At present, orthodontic treatment can be roughly divided into three categories according to the different types of orthodontic appliances: 1. Conventional lip-side orthodontic treatment: braces are glued on the lip side of the teeth (outside, close to the side of the lips), which is commonly known as “small steel teeth”, and they can be looked at by outsiders in daily life, and are divided into metal braces and ceramic braces, and ceramic braces are comparatively more beautiful. Lip-side orthodontic treatment is the most widely used and common orthodontic method. 2.Lingual orthodontic treatment: braces are glued on the lingual side of the teeth (inside, close to the tongue side), belonging to the invisible orthodontic treatment, which can’t be found by outsiders in daily life, and it doesn’t affect the aesthetics at all, with a relatively wide range of indications, and most of the patients are suitable for it. 3. Transparent orthodontic treatment: belonging to invisible orthodontic treatment, the orthodontic appliance is completely transparent, not affecting the aesthetics, and the patient can take off and wear it by himself, which is more comfortable, of course, the cost is relatively high. The indications of transparent orthodontic treatment are more strict and should be evaluated by professional doctors.