A case of inverted supernumerary tooth in the right nasal cavity in a 4-year-3-month-old girl during the deciduous dental stage was presented. Previous reports and etiology were reviewed.
It was possible to extract the tooth through the nostril and it seemed to be a deciduous supernumerary tooth from the morphological structure and the patient's age at the onset of disease.
The etiology of intranasal tooth is unclear. We speculate that the supermumerary tooth in this case was caused by extrusion of a deciduous tooth germ into the nasal cavity at the formation of primary palate.