Introduction: Guided tissue regeneration (GTR) is a successful treatment procedure of periodontal reconstructive surgery. Adverse effects can be observed after GTR procedure, but external root resorption is rarely reported at clinical studies. Invasive cervical resorption is a clinical term used to describe a relatively uncommon, insidious, and often aggressive form of external root resorption. Methods: The present case demonstrates an invasive cervical resorption that is a potential late complication of GTR in a maxillary canine of a 59-year-old male patient. After the surgical intervention and root canal treatment, the resorption was subsequently sealed with mineral trioxide aggregate. Results: The 1-year follow-up demonstrates no pathologic changes on clinical and radiographic examinati...