Background: Ingestion of dental instruments is rare during dental surgery but can result in serious complications. Here we describe a case in which an endodontic hand file was accidentally misplaced in situ during endodontic (root canal) therapy. Plain radiographs were used to identify its location, and serial imaging was used to monitor passage of the endodontic file through the gastrointestinal tract, and it ultimately passed without intervention. We conclude by describing methods for surveillance and management of ingested dental instruments. Case report: A 62-year-old Caucasian male presented to the Emergency Department approximately 2 hours after suspected ingestion or inhalation of an endodontic hand file. He had experienced two episodes of excessive coughing and dyspnea while undergoing endodontic therapy, and was promptly referred by his dentist for further investigation. On admission, plain abdominal radiographs confirmed the position of the file in the duodenum, and serial radiographs were used to monitor its transition and clearance through the gastrointestinal tract. During this time, the patient did not demonstrate any clinical signs of bowel perforation, nor was there any radiographic evidence of pneumoperitonium. The patient was discharged after a final radiograph confirmed the absence of the foreign body. Conclusion: Ingestion and inhalation of dental instruments can be life threatening and should be managed cautiously, with early input from general surgeons, gastroenterologists, or respiratory physicians for possible endoscopic retrieval, emergent laparotomy, or surgical intervention. Imaging studies are useful for discerning the position of the foreign body and to determine whether retrieval is possible, and the management will ultimately depend on the position and characteristics of the foreign body, as well as risk factors from the patient which may increase the likelihood of perforation, obstruction, or impaction.