1.The general treatment procedure of dental and maxillofacial malocclusion (bony malocclusion) is: preoperative orthodontics – orthognathic surgery – postoperative orthodontics; after the end of preoperative orthodontics, due to the de-compensatory movement of teeth, the patient’s deformity status may look more serious than before orthodontics; 2.Depending on the patient’s specific situation, the preoperative orthodontic process may require tooth extraction, osteocortical incision, surgically assisted rapid arch expansion, implant support resistance and other related Surgical treatment. 3.Orthognathic surgery usually needs to be performed under general anesthesia, and there is a possibility of general anesthesia accidents. 4.The lower alveolar nerve, chin nerve and infraorbital nerve may be damaged during orthognathic surgery, and numbness of the lower lip, chin and infraorbital skin may occur after surgery; about 90% of patients can recover, about 10% have permanent numbness, but as long as the nerve is not broken, most of them will recover in about 3 to 6 months. 5.Orthodontic treatment is usually needed for about one year before surgery. After orthognathic surgery to move the bone block of the jaw, the occlusal relationship cannot reach the best temporarily, and it still needs about six months of postoperative orthodontic treatment for adjustment. 6, orthognathic surgery area is located around the upper respiratory tract, intraoperative trauma and postoperative wound tissue swelling, bleeding can affect the upper respiratory tract, serious cases may appear upper respiratory obstruction, need to perform emergency tracheotomy rescue; to ensure postoperative safety, prevent respiratory difficulties, postoperative usually need to nasal intubation with a tube for a day, if necessary, need to enter the ICU monitoring. 7. The surgery requires the displacement of the bone segment to a new position to achieve a good occlusal relationship according to the design requirements, and there may be insufficient blood supply to the bone segment, which may lead to pulpal necrosis and tooth loosening after surgery, and very rarely, ischemic necrosis, loss or non-healing of the bone segment. 8.Orthognathic surgery has more intraoperative bleeding and may require blood transfusion treatment. There may also be a small amount of blood leakage in the short term after surgery. If significant bleeding occurs, surgical exploration may be required to stop the bleeding. 9.After orthognathic surgery, there may still be a mild deformity of the jaw and face, and the corresponding surgical treatment will be needed to adjust it later. 10.If accidental fracture may occur after orthognathic surgery, titanium plate fixation and intermaxillary wire ligation fixation are required. 11.Titanium plates and nails are needed for fixation between bone segments in orthognathic surgery, and the possibility of titanium plate rejection and fracture may occur in rare cases after surgery; usually titanium plates and nails need to be surgically removed six months after surgery. 12.There is a possibility of postoperative wound infection and delayed healing. 13.There is no definite conclusion on the relationship between orthognathic surgery and temporomandibular joint disease. Usually, patients with temporomandibular joint disorder before surgery will have improved symptoms after surgery; however, as the condyle will be displaced to a certain extent after orthognathic surgery, it may also cause temporomandibular joint symptoms such as local pain, joint popping and mouth opening limitation, or aggravate the original joint disorder symptoms, which may require further surgery. 14.After mandibular surgery recession, the jaw angle may widen, affecting the aesthetics and requiring corresponding surgical treatment; after mandibular surgery recession, the pharyngeal cavity narrows, and sleep breathing obstruction symptoms such as snoring may occur after surgery. 15.After the upper jaw surgery, it may cause nasal septum curvature, nasal obstruction and nasal deviation deformity, which need surgical treatment. 16.After orthognathic surgery, a liquid diet for 2 weeks, a semi-liquid diet for 1-2 weeks, a soft diet for 1 month and then a general diet; after surgery, attention should be paid to keep the oral hygiene clean, and functional exercises such as opening training, as well as long-term follow-up to prevent recurrence.