disorders (e.g. epilepsy). this usually involves a dental examination, and possibly electroencephalography if a seizure disorder is suspected. polysomnography shows increased masseter and temporalis muscular activity during sleep. polysomnography may involve electroencephalography, electromyography, electrocardiography, air flow monitoring and audio–video recording. it may be useful to help exclude other sleep disorders; however, due to the expense of the use of a sleep lab, polysomnography is mostly of relevance to research rather than routine clinical diagnosis of bruxism. tooth wear may be brought to the person's attention during routine dental examination. with awake bruxism, most people will often initially deny clenching and grinding because they are unaware of the habit. often, the person may re-attend soon after the first visit and report that they have now become aware of such a habit. several devices have been developed that aim to objectively measure bruxism activity, either in terms of muscular activity or bite forces. they have been criticized for introducing a possible change in the bruxing habit, whether increasing or decreasing it, and are therefore poorly representative to the native bruxing activity. these are mostly of relevance to research, and are rarely used in the routine clinical diagnosis of bruxism. examples include the "bruxcore bruxism-monitoring device" (bbmd, "bruxcore plate"), the "intra-splint force detector" (isfd), and electromyographic devices to measure masseter or temporalis muscle activity (e.g. the "bitestrip", and the "grindcare"). icsd-r diagnostic criteria the icsd-r listed diagnostic criteria for sleep bruxism. the minimal criteria include both of the following: a. symptom of tooth-grinding or tooth-clenching during sleep, and b. one or more of the following: abnormal tooth wear grinding sounds discomfort of the jaw muscles with the following criteria supporting the diagnosis: c. polysomnography shows both: activity of jaw muscles during sleep no associated epileptic activity d. no other medical or mental disorders (e.g., sleep-related epilepsy, which may cause abnormal movement during sleep). e. the presence of other sleep disorders (e.g., obstructive sleep apnea syndrome). definition examples bruxism is derived from the greek word βρύκειν (brykein) "to bite, or to gnash, grind the teeth". people with bruxism are called bruxists or bruxers and the verb itself is "to brux". there is no widely accepted definition of bruxism. 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. bruxism has two distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism)."all forms of bruxism entail forceful contact between the biting surfaces of the upper and lower teeth. 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. clenching (or clamping), on the other hand, involves inaudible, sustained, forceful tooth contact unaccompanied by mandibular movements."a movement disorder of the masticatory system characterized by teeth-grinding and clenching during sleep as well as wakefulness." "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." "parafunctional grinding of teeth or an oral habit consisting of involuntary rhythmic or spasmodic non-functional gnashing, grinding or clenching of teeth in other than chewing movements of the mandible which may lead to occlusal trauma." "periodic repetitive clenching or rhythmic forceful grinding of the teeth." classification by temporal pattern comparison of typical features of sleep bruxism and awake bruxism. sleep bruxismawake bruxism occurrencewhile asleep, mostly during periods of sleep arousalwhile awake time–intensity relationshippain worst on waking, then slowly gets betterpain worsens throughout the day, may not be present on waking noisescommonly associatedrarely associated activityclenching and grindingusually clenching, occasionally clenching and grinding relationship with stressunclear, little evidence of a relationshipstronger evidence for a relationship, but not conclusive prevalence (general population)9.7–15.9%22.1–31% gender distributionequal gender distributionmostly females heritabilitysome evidenceunclear bruxism can be subdivided into two types based upon when the parafunctional activity occurs – during sleep ("sleep bruxism"), or while awake ("awake bruxism"). this is the most widely used classification since sleep bruxism generally has different causes to awake bruxism, although the effects on the condition on the teeth may be the same. the treatment is also often dependent upon whether the bruxism happens during sleep or while awake, e.g., an occlusal splint worn during sleep in a person who only bruxes when awake will probably have no benefit. some have even suggested that sleep bruxism is an entirely different disorder and is not associated with awake bruxism. awake bruxism is sometimes abbreviated to ab, and is also termed "diurnal bruxism", db, or "daytime bruxing". sleep bruxism is sometimes abbreviated to sb, and is also termed "sleep-related bruxism", "nocturnal bruxism", or "nocturnal tooth grinding". according to the international classification of sleep disorders revised edition (icsd-r), the term "sleep bruxism" is the most appropriate since this type occurs during sleep specifically rather than being associated with a particular time of day, i.e., if a person with sleep bruxism were to sleep during the day and stay awake at night then the condition would not occur during the night but during the day. the icds-r defined sleep bruxism as "a stereotyped movement disorder characterized by grinding or clenching of the teeth during sleep", classifying it as a parasomnia. the second edition (icsd-2) however reclassified bruxism to a "sleep related movement disorder" rather than a parasomnia. classification by cause alternatively, bruxism can be divided into primary bruxism (also termed "idiopathic bruxism"), where the disorder is not related to any other medical condition, or secondary bruxism, where the disorder is associated with other medical conditions. secondary bruxism includes iatrogenic causes, such as the side effect of prescribed medications. another source divides the causes of bruxism into three groups, namely central or pathophysiological factors, psychosocial factors and peripheral factors. 