If you've spent any time on plastic surgery TikTok, you've probably seen the videos: a visible step-off along the jaw after jaw angle implant surgery, worse when clenching. Many people call this masseter dehiscence. Dr. Jonathan Zelken breaks down what's actually happening, and why the standard diagnosis might not always be the right one.
If you've been on TikTok or Instagram lately, and you follow anything related to jaw surgery or facial implants, there's a good chance you've come across videos of patients, some of them quite distressed, showing a strange contour abnormality along the lower jaw after jaw angle implant surgery, like a visible step-off, a double bubble, if you will, a shelf-like depression that deepens when you clench your teeth. The internet has labeled this masseter dehiscence. Actually, the literature has done this for some time. And surgeons, myself included, are now having to answer questions about it in every consultation.
Today I want to do something a little different. I don't just want to explain what masseter muscle dehiscence is. I want to question whether what we're actually seeing in many of these cases truly is dehiscence at all, and why that distinction matters enormously for how we treat it.
What Masseter Muscle Dehiscence Actually Means
Let's start with the anatomy and the definition. The masseter is the powerful muscle of mastication that runs from the cheekbone, the zygomatic arch, down to the lower jaw, the mandible. When you clench your teeth, you can feel it bulge just in front of your ear and along your lower jaw line. When jaw angle implants are placed, the surgeon accesses the mandibular angle through a small incision inside the mouth. The tissue elevated off the bone creates a pocket for the implant that includes the periosteum, a thin, paper-like connective tissue sleeve that covers the bone, as well as the overlying muscle attachments, collectively sometimes referred to as the pterygomasseteric sling.
But masseter dehiscence, in the traditional anatomical sense, means that the masseter muscle has detached completely, or separated from its insertion on the mandible, and has migrated upward toward the cheekbone.
Why the Jaw Looks Hollow: Classical Mechanism
So when that happens, you can imagine the lower border of the jaw appears hollow or deficient with muscle contraction, because the muscle that normally fills this space is no longer there. It's retracted upward. That's just the classical definition, and that's the mechanism that most of the literature and most of the surgical discussions about this complication are based on.
The Literature Problem: No Consistent Definition
Here's where things get complicated, and honestly, a little frustrating. If you go looking for the true incidence of masseter dehiscence after jaw angle implant surgery, you're not going to find a clean answer. The literature reports rates that vary very widely, with some series citing incidences as low as a few percent, and others going as high as 20 to 30 percent. Twenty to thirty percent. That would be an extraordinary complication rate for an elective aesthetic procedure.
The problem is there is no consensus definition being applied uniformly across these studies. Different surgeons are likely calling different things by the same name, and some may be reporting any visible contour change as dehiscence. Others may require imaging confirmation of muscle displacement. Some series include patients who had minimal symptoms and did not seek revision; others capture only the patients who came back with complaints. This inconsistency makes it nearly impossible to give a patient a realistic and reliable number during a consultation.
Dr. Zelken's Own Practice: ~100 Jaw Angle Implants
The surgeon also matters. And it raises a question I think is genuinely worth exploring: are all these cases the same phenomenon, or are we grouping together several distinct anatomical events under one label? In my own practice, I have placed approximately 100 jaw angle implants over the past two years. Of those, I'm aware of one case that raised concern for masseter dehiscence. I say "aware of," because underreporting is real. Patients may experience mild changes and never return, or attribute them to normal healing variations.
A Patient Case That Raised Concern
This patient I'm thinking of was a young man who came to me for jaw widening and lengthening surgery. He had notably prominent masseters to begin with, which is a relevant detail. His implants were custom designed, and I was intentionally conservative with those dimensions. The access was through an intraoral approach, which I used to elevate the periosteum off the mandibular angle using a blunt instrument called an osteotome. I elevated what is described as the pterygomasseteric sling, although, as I'll explain, I'm not sure that term is entirely accurate either.
At approximately four months postoperatively, the patient sent photographs and a text message describing a double bubble, a visible contour irregularity along the lower jaw at certain angles when he clenched his jaw shut. He had found videos online that mirrored his appearance and was understandably concerned about what to do next.
Dynamic Examination: What He Observed
I invited this young man back immediately and photographed him at rest and during dynamic jaw clenching. What I observed was this: there was a noticeable step-off, for sure, a shelf-like depression at the lower border of the masseter that became more pronounced when he clenched his jaw, and the contour deepened. But here's what caught my attention: the length of the masseter did not ever shorten when he clenched his jaw.
The Key Finding: Muscle Length Didn't Shorten
In true masseter dehiscence, when the muscle retracts upward toward the cheekbone, you'd expect the functional length of the visible muscle to shorten significantly. The muscle literally sits higher on the face. But that's not what I was seeing at all. The muscle was the exact same length as it was pre-operatively. It was just developing a surface contour change, almost a depression at the lower pole.
