歯胚形成不全を呈する未熟歯に対するマイクロサージェリー：長期経過観察を伴う症例報告

Dens invaginatus (DI) is a rare dental anomaly characterized by the infolding of enamel and dentin into the pulp cavity during tooth development. This condition often leads to complex endodontic challenges, predisposing affected teeth to caries, pulp necrosis, and chronic periapical abscesses. This case report describes the successful management of a maxillary lateral incisor with Type II DI complicated by a chronic periapical abscess, using an endodontic microsurgical approach. A 10-year-old girl presented with a chief complaint of recurrent swelling in the maxillary left incisor area. Clinical examination revealed a malformed maxillary left lateral incisor with Grade II mobility and a fluctuant gingival swelling. Periapical radiography and cone-beam computed tomography (CBCT) confirmed DI with an immature apex, significant periapical rarefaction, and fenestration of the labial cortical bone. Endodontic microsurgery treatment was performed, involving flap reflection, lesion excision, root canal irrigation with 1% sodium hypochlorite (NaOCl), and retrofilling using a calcium-silicate-based sealer (CeraSeal) and bioceramic putty (CeraPutty). The surgical site was sutured, and postoperative care instructions were provided. Histological examination confirmed a periapical cyst. Follow-up examinations revealed favorable soft tissue healing, mucosal sinus tract closure, and complete bone regeneration at the surgical site. CBCT evaluation at 3 years confirmed full buccal bone regeneration. This case demonstrates that endodontic microsurgery can be a successful treatment option for managing complex DI cases with chronic periapical abscesses when orthograde endodontic treatment is not feasible. CBCT imaging plays a pivotal role in diagnosis, treatment planning, and postoperative assessment. Further clinical research is warranted to evaluate the long-term outcomes of microsurgical management in similar developmental anomalies.