Chin implant augmentation is done in both men and women but the aesthetic goals are often different. While the amount of horizontal chin projection differs amongst each patient, the shape of the augmented chin from the front view can be very gender specific. While women may prefer a more narrow or even v-shaped chin appearance, men usually prefer a wider and even square-shaped chin result.
The desire for a square chin shape in men is not new and off-the-shelf implants have been designed to do so since the 1990s. (style 1 and style 2 square chin implants) While these square chin implant designs are wider than the traditional anatomic implant shapes they have never been particularly satisfactory from my experience. While they are wider they are either too narrow (style 1) or too wide (style 2) to look right in most men. Beyond their width the ‘squareness’ of the implant does not really create a square chin look. The corners are too round and indistinct to really create a good square chin appearance for most men.
I once asked the original designer of the square chin implant how he came up with the square chin implant design and is comment was…’it looked good in a skull model’. At that time in history that may have been the only design approach possible. But today we have the major advantages of custom implant designs which can teach us a lot of about the effects of various implant shapes that go beyond the theoretical design on a skull model.
From custom implant design experience a square chin implant must look a lot more square in the design than one would think. It is important to be aware that how an implant design looks on the bone is not reflection of exactly how it will look like when it it covered with soft tissue. The thicker chin pad soft tissue layer will soften or dampen any sharp edges or more angular implant features. Is if you want a more square chin appearance the implant design must look ultra square or over square. Such squareness is determined by how sharp the transition is from the from the front of the implant to the sides. While a 90 degree change is probably too much, a 100 to 105 degree angle is not.
Making a square chin implant is also affected by the width of the implant. By definition squareness means the implant will get wider by some amount. How much width is enough and how much is too wide is always the pertinent question. Each patient has to be evaluated on their own in that regard but, as a general rule, the squareness of a chin implant (where it turns the corner from front to the side) should not exceed the canine tooth on a 3D CT scan. This usually correlates to a vertical line dropped down from the mouth corners externally.
One dimensional change that can help maximize the appearance of a square chin implant is of any vertical lengthening is needed. Even a few millimeters of vertical lengthening with the horizontal increase helps stretch the soft tissue chin pad to show the implant design even more. But this should only be done IF it has been shown before surgery that some vertical lengthening is aesthetically beneficial.
All square chin implants will have a midline marker. (blue line in a 1 millimeter vertical indentation) This should not be confused with any attempt at making a cleft chin. (which could never be accomplished by a 1mm indentation in the implant) This helps orient the implant for midline placement and is often where a single screw fixation is placed.
Dr. Barry Eppley