Retreatment of Mandibular Incisors Associated With Root Canal Variations and Periapical Cyst: A Case Report With 3‐Year Follow‐Up

Mandibular incisors have been found to have a complex anatomy of the root canal system. Missed root canals are the most likely cause of treatment failure, and the persistent intra-radicular infections can lead to periapical lesions and toothlessness. This article reports a rare case of the mandibular incisors with two root canals complicated by periapical cysts after root canal treatment. Radiological evidence showed that the lingual root canal was inadequately treated. Root canal retreatment and endodontic microsurgery were performed to eliminate the inflammation. After a 6-month follow-up, new bone formation and mandibular incisors were completely asymptomatic. Finally, ceramic crown restoration was performed. Two root canals with Vertucci Type IV morphology were identified in the mandibular incisors. Variations in the incisor root canal can be effectively detected using CBCT and endodontic microscopy. Systematic management, including reintervention of the missed root canal and microsurgery, can achieve healing of extensive periapical cysts.