Case Report:
A 21-year-old female Caucasian patient was referred for the evaluation of a central incisor due to mobility and a sinus tract. The patient had previously completed orthodontic therapy, after which a fixed retainer was placed lingual to the six maxillary anterior teeth. She reported a history of trauma with a fork, after which she began experiencing mobility of the tooth and sensitivity while eating. Clinical evaluation revealed that tooth #21 presented with grade III mobility, pain upon palpation and percussion, and no response to cold or hot stimuli. Furthermore, an active sinus tract was present clinically in the area corresponding with the apex of tooth #21.
Radiographic evaluation with intraoral radiographs revealed the presence of a periradicular lesion in the mesial part of the root, corresponding to irregular anatomy in the same area (Figure 2a). In order to further evaluate the periradicular lesion and the anatomy of the canal system, cone-beam computed tomography (CBCT) was advised. An evaluation of the CBCT images revealed a dilaceration of the main root into two individual root canals in the apical area. The mesial root was found to extend into the mesial-buccal part of the tooth, as seen from occlusal slices (Figure 3a-3e). In addition, a complete loss of the buccal wall was noted, which made the prognosis of endodontic treatment much worse than initially believed. Since no evidence of previous carious lesions were found, the pathology might have occurred due to intense orthodontic movement or a previous trauma which the patient did not recall. The treatment options were either to treat endodontically, or proceed with extraction and restore the #21 territory either with a fixed partial bridge or placing an implant.
The patient was informed about the overall condition of the tooth and the treatment alternatives. She elected to proceed with the more conservative treatment option of saving tooth #21 with a root canal treatment and repositioning of the orthodontic palatal splint, which was broken.
The tooth was anaesthetised, and isolation was achieved by placing a rubber dam over the six maxillary anterior teeth and then isolating the palatal of tooth #21 with a chemical dam. Access was gained with a long round bur mounted in a high speed handpiece. The pulp chamber was found to be dark and void of biological content. Through scouting with a 10 k file, the main canal exit was located, and the working length was measured with the use of an apex locator (Morita Root ZX, Tokyo, Japan ). Afterwards, the hand file was pre-shaped in the last one millimetre, and the lateral walls were precisely scouted to locate and enter the second mesio-buccal canal of the tooth. The working length of the second canal was also measured with an apex locator. K-files were used to radiographically confirm the working length (Figure 2b).
Chemomechanical preparation of both canals was performed with 35.04 rotary files (Race Evo, FKG Dentaire, LaChaux de Fonts, Switzerland). The root canals were copiously irrigated with a 5.25% sodium hypochlorite solution in a Luer lock syringe with an Iriflex (PD, Le Lochle, Swicherland) needle. A premixed calcium hydroxide paste was placed into the canals (Multi-Cal, Pulpdent, Watertown, USA) for a week. During the second appointment, calcium hydroxide was removed with an Xp Endo Finisher at 1000 rpm/1 torque (FKG Dentaire, LaChaux de Fonts, Switzerland) ; then, the same file was used to activate a 5.25% sodium hypoclorite solution for 30 sec. Afterwards, the canals were irrigated for 2 min with 17% EDTA, which was also activated for 30 sec. The final irrigation was performed with sodium hypochlorite for 3 min. Gutta percha cones were fitted, and the canals were dried with paper cones. A bioceramic sealer was placed in the canal space (BC sealer, FKG Dentaire, LaChaux de Fonts, Switzerland), and then the cones were inserted and cut in the canal orifice using a cold hydraulic technique. (Figure 2c) A temporary filing was placed (Figure 2d), and the patient was referred back to her general dentist for the final restoration and repositioning of the orthodontic splint. Since there were no complaints and due to the restrictions of the COVID-19 pandemic, the follow-up was performed after two years. Clinically, the tooth was functional and stable, and the lesion demonstrated radiographic healing (Figure 2e). After the finishing the treatment and until the follow-up, the patient did not experience any pain or discomfort in the area. In the two year follow-up no discoloration was evidenced in the tooth #21.