BACKGROUND: Traumatic intrusion of permanent incisors is one of the most severe forms of dental injury and is frequently associated with complications such as pulp necrosis, root resorption, and ankylosis. Although IADT guidelines provide structured recommendations based on the stage of root development and degree of intrusion, some clinical situations remain borderline, particularly cases presenting an open apex in an otherwise nearly mature root, making classification and treatment planning challenging.

CASE REPORT: A 7-year-old girl presented with severe intrusive luxation (>10 mm) of the permanent right maxillary central incisor. Clinical and radiographic assessment revealed a wide apical foramen but near-complete root length, placing the case in a borderline category. A multidisciplinary plan was initiated, consisting of surgical repositioning and flexible splinting, followed by orthodontic extrusion. After 2 months of traction, undesirable intrusion of the adjacent incisors occurred, while the affected tooth failed to extrude, raising suspicion of ankylosis and leading to suspension of active orthodontic forces. Due to concurrent maxillary constriction, rapid palatal expansion was performed. Unexpectedly, spontaneous re-eruption of the intruded incisor occurred shortly after completing expansion, without further orthodontic intervention.

CONCLUSIONS: This case illustrates borderline presentations can require adaptive and individualized treatment strategies beyond standard guideline recommendations. The spontaneous re-eruption observed after expansion suggests orthopedic interventions modify local conditions, potentially facilitating natural repositioning, even in teeth initially suspected of ankylosis. Nevertheless, the relationship between expansion and eruptive recovery should be interpreted as hypothetical rather than causative. Further clinical reports are needed to elucidate the biological mechanisms underlying this phenomenon and define its potential therapeutic relevance.

Keywords: Case Reports, Child, Incisor, Orthodontics, Corrective, Tooth Injuries, Tooth, Impacted