Last updated: 02/17/2009

Mentoplasties fall into two large categories: procedures that augment (increase) small or receding chins; and those that reduce large or protruding chins. Chin augmentation is done more frequently than chin reduction, reflecting the fact that microgenia...

(small chin) is the most common abnormality of the chin.

Chin augmentation

Chin augmentation can be performed by inserting an implant under the skin of the chin or by performing a sliding genioplasty. Insertion of an implant takes 30–60 minutes, while a sliding genioplasty takes slightly longer, 45–90 minutes. If the mentoplasty is done together with orthognathic surgery, the operation may take as long as three hours.

Chin implants are used in patients with mild or moderate microgenia. At one time they were made of cartilage taken from donors or from other sites on the patient's body, but as of 2003 alloplastic implants (made from inert foreign materials) are used more often because they reduce the risk of infection. To insert the implant, the surgeon can choose to make the incision under the chin (submental) or inside the mouth (intraoral). In either case, the surgeon cuts through several layers of tissue, taking care to avoid damaging the major nerve in the chin. The surgeon makes a pocket in the connective tissue inside the chin and washes it out with an antiseptic solution. The sterile implant is then inserted in the pocket and positioned properly. The incision is closed and the wound covered with Steri-Strips.

A sliding genioplasty may be performed if the patient's chin is too small for augmentation with an implant, or if the deformity is more complex. In this procedure, the surgeon cuts through the jawbone with an oscillating saw and removes part of the bone. He or she then moves the bone segment forward, holding it in place with metal plates and screws. After the bone segment has been fixed in place, the incision is closed and the patient's head is wrapped with a pressure dressing.

Chin reduction

Reduction of an overly large or protruding chin may be done either by direct reduction or a sliding genioplasty. In a direct reduction, the surgeon makes either a submental or an intraoral incision and removes excess bone from the chin with a burr. A sliding genioplasty reduction is similar to a genioplasty to augment the chin, except that the bone segment is moved backward rather than forward.