Treating pathological defects that are caused by resorption in teeth can be challenging. The task is complicated further if the resorption extends beyond the restrains of the root. The aim of this report is to describe a case of extensive internal tunneling resorption (ITR) associated with invasive cervical resorption (ICR) in a maxillary right lateral incisor and its nonsurgical treatment. A 22-year-old male was referred to the department of endodontics with a chief complaint of discolored maxillary right lateral incisor or tooth 12 and a history of trauma. An extensive ITR associated with ICR accompanied by apical periodontitis was detected on a preoperative radiograph which was confirmed on a cone-beam computed tomography (CBCT) scan in a maxillary lateral incisor. After chemomechanical debridement and withdrawal of a separated file in the canal, calcium hydroxide was placed as an intracanal medicament for 2 weeks. Biodentine (BD) was used to obturate the defect as well as entire root canal system and to restore ICR. On a 5-year follow-up, the tooth was functional, and periapical healing was evident. Based on results of this case, successful repair of ITR associated with ICR with BD may lead to resolution of apical periodontitis. Trauma to teeth may lead to resorption which may be internal, external, and or a combination of both which may be asymptomatic in some patients. Preoperative assessment using CBCT imaging achieves visualization of location and extents of resorptive defects. Bioactive materials like BD may lead to favorable results in treating such extensive defects.