If a piece of a baby tooth has fallen out after a root canal, you need to choose between observation or filling treatment, depending on the timing of the tooth replacement. If a piece of milk tooth has been lost after root canal treatment, if the tooth is about to be lost, the root has begun to resorb, and the succeeding permanent tooth is about to erupt, then observation is recommended. If the tooth is about to fall out, the root has begun to resorb and the succeeding permanent tooth is about to erupt, it is recommended that the tooth be observed and the oversharpened cusp be resharpened to prevent it from damaging the mucous membrane and the tongue. If the tooth will not be replaced in the short term, it is recommended that the tooth be refilled as soon as possible to prevent the infiltration of saliva and bacteria in the defective area, which will lead to the failure of root canal treatment and affect the eruption of the inherited permanent teeth; if there is too much defect and insufficient remaining tooth tissue, it is recommended to carry out a temporary crown restoration. It is recommended to go to the stomatology department of a regular hospital to assess the condition after examination by a physician and choose an appropriate treatment plan.