The main manifestation is that the upper jaw teeth are on the inner side of the lower jaw teeth when biting, the lower jaw protrudes, the upper jaw is sunken, and the height of the lower third of the face is reduced, affecting the appearance. As we grow older, the protrusion of the lower jaw becomes more pronounced, forming a crescent face, which seriously affects the aesthetics and even causes social difficulties and psychological disorders, and the earlier the conventional orthodontic age, the better. Early intervention is performed at the age of 4-6 years during the period of mastoid dentition, either with maxillary jaw pads or mandibular joint-crowned beveled guides. Simple individual retrusions can be gradually released using the bite sled method. The orthodontic treatment during the period of the replacement teeth is mainly at the age of 6-12 years, and functional orthodontic appliances are routinely used, such as maxillary anterior retractable orthodontic appliances, FR orthodontic appliance with reverse double plates, and 2×4 orthodontic techniques. Orthodontic treatment in the permanent phase is mainly after the completion of tooth replacement, mainly using fixed or movable braces. Severe retrogressions that lead to bony deformities may require surgery, such as combined orthognathic-orthodontic treatment.