Extrusive Luxation of an Immature Central Incisor After a Bicycle Fall
A 9-year-old boy is brought to the emergency department 3 hours after falling from a bicycle. He did not lose consciousness and has no other injuries apart from a lacerated upper lip. Tooth 11 is extruded about 4 mm, grade II mobile, tender to percussion and does not respond to cold testing. Tooth 21 has an uncomplicated crown fracture with dentine exposed but no pulp exposure and responds normally to cold. Both central incisors have wide open apices with parallel root walls and roughly two-thirds root development. A periapical radiograph shows a widened periodontal ligament space at the apex of 11 but no root fracture and no alveolar fracture. Tetanus status is uncertain; he has had three primary doses but no booster. He is otherwise healthy and takes no medication.
1. Set out your immediate management in the order you would carry it out, and state explicitly what you would not do.
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Order of management:
- Clear the patient first - airway, head injury, level of consciousness, other injuries. A dental emergency in a 9-year-old after a bicycle fall is not automatically a dental-only problem.
- Radiographs before touching the tooth - periapical and, if needed, occlusal views to exclude root and alveolar fracture. You already have a periapical; extend if the picture is unclear.
- Local anaesthesia by buccal infiltration of 2% lidocaine with 1:100,000 adrenaline, then reposition 11 with firm, slow axial digital pressure, handling only the crown, until it sits level with 21.
- Clean and inspect the gingival margin, irrigate with saline, remove any clot from the socket, and check the occlusion in centric occlusion.
- Suture the lip laceration and give tetanus prophylaxis - he needs a booster given an incomplete course and a contaminated wound.
- Splint (see next task), give analgesia and written instructions, and arrange follow-up.
What I would not do:
- Do not extract, and do not leave the tooth extruded - delayed repositioning increases the risk of pulp necrosis and ankylosis.
- Do not place a rigid splint.
- Do not start root canal treatment now, and do not diagnose pulp necrosis from a single negative cold test in an immature tooth.
- Do not prescribe antibiotics routinely (see next task).
- Do not scrub or dry the root surface or handle it with forceps.
2. Justify your choice of splint type and duration, and state your position on antibiotics and adjunctive medication with reasons.
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Splint: a flexible splint for 2 weeks - 0.016-inch nickel-titanium wire or monofilament nylon bonded with composite to 11 and the adjacent 12 and 21, placed passively so it does not hold the tooth under tension.
Why flexible and why 2 weeks: extrusive luxation is a periodontal injury with a favourable chance of PDL healing if the tooth is repositioned and allowed physiological movement. Rigid or prolonged splinting is associated with ankylosis and replacement resorption, which is catastrophic in a tooth with an open apex that still has the potential to revascularise. Two weeks is sufficient for the initial PDL repair in extrusive luxation; the same injury with a root fracture or alveolar fracture would need four weeks, which is not the case here.
Antibiotics: not routinely indicated for luxation injuries. There is no evidence that prophylactic antibiotics improve pulpal or periodontal outcomes, and unnecessary prescribing drives resistance. Use them only if there is an associated soft-tissue wound requiring cover or if the child were medically compromised - neither applies.
Adjunctive care: paracetamol with or without ibuprofen for 3–5 days (ibuprofen is appropriate here because there is no bleeding disorder), a soft diet for 2 weeks, avoidance of the tooth for biting, and a 0.1–0.12% chlorhexidine mouthrinse twice daily for 1 week to keep the sutured lip and gingival margin clean. Give written after-hours instructions covering what to do if the tooth darkens or becomes painful.
3. The mother asks what will happen to the tooth long term. Explain the prognosis, the follow-up schedule, and what you would do if the tooth became necrotic with an open apex at 6 months.
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Prognosis: the tooth has three possible futures - revascularisation with continued root development (best), pulp canal obliteration (common and usually harmless, but needs monitoring for signs of apical pathology), or pulp necrosis with infection. An immature tooth with an open apex and parallel walls has good revascularisation potential, and a negative cold test in the first weeks to months is common and often a false negative. The mother should be told this plainly so she does not panic at the first review.
Follow-up: 2 weeks (splint removal), 4 weeks, 3 months, 6 months, 1 year, then annually for 5 years. At each visit: sensibility testing, percussion, mobility, gingival margin level, and a periapical radiograph looking for inflammatory root resorption, periapical radiolucency and continued root development. Also review 21 at each visit - an uncomplicated crown fracture with exposed dentine should be sealed with glass ionomer or composite now to protect the pulp.
If necrosis with an open apex is confirmed at 6 months (radiolucency plus clinical signs, not a single negative sensibility test): the first choice is a regenerative endodontic procedure - disinfection with sodium hypochlorite at low concentration, minimal or no instrumentation, creation of a blood clot, and a coronal seal - because it offers the chance of further root thickening and continued apical closure. An MTA or bioceramic apical plug with a coronal restoration is the alternative if regeneration is not feasible or has failed. Extraction and space management is the last resort and should be discussed with the parent only if the tooth is unrestorable.