Orthognathic surgery refers to the surgical correction needed to fix substantial abnormalities of the maxilla (upper jaw), the mandible (lower jaw), or both. The abnormality may be a birth defect, a growth defect, or the result of traumatic injuries to the jaw area.
Orthognathic surgery is generally performed by an oral and maxillofacial surgeon to correct malocclusion (bad bite) in cases where routine orthodontic treatment has not or will not be effective. Orthognathic surgeries include the reconstruction of the mandible or maxilla, mandibular ramus, maxilla osteotomy, and mandibular osteotomy.
There are several classifications of malocclusion (the improper coming together of teeth) which may require orthognathic surgery:
Class I Occlusion – This malocclusion means that the lower anterior incisors sit directly behind the upper anterior incisors when the patient bites down. This is considered less destructive than Class II and Class III malocclusions.
Class II Malocclusion – This is identified when the lower anterior incisors lie significantly behind the upper anterior incisors during the biting process, in some cases hitting the soft tissue behind the upper incisors. This is commonly referred to as an overbite and can cause discomfort, bone damage, excessive wear of the front teeth, and tooth loss.
Class III Malocclusion – This is commonly known as an underbite and occurs when the lower anterior incisors and lower jaw are positioned beyond the upper teeth, making the lower jaw much more prominent than the upper jaw.
Reasons for orthognathic surgery
The malocclusion of the teeth can create greatly destructive forces among the five powerful muscles that control the closing and opening of the jaw. These muscles generate a tremendous force when clenching, grinding or chewing. Misalignment can seriously damage the function and aesthetic appearance of the teeth in many ways if left untreated, such as:
Tooth Wear – In the case of an overbite, the pressure and wear on the teeth is not spread evenly. This can also lead to TMJ, migraine headaches, and tooth loss.
Chronic Jaw, Muscle Pain & Headache – The misalignment of the teeth alters the way the facial muscles interact. In some cases, the meniscus cartilage, which acts as a buffer between the jawbones, can be painfully damaged.
Loose Teeth – When uneven pressure is continually exerted in unintended places or soft tissue is damaged by an overbite, adjacent teeth may become loose in their sockets which causes pain and reduces proper function.
Tooth Sensitivity – As teeth become damaged by constant use, the enamel becomes thinner and the nerves are less protected. This lack of protection can lead to sharp pains when hot or cold foods are eaten.
Difficulty Swallowing, Chewing, or Biting Food – Each can be associated with muscle pain and/or poor alignment of the upper and lower jaws.
What does orthognathic surgery involve?
When the dentist identifies a patient as a candidate for orthognathic surgery, a complete photographic analysis is initially undertaken. This includes panorex x-rays, cephalometric x-rays, models, impressions, and radiographs. Your oral & maxillofacial surgeon, your orthodontist and your dentist will work together and consider how the corrective surgery will impact both proper jaw function and the aesthetic appearance of the entire face.
Generally, orthodontic braces are necessary to align the arches and straighten the teeth prior to the surgery, and additionally, retainers may be used after the surgery. During maxillary surgery, the upper jaw is moved and may be secured in position using tiny plates, wires, rubber bands and screws. Surgery on the mandible is performed using bone grafts to align the lower jaw into the correct position. Orthognathic surgery generally requires a general anesthesia and a good deal of aftercare. Pain medication will be prescribed as necessary, and you’ll be given post treatment advice for your recovery. You may also be provided with a modified diet (if required).