Surgical Management of a Large Radicular Cyst in a Maxillary Incisor Following Failed Regenerative Endodontics and Apical Plug in an Adolescent: A Case Report.

This case report describes the surgical treatment of a large radicular cyst in a maxillary incisor of an adolescent, following an unsuccessful regenerative endodontic procedure (REP) and an apical plug. It highlights minimally invasive, age-appropriate decision-making. A 14-year-old boy presented with an acute abscess (pain, swelling, and fever) in the right maxilla. Tooth #11 was nonvital, with apical resorption, an open apex, and a huge radiolucent lesion involving Tooth #12, confirmed by CBCT. Initial treatment included incision/drainage, calcium hydroxide dressing, and antibiotics, which resolved symptoms. REP was performed 3 months after presentation (inducing a blood clot, placing biomaterial, and coronal sealing). Partial healing was noted at 8 months, but lesion recurrence occurred asymptomatically at 19 months. An apical plug using calcium-enriched mixture (CEM) was inserted, with slight extrusion observed. Despite patient comfort, follow-ups at 37 and 44 months showed persistent nonhealing; CBCT revealed a 12 × 18 mm lesion, CEM extrusion in Tooth #11, and resorption defects. Because of the failure of nonsurgical endodontic treatments and the patient now being 18 years old, surgical intervention was performed. This involved mucoperiosteal flap elevation, enucleation of the cystic lesion, without resecting the root-end, followed by root-end preparation and filling/sealing with CEM cement in Tooth #11 and the vital #12 (due to cystic involvement). A bone substitute was also placed. Histopathology confirmed a radicular cyst. One year after surgery, radiographic healing and bone regeneration were complete, and the tooth remained functional and asymptomatic. This case highlights that extensive cystic pathology may limit the predictability of REP in certain extensive cystic lesions and supports staged surgical intervention after conservative methods fail at skeletal maturity.