How do I know if I grind my teeth at night?

Maybe your partner has mentioned a grating sound from your side of the bed, or you keep waking up with a heavy jaw and your dentist pointed at a flattened tooth edge at your last check-up. You were asleep, so you remember none of it. Plenty of people find out this way, and there are good ways to get a clearer answer.

Below you will find the signs that point to night-time grinding, how experts weigh them and what a dentist or sleep study adds, plus a one-week check to do at home.

Key takeaways

You usually find out from outside clues: someone hears you grind, your jaw aches when you wake up, or your teeth are worn, broken or sensitive (NHS, 2026). Experts now sort each clue by where it comes from: your own report, a clinical exam or a device measuring jaw muscle activity in sleep (Verhoeff et al., 2025).

• Your own impression is a useful start, but in studies it often misses or overcalls real grinding.
• A dentist looks for tooth wear, ridges on your tongue and cheeks, and a strong, tender chewing muscle.
• A sleep study gives the most certain answer and is only needed in some cases (Cleveland Clinic, 2023; Balasubramaniam et al., 2026).

What are the signs that you grind your teeth at night?

The NHS lists a painful jaw, worn-down or broken teeth that can become more sensitive, headaches, earache and disturbed sleep, and says it is worth seeing a dentist if your partner tells you that you grind in your sleep (NHS, 2026). Cleveland Clinic adds headaches or facial pain especially in the morning, sore jaw muscles, pain when eating, trouble opening and closing your mouth, earaches and ringing in the ears (Cleveland Clinic, 2023). Grinding is more likely with stress and anxiety, which the NHS calls the most common cause, and it is also linked to smoking, a lot of alcohol or caffeine and some medicines for sleep problems, depression or anxiety (NHS, 2026).

Those headaches can be felt at the temples, where one of your chewing muscles, the temporalis, sits. If headaches are your main complaint, read can teeth grinding cause headaches? For the sore jaw on waking, see why does my jaw hurt when I wake up?

Some clues live inside your mouth. A recent review lists tooth wear, loose teeth, an enlarged masseter muscle, tooth sensitivity and tongue indentations among the things dentists check, along with a white line on the inside of the cheek (linea alba), lip impressions and a scalloped tongue edge (Balasubramaniam et al., 2026).

Can you grind your teeth at night and not know it?

Yes, and your own guess turns out to be a shaky guide. In a New York sleep lab study of 124 women with jaw muscle pain and 46 women without it, self-reported grinding did not predict whether moderate or severe sleep bruxism was actually measured over the night (Raphael et al., 2015).

A Brazilian study of 50 young adults compared common signs against a portable muscle-activity (EMG) device. Being aware of grinding or grinding sounds picked up 80 per cent of the people the device flagged, but it also produced a lot of false alarms. Headaches, muscle fatigue, jaw joint noises and tooth signs each caught only about 38 to 59 per cent. The authors concluded that these signs are fine for screening and cannot confirm the diagnosis on their own (Grossi et al., 2024).

What do possible, probable and definite bruxism mean?

In 2013 an international expert group defined bruxism as repeated jaw muscle activity with clenching or grinding of the teeth, or bracing or thrusting of the lower jaw, and split it into sleep and awake bruxism. Their 2018 update kept a grading system meant to show how confident you can be that an assessment is right, and stated that self-report as well as instrumental methods such as EMG can be used (Lobbezoo et al., 2018). The same update described bruxism in otherwise healthy people as a behaviour rather than a disorder, one that can be a risk factor, or sometimes a protective one, for certain problems (Lobbezoo et al., 2018).

The three grades work like this (Walentek et al., 2024):

1. Possible sleep bruxism is based on your own report only, for example in a questionnaire.
2. Probable sleep bruxism is based on a positive clinical examination, with or without your own report.
3. Definite sleep bruxism is based on an instrumental assessment, such as a sleep study.

At a 2024 consensus meeting the experts revised this ladder. They now recommend replacing possible, probable and definite with subject-based (your own report), clinically based and device-based, because each tool may capture a different side of bruxism, and they dropped "in otherwise healthy individuals" from the definitions (Verhoeff et al., 2025).

How does a dentist check for night grinding?

Cleveland Clinic says dentists usually diagnose bruxism from a physical exam and your symptoms (Cleveland Clinic, 2023). Expect questions about your sleep and pain, a look at your teeth for wear and cracks, and a feel of your chewing muscles. The review mentioned above also lists checks for muscle pain or fatigue, tongue scalloping and the white cheek line (Balasubramaniam et al., 2026).

