Bruxism (Teeth Grinding and Clenching)

Table of Contents

1. What Bruxism Is
2. Sleep Bruxism and Awake Bruxism
3. How Common Bruxism Is
4. Causes and Risk Factors
5. Symptoms
6. How Bruxism Is Diagnosed
7. Treatment
8. Prevention and Day-to-Day Measures
9. Bruxism in Children
10. Bruxism, Jaw Pain and Headache
11. Complications
12. Warning Signs and Urgent Signs
13. Key Research Papers
14. Connections
15. Featured Videos

What Bruxism Is

In 2013 an international group of bruxism experts agreed on one definition: bruxism is repetitive jaw-muscle activity marked by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible (the lower jaw) [1]. “Clenching” means pressing the teeth together hard without moving them. “Grinding” means sliding them against each other, often with an audible scraping noise. “Bracing” and “thrusting” mean holding or pushing the lower jaw in a fixed position, sometimes with the teeth not touching at all.

The muscles doing the work are the jaw-closing muscles. A review in the British Dental Journal names the masseter (the thick muscle at the angle of the jaw, which bulges when the teeth bite down), the temporalis (the fan-shaped muscle at the temple) and other jaw muscles [4]. These are among the strongest muscles in the body for their size, which is why prolonged clenching can do real damage to teeth.

A behaviour, not a disease

The most important idea in modern bruxism research is that bruxism itself is not automatically a disorder. A 2018 international consensus concluded that, in otherwise healthy people, bruxism is best seen as a behaviour that can be a risk factor — and possibly a protective factor — for certain clinical consequences, rather than as a disease in its own right [2]. A 2016 commentary by researchers in the field reached a similar conclusion: the strongest evidence did not support sleep bruxism as a disorder, because a behaviour on its own is not something that is diagnosed — disorders are [11].

The British Dental Journal review adds that sleep bruxism, once viewed as a dysfunctional movement, is now accepted as a centrally controlled activity — driven by the brain, not by the way the teeth meet — with various body-wide risk factors. It also notes the suggestion that sleep bruxism may have a protective role during sleep, for example in keeping the airway open or stimulating saliva flow [4]. That is a hypothesis, not an established fact, but it explains why experts stopped treating every grinder as a patient.

The definitions were updated again at a 2024 expert workshop. The phrase “in otherwise healthy individuals” was removed from the definitions of sleep and awake bruxism, and the grading system was revised to combine self-report, clinical examination and device-based measurement [3].

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Sleep Bruxism and Awake Bruxism

The 2013 consensus separated bruxism into two forms by time of day [1], and the 2018 consensus defined each one more closely [2]:

• Sleep bruxism is jaw-muscle activity during sleep. It can be rhythmic (repeated bursts, the classic grinding noise a bed partner hears) or non-rhythmic (sustained clenching).
• Awake bruxism is jaw-muscle activity during wakefulness, marked by repetitive or sustained tooth contact and/or bracing or thrusting of the lower jaw. It is usually silent clenching — at a desk, while driving, while concentrating or under stress.

The two forms behave differently. A 2025 meta-analysis notes that awake bruxism is more strongly associated with psychosocial factors — stress, anxiety and emotional strain — than sleep bruxism is [7]. A review in Pain points out that they may also have different effects on headache, which is why researchers keep them apart [15].

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How Common Bruxism Is

Bruxism is very common, though the numbers depend heavily on how it is measured. A 2024 systematic review and meta-analysis of studies from 2003 to 2023 reported [6]:

• a global prevalence of 22.22% for bruxism overall (sleep and awake combined);
• 21% for sleep bruxism and 23% for awake bruxism;
• 43% for sleep bruxism in studies that used polysomnography (an overnight sleep-lab recording);
• the highest sleep-bruxism figure in North America (31%), followed by South America (23%), Europe (21%) and Asia (19%).

The same analysis concluded that one in four individuals may experience awake bruxism, and reported bruxism as a significant factor among women [6]. It could not estimate prevalence for Africa or Australia because there were too few studies.

A 2025 meta-analysis focused on awake bruxism in adults, pooling 66 studies with 39,823 people. In the general population, self-reported “possible” awake bruxism averaged 25.9% and clinically based “probable” awake bruxism 16.0%. It was far higher in particular groups: 50.0% in people with temporomandibular disorders (jaw-joint and jaw-muscle disorders) and 40.1% in people with systemic (body-wide) conditions [7].

