Bruxism (Teeth Grinding)

Habitual grinding or clenching of teeth, either during sleep or as an unconscious habit during waking hours, is known as Bruxism and commonly called as “Teeth Grinding”.

Pavon described bruxism as one of the most common, complex and destructive dental functional disorder (parafunctional habit). Initially, it is difficult to identify mainly as the patients themselves are unaware of it. According to Nadler, bruxism affect a large percentage of the population, including all age groups. In some individuals it may be considered as an attempt to cope with stress and anxiety.

Bruxism, usually, does not have any harmful effects but when it occurs on regular basis, it causes tooth wear, occlusal trauma, temporomandibular joint problems, and hypertrophy of muscles. Correct diagnosis is necessary for its treatment.


Drum introduced the term “parafunction”. Parafunctional activities, also known as muscle hyperactivity, are non-functional, oro-mandibular or lingual activities such as  bruxism, jaw clenching, tooth tapping, cheek biting, lip biting, and object biting.

These habits are different from functional activities that are controlled muscle activities such as chewing, speaking and swallowing.


  • American Academy of Orofacial Pain defined bruxism as “diurnal or nocturnal parafunctional activity including clenching, bracing, gnashing, and grinding of the teeth.”
  • American Sleep Disorders Association defined bruxism as “tooth grinding or clenching during sleep plus one of the following: Tooth wear, sounds or jaw muscle discomfort in the absence of medical disorder.”
  • Zarb and Carlsson defined bruxism as “nocturnal clenching and grinding of teeth.”
  • Clenching

Clenching of the teeth is defined as forceful closure of the opposing dentition in a static relationship of the mandible to the maxilla in either maximum intercuspation or an eccentric position.

  • Grinding

Grinding of the dentition is defined as forceful closure of the opposing dentition in a dynamic maxillomandibular relationship as the mandibular arch moves through various excursive positions.





Clinical Features:

Bruxism causes sustained muscle contraction for long periods, reduces blood flow within the muscle tissues, creating the symptoms of fatigue, pain, and spasms.

Patients having bruxism may present with grinding or grating noise. Glaros and Rao have reviewed the habit and divided its effects into 6 major categories.

  1. Effects on dentition
  2. Effects on periodontium
  3. Effects on masticatory muscles
  4. Effects on temporomandibular joint
  5. Head pain
  6. Psychologic and behavioural effects

Firmly established habits show:

  • Severe wearing or attrition of teeth-occlusal wear, wear in between teeth producing sensitivity.
  • Harm the gums resulting in loosening or drifting of teeth, causes gum recession with alveolar bone loss.
  • Continuous clenching and grinding causes muscle stress leading to temporomandibular joint problems.
  • Results in masseter muscle hypertrophy, may interfere with maintenance of the rest position, cause trismus (difficulty in opening mouth).
  • While it has been suggested that bruxism may give rise to facial pain and headache, these are very difficult manifestation to evaluate and correlate.



The causes of Bruxism are not completely clear. There is no single factor that is responsible for bruxism. Multiple causative factors of bruxism are:

  • Morphological factors: dental occlusion and the anatomy of the jaws may be associated with bruxism.
  • Psychosocial factors: Stress, anxiety and certain personality characteristics.
  • Special neurotransmitters
  • Patho-physiological factors such as diseases, trauma, genetics, smoking, alcoholism, caffeine intake, illicit drugs and medication.
  • Sleep disorders (sleep apnoea and snoring).

According to Nadler and Meklas, causes of Bruxism are:

  • Local Factors: Mild occlusal disturbances, which produces mild discomfort to the patient. Unconscious attempts of an individual to establish a greater number of teeth in contact or to counteract a local irritating situation leads to bruxism.
  • Systemic Factors: Gastrointestinal disturbances, subclinical nutritional deficiencies, and allergy or endocrinal disturbances have all been reported as significant causative factors, but their role is difficult to assess. Bruxism, sometimes may also be hereditary.


