Some people finish a course of braces with straight teeth and a bite that still does not close properly. When that happens, the cause is often the jaw bones rather than the teeth: the lower jaw is set too far forward or back, or the two jaws grew at different rates. Orthodontic appliances can tip and slide teeth through bone, but they cannot shorten, lengthen or rotate a jaw. Orthognathic surgery is the procedure that does that, and it is usually planned together with braces.
Braces move teeth, surgery moves bone
A useful way to picture it is a house and its furniture. Braces and aligners rearrange the furniture. If the rooms themselves are the wrong size or in the wrong place, rearranging furniture only goes so far. In the mouth, that means teeth can be straightened within each jaw, as described in our guide to straightening crooked teeth, but if the upper and lower jaws are mismatched in length, width or height, the teeth cannot meet in a stable, comfortable bite without the jaws being moved.
Orthognathic surgery is carried out by an oral and maxillofacial surgeon in hospital, under general anaesthetic. The surgeon cuts and repositions the upper jaw, the lower jaw, or both, then holds the bone in its new place with small plates and screws while it heals. Sometimes the chin is adjusted at the same time. An orthodontist manages the braces on either side of the operation, and the two plan the case together.
Signs the problem sits in the jaws
No single feature decides it, and the final judgement comes from records such as X-rays, scans, photographs and measurements of the face. Even so, some patterns point towards a skeletal cause:
- the lower front teeth sit well in front of the upper front teeth (a marked underbite)
- the lower jaw looks small or set back, with a large gap between the upper and lower front teeth
- the front teeth do not touch at all when the back teeth are together (an open bite)
- the chin or jaw is visibly off centre
- chewing, biting through food or certain speech sounds are difficult because of how the jaws meet
Jaw position can also narrow the airway in some people, and moving the jaws forward is one of the surgical options considered for selected adults with obstructive sleep apnoea. That decision is made by a sleep physician and surgeon, not on the basis of the bite alone. Our article on overbites, underbites and crossbites explains how these bite types are described.
Why the bite can look worse before surgery
This part surprises most people. Before the operation, braces are used to line the teeth up within each jaw so that they will fit together once the jaws are moved. Over the years, teeth often lean to compensate for a jaw mismatch, for example lower front teeth tipping backwards to meet a lower jaw that sits too far forward. The orthodontist undoes that compensation, which can make the bite look more pronounced for a while. This preparation often takes around 18 months to two years, although it varies with the case.
The appliance does not have to be conventional metal brackets. Some cases suit lingual braces, and some surgical plans now use clear aligners for part of the treatment. The orthodontist and surgeon decide what will give the surgeon the most predictable result.
The weeks after the operation
The operation itself typically takes a few hours, followed by one to a few nights in hospital. Swelling peaks in the first several days and settles over the following weeks, with some residual swelling taking a few months to resolve fully. A soft or blended diet is needed while the bone heals, and most people take a few weeks off work or study. The jaws are usually no longer wired shut; small elastics may guide the bite instead.
Numbness of the lower lip and chin is common after lower jaw surgery because a sensory nerve runs through the bone. In most people feeling returns gradually over months, but in a minority some altered sensation remains long term. Other risks, such as infection, bleeding, relapse of the jaw position and changes to the jaw joints, are discussed with the surgeon before consent. Once the bone has healed, a shorter period of braces fine tunes how the teeth meet, often several months, followed by retainers.
When camouflage is a reasonable alternative
Not every jaw mismatch needs an operation. Where the difference is mild, braces or aligners can sometimes tip the teeth to disguise it, an approach called orthodontic camouflage. The bite may function well, but the facial profile does not change, and there are limits to how far teeth can safely be moved over the bone. For some concerns that are mainly about appearance, smaller procedures can help, as our guide to gummy smile treatment shows. Weighing camouflage against surgery is a conversation for a registered orthodontist and maxillofacial surgeon, and it depends on age, severity, symptoms and what the patient wants.
Questions we are often asked
Can jaw surgery be done before growth has finished?
It is usually delayed until jaw growth has stopped, which is often around the late teens in females and a little later in males. Operating too early risks the jaw continuing to grow after correction.
Is this cosmetic surgery?
Its main purpose is functional: correcting how the jaws and teeth meet for chewing, speech and long term stability. Changes in facial balance are a consequence of moving the bones, and they are part of the planning discussion.
Where does a general dentist fit in?
A general dentist is often the first to notice that a bite problem looks skeletal. At Lumi Dental we can take records, including 3D X-ray imaging, explain the findings and refer you to a registered orthodontist and oral and maxillofacial surgeon. The surgery itself is a hospital procedure and is not done in a dental practice. For dental treatment in the chair, Lumi offers happy gas, inhaled pain relief, oral sedation and IV sedation if you are anxious.
Getting your bite assessed
If you have been told your bite is a jaw problem, or you suspect it after braces, an assessment is the place to start. Read about care at our Melrose Park practice or check the current deals page for consultation options. This article is general information and not a substitute for personal orthodontic or surgical advice.
