Retreatment And Surgery For Mandibular Premolar With C-Shaped Canals.

This case report explores the combined approach of root canal retreatment and apical surgery for a mandibular first premolar with C-shaped root canals, with a 2-year follow-up demonstrating treatment stability, offering insights for clinical management of complex root canal anatomies. This case report details a 67-year-old female with a recurrent gingival sinus tract adjacent to a previously crowned left mandibular first premolar. Imaging revealed a C-shaped root canal configuration, an untreated dorsal canal, and apical/mid-root radiolucencies. Initial nonsurgical retreatment resolved symptoms temporarily, but the sinus tract recurred after 14 months. Surgical exploration exposed a mesial radicular groove, addressed via apical surgery and bioceramic sealing. Successful healing at the 2-year follow-up highlights the efficacy of combined nonsurgical-surgical strategies for complex C-shaped canal anatomies. Successful root canal therapy relies on understanding complex anatomies like C-shaped canals, prevalent in mandibular premolars . CBCT enhances detection of missed canals/radicular grooves, which harbor biofilm and accessory canals, complicating disinfection. This case combined retreatment, apical surgery, addressing extraradicular infection. Radicular grooves reduce dentin thickness, risking perforation; small-taper NiTi files minimize risks. Intentional replantation offers direct access but risks root damage. Integrated strategies emphasizing 3D diagnosis, precise intervention, and biomaterial sealing optimize outcomes in anatomically challenging cases. This case reports successive therapy for a mandibular first premolar with C-shaped root canals and underscores the importance of thorough examination, the selection of feasible operations, and the use of innovative biomaterials for endodontic retreatment.