When one thinks of a short or small chin, most are envisioning it deficient in the horizontal dimension. (profile view) While this does make up the majority of cases of chin augmentation, there are other dimensions in which a chin can also be ‘short’. The second most common cause of chin deficiency is in the vertical dimension or its height.
A vertically short chin is apparent in several ways. First, there is an apparent small lower face compared to the middle and upper face. As the aesthetically balanced face is divided into equal thirds, the lower third (between the lower lip and the bottom edge of the chin) will look small in height compared to the rest of the face. Second, the labiomental crease (the groove between the lower lip and chin prominence) will often be indented further in or deeper than normal. Lastly, a vertically short chin may also be associated with an underbite although not exclusively so.
Correction of the vertically short chin is primarily done by a chin osteotomy and downgrafting. Placing a chin implant further down on the chin prominence may help a little (a few millimeters) but can not make a big difference. Changing the vertical length of the chin bone addresses the actual problem and is far more effective.
A chin osteotomy is done through an incision on the inside of the lower lip. The chin bone is easily and quickly exposed and the mentalis muscle lifted off. A saw is used to make a horizontal cut way below the roots of the front teeth. The lower end of the chin bone is dropped down and the predetermined amount of vertical length needed (bone gap) is maintained by a small titanium plate and screws. This bone gap is best grafted and the usual choice is hydroxyapatite blocks wedged into the open space. These blocks will eventually become incorporated into the new bone which will eventually fill in between the cut ends of the chin. The mentalis muscle is resuspended up over the plate and the incision closed with dissolveable sutures.
This vertical chin lengthening method can be opened up to almost any distance, from a few mms to up to over a cm. As a general rule, it usually must be at least 6mms or more to see an appreciable change in the height of the chin. The amount of chin lengthening needed can be precisely determined beforehand by simple photographic analysis and a millimeter ruler. Cephalometric tracings are the most exacting method but does require that type of orthodontic x-ray to be available.
While the cost and recovery from a chin osteotomy is more than from a chin implant (an extra week or so of prolonged swelling and chin stiffness), its superior results are worth this short-term sacrifice. Bringing the lower third of the face into proportionate balance can make for a very pleasing facial change in both profile and frontal views.
Dr. Barry Eppley
Indianapolis, Indiana