Professional perspective
Clinical relevance
- Differentiating sleep from awake bruxism as a basis for counseling
- Framing bruxism as a behavior with potential risk-factor, protective, or neutral status rather than a default diagnosis
- Differential diagnosis against attrition and other forms of tooth wear
- Realistic patient education on the benefit of occlusal splints: protective, not curative
Classification and definition
The international expert consensus (Lobbezoo et al., 2013; updated 2018) defines bruxism as repetitive masticatory muscle activity, characterized by grinding or clenching of the teeth and/or by bracing or thrusting of the mandible, specified as sleep bruxism or awake bruxism depending on circadian occurrence. The 2018 update explicitly addresses whether bruxism should be classified as a disorder in its own right or as a behavior with potential risk-factor status for certain clinical conditions; the field has increasingly moved toward the latter view, since bruxism without identifiable adverse consequences does not necessarily carry disease status. More recent work from the same research group discusses evidence that bruxism may, in some circumstances, serve a physiological, potentially protective function, which the current definitions increasingly aim to accommodate.
A closed, invitation-only workshop held at the IADR General Session in March 2024 revisited these definitions in detail; its report, published in 2025 (Verhoeff, Lobbezoo, et al.), provides a glossary of current terminology, addresses frequently raised points of confusion, and proposes a road map for further consensus work.
Clinical implications
Isolated bruxism, without wear or symptoms, does not by itself justify treatment. The clinically relevant question is whether measurable consequences are present: tooth wear, muscle or joint symptoms, or reported pain.
Tooth wear attributed to bruxism should be assessed in the context of possible co-occurring erosion or abrasion, since these mechanisms interact and rarely explain a wear pattern in isolation.
Etiology: different mechanisms
For sleep bruxism, evidence for a causal role of occlusal factors is considered weak; more recent literature instead places sleep bruxism downstream of sleep-related micro-arousals: brief rises in autonomic cardiac and respiratory activity that occur physiologically several times per hour of sleep. For awake bruxism, physiology and pathology are comparatively less well studied; psychosocial factors such as stress and anxiety are considered relevant. Genetic factors and lifestyle factors, including caffeine, alcohol, and tobacco, are discussed as contributors to both forms.
Epidemiology
A 2024 systematic review and meta-analysis estimated global prevalence at approximately 21 percent for sleep bruxism and 23 percent for awake bruxism, with considerable regional variation; sleep bruxism identified through polysomnography specifically was estimated substantially higher, at approximately 43 percent. Objective recordings of this kind detect many episodes that remain clinically silent and would not otherwise be recognized, which explains much of the gap between self-reported and instrument-based prevalence.
Management: occlusal splints
A Cochrane review (Macedo et al., 2007) on the efficacy of occlusal splints for sleep bruxism concluded that reliable evidence was lacking for reducing sleep-related outcome measures, such as the number of bruxism episodes per hour, though a possible benefit emerged for protecting teeth from wear. The authors called for methodologically stronger randomized trials with standardized outcome measures. More recent systematic reviews, published between 2021 and 2024, present a more mixed picture: several report a positive effect on bruxism episodes for specific splint designs, particularly adjustable or biofeedback-based appliances, though evidence across reviews remains inconsistent and the overall evidence base is still considered limited. The distinction between protective function and treatment of the underlying cause remains clinically important and should be made explicit in patient counseling.
What the data does not currently show
- Evidence that occlusal splints, as a general category, reduce bruxism activity itself remains inconsistent, with some newer designs showing promising but not yet confirmed signals
- No confirmed causal role of occlusal factors in sleep bruxism
- Physiology and pathology of awake bruxism remain considerably less studied than sleep bruxism
- No established German S-level clinical guideline specific to bruxism, unlike caries prevention (AWMF 083-021)
Evidence summary
What current evidence supports
- Sleep and awake bruxism are internationally defined as distinct phenomena, most likely with different underlying mechanisms
- Bruxism is not inherently pathological; current consensus frames it as potentially harmless, a risk factor, or occasionally protective, depending on context
- Global prevalence is estimated at approximately 21 percent for sleep bruxism and 23 percent for awake bruxism, higher when measured objectively via polysomnography, in part because objective methods detect clinically silent episodes
- Occlusal splints reliably protect tooth structure from further wear
What remains uncertain
- Whether specific splint designs can reliably reduce bruxism activity itself, beyond their established protective function
- The relative contribution of genetic, psychological, and lifestyle factors across individuals
- Why awake bruxism remains comparatively understudied relative to sleep bruxism
- How the terminology proposed in the 2025 consensus workshop report will be adopted across future bruxism research and classification
Lobbezoo, Ahlberg, Raphael, et al. (2018), in the Journal of Oral Rehabilitation, published the updated international expert consensus, refining the definitions of sleep and awake bruxism and discussing bruxism's classification as behavior versus disorder.
Macedo, Silva, Machado, Saconato, and Prado (2007), in a Cochrane systematic review, found insufficient evidence for a reliable reduction in grinding activity from occlusal splints, alongside a possible benefit for tooth protection.
Zieliński, Pająk, and Wójcicki (2024), in the Journal of Clinical Medicine, conducted a systematic review and meta-analysis establishing current global prevalence estimates for sleep and awake bruxism across pediatric and adult populations.
Verhoeff, Lobbezoo, Ahlberg, et al. (2025), in the Journal of Oral Rehabilitation, reported the outcomes of the 2024 IADR international consensus workshop, clarifying terminology and outlining open questions for future bruxism research.