Children grind too. A 2024 scoping review of 144 publications on children and adolescents found sleep-bruxism prevalence ranging from 5% to 50%, depending on age and on how strictly it was diagnosed [8].

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Causes and Risk Factors

No single cause explains bruxism. Reviews describe it as multifactorial — several influences combine, and they differ between sleep and awake bruxism.

The brain and sleep

Sleep bruxism is understood as centrally controlled — it originates in the brain’s control of sleep and movement rather than in the shape of the bite [4]. In children and adolescents, the scoping review describes it as arousal-associated: it tends to occur alongside brief shifts toward lighter sleep [8].

Stress, anxiety and genetics

A 2022 review lists genetics, stress, oral habits (such as nail or pen biting and gum chewing) and changes in the central nervous system among the causes it considers [5]. Psychosocial strain is tied more strongly to awake bruxism than to sleep bruxism [7].

Sleep-related breathing problems

In children, the scoping review names obstructive sleep apnoea (repeated blockage of the airway during sleep), snoring, nightmares, behavioural problems, allergies and mouth breathing as risk factors [8]. The idea that sleep bruxism may help keep the airway open is one reason researchers look at breathing and grinding together [4].

Medications and recreational substances

Medications and addictive substances are recognised as outside (“exogenous”) risk indicators for bruxism, and some medications may also reduce it. A 2021 review of this question concluded, however, that there is insufficient evidence to draw definite conclusions about which medications or substances cause or worsen bruxism, or which ones ease it [10]. As general background, the substances most often discussed in this context include certain antidepressants, stimulant drugs, nicotine, alcohol and caffeine.

The bite is not the main cause

For decades, a “bad bite” was blamed for grinding, and teeth were ground down to correct it. The British Dental Journal review states that irreversible occlusal adjustments — permanently reshaping the biting surfaces — have no basis in evidence in the management of bruxism [4].

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Symptoms

Many people with bruxism have no symptoms at all. Sleep bruxism in particular often goes unnoticed by the grinder, who is asleep — a bed partner, parent or roommate hears it first [9]. When signs do appear, the reviews describe these [4][5][9]:

• Grinding sounds during sleep, reported by someone else.
• Jaw muscle tiredness or pain on waking, sometimes with stiffness when opening the mouth.
• Morning headache, often felt at the temples.
• Worn, flattened or chipped teeth, especially the biting edges of the front teeth and the tips of the back teeth.
• Cracked teeth and fillings or crowns that break repeatedly.
• Sensitive or painful teeth, as wear exposes the inner dentin.
• Enlarged jaw muscles (masseter hypertrophy), which can make the lower face look squarer.
• Jaw-joint pain or locking on waking.
• Tongue or lip indentations — marks left by the tongue and lips being pressed against the teeth.

Awake bruxism is often noticed only when a person catches themselves with the teeth pressed together while concentrating, driving or under strain.

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How Bruxism Is Diagnosed

Possible, probable and definite

The 2013 consensus proposed a three-level grading system [1]. A review on children summarises how it works for sleep bruxism [9]:

• Possible — based only on self-report or on family members hearing grinding during sleep.
• Probable — that report plus clinical findings suggestive of bruxism, such as abnormal tooth wear, enlarged or tender masseter muscles, or tongue and lip indentations.
• Definite — the history and examination confirmed by polysomnography (an overnight sleep study that records brain waves, breathing and muscle activity), preferably combined with video and audio recording.

The International Classification of Sleep Disorders sets minimum criteria for sleep bruxism: frequent or regular tooth-grinding sounds during sleep (at least three nights a week for at least three months) plus at least one of abnormal tooth wear, morning jaw muscle fatigue or pain, temporary headache, or jaw locking on waking [9].

The limits of each method

Polysomnography is the gold standard but, as the children’s review explains, it is costly, time-consuming and needs skilled staff, so it is not available in most clinics. In everyday practice the diagnosis rests on the history and the examination [9]. That has a cost in accuracy: a 2016 commentary pointed to the poor sensitivity of self-report compared with sleep-lab recording, and poor agreement between clinicians’ judgements and portable sleep recordings [11].

The 2018 consensus accepted both non-instrumental approaches (notably self-report) and instrumental approaches (notably electromyography, which records the electrical activity of the jaw muscles through skin sensors). It also concluded that fixed cut-off points for “having” or “not having” bruxism are not appropriate in otherwise healthy people, and that jaw-muscle activity is better described on a continuum [2]. The 2025 update keeps this three-source approach — self-report, clinical examination and device-based tools [3].

