Orthognathic surgery can be done when you are 40 years old and your physical condition permits. 1. Orthognathic surgery is a widely used corrective surgery for all kinds of dental and maxillofacial deformities, even craniofacial developmental deformities. The basic procedure of modern orthognathic surgery is standard bimaxillary surgery. Orthognathic surgery has two important purposes, including changing cosmetic deformities and restoring the physiological function of the oral-mandibular system. 2. Deformities involving the jaws include: anterior-posterior deformities, such as maxillary protrusion, maxillary retrusion, etc.; vertically oriented deformities, such as long-face syndrome, short-face syndrome, etc.; and asymmetrical deformities of the face and jaws, such as hemifacial dysplasia and condylar hypoplasia. Generally speaking, there is no upper age limit for orthognathic surgery, as long as the physical condition allows, you can receive orthognathic surgery under the guidance of the doctor.