Orthognathic surgery — it does not shave the jaw, it cuts the jawbones and moves them

Orthognathic surgery cuts the upper jaw (maxilla) and lower jaw (mandible), moves them, and fixes them with plates.

It is often confused with facial contouring, but they do different things. Contouring shaves the outer surface of bone to change width and line; orthognathic surgery cuts through the bone and moves the whole piece. Which means the way the teeth meet changes.

That is the first thing to understand on this page. Move the jawbones and the bite changes; change the bite and chewing changes. So this operation is carried out as one package with orthodontics.

• Pre-surgical orthodontics — the teeth are moved first, so they will meet once the bone is repositioned. During this period you pass through a stage where the face looks less aligned, not more.
• Surgery
• Post-surgical orthodontics — refining the bite in its new position.

The whole schedule is usually one to two years. The surgery itself is one day inside it.

And it is often performed where function is involved — prognathism, a recessed chin, asymmetry, open bite. In those cases it is less a cosmetic operation than an operation about function, and the judgement belongs to orthodontics and oral and maxillofacial surgery.

The incisions are inside the mouth, so no scar shows outside.

The lower lip and chin go numb. The inferior alveolar nerve runs through where the lower jaw is cut, and this is the most common aftereffect of the operation. Most of it returns over months, but some being permanent is not rare. Hear this clearly before the operation.

You will not chew properly for weeks. There may be a period with the jaws held together by elastics or fixation, and a liquid diet through it. Losing weight is normal.

The swelling is the largest in this layer. The first two weeks are worst, and the final shape takes six months to a year. Do not judge the result before then.

Revision is hard. Reopening bone that has been cut and fixed raises the risk.

There are rare but serious complications — bleeding, infection, failure of fixation, jaw joint problems, airway problems. This is four to seven hours under general anaesthesia.

Operating before the orthodontics is finished leaves a bite that does not meet. Do not skip that order to pull the date forward.

Get your consultation where oral and maxillofacial surgery and orthodontics work together. This is not an operation one person decides alone. The orthodontic plan and the surgical plan have to be built together from the start.

Ask to see the 3D imaging and the plan. CT data is now used to simulate where and how far the bone will move before the operation. Look at that plan and have it explained.

Bring your functional symptoms written down — difficulty chewing, speech, jaw pain, lips not closing. Talk only about appearance and the plan tilts one way.

Not smoking matters especially here. This is an operation where bone has to knit, and smoking impedes both bone healing and gum healing.

Prepare for the weeks after in advance: liquid diet, time off work or study, transport, oral hygiene. This is the operation in this layer that needs the most preparation.

Do not read the face during the swelling as the result.

It cannot be undone. Cut bone in a new position does not go back.

This is not only about the face. The bite changes, so chewing, speech and sometimes breathing are involved. That is why this operation is not something to decide on appearance alone; a functional assessment has to sit alongside.

The schedule is long. Deciding by looking at the surgery date alone underestimates the one to two years of orthodontics on either side — part of which is a stage where the face looks more awkward, not less.

If you only want to change the shape of the jaw, there are other options. Facial contouring, which reshapes only the outer surface of bone, and fat grafting, which corrects line with volume, leave the bite alone. Having orthognathic surgery with no bite problem is taking the largest operation for the smallest reason.

Consider first whether you could accept lasting altered sensation. It is the most common permanent change from this operation.

Whether to have it is decided in consultation, and it is better not to decide from one clinic's account.