An undesirable injury of adjacent teeth is one of many accidents that may occur during implant placement. Limited surgical access in a noncooperative patient can induce apical root transection. When endodontic pathosis is identified, root canal treatment is often initiated to prevent implant microbial contamination. This case report demonstrates the successful resolution of implant endodontitis by endodontic intervention without any surgical treatment in a patient presenting a moderate mental disorder.