Background: The desired shape of the chin can be very gender specific. Men often prefer a wider and even a more square chin shape. Conversely women usually prefer a more narrow chin shape and most contemporarily a tapered v-shape. While achieving a wider chin shape in men usually requires addition using an implant, attaining a tapered chin shape in females is commonly done through bone subtraction.
In the horizontally short female chin a more tapered shape can be achieved by moving the chin bone forward. This has a naturally tapering effect as the u-shaped chin projection is further advanced. This can be even further tapered if needed by the classic mini-v line surgery (inverted t-shaped bone genioplasty) in which a central wedge of bone is removed whether the chin is horizontally advanced or not.
An alternative approach is the alloplastic mini v-line surgery for females where an implant is used to create the tapered chin appearance. This is only applicable if the chin is horizontally short so the more narrow shape of the implant can be reflected as the soft tissue chin pad is pushed forward and wraps around it. In most such cases a standard chin imply can be used by modifying its shape and placing it on a normal bone surface. But when the underlying bone surface is not ideal (asymmetric, deformed or non-smooth) a custom chin implant approach is usually better.
Case Study: This female had a prior history of bony chin surgery consisting of a horizontal advancement followed by various procedures to reshape it and reduce it. This left her with a chin that was both horizontally and vertically deficient with a large mobile soft tissue pad. She temporarily augmented her chin with hyaluron-based filler which helped a bit did not achieve her ideal augmentation goals. 
A custom chin implant was designed per her specifications with the goal of achieving a chin that had more horizontal projection (8mm), increased vertical length (5mm) and a very narrow shape. She wanted to keep it narrow with no added width so the implant design looked very much like a pointy prominence.
Under general anesthesia and through her existing submental incision the soft tissue chin pad was elevated off of the bone. In doing so a large amount of gel filler extruded. With complete bone exposure all visible plate and screw hardware was removed.
The custom chin implant was opened and its potential shape on the chin could be seen. Its underside had a cuplike appearance.
Because of its cuplike underside shape it was inherently unstable on the end of the remaining deformed chin bone. Triple screw fixation was used with long screws (15mms) drilled through the implant into the bone.
When trying to achieve a very tapered v-shape chin in females, or the reverse in men for a square shaped chin, it is important to remember that custom implant designs must often be exaggerated. They may look unnatural compared to the underlying bone but that doesn’t translate directly to how it will look on the outside. The overlying soft tissue chin pad is thick and will blunt the effect of what lies underneath it. Admittedly even I was a little concerned about this unusually shaped chin implant design with such a narrow base. But multiple surgeries with thicker stiffer scar tissue prevented an overly narrow or pinched look to the chin.
Case Highlights:
1) Bony chin deformities can be reshaped through the use of a specially designed custom implant.
2) In designing a custom chin implant only the bone is seen on a 3D CT scan and the impact of the overlying soft tissue chin pad on the final external aesthetic result is speculative.
3) To create a desired chin shape the design of a custom implant must often be exaggerated.
Dr. Barry Eppley
Indianapolis, Indiana