Successful Pulp-Preserving Treatment for Peri-invagination Periodontitis of Double Dens Invaginatus With Oehlers Type IIIA and IIIB: A Case Report

Dens invaginatus (DI), which often occurs in the maxillary lateral incisor, is an important issue in endodontics because the treatment complexity increases depending on the degree of invagination and the vitality or nonvitality of the pulp. An 11-year-old female patient with a sinus tract in the gingiva of the maxillary lateral incisors showed peri-invagination periodontitis and double DI on radiography. Cone-beam computed tomographic imaging was used to examine the structure in the root canal in detail, and Oehlers type IIIA and IIIB DI was found. It was also shown that the patient's bone defect was caused by type IIIA. Because a healthy reaction was observed in the pulp test, the final diagnosis was peri-invagination periodontitis associated with type IIIA of the double DI with vital pulp. We expected the lesion to heal by treating only the type IIIA invaginated pseudo-root canal while preserving the healthy pulp. The invaginated root canal was cleaned under a microscope using ultrasonic instruments and nickel-titanium files to minimize irritation to the pulp. Because the lesion shrinkage was confirmed by cone-beam computed tomographic imaging taken 3 months after the start of treatment, vertical compaction of the warm gutta-percha technique was performed. At the 6-month postoperative recall, the pulp was normal, and the lesions were further improved. Treatment of the main root canal of double DI is complicated. However, proper diagnosis and careful cleaning of the invaginated root canal are essential for healing while preserving the pulp.