External cervical resorption refers to resorption that affects the periodontium and hard dental tissue, and in later stages, pulpal tissue. The initiation of resorption is mostly located on the cervical aspect of the affected tooth, i.e., below the epithelial attachment. Although the exact mechanism of its occurrence has not yet been clarified, it is considered that its etiology is multifactorial and that the predisposing factors have a mutually synergistic effect on both its occurrence and progression. The clinical and radiographic presentation of ECR is highly variable, with no classic presentation; most often, it is asymptomatic and discovered as an incidental finding on a radiograph. In diagnosis, but also in the selection of a therapeutic procedure, a key role is played by CBCT scanning, which, due to its greater precision and sensitivity, will enable the creation of a high-quality and targeted therapy plan. Unfortunately, an advanced, unrecognized lesion that has involved most of the tooth structure and penetrated into the root canal will eventually result in tooth extraction. Therefore, it is important to understand the nature of the resorptive lesion and its causation in order to recognize and manage it in a timely and appropriate manner.