A dentist examining for bruxism typically looks at wear facets (flat shiny patches on the teeth), cracks, broken restorations, the size and tenderness of the masseter and temporalis muscles, the movement of the jaw joint, and the inside of the cheeks and the tongue.

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Treatment

Because bruxism is regarded as a behaviour, the British Dental Journal review states that bruxism in itself does not require treatment; management is indicated only where problems arise from it [4]. No cure exists that reliably stops grinding for good. Treatment aims at three things: protecting the teeth, reducing pain, and lowering the muscle activity where possible.

Occlusal splints (night guards)

An occlusal splint is a hard or soft plastic appliance worn over the upper or lower teeth, usually at night. It places a replaceable layer between the teeth so the plastic wears instead of the enamel. The British Dental Journal review describes oral appliances as aiming primarily to protect the teeth from damage, though they may also reduce muscle activity [4].

How much splints reduce the grinding itself is less clear:

• A 2022 systematic review of adult sleep bruxism found that oral appliance therapy with stabilisation splints tended to reduce the number of sleep-bruxism events, though not significantly more than other types of splints [12].
• A 2021 systematic review of 14 studies found insufficient evidence that occlusal splints provide a benefit over no treatment, other oral appliances, electrical nerve stimulation (TENS), behavioural or drug therapy, and rated all the studies at medium to high risk of bias [13].

Botulinum toxin injections

Botulinum toxin type A is a nerve-blocking protein injected into the masseter and sometimes the temporalis muscle to weaken them for a few months. The British Dental Journal review states that it appears to reduce the frequency of bruxism, but that concerns have been raised about possible adverse effects [4]. The 2022 adult review also found significant reductions in specific sleep-bruxism measures with botulinum toxin, with side effects reported [12].

A 2024 randomised controlled trial compared the two main options directly in 60 adults with probable sleep bruxism and jaw muscle pain. Jaw pain fell significantly at 3 and 6 months with both the occlusal splint and botulinum toxin A, with no difference between them on the main pain score. The splint group did better on several jaw-movement measures, including pain-free and maximum mouth opening. In the botulinum toxin group, 23 of 29 participants (79.3%) reported mild discomfort when chewing. Both groups improved in oral-health-related quality of life [14].

Biofeedback and behavioural approaches

Biofeedback uses a sensor that detects jaw-muscle activity and gives a signal — a sound, a vibration or a mild stimulus — so the person learns to release the clench. The 2022 adult review found that biofeedback produced significant reductions in specific sleep-bruxism measures, while the potential benefits of cognitive-behavioural therapy (a structured talking therapy) were not well supported [12]. The British Dental Journal review lists biofeedback, relaxation and improved sleep habits among the behavioural strategies used [4].

Medications

The 2022 adult review found that rabeprazole (a stomach-acid reducer), clonazepam (a sedative of the benzodiazepine class) and clonidine (a blood-pressure medicine) each showed significant reductions in specific sleep-bruxism measures, but that several side effects were reported; it concluded that larger, longer, more rigorous trials are needed [12]. Medicines are not a routine first approach, and the review of drugs and bruxism found the overall evidence insufficient for firm conclusions [10].

Repairing the damage

Worn or cracked teeth are restored with fillings, bonding or crowns. Dentists treating a heavy grinder often pair restorations with a splint, because grinding is listed among the causes of prosthodontic complications — broken crowns, bridges and dentures [5].

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Prevention and Day-to-Day Measures

There is no proven way to prevent bruxism from starting. What the literature describes are measures aimed at lowering its triggers and limiting harm:

• Sleep habits. The British Dental Journal review lists improvement of sleep hygiene — regular sleep times and a calm bedtime routine — among behavioural strategies [4], and the children’s review states that the importance of sleep hygiene “cannot be over-emphasized” [9].
• Relaxation. Relaxation methods are among the behavioural strategies used for bruxism [4].
• Daytime awareness. For awake bruxism, a common approach described in dental practice is learning the resting jaw position — lips together, teeth apart, tongue resting on the roof of the mouth — and noticing when the teeth are pressed together. This is general background; the trials on it are small.
• Attention to sleep and breathing. Since snoring, sleep apnoea, allergies and mouth breathing are risk factors in children, the scoping review describes management that includes assessing for these other conditions, alongside appliances such as mandibular advancement devices and rapid maxillary expansion [8].
• Protecting the teeth. For people who already show wear, a splint limits further damage [4].

