This is a time-sensitive emergency. The treatment decision depends on the size of the exposure, the time elapsed since injury, the stage of root development, and the concomitant periodontal injuries.

• Immature apex (open apex) with small exposure (less than 1 mm) and short elapsed time (less than 24 hours): Partial pulpotomy (Cvek technique)—remove 2 mm of superficial pulp tissue at the exposure site with a sterile high-speed diamond bur under copious water irrigation, achieve hemostasis with saline-moistened cotton pellet (within 5 minutes), and place calcium hydroxide or MTA directly over the pulp wound. This preserves the remaining vital radicular pulp, allowing continued root development (apexogenesis).
• Immature apex with large exposure or delayed presentation (more than 24 hours): Cervical pulpotomy or full pulpectomy with apexification (MTA apical barrier, or calcium hydroxide apexification, or regenerative endodontic procedure).
• Mature apex (closed apex): Root canal treatment is generally indicated. In the emergency setting, a pulpotomy with calcium hydroxide or MTA can be performed to control pain and prevent bacterial contamination, with definitive endodontic treatment completed within 1-2 weeks.

Luxation Injuries

Concussion and subluxation: No active treatment is required in the acute phase. Monitor pulpal and periodontal status at 4 weeks, 8 weeks, 6 months, and 1 year. Instruct the patient to maintain a soft diet for 1-2 weeks and practice optimal oral hygiene with chlorhexidine mouth rinse (0.12%) twice daily for 1 week to control gingival inflammation at the injured site.

Extrusive luxation: Reposition the tooth by gently pushing it back into the socket with digital pressure under local anesthesia. Stabilize with a flexible splint for 2 weeks. For teeth with closed apices that have been severely displaced (more than 2 mm of extrusion), the risk of pulp necrosis exceeds 90%, and root canal treatment should be initiated 7-10 days post-injury with calcium hydroxide intracanal medication. For teeth with open apices, monitor for spontaneous revascularization (pink spot indicating vital pulp) and perform root canal treatment only if signs of pulp necrosis develop (periapical radiolucency, inflammatory root resorption, gray discoloration).

Lateral luxation: Under local anesthesia, disengage the tooth from its locked position by applying apical and labial/lingual digital pressure, then reposition it into the socket. Verify repositioning radiographically. Stabilize with a flexible splint for 4 weeks. For teeth with closed apices, the incidence of pulp necrosis approaches 100% due to the apical neurovascular bundle rupture; root canal treatment with calcium hydroxide should be initiated 7-10 days post-injury. For teeth with open apices, monitor for spontaneous revascularization, though the prognosis is guarded.

Intrusive luxation: Treatment depends on the degree of intrusion, stage of root development, and tooth type.

• Immature apex, mild to moderate intrusion (less than 7 mm): Allow spontaneous re-eruption. The open apex provides a pathway for pulpal revascularization, and spontaneous re-eruption typically occurs within 2-6 months in teeth with open apices. Monitor monthly for eruption progress and pulp vitality.
• Immature apex, severe intrusion (more than 7 mm): Orthodontic or surgical repositioning. If spontaneous re-eruption does not commence within 3-4 weeks, initiate orthodontic extrusion.
• Mature apex, mild intrusion (less than 3 mm): Allow spontaneous re-eruption or orthodontic repositioning. Root canal treatment should be initiated 7-10 days post-injury (calcium hydroxide), as pulp necrosis is inevitable.
• Mature apex, moderate to severe intrusion (more than 3 mm): Surgical repositioning, flexible splint for 4 weeks, and root canal treatment initiated 7-10 days post-injury.

Avulsion: The True Dental Emergency

Avulsion of a permanent tooth is the most time-critical dental emergency. The prognosis for periodontal ligament (PDL) healing is directly and inversely proportional to the extraoral dry time. Every minute the tooth is out of the socket in a dry environment, PDL cells undergo irreversible necrosis. The goal of emergency management is to minimize extraoral dry time and to preserve the viability of the PDL cells remaining on the root surface.

Emergency instructions at the scene of injury (first aid):

1. Find the tooth. Hold it by the crown (the white part), never by the root (the yellowish part). Touching the root crushes the PDL cells and worsens the prognosis.
2. If the tooth is dirty, rinse it briefly (maximum 10 seconds) under cold running water. Do not scrub, scrape, or use soap or chemicals. Do not dry the tooth or wrap it in tissue.
3. Immediately replant the tooth into the socket. The patient (or parent/caregiver) should push it into place using the adjacent teeth as a guide. Bite on a handkerchief or gauze to hold it in position.
4. If replantation is not possible (unconscious patient, uncooperative child, or fractured socket precluding replantation), place the tooth in a suitable storage medium—in order of preference: Hank's Balanced Salt Solution (HBSS, commercially available as Save-A-Tooth), cold milk (preferably whole milk), saliva (buccal vestibule for a cooperative patient who is not at risk of swallowing), or saline. Water is the least suitable storage medium, as its hypotonicity causes rapid PDL cell lysis.
5. Seek emergency dental treatment immediately. The patient should be seen within 60 minutes of avulsion; beyond this, the prognosis declines precipitously.

In-office emergency management of avulsed permanent tooth:

Scenario 1: Tooth replanted at the scene or within 60 minutes, with closed apex.

