Background: The most common aesthetic deformity of the lower jaw is asymmetry. Whether it is very visible or known only to the patient, lower jaw asymmetry is very common and is probably the norm rather than the exception. This is clearly evident in the many 3D CT scans I see where almost everyone has some degree of bony jaw asymmetry. This is not surprising given how the lower jaw develops from paired embryonic arches from each side merging in the middle. It is hard to imagine that such a complex merging process always results in a perfectly symmetric lower jaw.
Many lower jaw asymmetries are minor in nature and are most commonly seen with differences in the vertical length and width of the jaw angles. This is usually no greater than 3 to 5mms which may seem to be slight. But when augmenting the jawline such small amounts of asymmetry become magnified as they become enlarged if they are not recognized and accounted for in the implant design between the two sides. This is one of advantages of a custom jawline implant design.
Case Study: This male presented for jawline augmentation. He was aware of some chin and jaw asymmetry which was vey clear on his 3D CT scan. The left jaw angle was higher and less wide with a lower inferior border on the right side. The differences in the two side resulted in some chin asymmetry as well.
A custom jawline implant was designed that provided both the desired amounts of chin and jaw angle augmentation and also addressed the bony asymmetry as well.
The subtle differences in the thicknesses of the implant in the asymmetry correction could be appreciated in the color thickness mapping. The total implant volume was 17ccs.
Under general anesthesia and through an external submental incision combined with two intraoral posterior vestibular incisions, the jawline implant was introduced in a front to back one-piece insertion technique. It is the flexibility of the implant jaw permits this insertion technique to be effective. Double screw fixation was done at each corner. (chin and jaw angles)
It is important to remember that a jawline implant addresses the bony asymmetry. It can not account for what contribution to the asymmetry may also come from the soft tissues.
1) Asymmetries of the lower jaw are very common which present as chin and jaw angle side differences.
2) A custom jawline implant can be designed to correct the bony asymmetries of the lower jaw.
3) A front to back insertion technique is preferred to maintain the one-piece construct of the implant and to reduce the risk of infection.
Dr. Barry Eppley