Malocclusion is an abnormality that occurs during a child’s growth and development and is a developmental malformation. With the deepening of clinical research, the concept of modern malocclusion is far from only referring to the misalignment and misalignment of the teeth, but refers to a variety of deformities caused by the teeth, dental arch, jaws, and craniofacial incongruities: 1, individual tooth misalignment refers to the deviation of the individual teeth from the normal position in the arch, including the teeth of the lip or buccal misalignment, lingual or palatal misalignment, proximal or distal misalignment, high, low, rotational, translocation, and easy to inclined axis Abnormalities in tooth arrangement include crowding and spacing of teeth; 3. Abnormalities in arch shape include asymmetry and narrowness of the arch, high arch of the palate, etc.; 4. Abnormalities in the relationship between the dental arch, jaws, and craniofacial region include anterior anticollision, anterior anticollision of the jaws, anterior deep coverage of the jaws, anterior maxillofacial protrusion, anterior maxillomandibular protrusion, one side of the anticollision of the face is not symmetrical, the anterior deep coverage of the face of the lower 1/3 of the height of the insufficient, the anterior open surface 1/3 height increase in height. The height of the lower 1/3 of the face increases; 5, facial abnormalities, including facial protrusion, open lips and teeth, facial depression, jawbone retraction, left and right asymmetry, facial cleft, cleft lip, mandibular cleft, and so on.