Endodontic management of a C-shaped maxillary first molar with three independent buccal root canals by using cone-beam computed tomography
A 26-year-old woman was referred from a private dental clinic to Wonkwang University Dental Hospital for root canal treatment of maxillary left first molar. The patient's medical history was noncontributory. Medical history revealed spontaneous pain on the upper left side of her face for the past several days. Clinical examination showed a large distal temporary restoration and tenderness to percussion on the maxillary left first molar. Diagnostic radiograph showed the presence of subgingival caries in the distal area of the tooth (). On the basis of clinical and radiographic examination, the patient's condition was diagnosed as pulp necrosis with acute apical periodontitis and endodontic treatment was recommended.\nAfter profound anesthesia and rubber dam isolation, temporary restoration was removed. The pulp chamber was rinsed using 2.5% sodium hypochlorite. The evaluation of pulpal floor using an endodontic explorer revealed only 2 obvious canal orifices: mesiobuccal and palatal. Working length of the mesiobuccal and palatal canals was determined using an apex locator (Root ZX, Morita, Tokyo, Japan). The radiograph for determining the working length indicated a possibility of furcal perforation on buccal root (). To rule out the occurrence of perforation and the presence of any additional roots/canals, CBCT imaging of the tooth was performed. Informed consent was obtained from the patient, and a CBCT of the tooth was performed (Alphard VEGA, Asahi Roentgen Ind. Co., Kyoto, Japan) using a tube voltage of 80 kV and tube current of 8 mA. We used the D mode of the CBCT, which has the smallest field of view (FOV) covering only 2 to 3 teeth. All protective measures were taken to protect the patient from scattered radiation. Transverse slices of the tooth were obtained at different levels to determine the mesiobuccal and distobuccal canal morphology (). The buccal root showed 3 root canals in the C-shaped root that extended from the cervical third up to the junction of the middle and apical third.\nEndodontic ultrasonic tips (CPR tips, Spartan, Fenton, MO, USA) used for eliminating pulp stones and obstructions under dental operating microscope (OPMI pico Dental Microscope, Carl Zeiss, Oberkochen, Germany) revealed mesiolingual and distobuccal canals (). Working length was estimated by using electronic apex locator (Root ZX) and was confirmed using a radiograph. All the 4 canals were prepared using ProTaper nickel-titanium rotary instruments (Dentsply-Maillefer, Ballaigues, Switzerland) and irrigated using 2.5% sodium hypochlorite (NaOCl) solution.\nAt the next appointment, the canal system was irrigated using 17% ethylenediaminetetraacetic acid (EDTA) solution for 1 min, and then soaked using NaOCl solution for 30 minutes prior to obturation for control the debris may exist within isthmus between the buccal canals. Then, the canals were dried and obturated by using warm vertical compaction technique. A final radiographic examination confirmed the accuracy of the endodontic treatment and the presence of 3 different apical foramina for each of the buccal canals ().