Premature tooth replacement does not necessarily indicate advanced bone age; tooth growth is linked to bone development, but the embryonic origin is not identical and the growth stages are not exactly parallel. Early tooth replacement is associated with a variety of factors, and if there are no abnormal symptoms such as abnormal tooth growth or loose teeth, there is generally no need to worry too much. The average age of starting tooth replacement is around 6 years old, with 5-7 years old being within the normal range, and tooth replacement usually ends around 12 years old. The common reasons for early tooth replacement include genetics, excess nutrition, early development, hyperthyroidism, periodontal disease and many other factors. Therefore, premature tooth replacement can be accompanied by observation of the child for symptoms of over-maturity such as speech and behavior patterns, and also attention to the presence of diseases such as dental trauma and periodontal inflammation. When abnormalities occur, immediate medical diagnosis is needed and, if necessary, targeted treatment should be administered. When tooth replacement is too early and there are no other symptoms, tooth development can be promoted by consuming more foods rich in protein, vitamins, calcium, phosphorus, fluoride and other nutrients, and also by chewing some tough foods to enhance the hardness of teeth. Bone development is usually closely related to growth hormone, thyroid hormone and sex hormone, etc. Clinical examination can be done by X-ray to check the ossification of the long bone epiphysis to predict the bone age, and people who suspect that the bone age is large can go to the hospital for relevant examination to clarify the situation.