Chin surgery — cutting the bone and placing an implant are two different operations

Chin surgery deals only with the lowest part of the face, the chin itself.

Two methods go by one name. Drawing that distinction is what this page is for.

One: cutting and moving the bone (sliding genioplasty). The chin bone is cut horizontally and then brought forward, set back, shifted to one side, or shortened by removing a segment. The moved bone is fixed with screws or a plate. Because the bone itself is changed, this cannot be undone.

Two: placing an implant. Material is set in front of the chin bone, increasing projection only. It can be removed. But removal does not always return things to how they were — resorption of the bone under an implant has been reported.

Which one depends on what you want changed. If projection is the only issue, both methods are used. Shortening, setting back, and correcting a sideways twist cannot be done with an implant.

And here is what this operation does not do. Chin surgery does not change how the teeth meet. If the problem comes from the relationship between the upper and lower jaws, that is the territory of orthognathic surgery, and that is a far larger operation. Where the appearance actually comes from is the question that has to be settled first.

The incision is usually inside the mouth, leaving no external scar, under general anaesthesia. An approach from under the chin also exists, and that does leave a visible scar.

A nerve runs close by. The nerve serving sensation in the chin, lower lip and lower front teeth (the mental nerve) lies right beside the operative field. Reduced sensation is common and usually recovers over months, but it can persist. This is the first thing to hear about in this operation.

The implant route has problems of its own. Displacement, infection, a palpable edge, and resorption of the bone underneath. If the bone has been resorbed, removing the implant can leave the chin looking less projected than at the start.

The bone route has problems of fixation and healing. The moved segment may fail to unite, and screws or plates may be palpable or need removing later.

Lower lip movement can change. An approach through the mouth passes the muscles that pull the lip down. Your smile may look different for a while.

The gums and tooth roots are close. The cut has to sit below the roots. That is why imaging is needed beforehand.

Bringing the chin far forward changes the folds above it. People are surprised to find the crease under the lip looking deeper when only the chin was moved.

Swelling lingers here. It takes months before the final shape can be judged.

Get imaging and establish the cause first. A small chin bone, a lower jaw set back as a whole, and an upper jaw pushed forward can look similar and are different problems. If the cause lies in the relationship between the jaws, moving the chin alone will not settle it.

Do not look only at the profile. A sideways twist does not show in profile; look at the front and three-quarter views too.

Say 'longer' and 'forward' as separate words. They are different directions and need different methods.

If an implant is used, get the material and product name in writing. You will need it if it is ever removed or exchanged.

If you choose the bone route, ask in advance whether the hardware will be removed later.

Not smoking matters especially here. It bears directly on healing inside the mouth and on bone union.

Expect soft food for several days, particularly with an approach through the mouth.

This page marks reversibility as 'partial' because it holds two operations. An implant can be removed; a cut bone cannot be uncut. Which route you take decides that difference.

The chin is seen together with the rest of the face. It makes an impression alongside the nose, the mouth and the angle of the neck. Changing one part precisely can still leave the whole reading differently than expected.

Small changes are harder to judge than large ones. Agreeing a few millimetres in advance from photographs is not easy.

Ask for numbers on how common changed sensation is and how long it lasts. It is the complaint that most often persists after this operation.

Whether to have it done is settled with a doctor, and it is better not to settle it on one consultation alone.