Abstract:

Root canal treatment of teeth with complex canal morphology, such as S-shaped curvatures, presents significant clinical challenges and increases the risk of procedural errors. Mandibular second molars may exhibit severe canal curvatures, particularly in the mesial root, complicating instrumentation and disinfection.
This case report describes the successful single-visit endodontic treatment of a mandibular second molar (tooth 37) in a patient diagnosed with asymptomatic pulpitis due to deep caries. The mesial root exhibited an S-shaped curvature, requiring a careful and controlled instrumentation approach.
After anesthesia and rubber dam isolation, canal preparation was performed using a combination of hand and nickel-titanium rotary instruments. Initial coronal preflaring was achieved using rotary instruments to facilitate apical access. Canal patency was established using a pre-curved stainless steel hand file. Glide path preparation and subsequent shaping were completed using flexible nickel-titanium systems. The distal canal was prepared to a larger apical size due to its anatomical characteristics. Standard irrigation protocols were applied, and obturation was completed in the same visit.
The treatment was completed without complications, and the patient remained asymptomatic.
This case highlights the importance of proper technique, instrument selection, and clinical strategy in managing complex root canal anatomy. Single-visit endodontic treatment can be a predictable and efficient approach when adequate disinfection and canal preparation are achieved.

Keywords: S-shaped canal, mandibular molar, single-visit endodontics, curved canals, nickel-titanium instruments