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Bruxism in Children

Grinding is common in childhood and usually harmless. A narrative review on children states that sleep bruxism in childhood is typically self-limited and does not require specific treatment; it describes removing triggering factors where possible, a relaxed and enjoyable bedtime, and limiting mental stimulation and physical activity before bed [9]. It adds that, because a child’s face and jaws are still growing, the benefits and risks of oral devices have to be weighed, and that drug treatment is rarely used in children [9].

The 2024 scoping review describes children’s sleep bruxism as arousal-associated and linked with behavioural problems and sleep disorders (obstructive sleep apnoea, snoring, nightmares) as well as allergies and mouth breathing. Management options it lists include occlusal splints, mandibular advancement appliances (which hold the lower jaw forward), rapid maxillary expansion (an orthodontic device that widens the upper jaw) and some medications, the last supported by limited evidence [8].

A 2023 systematic review of randomised trials in children and adolescents found seven eligible studies. Signs and symptoms of sleep bruxism were reduced with the drugs hydroxyzine and diazepam and with extracts of Melissa officinalis (lemon balm), while improvements with occlusal splints and physiotherapy were not statistically significant compared with control groups. The authors concluded that the evidence was not enough to establish a treatment protocol [16].

Both pediatric reviews agree that the evidence for any specific childhood treatment is limited or inconclusive [9][16].

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Bruxism, Jaw Pain and Headache

Bruxism, temporomandibular disorders (problems of the jaw joint and chewing muscles) and headache often occur together, but which causes which is unsettled. A 2024 review in the journal Pain concluded that bruxism is not a painful disorder in itself but may — particularly together with a temporomandibular disorder — worsen pre-existing headache. It found research suggesting a correlation between awake bruxism and tension-type headache, and between jaw-disorder pain and migraine, while noting that psychosocial factors may confound these links and that causality is hard to prove [15].

The awake-bruxism meta-analysis found the habit in half of people with temporomandibular disorders (50.0%) [7]. A 2022 review lists headaches, jaw-joint pain and chewing-muscle pain among the consequences bruxism often causes [5].

The children’s systematic review likewise describes tension headaches, chewing-muscle pain and fatigue among the consequences of sleep bruxism in childhood [16].

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Complications

When bruxism does cause harm, the reviews describe these consequences [4][5]:

• Tooth surface loss — mechanical wear that flattens and shortens teeth. Grinding is one of several factors linked with acid wear of the teeth; see Dental Erosion.
• Fractured teeth and restorations — cracked cusps, broken fillings, crowns, bridges and dentures.
• Hypersensitive or painful teeth once enamel wears through; see Tooth Sensitivity.
• Loss of periodontal support — heavy forces on teeth already weakened by periodontitis can speed their loosening.
• Masticatory muscle hypertrophy — enlarged chewing muscles.
• Jaw-joint pain, chewing-muscle pain and headache.

A deep crack that reaches the pulp (the nerve and blood vessels inside the tooth) can let bacteria in and lead to a tooth abscess.

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Warning Signs and Urgent Signs

Most bruxism is a slow, long-term problem. Some signs point to damage or to a different condition:

• A tooth that hurts sharply on biting and then releasing, or a piece of tooth that breaks off, can mean a cracked tooth. Cracks that reach the pulp can lead to infection.
• A jaw locked open or locked closed, or a sudden inability to open the mouth, is a jaw-joint problem that dentists and emergency services treat as urgent.
• Swelling of the face, jaw or neck, fever, or difficulty swallowing or breathing with a broken or painful tooth are signs of a spreading dental infection, which can be life-threatening.
• Loud snoring with pauses in breathing, gasping or choking during sleep are signs of obstructive sleep apnoea, a risk factor for bruxism in children [8] and a condition with effects well beyond the teeth.
• Jaw pain together with chest pressure, shortness of breath, sweating or pain spreading to the arm can be a sign of a heart attack rather than a jaw problem, and is a medical emergency.
• A new, severe or different headache, especially with weakness, confusion, vision changes or a stiff neck, is not explained by grinding and can signal a serious condition.

