Editing Bruxism (section)

==Signs and symptoms==
Most people who brux are unaware of the problem, either because there are no symptoms, or because the symptoms are not understood to be associated with a clenching and grinding problem. The symptoms of sleep bruxism are usually most intense immediately after waking, and then slowly abate, and the symptoms of a grinding habit which occurs mainly while awake tend to worsen through the day, and may not be present on waking.<ref name="Scully 2008" /> Bruxism may cause a variety of signs and symptoms, including:
[[File:Topviewtooth.jpg|right|thumb|View from above of an anterior (front) tooth showing severe tooth wear which has exposed the dentin layer (normally covered by enamel). The pulp chamber is visible through the overlying dentin. Tertiary dentin will have been laid down by the pulp in response to the loss of tooth substance. Multiple fracture lines are also visible.]]
* A grinding or tapping noise during sleep, sometimes detected by a partner or a parent.<!--<ref name="Macedo 2009" /> --> This noise can be surprisingly loud and unpleasant, and can wake a sleeping partner.<!--<ref name="Macedo 2009" /> --> Noises are rarely associated with awake bruxism.<ref name="Macedo 2009" />
* Other parafunctional activity which may occur together with bruxism:<ref name="Macedo 2009" /> cheek biting (which may manifest as [[morsicatio buccarum]] or [[linea alba (cheek)|linea alba]]),<ref name="Scully 2008" /><ref name="Heasman 2008" /> or lip biting.
* A burning sensation on the tongue (see: [[burning mouth syndrome|glossodynia]]),<ref name="Macedo 2009" /> possibly related to a coexistent "tongue thrusting" parafunctional activity.
* Indentations of the teeth in the tongue ("[[crenated tongue]]" or "scalloped tongue").<ref name="Heasman 2008" />
* [[Hypertrophy]] of the [[muscles of mastication]] (increase in the size of the muscles that move the jaw),<ref name="Heasman 2008">{{cite book |veditors=Heasman P |title = Master Dentistry Vol I: Restorative dentistry, paediatric dentistry and orthodontics |year = 2008 |publisher = Churchill Livingstone |location = Edinburgh |isbn = 9780443068959 |page = [https://archive.org/details/masterdentistry0000unse/page/177 177] |edition = 2nd |url = https://archive.org/details/masterdentistry0000unse |url-access=registration}}</ref> particularly the [[masseter muscle]].<ref name="Macedo 2009" /><ref name="Scully 2008" /><ref name="Kalantzis 2005">{{cite book |vauthors=Kalantzis A, Scully C |title = Oxford handbook of dental patient care, the essential guide to hospital dentistry. |year = 2005 |publisher = Oxford University Press |location = New York |isbn = 9780198566236 |edition = 2nd |page = 332 }}</ref>
* Tenderness, pain or fatigue of the muscles of mastication,<ref name="Macedo 2009" /> which may get worse during chewing or other jaw movement.<ref name="Scully 2008" />
* [[Trismus]] (restricted mouth opening).<ref name="Macedo 2009" />
* Pain or tenderness of the [[temporomandibular joint]]s,<ref name="Macedo 2009" /> which may manifest as preauricular pain (in front of the ear), or pain referred to the ear ([[otalgia]]).<ref name="medline plus">{{cite web |url = https://www.nlm.nih.gov/medlineplus/ency/article/001413.htm |title = Bruxism |publisher = [[United States National Library of Medicine]] |date = 28 April 2008 |access-date = 11 June 2009 }}</ref>
* Clicking of the temporomandibular joints.<ref name="Shetty 2010" />
* Headaches,<!--<ref name=ICSD-R /> --> particularly pain in the [[Temple (anatomy)|temples]],<ref name="Shetty 2010" /> caused by muscle pain associated with the temporalis muscle.
* Excessive tooth wear,<ref name="Heasman 2008" /> particularly [[attrition (dental)|attrition]], which flattens the occlusal (biting) surface, but also possibly other types of tooth wear such as [[abfraction]], where notches form around the neck of the teeth at the gumline.<ref name="Neville 2001">{{cite book |vauthors=Neville BW, Damm DD, Allen CA, Bouquot JE |title = Oral & maxillofacial pathology |year = 2002 |publisher = W.B. Saunders |location = Philadelphia |isbn = 978-0721690032 |pages = 21,58,59,173 |edition = 2nd }}</ref>
* Tooth fractures,<ref name="Macedo 2009" /> and repeated failure of dental restorations (fillings, crowns, etc.).<ref name="Tyldesley 2003">{{cite book |vauthors=Tyldesley WR, Field A, Longman L |title = Tyldesley's Oral medicine |year = 2003 |publisher = Oxford University Press |location = Oxford |isbn = 978-0192631473 |pages = 195 |edition = 5th }}</ref>
* [[Dentine hypersensitivity|Hypersensitive teeth]],<ref name="Macedo 2009" /> (e.g. dental pain when drinking a cold liquid) caused by wearing away of the thickness of insulating layers of dentin and enamel around the [[dental pulp]].
* Inflammation of the [[periodontal ligament]] of teeth, which may make them sore to bite on, and possibly also a degree of loosening of the teeth.<ref name="Macedo 2009" />
Bruxism is usually detected because of the effects of the process (most commonly tooth wear and pain), rather than the process itself. 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 muscles of mastication that act to move the jaw can also be affected since they are being utilized over and above of normal function.<ref name="Wassell 2008" />

