Transnasal endoscopic removal of displaced dental implants in the maxillary sinus can be done easily under local anesthesia. However, very little is known regarding the precaution of this technique. In this report, we present the case of a 63-year-old man who visited the otolaryngologic department with a displaced dental implant in the maxillary sinus. Transnasal endoscopic removal of the displaced dental implant was planned and performed. However, the displaced dental implant was lost during removal. The implant was not seen in the other parts of the nasal cavity nor in the other parts of the oral cavity. Finally, radiographs revealed the presence of the dental implant at the level of the esophagus, although the patient did not notice anything because of local anesthesia. Thus, we conclude that operators should take into account the possibility of aspiration or swallowing of an implant through the posterior nasal aperture during the removal procedure. Precautions should be taken to avoid the possibility of implant aspiration or implant ingestion.