Many parents are confused as to whether children often have misaligned teeth during tooth replacement, but whether they need treatment or orthodontic treatment after tooth replacement. In fact, the misalignment of teeth or misaligned bite during tooth replacement should be analyzed on a case-by-case basis. During the period of tooth replacement there is a temporary gap between the incisors, bite deep, mild crowding of teeth is a normal phenomenon, can be observed, do not worry. With growth and development, these conditions will gradually disappear or be relieved, and there is no need for orthodontic treatment. Timely intervention and treatment are needed if the following conditions occur Severe maxillary or mandibular developmental deformities, such as excessively protruding maxillary dentition, excessively protruding mandibular dentition (pocket tooth, envelope), and excessively small mandibular dentition (small chin) should be given timely intervention and treatment without waiting for tooth replacement to guide the jaws to develop in the normal direction and minimize the degree of deformity. Children with bad oral habits, such as mouth breathing, biting the lower lip, eating fingers and other habits, should be blocked these bad habits to prevent the occurrence of malocclusion. It cannot wait until after tooth replacement. Serious errors of individual teeth, such as serious twisting of incisors, teeth antithesis (the lower teeth bite the front of the upper teeth) need to be corrected in time, do not need to wait until after the replacement of teeth, in order to prevent serious dental trauma in addition to the above, the rest of the misalignment of teeth such as crowding, whistling teeth, double jaw protrusion and other cases should be corrected when? Generally speaking, the best time is just after the replacement of milk teeth, generally speaking, the best age of 10 to 12 years old for girls and 10 to 13 years old for boys.