Retreatment of failed endodontic cases: A case series highlighting clinical challenges.

Root canal treatment failure commonly results from persistent intracanal infection, missed canal anatomy, inadequate obturation, or procedural complications, often presenting as persistent symptoms or periapical pathology. Nonsurgical endodontic retreatment remains the most conservative and predictable approach for managing such failures by addressing etiological factors while preserving the natural dentition. This case series reports the nonsurgical retreatment of three failed endodontic cases presenting with significant clinical challenges, including a separated instrument, calcified canals, anatomical variation in the form of radix paramolaris, persistent intracanal infection and ledge. All cases were managed using a systematic retreatment protocol involving removal of existing obturating material, canal renegotiation, biomechanical preparation with activated irrigation, and the use of intracanal medicaments where indicated, followed by definitive obturation and appropriate postendodontic restoration. Successful resolution of symptoms, management of procedural complexities, and restoration of function were achieved in all cases. The findings highlight that meticulous retreatment protocols, adjunctive activation techniques, and sound restorative planning can result in favorable clinical outcomes even in complex retreatment scenarios.