[Research progress on external cervical resorption]

External cervical resorption (ECR) is a progressive, osteoclast-mediated destructive disease of dental hard tissues that originates at the cervical region of the root. Characterized by its insidious onset and diagnostic challenges at early stages, ECR can lead to severe tooth structure loss and even tooth extraction. Although the precise patho-genesis remains unclear, it is thought to be associated with local stimuli, certain medications, and systemic conditions. Cone beam computed tomography (CBCT) is currently the key imaging modality for three-dimensional assessment and accurate staging of ECR. Treatment should be based on such three-dimensional evaluation and follow a stepwise strategy tailored to the extent, depth, and pulpal involvement of the lesion: minimally invasive restoration with bioactive materials for early or localized defects; comprehensive manage-ment including root canal treatment, intentional replantation, or combined guided tissue regeneration for lesions involving the pulp or exhibiting extensive spread; and extraction with site preservation as a final restorative-oriented option for non-retainable teeth. This review systematically elaborates on the etiological factors, pathological mechanisms, clinical manifestations, image-based classification systems, diagnosis, and management of ECR, aiming to provide insights for precise clinical decision-making. Future research directions, such as early biomarker identification and targeted pharmacological intervention, are also discussed.