External invasive root resorption may occur as a consequence of trauma, orthodontic treatment, intracoronal bleaching and surgical procedures and may lead to the progressive and destructive loss of tooth structure. Depending on the extent of the resorptive process, different treatment regimens have been proposed. A 20-year-old female patient presented with tooth showing signs and symptoms of pain in 21 with extensive invasive resorption in middle third of root canal. After root canal treatment, The resorption area was chemomechanically debrided using ultrasonic tips and irrigant solution. MTA was used to fill the resorptive defect and the coronal access was temporarily sealed. Radiographs at 3 and 12 months showed adequate repair of the resorption and endodontic success. Clinically, the tooth was asymptomatic and found to be functioning well.