Teeth Grinding: Why It Happens, and Why a Mouth Guard Is Not the Whole Answer

The short answer

Teeth grinding is a muscle problem with dental consequences. The masseter, the thick chewing muscle at the angle of your jaw, contracts far harder and far more often than it should. A guard stops your teeth taking the damage. Treating the muscle reduces the force being applied in the first place, which is why patients who have worn a guard for years and still wake up aching often get relief from it.

How you find out you are doing it

Almost never by noticing. The usual routes are a dentist pointing out flattened edges, chipped enamel or a cracked filling; a partner describing the noise; a headache at the temples every morning; or a jaw that aches by mid-afternoon.

One of Dr Toro’s own patients put it more bluntly than any clinical description: “I used to grind my teeth like a machine and even cracked two veneers prior to having my jaw treated.”

What is actually happening

Like any muscle worked hard and often, the masseter adapts by getting stronger and bigger. That produces two separate problems at the same time.

Clinically, the force wears enamel down, cracks fillings, crowns and veneers, and refers pain into the jaw, the temples, the ear and the neck. It also disrupts sleep quality even when it does not wake you.

Cosmetically, an enlarged masseter widens the lower face. This is why some people in their thirties notice their jaw squaring off without having gained weight, and occasionally it is the reason they book: the grinding turns out to be the explanation for a change they had put down to age.

Why the guard is only half of it

A mouth guard is worth having and Dr Toro will tell you to keep wearing it. It puts a barrier between your teeth and the force, which protects the surfaces and is not nothing.

What it cannot do is tell the muscle to stop. The contraction still happens, with the same intensity, against a piece of acrylic instead of your molars. The jaw ache, the temple headache and the neck tension all come from the muscle working, not from the teeth touching, which is why they survive the guard.

What treating the muscle involves

A carefully measured dose of a prescription-only medicine, the one most people know as Botox, is placed into the masseter on each side. It reduces how hard that muscle can contract without stopping you chewing. Treatment takes about 20 minutes with a very fine needle, and most people go straight back to their day.

Relief usually arrives between two days and two weeks: less grinding, less jaw discomfort, better sleep. Slimming of the jawline takes longer, around four weeks, because a muscle has to reduce in bulk rather than simply relax. The effect generally lasts three to six months.

The dose here is considerably larger than for a cosmetic expression line, because the masseter is thick and powerful. That is why it is assessed and priced separately, and why it belongs with someone who knows the anatomy well.

What this treatment is not for

It is not a treatment for TMJ disorder as a diagnosis. That term covers several different problems, some inside the joint itself and some dental, and a number of them need a dentist or a maxillofacial specialist rather than an aesthetic clinic. Treating the masseter often relieves the muscular pain that comes with clenching, which is a narrower and more honest claim.

It also does not address why you are grinding. Stress, disrupted sleep, caffeine, alcohol and some medications all drive it, and so does a bite problem. Treating the muscle buys your teeth and your jaw considerable relief while you deal with the cause, and Dr Toro will say plainly when the cause is where your attention should go.

When to see someone

If you are waking with headaches, your jaw aches through the day, your dentist has mentioned wear, or a partner has told you what you sound like at three in the morning, it is worth having assessed. If you have already invested in crowns or veneers, it is worth doing sooner: replacing them is considerably more expensive than protecting them.