Bruxism is an umbrella term grouping together different motor phenomena of jaw muscles, such as grinding, and/or clenching of the teeth and bracing, and/or thrusting of the mandible. It can occur during sleep (sleep bruxism [SB]) or wakefulness (awake bruxism [AB]).
Aetiology 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.
The condition covers a pathophysiological continuum, and treatment need depends on the presence of clinically relevant consequences rather than the presence of bruxism itself.
Depending on the amount of muscle activity and the resistance of the target structures, 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.
A diagnostic grading for clinical and research purposes has been recently proposed, recommending that any investigation specifies the diagnosis of sleep or awake bruxism as 'possible', 'probable', or 'definite' based on the diagnostic approach being used.
Self-report, questionnaires, and interviews are suitable, at best, to identify a possible bruxism, while integration with clinical examination leads to a diagnosis of probable bruxism. For a definite diagnosis, measurement with audio-video polysomnography (PSG) or, alternatively, sleep-time electromyography (EMG) is needed for SB. Hour-long, wake-time EMG or, as an emerging option, ecological momentary assessment (EMA) is needed for a definite AB diagnosis.
Treatment is symptomatic and conditioned by the lack of evidence about when bruxism should actually be treated. Management options include different types of oral appliances (OA), cognitive-behavioural approaches (counselling, biofeedback, contingent electrical stimulation, relaxation techniques, hypnosis), psychotherapy, physiotherapy, and, rarely, relaxant drugs for short-term use.
Bruxism is a clinical phenomenon that can manifest in both children and adults. In 2013, an international panel of experts updated the consensus bruxism definition as: a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has 2 distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism [SB]) or during wakefulness (indicated as awake bruxism [AB]). 
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 of the Academic Advisory Board of Sunstar Suisse S.A for GrindCare®. FL receives research funding from Sunstar Suisse S.A and SomnoMed. FL is an author of several references cited in this topic.
Associate Professor School of Dentistry
Department of Neuroscience
University of Padova
DM is an author of several references cited in this topic.
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.
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 monograph.
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