When a seven-year-old’s incisors have fallen out for almost a year and still haven’t grown, the possible clinical causes include vitamin D and calcium deficiency, blocked teeth, and missing permanent teeth. 1. Lack of vitamin D and calcium: Vitamin D is an essential vitamin, which affects the body’s absorption of calcium and has an impact on the development of teeth and other bones; calcium is the basis for the development of teeth and bones, and its deficiency will have a serious impact on the development of teeth and other bones. 2. Dental obstruction: when the milk teeth fall out too early, the child also frequently uses the gums to chew food, which makes the gums keratinized and thickened, thus making it difficult for the permanent teeth to erupt. 3. Loss of permanent teeth: When the child’s incisors are lost with damaged roots or accompanying loss or congenital factors, the roots of permanent teeth will be missing, and the incisors will not be able to grow back. Parents are advised to take their children to the hospital stomatology department for dental radiographs in order to clarify the specific cause of the disease so that targeted treatment can be carried out.