Bruxism is an umbrella term grouping together different motor phenomena of jaw muscles, including teeth grinding, teeth clenching and bracing or thrusting of the mandible.
Bruxism can occur during sleep (sleep bruxism [SB]) or wakefulness (awake bruxism [AB]).
Etiology is mainly dependent on central factors (stress sensitivity, emotions, personality features, sleep regulation, autonomic nervous system), rather than on peripheral nervous system function or dental morphology and occlusion.
In healthy individuals, bruxism can be considered a muscle behavior, which can be harmless or represent a risk factor for clinical consequences, rather than being a disorder per se. Treatment need depends on the presence of clinically relevant consequences rather than the presence of bruxism itself.
Bruxism may result in tooth wear or cracks, fracture of dental restorations, implant failure, muscle hypertrophy, pain and/or fatigue in jaw muscles, headache, toothache, disturbance of bed partner's sleep, and reduction in overall quality of life.
Treatment is symptomatic. Management options include different types of oral appliances (OA), cognitive-behavioural approaches, psychotherapy, physiotherapy, and, rarely, relaxant drugs for short-term use.
Treatment of any conditions associated with bruxism should also be optimized. Bruxism may be self limiting, particularly in children. Therefore, observation only strategies may be appropriate.
Historically, classifications and definitions of bruxism have varied widely. An international consensus meeting in 2017 defined bruxism as follows:
Sleep bruxism (SB): a masticatory muscle activity during sleep that is characterized as rhythmic (phasic) or nonrhythmic (tonic) and is not a movement disorder or a sleep disorder in otherwise healthy individuals.
Awake bruxism (AB): a masticatory muscle activity during wakefulness that is characterized by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible and is not a movement disorder in otherwise healthy individuals.
SB and AB are considered as separate conditions. Both definitions emphasize masticatory muscle activity because this may have clinical consequences.
Classical bruxism activities are clenching and grinding of the teeth. However, there is an emerging consensus that bruxism may involve masticatory muscle activity without tooth contact. For example, bracing describes forcefully maintaining a certain mandibular position and thrusting describes forcefully moving the mandible in a forward or lateral direction.
History and exam
Key diagnostic factors
- grinding noises
- oral parafunctions
- tooth wear and soreness
- jaw muscle or temporomandibular joint (TMJ) pain
- jaw muscle tenderness
- stress and anxiety
- caffeine, nicotine, or alcohol use
- history of sleep disorders
- selective serotonin-reuptake inhibitor or dopamine antagonist use
- ecstasy or cocaine use
- muscle hypertrophy
Other diagnostic factors
- tooth hypersensitivity
- fracture of dental restorations
- oral mucosal changes
- record of bruxism events and associated behavior
- oral appliance wear
- smoking, caffeine, alcohol consumption
- stress sensitivity and anxiety personality traits
- snoring, sleep apnea, and other sleep disorders
- medication use
- genetic disposition
- primary motor disorders
1st investigations to order
- clinical diagnosis
Investigations to consider
- polysomnographic (PSG) study
- electromyography (EMG)
- ecological momentary assessment (EMA)
Frank Lobbezoo, DDS, PhD
Professor, Chair, and Vice Dean
Department of Oral Health Sciences
Academic Centre for Dentistry Amsterdam (ACTA)
MOVE Research Institute Amsterdam
University of Amsterdam
VU University Amsterdam
FL is a member (unpaid) of the Academic Advisory Boards of Sunstar Suisse S.A for GrindCare® and for Oral Function. FL receives research grants from Sunstar Suisse S.A, Airway management, Vivisol, SomnoMed-Goedegebuure, and Health Holland. FL is an author of several references cited in this topic.
Daniele Manfredini, DDDS, PhD
Full Professor Oral Physiology and Gnathology
School of Dentistry
University of Siena
DM is an author of several references cited in this topic.
Alessandro Bracci, DDS
School of Dentistry
Department of Neuroscience
University of Padua
AB is the inventor of and owns the copyright for the software BruxApp. AB is an author of a reference cited in this topic.
Professor Daniele Manfredini, Professor Frank Lobbezoo, and Alessandro Bracci would like to gratefully acknowledge Professor Peter Svensson, a previous contributor to this topic.
PS is chairman of the clinical advisory board and has received fees for consulting for Medotech, the manufacturer of GrindCare. PS is also an author of several references cited in this topic.
Alan Glaros, PhD
Associate Dean and Professor
Kansas City University of Medicine and Biosciences
AG is a member of the clinical advisory board of Medotech and has received GrindCare devices for evaluation. AG is an author of a reference cited in this topic.
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