External Cervical Resorption Secondary to Orthodontic Treatment in a Previously Traumatized Tooth: A Case Report

A history of dental trauma and orthodontic treatment can directly or indirectly cause external root resorption (ERR), which may significantly compromise the structural integrity, pulp vitality, and periapical health of affected teeth. External cervical resorption (ECR) is an invasive form of ERR that originates at the cementoenamel junction and progresses three-dimensionally along the root surface. In this case, a 20-year-old woman presented with discoloration of the maxillary right central incisor following orthodontic treatment, with a history of prior dental trauma. The maxillary right central and lateral incisors were diagnosed with pulp necrosis and asymptomatic apical periodontitis. Cone-beam computed tomography revealed a large periapical radiolucency associated with both teeth. Multiple forms of ERR were observed, including Patel Class 3Cp ECR on the palatal surface, extending into the interproximal area of the maxillary right central incisor. After endodontic intervention, persistent symptoms necessitated apical surgery for enucleation of the periradicular pathology. Intentional replantation was considered but abandoned following intraoperative assessment. In the end, the affected tooth was extracted because of compromised structural integrity and poor periodontal support. This case highlights that ECR may remain undetected and progress to advanced structural damage, with pulpal involvement and periradicular pathology, resulting in complex management and potential tooth loss.