  • Psychological Factors: It is believed to be the most common cause; but none of the studies published in the literature regarding the role of psychosocial factors in aetiology of bruxism is conclusive. It has been found to be associated with high levels of anxiety, stress, and emotional tension. In children, nervous tension manifests as and may be related to chronic biting or chewing of toys. Some studies suggest that sleep bruxism episodes are a part of sleep arousal response. Bruxing children are more anxious than non-bruxers. A multifactorial large scale population study about sleep bruxism revealed highly stressful life as a significant risk factor.


  • Occupational Factors: Bruxism, sometimes present itself as an occupational habit. Certain occupations requiring precise work such as that of watchmaker, athletes engaged in physical activities favour the development of bruxism. Voluntary bruxism is also recognized in people who are habitual of chewing gum, tobacco, or objects such as tooth or pencils.



Bruxism is not a life-threatening disorder but it affects the quality of life by causing dental problems, such as tooth wear, tooth sensitivity, facial pain etc. Therefore, its early assessment is very essential. Methods to diagnose it are:

  • Questionnaires used for both clinical and research purposes
  • Clinical examination of oral cavity looking for tooth surface wear, tooth mobility, tooth sensitivity, gum recession, discomfort and pain in jaw.

Some of the methods of assessing bruxism are:

  • Masticatory muscle Electromyographic recording (EMG)
  • Polysomnographic (sleep laboratory) recordings for sleep bruxism generally include electroencephalogram, EMG, electrocardiogram and thermally sensitive resistor (monitoring air flow) signals along with simultaneous audio–video recordings.



Identification of the problem is necessary to prevent it.

  • If it is due to stress, focus on reducing it through relaxation, meditation, counselling etc.
  • If it is due to a sleeping disorder; treatment of the sleeping disorder is a prerequisite.
  • Reduce consumption of foods and drinks containing caffeine.
  • Avoid chewing objects such as pen or pencils, pins etc.
  • Place your tongue between your teeth, if you notice yourself clenching or grinding during the day
  • Visit the dentist for proper diagnosis and treatment of the condition.



Bruxism may occur during sleep or wakefulness; according to The American Academy of Sleeping Disorders. It is of two types:

  1. Awake or diurnal Bruxism
  2. Sleep or nocturnal Bruxism

Awake or Diurnal Bruxism

Awake Bruxism occurs (AB) during daytime and it is a semi voluntary ‘clenching’ activity. It is also known as Diurnal Bruxism (DB). It consists of clenching and grinding as well as other oral habits such as cheek and tongue biting, finger and thumb sucking, and many occupational habits such as biting on pins or pencils etc. performed throughout the day.

It is predominant in females and is usually associated with a stressful lifestyle. This disorder is more common in younger population.

Sleep Bruxism or Nocturnal Bruxism

Grinding teeth while sleeping either during daytime or during night is termed as ‘Sleep Bruxism’ (SB). It is also known as Nocturnal Bruxism. SB is an oro-mandibular behavior and it consists entirely of clenching and/ or grinding of teeth, and often occurs in association with certain stages of sleep. It was recently grouped as sleep related movement disorder according to recent classification of sleep disorders.



  • There is no specific treatment that can stop Sleep Bruxism. Treatments such as habit awareness therapy, habit reversal therapy, and relaxation techniques may eliminate Awake Bruxism.
  • If the underlying cause of Bruxism is an emotional one, the nervous factor must be corrected if the disease is to be cured.
  • Removable splints (occlusal splints, occlusal bite guard, night guards, bite plate , can  be worn at night to immobilise the jaws or to guide the movement so that periodontal damage is minimal.
  • Recently, Botulinum toxin (Botox) has been found to be very successful in the treatment of bruxism. When Botox is injected into the masseter muscle, it weakens the muscle enough to stop the grinding and clenching, but not so much as to interfere with chewing or facial expressions.




  • PUBLISHED DATE : Jun 11, 2019
  • CREATED / VALIDATED BY : Dr Rida Ziaul
  • LAST UPDATED ON : Jun 11, 2019


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