ENDODONTIC TREATMENT OF CHRONIC APICAL PERIODONTITIS OF THE MANDIBULAR SECOND MOLAR WITH C-SHAPED ROOT CANAL CONFIGURATION IN AN ADOLESCENT PATIENT: A CLINICAL CASE

Background: C-shaped root canal configuration of the mandibular second molar is among the most challenging g anatomical variants in endodontic practice, with a reported prevalence of 8–45% depending on ethnicity. Its complex internal morphology - including isthmuses, lateral recesses, and a ribbon-like canal space -substantially impedes complete mechanical debridement and promotes persistence of microbial biofilm. In adolescent patients, chronic apical periodontitis associated with such anatomy frequently follows an asymptomatic course and may be discovered incidentally on routine radiographic examination. Objective: To present the clinical decision-making process, step-by-step treatment protocol, and 20-month radiographic outcomes of nonsurgical endodontic treatment of a mandibular second molar with C-shaped root canal configuration in a 14-year-old patient, with particular focus on the justification for single-visit treatment without calcium hydroxide dressing and the management of incidental gutta-percha extrusion. Materials and Methods: A 14-year-old female patient was referred with asymptomatic chronic apical periodontitis of tooth 4.7, incidentally detected on routine periapical radiography. A C-shaped root canal configuration was identified clinically following access preparation. CBCT was deliberately omitted based on ALARA principles, absence of acute symptoms, and availability of adequate periapical radiographic data. Treatment was completed in a single visit under local anesthesia (4% articaine with epinephrine 1:100,000) and rubber dam isolation. Working length was determined electronically (E-Pex Pro apex locator) and confirmed radiographically. Canal preparation was performed with NiTi rotary instrumentation (SoCo system) to apical size 40.04. A structured three-step irrigation protocol was applied: 3% NaOCl with ultrasonic activation, 17% EDTA (60 sec), and 2% chlorhexidine as a final rinse, with intermediate saline flushes. Obturation was performed using lateral condensation with guttapercha and a eugenol-free epoxy resin sealer (AH Plus, Dentsply Sirona, Germany). Calcium hydroxide dressing was not used. Results: A minor incidental extrusion of gutta-percha beyond the apical foramen was noted intraoperatively without sealer extrusion. The patient remained completely asymptomatic throughout the follow-up period. Periapical radiography at 20 months confirmed complete resolution of the periapical lesion, normalization of the periodontal ligament space, and stable obturation without signs of material displacement. Conclusions: Successful nonsurgical single-visit endodontic treatment of chronic apical periodontitis in a mandibular second molar with C-shaped root canal anatomy is achievable without CBCT or intracanal calcium hydroxide dressing when a structured chemo-mechanical protocol with irrigant activation is rigorously applied. The robust healing capacity of periapical tissues in young patients contributes to favorable long-term outcomes even in anatomically complex cases with minor procedural deviations. The presented protocol offers a reproducible, evidence-based, and radiation-conservative algorithm for managing similar cases.