Invasive cervical resorption (ICR) is a destructive and progressive resorption type with an uncertain etiology. Cone-beam computed tomography is of great importance for reaching a definitive diagnosis. Once diagnosed, a multistage treatment is required to eliminate the pathology. Removal of excessively vascularized granulation tissue is considered one of the most important steps. Trichloroacetic acid at a concentration of 90% is the most commonly used chemical agent for this purpose. Furthermore, the granulation tissue that becomes avascular upon application of the acid is removed using bur or hand tools. In this case report, we present root canal treatment using trichloroacetic acid (Sigma-Aldrich, MO, US) at a concentration of 90% and the restoration with intracanal fiber post of ICR tooth with excessive crown destruction.Keywords: Internal resorption, trichloroacetic acid, upper incisors.