Bring your notes from home, because your dentist only sees you awake. The NHS notes that treatment for teeth grinding is not always needed, and a dentist may suggest a mouth guard or splint worn at night to protect your teeth from damage (NHS, 2026). Our teeth grinding page covers what else helps once you know.

When do you need a sleep study, a home device or an app?

Most people never need one. An overnight sleep study (polysomnography) can give a definitive diagnosis when it is needed (Cleveland Clinic, 2023). Reviewers describe a sleep study with audio and video as likely the most accurate method, but say it is not mandatory for diagnosis and is best reserved for select cases, such as when another sleep disorder is suspected (Balasubramaniam et al., 2026).

Portable EMG devices let you measure at home and pick up jaw muscle activity well. The same review points out that they cannot confirm you were asleep and, without sound, video or an exam, cannot reliably tell what kind of jaw activity they picked up, so it calls them helpful extras rather than a replacement for a full assessment (Balasubramaniam et al., 2026). Phone apps that record sounds overnight have, as far as I can find, not been well tested against a sleep lab, so treat a recording as a clue to play for your dentist.

Could it be linked to sleep apnoea?

Sometimes the two show up together. The NHS lists sleep problems such as snoring and sleep apnoea among the things teeth grinding is commonly linked to (NHS, 2026), and Cleveland Clinic describes a confirmed correlation while noting that it is still unclear which one drives the other (Cleveland Clinic, 2023).

Pay attention if a partner notices breathing that stops and starts, gasping, snorting or choking sounds, or loud snoring, or if you feel very tired during the day and wake with headaches. The NHS advises seeing a GP for these symptoms, and most people can do the sleep test at home (NHS, sleep apnoea). The evidence on cause and effect is covered in can sleep apnea cause teeth grinding?

Try it: a one-week night grinding check

This is a simple check you can do when you wonder whether night grinding is behind your symptoms. It will not diagnose anything, but it gives your dentist concrete notes to work with.

1. Ask whoever sleeps next to you to listen for grinding or grating sounds this week and to tell you in the morning.
2. Right after waking, before you get up, notice whether your cheeks or temples feel tired or tender and whether your mouth opens easily.
3. In the mirror, stick out your tongue and look at its edges. A wavy rim or tooth marks are worth writing down.
4. Gently pull one cheek aside with a clean finger and look for a white line running level with where your teeth meet.
5. Rest your fingertips on the muscle in front of your ears and bite down briefly. Compare both sides and note if one feels very bulky or sore.

Steps 3 to 5 are rough versions of what dentists look for (Balasubramaniam et al., 2026), so treat them as notes for your appointment. In the Brazilian study, the other signs only added useful information when people were already aware of grinding, clenching or tooth sounds (Grossi et al., 2024). That is why the first steps ask what you and the people around you have noticed.

How JawBuddy helps

JawBuddy is a digital companion for guided jaw exercises and self-management. If your check points towards grinding, our TMJ exercises page shows gentle jaw exercises to start with.

JawBuddy does not replace emergency care or an individual diagnosis from a qualified healthcare professional, so your dentist remains the right person to confirm whether you grind at night.

When should you see a doctor?

Right away / emergency

• Call 999 in the UK, 911 in the US or 112 in the EU if jaw pain comes together with chest pain or breathlessness. The NHS lists chest pain that feels tight or squeezing, chest pain spreading to your arms, neck or jaw, and severe difficulty breathing as heart attack warning signs (NHS, heart attack).

Soon

• Ask for an urgent GP appointment or call 111 if you cannot eat or drink, your jaw is locking or you have difficulty opening your mouth fully (NHS, TMD).
• Do the same if you have frequent, severe headaches, pain or tenderness at the side of your head or on your scalp, or vision problems such as double vision (NHS, TMD).
• See a GP if someone notices your breathing stopping and starting in your sleep, or you are constantly tired during the day (NHS, sleep apnoea).
• Book a dentist if you grind and have damaged or sensitive teeth, pain in your jaw, face or ear, or a partner who hears you grinding (NHS, 2026).

You can find out what your jaw does at night

Not knowing what your jaw does while you sleep can feel unsettling, but you and your dentist can read the clues together. Start the one-week check tonight and take your notes to your next dental appointment.

For the bigger picture on jaw problems, read our TMJ disorder guide.