Abstract Despite significant advancements in endodontic techniques, root canal therapy may sometimes fail, even when performed according to the highest clinical protocols. The predominant cause of endodontic failure is often persistent or secondary intraradicular infection, though certain cases may arise from nonmicrobial factors, whether intrinsic or extrinsic in nature. As the prevalence of previously treated teeth increases, endodontic retreatment has become an essential aspect of contemporary practice. It provides patients with a viable alternative to extraction, restoring the health and function of a compromised tooth. The primary aim of nonsurgical retreatment is to re-enter the root canal system, remove previous filling materials, and ensure effective cleaning, disinfection, and re-obturation to eliminate residual infection and promote periapical healing. Continuous progress in instrument design, magnification systems, and biocompatible materials has substantially improved the prognosis of retreatment procedures. These innovations support the preservation of natural dentition, minimising the dependence on complex and expensive prosthetic or implant-based restorations. When nonsurgical management is not feasible due to calcification, canal blockage, or complex anatomy, a surgical approach may be indicated to achieve complete debridement and sealing. Recent developments in techniques, materials, and technology have transformed endodontic retreatment from a challenging and unpredictable process into one with highly favourable success rates. This narrative review seeks to deliver a comprehensive and critical overview of the various types of endodontic failures and the current retreatment strategies, highlighting recent innovations that contribute to improved clinical outcomes.