Abstract: Objective: This case report presents a non-surgical retreatment of the tooth with chronic apical periodontitis caused by overfilling at the apex. Diagnosis and treatment: The patient’s medical history was collected and radiographic examinations were performed to confirm the diagnosis. With informed consent from the patient and guardian, non-surgical retreatment was performed on the affected tooth. Under microscopic guidance, the overfilled material was removed using the ‘weaving technique’ and microforceps. Root canal preparation and apical barrier placement were performed, followed by root canal filling and crown restoration after 14 months. Results: After 14 months, the periapical shadow had significantly reduced, the root canal filling appeared well-adapted, and the crown restoration was satisfactory. Conclusions: Non-surgical retreatment can achieve stable treatment outcomes for chronic apical periodontitis caused by overfilling, and if necessary, apical surgery can also be considered. .

Key words: overfilling at the apex, chronic apical periodontitis, removal of root canal foreign body, root canal retreatment, root-canal filling