===Pain===
Most people with bruxism will experience no pain.<ref name="Cawson 2002" /> The presence or degree of pain does not necessarily correlate with the severity of grinding or clenching.<ref name="Cawson 2002" /> The pain in the muscles of mastication caused by bruxism can be likened to muscle pain after exercise.<ref name="Cawson 2002" /> The pain may be felt over the angle of the jaw (masseter) or in the temple (temporalis), and may be described as a headache or an aching jaw. Most (but not all) bruxism includes clenching force provided by masseter and temporalis muscle groups; but some bruxers clench and grind front teeth only, which involves minimal action of the masseter and temporalis muscles. The temporomandibular joints themselves may also become painful, which is usually felt just in front of the ear, or inside the ear itself. Clicking of the jaw joint may also develop. The forces exerted on the teeth are more than the periodontal ligament is biologically designed to handle, and so inflammation may result. A tooth may become sore to bite on, and further, tooth wear may reduce the insulating width of enamel and dentin that protects the pulp of the tooth and result in hypersensitivity, e.g. to cold stimuli.

The relationship of bruxism with [[temporomandibular joint dysfunction]] (TMD, or temporomandibular pain dysfunction syndrome) is debated. Many suggest that sleep bruxism can be a causative or contributory factor to pain symptoms in TMD.<ref name="Tyldesley 2003" /><ref name="Shetty 2010" /><ref name="Scully 2008">{{cite book |last = Scully |first = Crispian |title = Oral and maxillofacial medicine: the basis of diagnosis and treatment |year = 2008 |publisher = Churchill Livingstone |location = Edinburgh |isbn = 9780443068188 |edition = 2nd |pages = 291, 292, 343, 353, 359, 382 }}</ref><ref name="Glick 2003" /> Indeed, the symptoms of TMD overlap with those of bruxism.<ref name="De Meyer 1997">{{cite journal |vauthors=De Meyer MD, De Boever JA |title=[The role of bruxism in the appearance of temporomandibular joint disorders] |language=fr |journal=Revue Belge de Médecine Dentaire |volume=52 |issue=4 |pages=124–38 |year=1997 |pmid=9709800}}</ref> Others suggest that there is no strong association between TMD and bruxism.<ref name="Cawson 2002" /> A systematic review investigating the possible relationship concluded that when self-reported bruxism is used to diagnose bruxism, there is a positive association with TMD pain, and when stricter diagnostic criteria for bruxism are used, the association with TMD symptoms is much lower.<ref name="Manfredini 2010">{{cite journal |vauthors=Manfredini D, Lobbezoo F |title=Relationship between bruxism and temporomandibular disorders: a systematic review of literature from 1998 to 2008 |journal=Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics |volume=109 |issue=6 |pages=e26–50 |date=June 2010  |pmid=20451831 |doi=10.1016/j.tripleo.2010.02.013}}</ref> In severe, chronic cases, bruxism can lead to [[myofascial pain]] and [[arthritis]] of the temporomandibular joints.{{medical citation needed|date=May 2013}}

