A 13-year-old female patient with no significant medical history, presented to the Department of Endodontics at the School of Dentistry, Mashhad University of Medical Sciences, Iran. Intraoral examination revealed a deep carious lesion in tooth 11 with no response to electrical (Parkell digital EPT, New York, USA) and thermal (Frisco spray, Arztbedarf, Frenchen, Germany) pulp tests while adjacent teeth responded within the normal ranges. The patient reported slight pain on palpation and percussion, and periodontal examination showed no probing or abnormal mobility. Crown morphology was normal and identical to tooth 21. Periapical radiograph displayed bifurcated roots in the mesiodistal direction with slight apical radiolucency and periodontal ligament (PDL) widening (Figure 1A). Cone-beam computed tomography (CBCT) using Planmeca ProMax 3D (Planmeca, Helsinki, Finland) was performed to improve assessment and revealed a two-rooted tooth with one orifice and two foramina (Figure 1B-1E). With the diagnosis of necrosis and chronic apical periodontitis, the tooth was considered for root canal treatment.
After administration a local infiltration with 2% lidocaine and 1:80000 epinephrine (Darupakhsh, Tehran, Iran), the tooth was isolated with rubber dam and disinfected. Under a dental operating microscope (Carl Zeiss Meditec Inc., Dublin, CA, USA), the access cavity was prepared with a high-speed long shank diamond No. 2 round bur (Jota AG, Ruthi, Switzerland) with continuous water spray. Canals were negotiated with #10 K-file (Mani Inc., Utsunomiya, Japan), and working length was determined as 20 mm for the mesial canal and 19 mm for the distal one by an electronic apex locator (E-Pex Pro; Eighteeth, Changzhou, China) and then confirmed with radiography (Figure 1F). Chemo-mechanical cleaning and shaping was performed by crown-down technique with M3 Pro Gold rotary files (United Dental, Sichuan, China), up to size 25/04 for both canals under copious irrigation with 5.25% sodium hypochlorite and normal saline alternately. Canals were dried with paper points (META, Chugbuk, South Korea), and master cone 30/04 (META, Chugbuk, South Korea) fit was checked with a periapical X-ray (Figure 1G). The obturation was performed with the warm vertical technique by FastFill (Fast Fill Obturation System; Eighteeth, ChangZhou, China) using gutta-percha and AH-26 sealer (Dentsply, Ballaigues, Switzerland). After the operation, the quality of the filling was evaluated on a periapical radiograph (Figure 1H). Finally, Cavit (Cavisol, Tehran, Iran) was applied as a temporary restoration and the patient was referred to the department of restorative dentistry for permanent restoration. At the 6-month follow-up, the tooth was clinically and radiographically asymptomatic (Figure 1I).