Jaw clenching and a square jaw: what masseter Botox can do

Your face looks wider at the bottom than you would like. Or your jaw aches in the morning, and your partner says you grind your teeth at night. Someone mentions jaw Botox, and you wonder if it could help, and whether it is safe to put it in a muscle you chew with.

Here is what it can do, what it cannot, and how long it really takes.

Why some jaws look wider

Three different things can make the lower face look wide. In a photo they look the same. Under the fingers they feel very different.

• Muscle. The masseter, the muscle you feel bulge at the back of your jaw when you clench. It gets bigger with heavy use, like any muscle, and some people simply inherit a larger one. This is what jaw Botox treats.
• Bone. A wide jaw angle is part of your skeleton. No injection changes bone.
• Fat. Soft fullness in the lower cheeks, forward of the muscle. Botox does not affect fat.

A quick check you can do: put your fingertips on the back of your jaw and clench your teeth. If you feel a firm bulge push out, muscle is likely part of the picture.

How it works

Botulinum toxin, often known by the brand name Botox, reduces how strongly a muscle contracts. When the masseter works less, it slowly shrinks over the following weeks, and the width it was adding to your face reduces.

It is a gradual change. You will not see a slimmer jaw the same week.

What to expect, week by week

• Weeks 1 to 2: chewing feels a little less powerful, especially with hard or chewy food. Nothing visible yet.
• Weeks 3 to 6: the muscle starts to reduce. Many people notice it first in photos, not in the mirror.
• Weeks 6 to 12: the visible narrowing. This is when to judge the result.
• Months 4 to 6: the muscle slowly returns. A repeat treatment around then often lasts longer than the first.

The treatment itself takes about 20 to 30 minutes. Most people go straight back to work. Small raised bumps at the injection points settle within an hour.

What about clenching and grinding?

Many people who clench or grind their teeth have large masseters, and some notice their jaw feels more relaxed after treatment.

But grinding, which doctors call bruxism, is a medical issue. It can wear down teeth and is linked to sleep and stress. It needs a dentist to look at your teeth and, often, a night guard. Using botulinum toxin for grinding is not one of its officially approved uses.

So if you grind, tell me. We will talk about it honestly, and I may suggest you see your dentist alongside any cosmetic treatment.

Risks, honestly

• Tired chewing. Common for the first two or three weeks, especially with hard food. It settles.
• A slightly uneven smile. Uncommon. It happens if the medicine reaches a nearby smile muscle. It wears off, and careful, deep placement makes it less likely.
• Hollowing at the jaw angle. From too strong a dose, particularly in a slim face. This is why I start gently.
• Bruising or tenderness at the injection sites. Usually mild.

I do not treat you if you are pregnant or breastfeeding, or if you have a nerve and muscle condition such as myasthenia gravis.

Who it is not right for

• If the width comes mainly from bone. That is a surgical question.
• If the fullness is mainly fat in the lower cheeks.
• If you have an older face with loose skin. Reducing the muscle can sometimes make the cheek look emptier, not slimmer.

How I do things

I feel both sides of your jaw while you clench and relax, and I take photos from the front and at an angle. Most people chew more on one side, so the muscle is often bigger on one side, and the dose is often different left and right.

The first session is deliberately gentle. It is easy to add a little at review. It is impossible to take back. I see you again at four to six weeks to check the result and adjust if needed.

Questions I get asked every week

How long until my jaw looks slimmer?

The visible change usually shows between six and twelve weeks. Chewing feels softer within the first two weeks.

How long does jaw Botox last?

Commonly about four to six months. With repeat treatments, the gap between sessions often gets longer.

Will it affect my smile or how I eat?

Chewing may feel weaker for a few weeks. An uneven smile is uncommon and temporary when it happens.

Can it help with teeth grinding?

Some people find their jaw feels more relaxed, but grinding is a medical issue. It needs a dentist’s assessment, and this is not an officially approved use of the medicine.

What if my jaw is wide because of bone?

Botox will not change bone. If bone is the main cause, I will tell you, and the option would be a surgical opinion.

Read more on my masseter Botox in Dubai page, or book a consultation.

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Sources

• Kim NH, Chung JH, Park RH, Park JB. The use of botulinum toxin type A in aesthetic mandibular contouring. Plastic and Reconstructive Surgery, 2005.
• Wu WT. Botox facial slimming/facial sculpting: the role of botulinum toxin-A in the treatment of hypertrophic masseteric muscle and parotid enlargement to narrow the lower facial width. Facial Plastic Surgery Clinics of North America, 2010.
• Fedorowicz Z, et al. Botulinum toxin for masseter hypertrophy. Cochrane Database of Systematic Reviews, 2013.
• Allergan (AbbVie), BOTOX® prescribing information — approved indications, warnings on neuromuscular disorders, pregnancy and lactation.