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Key Research Papers

1. Lobbezoo F, Ahlberg J, Glaros AG, Kato T, Koyano K, Lavigne GJ, et al. Bruxism defined and graded: an international consensus. J Oral Rehabil. 2013;40(1):2-4. PubMed PMID: 23121262
2. Lobbezoo F, Ahlberg J, Raphael KG, Wetselaar P, Glaros AG, Kato T, et al. International consensus on the assessment of bruxism: Report of a work in progress. J Oral Rehabil. 2018;45(11):837-844. PubMed PMID: 29926505
3. Verhoeff MC, Lobbezoo F, Ahlberg J, Bender S, Bracci A, Colonna A, et al. Updating the Bruxism Definitions: Report of an International Consensus Meeting. J Oral Rehabil. 2025;52(9):1335-1342. PubMed PMID: 40312776
4. Beddis H, Pemberton M, Davies S. Sleep bruxism: an overview for clinicians. Br Dent J. 2018;225(6):497-501. PubMed PMID: 30237554
5. Matusz K, Maciejewska-Szaniec Z, Gredes T, Pobudek-Radzikowska M, Glapiński M, Górna N, et al. Common therapeutic approaches in sleep and awake bruxism - an overview. Neurol Neurochir Pol. 2022;56(6):455-463. PubMed PMID: 36444852
6. Zieliński G, Pająk A, Wójcicki M. Global Prevalence of Sleep Bruxism and Awake Bruxism in Pediatric and Adult Populations: A Systematic Review and Meta-Analysis. J Clin Med. 2024;13(14). PubMed PMID: 39064299
7. Stanisic N, Saracutu OI, Colonna A, Wu W, Manfredini D, Häggman-Henrikson B. Awake Bruxism Prevalence Across Populations: A Systematic Review and Meta-Analysis. J Evid Based Dent Pract. 2025;25(3):102171. PubMed PMID: 40716827
8. Huynh N, Fabbro CD. Sleep bruxism in children and adolescents-A scoping review. J Oral Rehabil. 2024;51(1):103-109. PubMed PMID: 37743603
9. Leung AKC, Wong AHC, Lam JM, Hon KL. Sleep Bruxism in Children: A Narrative Review. Curr Pediatr Rev. 2024;21(1):40-50. PubMed PMID: 37724678
10. de Baat C, Verhoeff MC, Ahlberg J, Manfredini D, Winocur E, Zweers P, et al. Medications and addictive substances potentially inducing or attenuating sleep bruxism and/or awake bruxism. J Oral Rehabil. 2021;48(3):343-354. PubMed PMID: 32716523
11. Raphael KG, Santiago V, Lobbezoo F. Is bruxism a disorder or a behaviour? Rethinking the international consensus on defining and grading of bruxism. J Oral Rehabil. 2016;43(10):791-8. PubMed PMID: 27283599
12. Minakuchi H, Fujisawa M, Abe Y, Iida T, Oki K, Okura K, et al. Managements of sleep bruxism in adult: A systematic review. Jpn Dent Sci Rev. 2022;58:124-136. PubMed PMID: 35356038
13. Hardy RS, Bonsor SJ. The efficacy of occlusal splints in the treatment of bruxism: A systematic review. J Dent. 2021;108:103621. PubMed PMID: 33652054
14. Chisini LA, Pires ALC, Poletto-Neto V, Damian MF, Luz MS, Loomans B, et al. Occlusal splint or botulinum toxin-a for jaw muscle pain treatment in probable sleep bruxism: A randomized controlled trial. J Dent. 2024;151:105439. PubMed PMID: 39510242
15. Voß LC, Basedau H, Svensson P, May A. Bruxism, temporomandibular disorders, and headache: a narrative review of correlations and causalities. Pain. 2024;165(11):2409-2418. PubMed PMID: 38888745
16. Senff J, Bonotto DV, Hilgenberg-Sydney PB, Sebastiani A, Scariot R, Oda LY. Childhood and Adolescents Sleep Bruxism Treatment: A Systematic Review. Sleep Sci. 2023;16(3):e344-e353. PubMed PMID: 38196770

PubMed Topic Searches

1. PubMed: sleep bruxism consensus
2. PubMed: awake bruxism prevalence
3. PubMed: occlusal splints for bruxism
4. PubMed: botulinum toxin for bruxism
5. PubMed: sleep bruxism in children

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Connections

• Dentistry & Oral Health
• TMJ Disorder (Temporomandibular Joint Dysfunction)
• Tooth Sensitivity (Dentin Hypersensitivity)
• Dental Erosion (Acid Wear of the Teeth)
• Tooth Abscess (Dental Abscess)
• Tooth Decay (Dental Caries)
• Periodontitis (Gum Disease)
• Dry Mouth (Xerostomia)
• Obstructive Sleep Apnea
• Tension Headache
• Migraine
• Anxiety
• Insomnia
• Lemon Balm (Melissa officinalis)

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