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. to describe bruxism as a purely somatoform disorder does not reflect the mainstream, modern view of this condition (see causes). classification by severity the icsd-r described three different severities of sleep bruxism, defining mild as occurring less than nightly, with no damage to teeth or psychosocial impairment; moderate as occurring nightly, with mild impairment of psychosocial functioning; and severe as occurring nightly, and with damage to the teeth, temporomandibular disorders and other physical injuries, and severe psychosocial impairment. classification by duration the icsd-r also described three different types of sleep bruxism according to the duration the condition is present, namely acute, which lasts for less than one week; subacute, which lasts for more than a week and less than one month; and chronic which lasts for over a month. management treatment for bruxism revolves around repairing the damage to teeth that has already occurred, and also often, via one or more of several available methods, attempting to prevent further damage and manage symptoms, but there is no widely accepted, best treatment. since bruxism is not life-threatening, and there is little evidence of the efficacy of any treatment, it has been recommended that only conservative treatment which is reversible and that carries low risk of morbidity should be used. the main treatments that have been described in awake and sleep bruxism are described below. psychosocial interventions given the strong association between awake bruxism and psychosocial factors (the relationship between sleep bruxism and psychosocial factors being unclear), the role of psychosocial interventions could be argued to be central to the management. the most simple form of treatment is therefore reassurance that the condition does not represent a serious disease, which may act to alleviate contributing stress. sleep hygiene education should be provided by the clinician, as well as a clear and short explanation of bruxism (definition, causes and treatment options). relaxation and tension-reduction have not been found to reduce bruxism symptoms, but have given patients a sense of well-being. one study has reported less grinding and reduction of emg activity after hypnotherapy. other interventions include relaxation techniques, stress management, behavioural modification, habit reversal and hypnosis (self hypnosis or with a hypnotherapist). cognitive behavioral therapy has been recommended by some for treatment of bruxism. in many cases awake bruxism can be reduced by using reminder techniques. combined with a protocol sheet this can also help to evaluate in which situations bruxism is most prevalent. medication many different medications have been used to treat bruxism, including benzodiazepines, anticonvulsants, beta blockers, dopamine agents, antidepressants, muscle relaxants, and others. however, there is little, if any, evidence for their respective and comparative efficacies with each other and when compared to a placebo. a multiyear systematic review to investigate the evidence for drug treatments in sleep bruxism published in 2014 (pharmacotherapy for sleep bruxism. macedo, et al.) found "insufficient evidence on the effectiveness of pharmacotherapy for the treatment of sleep bruxism." specific drugs that have been studied in sleep bruxism are clonazepam, levodopa, amitriptyline, bromocriptine, 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. when bruxism is related to the use of selective serotonin reuptake inhibitors in depression, adding buspirone has been reported to resolve the side effect. tricyclic antidepressants have also been suggested to be preferable to selective serotonin reuptake inhibitors in people with bruxism, and may help with the pain. prevention of dental damage bruxism can cause significant tooth wear if it is severe, and sometimes dental restorations (crowns, fillings etc.) are damaged or lost, sometimes repeatedly. most dentists therefore prefer to keep dental treatment in people with bruxism very simple and only carry it out when essential, since any dental work is likely to fail in the long term. dental implants, dental ceramics such as emax crowns and complex bridgework for example are relatively contraindicated in bruxists. in the case of crowns, the strength of the restoration becomes more important, sometimes at the cost of aesthetic considerations. e.g. a full coverage gold crown, which has a degree of flexibility and also involves less removal (and therefore less weakening) of the underlying natural tooth may be more appropriate than other types of crown which are primarily designed for esthetics rather than durability. porcelain veneers on the incisors are particularly vulnerable to damage, and sometimes a crown can be perforated by occlusal wear. example occlusal splints occlusal splints (also termed dental guards) are commonly prescribed, mainly by dentists and dental specialists, as a treatment for bruxism. proponents of their use claim many benefits, however when the evidence is critically examined in systematic reviews of the topic, it is reported that there is insufficient evidence to show that occlusal splints are effective for sleep bruxism as well as bruxism overall. furthermore, occlusal splints are probably ineffective for awake bruxism, since they tend to be worn only during sleep. however, occlusal splints may be of some benefit in reducing the tooth wear that may accompany bruxism, but by mechanically protecting the teeth rather than reducing the bruxing activity itself. in a minority of cases, sleep bruxism may be made worse by an occlusal splint. some patients will periodically return with splints with holes worn through them, either because the bruxism is aggravated, or unaffected by the presence of the splint. when tooth-to-tooth contact is possible through the holes in a splint, it is offering no protection against tooth wear and needs to be replaced. occlusal splints are divided into partial or full-coverage splints according to whether they fit over some or all of the teeth. they are typically made of plastic (e.g. acrylic) and can be hard or soft. a lower appliance can be worn alone, or in combination with an upper appliance. usually lower splints are better tolerated in people with a sensitive gag reflex. another problem with wearing a splint can be stimulation of salivary flow, and for this reason some advise to start wearing the splint about 30 mins before going to bed so this does not lead to difficulty falling asleep. as an added measure for hypersensitive teeth in bruxism, desensitizing toothpastes (e.g. containing strontium chloride) can be applied initially inside the splint so the material is in contact with the teeth all night. this can