Conservative management of double dens invaginatus with blunderbuss apex and periapical abscess of maxillary lateral incisor using guided endodontics: Case report with 5-year follow-up

Double dens invaginatus (double DI), an exceptionally rare anomaly with dual enamel-lined invaginations, poses significant endodontic challenges due to complex anatomy. This case report describes management of Type I and II double DI in the right maxillary peg-shaped lateral incisor (#12) associated with a blunderbuss apex and chronic periapical abscess using guided endodontics. A 34-year-old female presented with discolored upper right anterior teeth associated with pain and a discharging gingival sinus. Tooth #11 was diagnosed with pulp necrosis and chronic apical periodontitis, and tooth #12 was diagnosed with chronic periapical abscess associated with double DI and blunderbuss apex. Nonsurgical root canal treatment was performed using three-dimensional-printed guide templates for access opening, followed by chemo-mechanical debridement, 8-week Ca (OH) 2 medicament placement, Mineral trioxide aggregate (MTA) apexification, thermoplasticized obturation, and double DI sealing. Five-year follow-up showed complete symptom resolution, sinus closure, and bony healing.