ObjectiveThis study aimed to investigate the prognosis of permanent teeth with external root resorption (ERR) caused by adjacent impacted teeth.MethodsA total of 75 ERR teeth (permanent teeth) caused by adjacent impacted teeth of 63 patients were included. The prognosis of ERR teeth was analyzed followed by minimally invasive extraction of the adjacent impacted teeth. The time of follow-up was six months. The relationship between prognosis of ERR teeth and patients’ age, gender, root number, type of root resorption and degree of root resorption were analyzed.ResultsIn the 75 ERR teeth, 67 teeth (89.3%) did not show pulpitis symptoms. The clinical outcome was found to be related with age (r=0.330,PP>0.05). Pulpitis symptom was not found in ERR teeth of patients under 30 years old.ConclusionFor ERR teeth caused by adjacent impacted teeth, keeping the pulp vital after surgical removal of impacted teeth is highly probable. Post-operative follow-up instead of preventive root canal therapy of ERR teeth is recommended.