Strictly speaking, there is no time limit for orthodontic treatment as long as the periodontal condition is good. However, different types of malocclusion have different optimal orthodontic treatment periods. Some malocclusions need to be treated early (3-5 years old), such as “bunions”, lip biting, finger sucking and other bad habits. For general malocclusion, it is advisable to visit the orthodontist for consultation and examination when permanent teeth begin to erupt (8 to 10 years old) because the eruption process of children’s permanent teeth can be observed early and regularly, and problems can be detected and solved in a timely manner, and the pre-growth period is an excellent period for functional orthodontic treatment. For most patients, the best age for fixed orthodontic treatment is between 12 and 16 years old, and some dentists call this age the “golden age of orthodontics”. However, for those few patients with severe jaw developmental deformities, orthodontic treatment alone is difficult to achieve the desired orthodontic effect, and combined orthodontic-surgical treatment must be performed in adulthood.