Improving chin profiles are usually addressed by implants or jaw surgery, but a better understanding of how soft-tissue dynamics also influence chin projection has prompted clinicians to look into the possibility of using onabotulinumtoxinA (Botox) as a non-surgical alternative.
Standards of facial beauty are tied to perceptions of symmetry and achieving that balance of the different structures make for pleasing (or otherwise) aesthetic profiles. The profile of the chin significantly contributes to this facial harmony. In fact, many cultures associate “strong” chins with a corresponding strength of character. Conversely, weak chins are seen as lacking in those same aspects.
Plastic surgeons offer augmentation procedures to patients, ranging from the insertion of implants to increase chin projection, to surgically repositioning the jaw to create that increased profile. But with a greater understanding of how soft tissue dynamics also influence chin projection, clinicians are also looking at non-surgical means either as alternatives or as adjunct procedures.
The hyperactivity of the muscle overlying the front part of the jaw (the mentalis) may play a role in distorting the skin and soft tissue overlying the chin. As the muscle contracts, it bunches up towards the lower lip and away from the bony contours; this subsequently blunts the chin profile.
Clinicians are looking at how onabotulinumtoxinA(a cosmetic form of Botulinum toxin) can help address this hyperactivity. Using onabotulinumtoxinA’s properties that prevent muscle contraction, they theorize that injections to the mentalis can cause it to relax and re-drape over the chin, which can redefine the contour. The July 2017 edition of the JAMA Journal of Facial Plastic Surgery has published the initial results of one such study.
From 2006 to 2012, eleven patients consulting for “weak chins” were evaluated and treated with onabotulinumtoxinA injections over the mentalis muscle. These patients were followed up over a period of several years, including photographic documentation and analysis of their respective profiles. Defined points in their chins were identified, and objectively measured before and after the procedures.
Improvements in the profiles were indeed seen, as evidenced by increased projection of the pogonion or the most anterior portion of the chin. Photos also showed a more rounded appearance of the chins, which is surmised to be the result of the relaxation of the mentalis muscle. All eleven patients reported satisfaction with the results, and no adverse effects were reported.
While the authors report these promising results, they caution that these initial findings do not mean that all patients are candidates for onabotulinumtoxinA injections. Correctly identifying which patients can benefit from standalone injections is important, as an alternative to invasive operations. On the other hand, it can still be of help in those patients where traditional augmentation procedures remain the treatment of choice, where adjunctive soft-tissue remodeling can help achieve the best possible results.
Written by Jay Martin, M.D.
Reference:  Hsu, A.K., Frankel, A.S. “Modification of Chin Projection and Aesthetics with OnabotulinumtoxinA Injection”. JAMA Facial Plastic Surgery. 2017: July 27. Doi: 10.1001/jamafacial.2017.0606
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