[2] Several symptoms are commonly associated with bruxism, including aching jaw muscles, headaches, hypersensitive teeth, tooth wear, and damage to dental restorations (e.g. crowns and fillings).

[6] There is a wide variation in reported epidemiologic data for bruxism, and this is largely due to differences in the definition, diagnosis and research methodologies of these studies.

It is possible for sleep bruxism to occur as early as the first year of life, after the first teeth (deciduous incisors) erupt into the mouth, and the overall prevalence in children is about 14–20%.

The large forces that can be generated during bruxism can have detrimental effects on the components of masticatory system, namely the teeth, the periodontium and the articulation of the mandible with the skull (the temporomandibular joints).

The exact location and pattern of attrition depends on how the bruxism occurs, e.g., when the canines and incisors of the opposing arches are moved against each other laterally, by the action of the medial pterygoid muscles, this can lead to the wearing down of the incisal edges of the teeth.

[15] Abfraction cavities are said to occur usually on the facial aspect of teeth, in the cervical region as V-shaped defects caused by flexing of the tooth under occlusal forces.

[1] Sleep bruxism is mainly characterized by "rhythmic masticatory muscle activity" (RMMA) at a frequency of about once per second, and also with occasional tooth grinding.

It is unclear whether people with bruxism tend to notice problems with the bite because of their clenching and grinding habit, or whether these act as a causative factor in the development of the condition.

[10] In some reported cases where bruxism is thought to have been initiated by selective serotonin reuptake inhibitors, decreasing the dose resolved the side effect.

[30][26] Specific examples include levodopa (when used in the long term, as in Parkinson's disease), fluoxetine, metoclopramide, lithium, cocaine, venlafaxine, citalopram, fluvoxamine, methylenedioxyamphetamine (MDA), methylphenidate (used in attention deficit hyperactive disorder),[29] and gamma-hydroxybutyric acid (GHB) and similar gamma-aminobutyric acid-inducing analogues such as phenibut.

[5] A diagnosis of bruxism is usually made clinically,[13] and is mainly based on the person's history (e.g. reports of grinding noises) and the presence of typical signs and symptoms, including tooth mobility, tooth wear, masseteric hypertrophy, indentations on the tongue, hypersensitive teeth (which may be misdiagnosed as reversible pulpitis), pain in the muscles of mastication, and clicking or locking of the temporomandibular joints.

[26] Examples of definitions include: "Bruxism is a repetitive jaw-muscle activity characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible.

In grinding and tapping this contact involves movement of the mandible and unpleasant sounds which can often awaken sleeping partners and even people asleep in adjacent rooms.

"[1]"Non-functional contact of the mandibular and maxillary teeth resulting in clenching or tooth grinding due to repetitive, unconscious contraction of the masseter and temporalis muscles.

[5] The World Health Organization's International Classification of Diseases 10th revision does not have an entry called bruxism, instead listing "tooth grinding" under somatoform disorders.

[4] Sleep hygiene education should be provided by the clinician, as well as a clear and short explanation of bruxism (definition, causes and treatment options).

[48] Many different medications have been used to treat bruxism,[11] including benzodiazepines, anticonvulsants, beta blockers, dopamine agents, antidepressants, muscle relaxants, and others.

"[49] Specific drugs that have been studied in sleep bruxism are clonazepam,[50] levodopa,[50] amitriptyline,[50] bromocriptine,[50] pergolide, clonidine, propranolol, and l-tryptophan, with some showing no effect and others appear to have promising initial results; however, it has been suggested that further safety testing is required before any evidence-based clinical recommendations can be made.

It is theorized to prevent tissue damages primarily by reducing the bite force from attempts to close the jaw normally into a forward twisting of the lower front teeth.

[30] A 2020 overview of systematic reviews found that botulinum toxin type A (BTX-A) showed a significant pain and sleep bruxism frequency reduction when compared to placebo or conventional treatment (behavioral therapy, occlusal splints, and drugs), after 6 and 12 months.

[16] BoNT injections are used in bruxism on the theory that a dilute solution of the toxin will partially paralyze the muscles and lessen their ability to forcefully clench and grind the jaw, while aiming to retain enough muscular function to enable normal activities such as talking and eating.

This treatment typically involves five or six injections into the masseter and temporalis muscles, and less often into the lateral pterygoids (given the possible risk of decreasing the ability to swallow) taking a few minutes per side.

With the temporary and partial muscle paralysis, atrophy of disuse may occur, meaning that the future required dose may be smaller or the length of time the effects last may be increased.

[citation needed] Biofeedback is a process or device that allows an individual to become aware of, and alter physiological activity with the aim of improving health.

[5][60] Electromyographic monitoring devices of the associated muscle groups tied with automatic alerting during periods of clenching and grinding have been prescribed for awake bruxism.

[5] Two thousand years ago, Shuowen Jiezi by Xu Shen documented the definition of Chinese character "齘" (bruxism) as "the clenching of teeth" (齒相切也).

[61] In 610, Zhubing yuanhou lun by Chao Yuanfang documented the definition of bruxism (齘齒) as "the clenching of teeth during sleep" and explained that it was caused by Qi deficiency and blood stasis.

In the 2000 film Requiem for a Dream, the character of Sara Goldfarb (Ellen Burstyn) begins taking an amphetamine-based diet pill and develops bruxism.

In George R. R. Martin's A Song of Ice and Fire series, King Stannis Baratheon grinds his teeth regularly, so loudly it can be heard "half a castle away".

Among people who have taken ecstasy, while dancing it is common to use pacifiers, lollipops or chewing gum in an attempt to reduce the damage to the teeth and to prevent jaw pain.