Overview: Facial asymmetry is a common clinical condition with many causes that can cause asymmetrical deformities. In order to have a comprehensive understanding of these diseases, the following series of presentations will be made to provide a comprehensive analysis and understanding from the causes of the disease to the systematic treatment of the disease. Analysis of the causes of facial asymmetrical deformities We often encounter patients who visit the clinic because of facial asymmetries, sometimes because the doctors are too specialized and do not have a deep understanding of the disease in question, they blindly reshape the face without knowing the cause of the asymmetry, which is counterproductive. For this phenomenon, the following list of diseases that cause asymmetrical deformities. First, the cause of facial asymmetry deformity. Causes are more, can be divided into two categories: 1, pathological causes, including the following diseases: A: abnormal proliferation of bone fibers B: neurofibroma C: condylar osteoma D: ossifying fibroma E: hemifacial atrophy F: vascular disease (hemangioma, lymphatic malformation, etc.) resulting in bone and soft tissue deformities G: facial lipoma H: malignant tumors caused by the deformity, which is a point of special attention. 2, developmental causes A: the first two cheek arch syndrome B: hemifacial underdevelopment C: facial cleft D: unbalanced development of the jaws caused by dental malformation (such as geodontia, bruxism, facial obliquity, small jaws, etc.) E: unbalanced development of the zygomatic bone caused by zygomatic malformation F: benign hypertrophy of the condyles, condylar osteoma 3, occlusal relationship (between the upper and lower teeth, teeth and teeth alignment relationship) whether it is pathological or developmental causes Whether the facial asymmetry is caused by pathological or developmental reasons, there may be “abnormal occlusal relationship”, which is often overlooked by some doctors. Bone tissue is sensitive to force, and where the stress is high, the bone tissue is tough and the bone cortex is thick; conversely, where the stress is low, the bone cortex is thin. The stress generated by a normal occlusal relationship positively promotes bones and teeth, while the stress generated by an abnormal occlusal relationship aggravates deformities. Therefore, the occlusal relationship must be given due attention. Through the above etiological analysis, it is easy to see: there are many etiological factors that cause facial asymmetry. Therefore, patients who encounter facial asymmetrical deformities must clarify the etiology and not blindly reshape! Treatment precautions: 1, clarify the cause, etiological treatment 2, usually do bone tissue plastic surgery first, then soft tissue plastic surgery 3, the bite relationship abnormal, to correct the bite relationship