Dentofacial malformation is generally referred to as dental and maxillofacial malformation, mainly refers to the abnormalities in the volume, morphology, and relationship between the upper and lower jaws and other bones of the craniofacial area, and the consequent abnormalities in the dental and jaw relationships and the function of the oromandibular system, and the appearance of the jaws and face. Orthognathic and maxillofacial malformations can be an independent growth and developmental abnormality, but can also be part of some congenital syndromes, i.e., orthognathic and maxillofacial malformations combined with congenital malformations of other organs throughout the body, and should be differentiated in diagnosis and treatment. Orthognathic surgery is a new branch of oral and maxillofacial surgery, with the study and treatment of dental and maxillofacial malformations as the main content, which includes the complete concept of preoperative and postoperative orthodontic treatment and orthognathic surgery combined with the treatment of dental and maxillofacial malformations, involving oral and maxillofacial surgery, orthodontics, plastic surgery, aesthetics, psychology and other related disciplines. The orthognathic surgical treatment of dental and maxillofacial malformations is generally chosen to be performed after the growth and development of the mandible is completed. At present, modern orthognathic surgery has formed a set of standardized and complete standardized treatment procedures, including preoperative diagnosis, determination of orthodontic treatment plan, preoperative orthodontic treatment, preoperative X-ray cephalogram measurement and effect prediction, model surgery to determine the surgical treatment plan, completion of perioperative preparation, orthognathic surgery, postoperative orthodontic treatment, follow-up observation, each step is very important and indispensable. Standard orthognathic surgical procedures: ① Preoperative orthodontic treatment: aimed at correcting misaligned teeth, especially those with long-term compensatory displacement after trauma to adjust the incongruent arch and relationships, align the teeth, and eliminate compensatory tilt of teeth. This is a very important step to obtain both functional and morphological results. For old fractures, this step can be omitted if the model surgical collocation results show that the occlusal relationship can be restored by osteotomy and repositioning. ②Confirm the surgical plan: After the orthodontic treatment before surgery, a final evaluation and prediction of the original surgical plan is made; necessary adjustments to the surgical plan or necessary additions to the orthodontic treatment can be made to make the upcoming surgery more realistic and achieve the best results. ③Pre-surgical preparation: In addition to the routine preparation for general anesthesia and blood transfusion, the guide plate and the required fixation device after the bone block is moved should be prepared according to the designed surgical style, and the patient should be fully explained according to the surgical plan, expected results and possible problems. ④ Correctly administered surgery: The surgery must be administered strictly according to the surgical design that has been predicted and redetermined preoperatively, and the plan must not be altered at will during the surgery, but necessary adjustments are allowed in conjunction with the reality during the surgery. ⑤ Post-operative orthodontic treatment: The purpose is to improve the functional and cosmetic effect, stabilize and consolidate the treatment effect. ⑥Tracking observation: to understand the possible changes of jaw and relationship after surgery and to evaluate the postoperative effect. The mobile, orthodontic bone block will usually be slightly displaced during the healing process. As long as it does not affect the clinical effect, the postoperative orthodontic consolidation treatment can be maintained; however, if there is an obvious tendency of recurrence, the corresponding treatment is required. According to the healing process after osteotomy and its biomechanical characteristics, the postoperative follow-up should last for at least 6 months. Commonly used orthognathic surgical techniques: (1) Maxillary anterior segmental osteotomy is mainly used to correct the anterior maxillary teeth and alveolar protrusion deformity; it can also be combined with mandibular anterior subapical segmental osteotomy to correct bimaxillary protrusion deformity. In addition to the aforementioned preoperative preparations, bilateral maxillary first bicuspids are usually extracted to allow the protruding anterior jaw to recede to a normal position. This is followed by preoperative orthodontic treatment and then surgery. In old jaw fractures, the anterior maxillary deformity is mainly caused by misalignment healing. (2) Sub-apical segmental osteotomy of the anterior mandible is mainly used for the correction of teeth and alveolar protrusion of the anterior mandible; correction of the Spee curve with excessive curvature; closure of certain types of anterior open jaws; correction of asymmetrical deformities of the lower dental arch, and correction of bimaxillary protrusion in conjunction with other procedures. For cases used to correct mandibular and alveolar protrusion, it is usually necessary to extract the bilateral mandibular first bicuspids and complete preoperative orthodontic treatment before performing mandibular surgery. (3) Intra-oral total maxillary horizontal osteotomy This procedure is performed by cutting the walls of the maxilla in accordance with the orientation of the maxillary LeFort type I fracture line, preserving only the soft tissue tissues, mainly the palatal mucoperiosteum. It is mainly used to: ①correct the anterior-posterior underdevelopment of the maxilla. (2) Correction of vertical underdevelopment of the maxilla. ③Correction of vertical overdevelopment of the maxilla (often accompanied by open jaw and underdevelopment of the lower jaw). (4) Correction of complex dental and maxillofacial deformities, especially those involving the upper and lower jaws, in conjunction with other procedures. (4) Transoral mandibular ascending sagittal splitting This procedure is widely used in the surgical correction of mandibular deformities, mainly for ① anteriorly migrating the mandible and correcting small mandibular deformities caused by underdevelopment of the mandible. It can also be used to correct true mandibular protrusion by receding the lower jaw. (iii) In synergy with other procedures, to correct complex cases containing small mandibular deformities. In addition, the commonly used procedure for mandible is the transoral mandibular ascending oblique osteotomy. (5) Chinplasty is a classic procedure of chinplasty, and the effect is better than that of prosthetic lining, and it is used for ① correction of chin that is too large and protruding. (2) Correction of receding chin that is too small. (iii) Correction of long vertical chins. (iv) Correction of insufficient left and right chin diameter. ⑤ Correction of chin deviation. (6) Correction of simultaneous chin abnormalities in conjunction with other surgeries. (6) Mandibular angle and chewing muscle hypertrophy Osteotomy of mandibular angle with intraoral incision or sagittal splitting of the lateral bone cortex in the mandibular angle area is often used, or a combination of the two, with partial resection of the inner layer of the occlusal muscle if necessary. (7) Asymmetrical orthodontic surgery Asymmetrical orthodontic deformities can be unilateral or involve both the upper and lower jaws, and can affect the soft tissues of the face. The most common are deviated chin deformity and mandibular deviated jaw deformity. This is followed by unilateral micromaxillary deformities and deviated facial deformities involving the upper and lower jaws and including the soft tissues. A common clinical deviated deformity can be hypertrophy and hyperplasia of the condyle on one side; it can also be hemimandibular overgrowth or even hemifacial and limbic overgrowth. In addition, due to injuries, tumors, temporomandibular joint diseases, etc. also often cause different types of dental and maxillofacial deformities, all of which can be treated using the principles and methods of orthognathic surgery. For these reasons, the clinical manifestations of asymmetrical dentofacial deformities vary greatly among individuals, and special attention should be paid when developing treatment plans.