===Tooth wear===
Many publications list tooth wear as a consequence of bruxism, but some report a lack of a positive relationship between tooth wear and bruxism.<ref name="Shetty 2010" /> Tooth wear caused by tooth-to-tooth contact is termed [[attrition (dental)|attrition]]. This is the most usual type of tooth wear that occurs in bruxism, and affects the occlusal surface (the biting surface) of the teeth. The exact location and pattern of attrition depends on how the bruxism occurs, e.g., when the [[canine tooth|canines]] and [[incisor]]s 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 [[Commonly used terms of relationship and comparison in dentistry|incisal]] edges of the teeth. To grind the front teeth, most people need to posture their mandible forwards, unless there is an existing edge to edge, class III incisal relationship. People with bruxism may also grind their [[Commonly used terms of relationship and comparison in dentistry|posterior]] teeth (back teeth), which wears down the [[cusp (dentistry)|cusps]] of the occlusal surface. Once tooth wear progresses through the [[Tooth enamel|enamel]] layer, the exposed [[dentin]] layer is softer and more vulnerable to wear and [[caries|tooth decay]]. If enough of the tooth is worn away or decayed, the tooth will effectively be weakened, and may fracture under the increased forces that occur in bruxism.

[[Abfraction]] is another type of tooth wear that is postulated to occur with bruxism, although some still argue whether this type of tooth wear is a reality.<ref name="Neville 2001" /> 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. It is argued that similar lesions can be caused by long-term forceful toothbrushing. However, the fact that the cavities are V-shaped does not suggest that the damage is caused by toothbrush [[Abrasion (dental)|abrasion]], and that some abfraction cavities occur below the level of the gumline, i.e., in an area shielded from toothbrush abrasion, supports the validity of this mechanism of tooth wear. In addition to attrition, [[Acid erosion|erosion]] is said to synergistically contribute to tooth wear in some bruxists, according to some sources.<ref name="Pettengill 2011">{{cite journal |author=Pettengill CA |title=Interaction of dental erosion and bruxism: the amplification of tooth wear |journal=Journal of the California Dental Association |volume=39 |issue=4 |pages=251–6 |date=April 2011  |doi=10.1080/19424396.2011.12221893 |pmid=21675679|s2cid=12323562 }}</ref>

===Tooth mobility===
The view that occlusal trauma (as may occur during bruxism) is a causative factor in [[gingivitis]] and [[periodontitis]] is not widely accepted.<ref name="Davies 2001">{{cite journal |vauthors=Davies SJ, Gray RJ, Linden GJ, James JA |title=Occlusal considerations in periodontics |journal=British Dental Journal |volume=191 |issue=11 |pages=597–604 |date=December 2001  |pmid=11770945 |doi=10.1038/sj.bdj.4801245a}}</ref> It is thought that the periodontal ligament may respond to increased occlusal (biting) forces by resorbing some of the bone of the alveolar crest, which may result in increased tooth mobility, however these changes are reversible if the occlusal force is reduced.<ref name="Davies 2001" /> Tooth movement that occurs during occlusal loading is sometimes termed [[fremitus]].<ref name="Wassell 2008" /> It is generally accepted that increased occlusal forces are able to increase the rate of progression of pre-existing [[periodontal disease]] (gum disease), however the main stay treatment is [[dental plaque|plaque]] control rather than elaborate occlusal adjustments.<ref name="Davies 2001" /> It is also generally accepted that periodontal disease is a far more common cause of tooth mobility and pathological tooth migration than any influence of bruxism, although bruxism may much less commonly be involved in both.<ref name="Wassell 2008" />