Botox in the Masseter

A 42-year-old female patient presented to our office seeking cosmetic treatment because she wasn’t happy with the appearance of her face. Upon examination, I noted that her face was very squared in the lower jaw, which can lead to a more masculine appearance and fuller face. Physical examination revealed that she had a very thick masseter muscle.

The patient confirmed a history of teeth grinding and waking up with daily migraine headaches. She reported that she had sought medical treatment from several doctors and dentists for the headaches and grinding and had gone through three different mouth guards and took a prescription medication for migraines, but nothing helped. The masseter muscle tends to be thick in patients who grind their teeth or clench tightly at night either because of nervousness or out of habit. With prolonged grinding and clenching, that muscle gets thicker and thicker over the years, which leads to a wider jaw.

I suggested treatment with injection of onabotulinumtoxinA (Botox) in her masseter muscle to relax the muscle so she would not be able to clench, grind, or bite down as hard. This relaxation in the muscle would lead to thinning of the muscle, which would result in thinning her face and alleviating her teeth grinding and headaches.

Figures 1a-b. Patient before (top) and one month after (bottom) injection of 100 units of Botox into the masseter.

The patient agreed to the treatment. I injected 100 units of Botox (See Figures 1a and 1b).

The patient returned for follow up one month later saying, “This has changed my life. I don’t take any of my migraine medicines any more, I don’t need my mouth guard any more, my face is thinner.”

Treatment Tips

Botox injection into the masseter muscle is ideal for patients who are grinding, clenching, and wearing out their teeth and need a lot of dental work, for patients who have frequent tension or migraine headaches, and for patients who do not like the shape of their face because of square or thick jaw line and who want to appear more feminine.

The amount of Botox needed to treat this area ranges between 60 and 100 units of Botox, depending on the thickness of the muscle. Patients can expect headaches and clenching to go away within a week and will see the full effects of jaw thinning about one month after treatment, when the muscle has had time to atrophy.

In 10 years of performing this treatment, I’ve never had one side effect other than some bruising, which is a potential side effect whenever you inject into the face. There’s no swelling, no downtime. It is the most magical treatment I’ve ever done. Patients can go back to their normal activities. They can exercise. They can do whatever they want that day. Most people come in during their lunch break, they get injected. You can’t even see the pinprick of the needle.

Patients should be counseled to return to the office for treatment every six months, which is longer than the typical two-month interval for injecting Botox in other areas. Most of my patients present back in six months and say they were just starting to get headaches again or were just noticing that it was time for treatment and with follow-up injection; they feel great again. I’ve never had a patient who wanted me to re-treat in less time because I inject a high enough dose. Under-dosing the muscle in efforts to get by with a smaller dose or because a patient wants to spend less money will definitely lead to the patient coming back sooner for follow-up treatment, and s/he won’t see the ideal effect for headaches.

Injection Pearls

When injecting into the masseter, it’s important to feel where the masseter muscle starts and ends. The masseter muscle is like a triangle, so I actually go into each vertex of the triangle and test it for the masseter. It’s also essential to know where the risorious muscle is, which holds the corner of the mouth out when you smile. It’s important to not hit the risorious muscle or that side will not move, resulting in a crooked smile.

For optimal results, be sure to use a high enough dose—if you under-dose, treatment will not be effective. It’s not like other injection areas where you can say, “OK, we’ll just inject 10 units and see what it looks like.” It doesn’t work the same way—you have to use a higher dose to ensure optimal results.