1. Confirm replantation position clinically and radiographically. Adjust if necessary.
2. Clean the area with saline. Suture any gingival lacerations.
3. Apply a flexible splint (composite and wire or fishing line, 0.3-0.4 mm diameter) for 2 weeks. The splint must be passive, not force-applying, and must not impede oral hygiene or occlude.
4. Administer systemic antibiotics: doxycycline (preferred for its anti-resorptive and anti-inflammatory properties in addition to antimicrobial activity) for patients over 12 years of age; for children under 12, penicillin V or amoxicillin. Duration: 7 days.
5. Assess tetanus status—avulsion injuries with soil contamination require tetanus prophylaxis per the patient's immunization history.
6. Root canal treatment: initiate 7-10 days post-replantation, after splint removal. The canal is medicated with calcium hydroxide (or ledermix paste if inflammatory root resorption is suspected) and definitive obturation is performed after resolution of any periapical pathology, typically at 2-4 weeks.
7. Instruct the patient: soft diet for 2 weeks, chlorhexidine mouth rinse (0.12%) twice daily for 1 week, brush all teeth except the splinted teeth for the first week, no contact sports.

Scenario 2: Tooth replanted at the scene, with open apex (immature tooth).

The goal is to preserve pulp vitality and promote continued root development. Do not initiate root canal treatment electively. Monitor for signs of pulp revascularization (return to normal color and sensibility, continued root development and apical closure on radiographs) at 4 weeks, 8 weeks, 3 months, 6 months, and 1 year. If pulp necrosis develops (periapical radiolucency, inflammatory root resorption, sinus tract), initiate apexification or regenerative endodontic procedures immediately. Splinting duration and systemic antibiotics as for closed apex.

Scenario 3: Tooth has been extraoral dry for more than 60 minutes.

The PDL is necrotic and non-viable. The treatment goal shifts from PDL healing to prevention of ankylosis-related replacement resorption and preservation of the alveolar ridge contour for future implant placement (in skeletally mature patients).

1. Remove the necrotic PDL from the root surface by gently debriding with gauze soaked in saline. Soak the tooth in 2% sodium fluoride solution for 20 minutes (inhibits osteoclastic activity and slows replacement resorption).
2. Perform extraoral root canal treatment (root canal treatment outside the mouth on a sterile field, obturate with gutta-percha, and seal the apex with MTA or composite). This avoids the need for post-replantation endodontic access, which risks additional trauma.
3. Replant the tooth. Flexible splint for 4 weeks.
4. Systemic antibiotics as above.
5. Inform the patient and parent that ankylosis and replacement resorption are inevitable despite treatment; the goal is to slow the resorption rate to buy years of function, preserving alveolar bone for future implant placement.

Root Fracture

If the coronal fragment is displaced, reposition it under local anesthesia. Verify repositioning radiographically. Stabilize with a flexible splint: for fractures in the cervical third, splint for 4 months (healing by calcified tissue is slower in the cervical region due to the proximity of gingival crevicular fluid); for fractures in the middle or apical third, splint for 4 weeks. Monitor at 4 weeks, 8 weeks, 3 months, 6 months, 1 year, and annually for 5 years. Healing outcomes for root fractures, in order of decreasing frequency: healing with interposition of hard tissue (calcified callus), healing with interposition of connective tissue (PDL-like tissue between fragments), healing with interposition of bone and connective tissue (if fragments are separated by more than 1 mm at the time of splinting), and non-healing with interposition of granulation tissue (inflammatory tissue between fragments, requiring endodontic treatment of one or both fragments). Pulp necrosis in root fracture occurs in approximately 25% of cases overall, higher for fractures in the cervical third and for teeth with closed apices.

Follow-up and Prognosis

The long-term prognosis of traumatized teeth depends on the type and severity of the injury, the stage of root development (immature has better prognosis for pulp survival), the time elapsed between injury and treatment, the quality of the initial treatment, and the patient's compliance with follow-up protocols. The most common complications following TDIs are:

• Pulp necrosis: Incidence highest in complicated crown fractures with delayed treatment, luxation injuries with closed apices, and root fractures in the cervical third.
• Pulp canal obliteration (PCO): A common sequelae of luxation injuries in teeth with open apices, representing accelerated secondary dentin deposition. PCO is a sign of pulp vitality, not pathology, and does not require endodontic treatment unless periapical pathology develops (approximately 5% of PCO cases).
• Inflammatory root resorption (external): Caused by necrotic infected pulp communicating with the PDL space through exposed dentinal tubules. Radiographically appears as bowl-shaped radiolucencies on the root surface. Treatment: root canal treatment with calcium hydroxide long-term intracanal medication (minimum 4 weeks, repeated as needed) to alkalinize the dentin, inactivate bacterial toxins, and arrest the resorptive process.
• Replacement resorption (ankylosis): Caused by irreversible damage to the PDL, typically from prolonged extraoral dry time. Osteoclasts resorb root substance, which is replaced by bone, progressively eliminating the PDL space. Radiographically: loss of PDL space, root appears continuous with alveolar bone. Clinically: high metallic (ankylotic) percussion sound, infraocclusion (in growing children, the ankylosed tooth fails to erupt with the adjacent teeth). No treatment arrests replacement resorption; decoronation (surgical removal of the crown, leaving the resorbing root in situ to preserve alveolar bone) is indicated in growing children prior to implant placement.

Conclusion

Traumatic dental injuries demand prompt, decisive, and evidence-based management. The clinician's immediate actions in the emergency setting exert a disproportionately large influence on the long-term survival of the traumatized tooth. The IADT guidelines, updated most recently in 2020, provide the most current evidence-based framework for clinical decision-making, but the fundamental principle remains unchanged: preserve pulp vitality whenever possible, minimize extraoral dry time in avulsion, stabilize with flexible splints that permit physiologic tooth movement, and commit to long-term follow-up to detect and manage complications before they become irreversible.