The age of 6 —-12 is usually a period of tooth replacement for children, a critical period of dental growth and development that requires special attention. To answer the question of what should be paid attention to when milk teeth change permanent teeth, we should first look at the general rule of milk teeth changing permanent teeth. The general rule of milk teeth for permanent teeth can be said as follows: time rule: usually, children change teeth between 6-12 years old, the earliest age of tooth replacement in about 6 years old, this is the time rule; location rule: our general new teeth permanent teeth, often in the lingual side of the milk teeth eruption; order rule: milk teeth for permanent teeth, it has a certain normal order rule, usually speaking is to change the lower teeth first and then change the upper teeth, first change the front teeth Symmetry law: when the milk teeth are replaced by permanent teeth, it is often symmetrical, that is, the left and right sides are symmetrical, and the symmetrical teeth will be replaced at the same time or within a very short time difference. Once we know these basic rules for the replacement of permanent teeth, parents can check whether the tooth replacement is normal for their children, and if there is any abnormality, they can seek timely medical attention. First, generally speaking, if the permanent teeth have erupted and the corresponding milk teeth are loose and not lost, we can consider pulling out the corresponding milk teeth so that the permanent teeth can erupt normally and smoothly. If the newly erupted permanent teeth have slight misplacement and misalignment, it is normal and parents do not need to worry about it, the teeth will adjust by themselves. Secondly, if the baby teeth are prematurely extracted or missing due to various reasons such as caries and periapical disease, it is necessary to make gap retainers to prevent the misalignment of teeth at this time. After the sixth age teeth erupted, we suggest to do the sulcus closure to prevent the caries. Thirdly, during the period of tooth replacement, we also suggest to pay more attention to maintain oral hygiene, and at the same time, we suggest to have an oral examination once in 3-6 months. Finally, we wish our children good oral health and good teeth.