Strictly speaking, after the age of 2 years and the eruption of all milk teeth, children should be examined regularly by an oral surgeon, leaving a longitudinal diagnostic record. If signs of malocclusion are detected, they should be closely observed and appropriate measures should be taken if necessary. However, due to our national limitations, many people do not have the conditions to frequently come to the hospital to receive examination, so we hope that the majority of parents can grasp a certain amount of knowledge about the prevention of malocclusion, early detection of malocclusion and early treatment, to achieve twice the result with half the effort. The following is a brief introduction to the different periods of children may occur wrong: First, before the age of 6 years old The oral cavity is all milk teeth, called milk teeth. 1, milk teeth period should cause parents to pay attention to the malocclusion is mainly the front teeth, commonly known as “Baotian” “pocket teeth”, this malocclusion will affect the normal development of children’s jaw and face, should be near the earliest possible correction. 2. If the baby teeth are extracted too early due to caries, the teeth on both sides of the missing teeth will move to the missing teeth, which will cause misalignment and crowding when the permanent teeth erupt in the future due to the lack of space; therefore, when the baby teeth are lost early, “gap retainer” should be made in time. 3. Children’s bad oral habits during the period of milk teeth, such as finger sucking, lip biting, etc., may cause malocclusion, which should be corrected in time. 4. Breast teeth are seldom crowded; after the age of 6, due to the growth of the jawbone, some gaps may appear between the milk teeth, and the teeth appear to be sparse. These gaps provide the necessary position for the eruption of permanent teeth, which is favorable and parents do not need to worry too much. Secondly, around 6-12 years old, the period of tooth replacement Many malocclusions occur in this period, so this period should pay attention to observation, find problems and deal with them in time, and it is best to receive regular checkups by stomatologists. 1.If the child has orthodontic malocclusion such as anterior anti-mandibular (pocket teeth), anterior protrusion of upper teeth (bruxism), and mandibular deviation in the process of tooth replacement, it will affect the development of the jaws and face, and should be corrected as early as possible. 2, should pay close attention to the replacement of milk teeth and permanent teeth, such as early loss of milk teeth, retained milk teeth, early eruption of permanent teeth, late eruption of permanent teeth or obstruction and other problems, should go to the hospital as early as possible to prevent the occurrence of malocclusion. 3. Children’s oral habits at this stage should also be corrected as early as possible. 4.Temporary malocclusion may occur in the normal process of tooth replacement, for example, there may be a slight outward twisting of the maxillary mesial incisors shortly after eruption, and at the same time, there is a small amount of gap between the two mesial incisors; there may be mild crowding in the incisal area, and so on, and with the completion of the replacement of the teeth, these conditions will disappear naturally. Crowding and misalignment of teeth (e.g., tiger teeth) can be corrected after all the teeth have been replaced, usually around 12 years old. Third, around 12 years old, the replacement of all teeth is completed, at this time for the permanent teeth. At this time, because the growth and development has not stopped, the orthodontic treatment of some bone malocclusion is very ideal. Most of the malocclusion can be corrected at this time. If we wait until 16-18 years old when growth and development is completed, some bone malocclusion will have to resort to surgery.