Integrated Endodontic and Restorative Management of C-Shaped Canals with Severe Coronal Loss in Mandibular Second Molar: A Case Report.

This case report describes the endodontic treatment of a lower right second molar with a C-shaped root canal in a 49-year-old woman exhibiting severe loss of coronal structure. Clinical examination revealed a cavity with temporary filling on tooth 47, which tested negative to cold stimuli but was positive to percussion and bite tests. Cone beam computed tomography (CBCT) scan revealed a C-shaped canal morphology with associated periapical radiolucency, graded as CBCT-PAI score 4. The canal was classified as C3 subdivision III (Melton et al), C3 type II (Fan et al), and ²47 M^2-2D^2-1 (Ahmed et al's). A non-surgical endodontic procedure was performed using metallurgically gold heat-treated files, passive ultrasonic irrigation, and warm hydraulic condensation obturation. Post-endodontic restoration included a post and core build-up with the wallpapering technique and a zirconia overlay. This case highlights the importance of CBCT imaging for diagnosis and treatment planning, careful selection of endodontic instruments and technique, and the use of advanced restoration methods to improve the outcome of challenging C-shaped canal treatments with extensive cavity involvement.