Avulsed Immature Central Incisor With 45 Minutes of Dry Time

Diagnosis

• Necrotic pulp with asymptomatic apical periodontitis, and suspected external inflammatory root resorption.

Principal risks

• External inflammatory resorption, which progresses fastest in the first months.
• Replacement resorption/ankylosis, the main threat after 45 minutes of dry storage.
• Pulp canal obliteration later, and loss of the tooth before facial growth is complete.
• The splint has been in place 4 weeks. A flexible splint for an avulsion without fracture should come out at 2 weeks; prolonged splinting increases ankylosis. Remove it now.
• Check tetanus status and the amoxicillin dose (about 50 mg/kg/day divided, within the maximum for his weight).

Inflammatory resorption versus ankylosis

• Inflammatory resorption: normal or increased mobility, normal or slightly dull percussion, bowl-shaped radiolucencies of the root with loss of lamina dura but a visible periodontal ligament space. It responds to endodontic treatment.
• Ankylosis: high-pitched metallic percussion, no mobility, progressive infraocclusion, and loss of the periodontal ligament space with bone replacing root. Endodontic treatment does not alter it.
• CBCT is more sensitive than periapical radiography for early change.

What each option does

• Regenerative endodontic procedure (REP): the only option that may allow continued root development and wall thickening, which matters enormously in a tooth with 1.5 mm apex and thin walls. The 45-minute dry time lowers the odds of revascularization, so this is a relative rather than absolute indication. Current guidance supports REP as first choice for immature permanent teeth with necrotic pulp and apical periodontitis when feasible, with resolution of disease and bone healing as the primary outcome and root development as secondary.
• MTA apexification: a predictable apical barrier in one or two visits with an excellent seal, but no further root development; the tooth stays thin-walled and fracture-prone. MTA is also difficult to remove if retreatment is ever needed.
• Calcium hydroxide apexification: months of visits, dentin weakening, and a higher fracture rate; largely superseded.

Decision

• Offer REP first, with explicit consent that if revascularization fails, bleeding cannot be induced, or the tooth becomes symptomatic, an MTA plug will be placed.
• Both child and parent must commit to follow-up; without that, apexification is the more honest choice.

First visit

• Local anesthesia, rubber dam, access preserving remaining walls; no instrumentation beyond the canal orifice.
• Irrigate 20 mL of 1.5% NaOCl per canal through a needle 2 mm short of working length to limit stem-cell toxicity, then 17% EDTA for 1 minute.
• Dry and place a medicament: calcium hydroxide, or a triantibiotic paste without minocycline (ciprofloxacin plus metronidazole) to avoid staining.
• Seal with a well-bonded temporary; contamination destroys the clot.

Second visit (1-4 weeks later, asymptomatic)

• Re-anesthetize, remove the medicament with irrigation, induce bleeding with a hand file 2-3 mm beyond the apex, and wait 10-15 minutes for a clot reaching the cervical level.
• Place a resorbable matrix if the clot is unstable, then 3-4 mm of MTA or bioceramic over the clot, then glass ionomer and composite.

Abandon the procedure if

• The tooth is unrestorable or has a crown-root fracture, or the walls are too thin to survive function.
• Bleeding cannot be induced after several attempts, in which case place an apical plug instead.
• The family cannot attend follow-up, or the tooth becomes symptomatic with a worsening lesion.

Follow-up

• 3, 6, and 12 months, then yearly until maturity; success is resolution of the lesion and absence of symptoms, with root thickening a bonus rather than a requirement.