An Alternative Hypothesis: Periosteal Stretching
This is where I want to make an argument that I feel has serious clinical implications. What if what we're calling masseter dehiscence in many of these cases is not true anatomical separation of the muscle from the bone at all?
Here is my alternative hypothesis. When we elevate the periosteum off the mandibular angle to create the implant pocket, we're stripping away that thin connective tissue sleeve. In some patients, the periosteum heals in a way that leaves a narrow isthmus of tissue bridging across the lower pole of the implant. The implant, particularly a widening or lengthening design, creates a convex surface beneath this bridge of thin periosteum, which is different from the thick masseter muscle. Over time, with the repetitive mechanical force of chewing and clenching, especially alongside weight loss, that periosteal isthmus stretches and thins over that hard, thick part of the implant. The masseter, which is not actually separated from its bony insertion, continues to function at its normal length.
Why This Distinction Changes Everything
The surface contour changes because the soft tissue envelope overlying the lower pole of the implant is no longer providing uniform support. What the patient and the camera see (a step-off, a depression with clenching) looks exactly like what we all think of as dehiscence. But what may actually be happening is a periosteal stretch mechanism over a prominent implant edge, without any true muscular separation. This distinction is not argumentative and it's not academic. It has direct implications for treatment.
On The Viral TikTok Case (Bray)
I also want to acknowledge a name some of you may have already searched, or you've probably seen this video, which is why you're here: a gentleman referred to as Bray, whose TikTok documenting what he believes to be masseter dehiscence has been viewed very widely. His presentation, from what I can observe externally as a surgeon, shares features with what I've just described. Without examining him (and he's not my patient), I cannot make a clinical judgment. But I raise this case because it's precisely the kind of situation where the treatment path chosen will depend entirely on whether the underlying mechanism is true dehiscence or simply periosteal stretching.
Surgical Treatment For True Dehiscence And Its Risks
Here is why this matters. The surgical treatment for true masseter dehiscence involves opening an external incision (a visible scar, along or below the jaw) and repairing the detached muscle back to the mandible, often at the pterygoid attachment or the periosteal lining. It's a real operation, with real recovery, a permanent mark on the skin, and its own risk.
If the underlying anatomy actually reflects true muscular separation (muscle elevated off bone, retracted upward, and shortened), then that repair is anatomically rational. But if we're dealing with periosteal stretching, not true dehiscence, over the lower pole of the implant, with the muscle still functionally attached and at normal length, then that repair doesn't really address the problem and is prone to failure. You'd be suturing tissue back to a structure that was never damaged in the first place. The result, in my view, would likely be disappointing and likely to recur, and the patient would have a visible scar now, with little to show for it.
Non-Surgical Strategy: Neurotoxin And Filler
For my own patient, and as a consideration for anyone in a similar situation, before committing to revision surgery, I offered a non-surgical strategy: neurotoxin injection (that could include Botox or Dysport) to selectively weaken the masseter muscle. By reducing the force of muscular contraction, we reduce the dynamic contour change that occurs with clenching. Simultaneously, a small amount of soft tissue filler can volumize that lower pole defect of the jaw, providing surface support where the periosteal envelope has thinned. My patient's result is currently satisfactory. He's really happy. The contour is improved and the dynamic step-off is less visible.
Transparency: What We Still Don't Know
I want to be very transparent now: we do not yet know the longevity of this strategy, or how often it's going to work for people. Neurotoxin does wear off, and filler can migrate or resorb. This is not a permanent solution, and I'm not presenting it as one. But I would submit that for a patient who may not have true dehiscence, a reversible, non-surgical approach that avoids a visible scar and a second operation is a reasonable first line before any surgical revision is attempted.
Bringing It Full Circle: Two Different Problems, One Label
So let me bring this full circle. The literature on masseter dehiscence is inconsistent. Reported incidences range widely and are likely influenced both by underreporting and by the absence of a standardized definition. The true incidence is genuinely unknown.
More importantly, what the literature calls masseter dehiscence may represent more than one distinct anatomical event. Some cases are likely true muscular separation, the classical definition. Others may represent periosteal stretching over the lower pole of a prominent implant, with the muscle functionally still intact. These two scenarios look similar on the surface; they look similar in photographs, and they look similar in viral TikTok videos, but they are not the same problem, and they may not respond to the same treatment.
My recommendation, if you are a patient who has experienced this after jaw implant surgery: seek evaluation from a surgeon who is willing to examine you dynamically, in person, not just at rest, and who is asking the question of whether your muscle length changes with clenching. And if you are a surgeon watching this, I think we owe it to our patients to be more precise about what we are diagnosing before we recommend an irreversible operation with a visible external scar.
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