Whether a child’s big teeth will change or not needs to be considered in the context of age, and cannot be generalized. The teeth that people commonly refer to as big teeth are often clinically referred to as molars, and there are two sets of teeth in a person’s life, which generally begin to change at the age of about 6. The first set of teeth is the milk teeth, usually 20, at this time the milk molar will be gradually replaced as we grow older. After the age of 6, the milk teeth will be replaced by permanent teeth, and the permanent molars will not be replaced at this time. After the permanent teeth are complete, there will be 32 teeth, not only the molars, but all the other teeth will not be replaced for life. In case of periodontitis, impacted injury or decay, the teeth can be damaged, loosened or even lost. Therefore, after tooth replacement, we should pay more attention to dental care and maintenance. After the permanent molars come out, it is recommended to have the sulcus closure treatment to prevent the decay of permanent teeth. In addition, teeth have the characteristic of bone calcification, so we can take vitamin D and calcium supplements in our daily life to make our teeth healthier.