Introduction: A bronchial foreign body is a dangerous medical emergency that is potentially life-threatening. Spontaneous expulsion should neither be expected nor experienced. Thus, early removal with a bronchoscope should be performed to prevent complications. Spontaneous expulsion of a bronchial foreign body is rare, with few cases reported. Additionally, its occurrence and associated clinical complications are not studied and unclear. We describe a patient in whom a bronchial foreign body was expectorated spontaneously and swallowed into the digestive tract.
Case Report: An 80-year-old male aspirated a tooth in the left lower airway during a dental procedure. Flexible bronchoscopy performed on the next day found no foreign body in either bronchial tree. However, it was found on the abdominal radiograph. It was considered to have been expectorated and then swallowed before bronchoscopy. One week later, the patient had passed it.
Conclusion: This case demonstrated that a bronchial foreign body can rarely be expelled spontaneously. Besides, an expelled foreign body can be swallowed, or it can migrate to another location. Regarding spontaneous expectoration and migration, injury to the airway and digestive tract can occur depending on its shape. However, such dangers have not been addressed, because spontaneous expectoration is rare and unrecognized. Recognizing these dangers and warning patients of them could avoid additional complications.

Keywords: Dental care, Foreign bodies, Foreign body migration, Spontaneous remission