The main reasons for premature loss of baby teeth include the following: 1.The formation of large caries damage of baby teeth: It leads to the inability to repair, or the generation of residual roots and crowns causing repeated infection, and sometimes there is swelling of the jaw and face and increase of body temperature, which needs to be extracted as soon as possible to prevent stimulation of the whole body and affect health. 2.Ectopic eruption of permanent teeth: It leads to the rapid resorption of baby teeth roots and premature loss when the loosening is too large. In case of accidental injury, the milk teeth may fall out directly or become inflamed with the surrounding tissues after semi-dislocation and have to be extracted.3. Gnawing on hard objects: when milk teeth often gnaw on hard food, rubber nipples or toys, slow resorption of the roots can be formed, sometimes intracanal resorption occurs, and the milk teeth will fall out prematurely after the loosening is gradually aggravated.