Accidental ingestion of dental prostheses requires immediate emergency action. The authors report a case of accidental ingestion of a dental prosthesis in a patient with a disorder of consciousness. The accidental ingestion was diagnosed by imaging examination, and the location of the dental prosthesis was explored under general anesthesia according to the preoperative examination images. However, no dental prosthesis was found in the hypopharyngeal region. The operators found a radiopaque region in the nasopharynx that was suspicious of a dental prosthesis by X-ray examination of the head and neck region. According to the X-ray examination, the dental prosthesis was removed from the nasopharynx. The patient's postoperative course was uneventful. Postural change for cases of accidental ingestion of dental prostheses may be a simple and important lifesaving step in addition to traditional methods.