Bruxism comes in two forms that share a name but differ in almost every other way. Sleep bruxism occurs during sleep as an involuntary motor behaviour. Awake bruxism happens during waking hours, typically as unconscious clenching during concentration or stress.

The distinction matters because these conditions involve different brain mechanisms—and treatments that work for one may fail entirely for the other.

Sleep bruxism: The brainstem condition

Sleep bruxism is classified as a sleep-related movement disorder. It involves rhythmic masticatory muscle activity (RMMA) that occurs during transitions between sleep stages, typically during lighter (non-REM) sleep phases.

Key characteristics:

• Brainstem-dominant: Sleep bruxism is generated by circuits in the brainstem, not the cortex. This means it operates below conscious control (Lavigne et al., 2008).

• Micro-arousal triggered: Episodes typically occur during brief arousals—shifts toward lighter sleep where the brain becomes momentarily more active. Research shows a characteristic sequence: cardiac acceleration → brain arousal → muscle activation → grinding (Kato et al., 2001).

• Not consciously controllable: Willpower and awareness techniques don't work because the behaviour happens during sleep when cortical control is offline.

• Rhythmic pattern: Often presents as rhythmic grinding with audible sounds, though tonic (sustained) clenching also occurs.

Prevalence: Approximately 8-13% of adults experience sleep bruxism, with rates highest in younger adults and declining with age (Zielinski et al., 2024).

Awake bruxism: The habit condition

Awake bruxism typically presents as sustained clenching, jaw bracing, or teeth contact during waking hours. Unlike sleep bruxism, it's cortically mediated—meaning higher brain functions are involved.

Key characteristics:

• Cortically-mediated: Awake bruxism involves the motor cortex and can be modified through conscious awareness and behavioural training (Bracci et al., 2024).

• Linked to stress and concentration: Often occurs during focused work, emotional tension, or stressful situations. The behaviour may serve as an unconscious coping mechanism.

• Unconscious but modifiable: People typically don't realise they're clenching, but once aware, they can voluntarily relax. This makes awareness training effective.

• Sustained pattern: Usually presents as prolonged clenching rather than rhythmic grinding. May also include jaw bracing without tooth contact.

Prevalence: Approximately 20-30% of adults experience awake bruxism—higher than sleep bruxism, likely because daytime hours provide more opportunities for the behaviour (Zielinski et al., 2024).

Why treatment must differ

The different brain mechanisms mean treatments that address one type may be irrelevant for the other.

For sleep bruxism

Because sleep bruxism is brainstem-generated:

• Awareness techniques work differently: Sleep clenching happens during micro-arousals (lighter sleep phases). Gentle awareness cues can prompt relaxation during these phases without fully waking you — a different mechanism than conscious daytime awareness, but still effective.
• Night guards protect but don't reduce: Splints prevent dental damage but don't address the underlying motor pattern. This is the current standard of care.
• Neurostimulation research is promising but products don't exist: Studies on contingent electrical stimulation show ~50% reduction in grinding episodes. However, devices like GrindCare that demonstrated these results were discontinued, leaving a gap between validated science and available treatments.
• Objective monitoring needed: Accurate diagnosis often requires multi-night monitoring, since single-night variability is high and self-report is unreliable for sleep behaviours.

For awake bruxism

Because awake bruxism is cortically-mediated:

• Awareness training is foundational: Regular check-ins throughout the day (like JawSense's Jaw Awareness prompts) build conscious recognition of an unconscious habit.
• Biofeedback can interrupt the loop: Real-time feedback when clenching is detected prompts voluntary relaxation, training new responses over time.
• Stress management helps: Since stress and concentration amplify the behaviour, addressing these factors provides supportive benefit (though rarely eliminates the habit alone).
• Self-monitoring is more intuitive: People can consciously notice daytime clenching through structured awareness practice. During sleep, wearable biofeedback provides the monitoring and cues automatically.

Common treatment mistakes

Treating both types identically. A night guard prescribed for someone whose primary issue is daytime clenching won't address the core problem. Similarly, awareness training prescribed for severe sleep grinding may leave the real issue untouched.

Relying only on verbal advice for sleep bruxism. Telling someone to "relax before bed" or "be aware of jaw tension" isn't enough on its own. Wearable biofeedback that delivers gentle cues during micro-arousals can help where verbal advice alone falls short.

Ignoring awake bruxism as "just stress." Awake bruxism is a distinct condition requiring specific interventions, not simply a stress symptom that will resolve when life calms down.

Relying solely on splints for either type. Night guards protect teeth but don't address behaviour. For comprehensive management, protection should be combined with approaches targeting the underlying pattern.

Getting the diagnosis right

Accurate identification is the essential first step. Key questions to differentiate:

• Does a bed partner hear grinding at night? (suggests sleep bruxism)
• Are mornings the worst time for jaw soreness? (suggests sleep bruxism)
• Do symptoms worsen during stressful work periods? (suggests awake bruxism)
• Does clenching occur during concentration, driving, or emotional moments? (suggests awake bruxism)

Many people have both types simultaneously, requiring a dual approach.

For sleep bruxism, objective monitoring can confirm suspicions when self-report is uncertain. Multi-night home monitoring captures the night-to-night variability that single assessments miss.

The bottom line

Sleep bruxism and awake bruxism share a name but involve different brain mechanisms requiring different interventions:

• Sleep bruxism: Brainstem-generated, not consciously controllable, requires protection and potentially neurostimulation-based approaches
• Awake bruxism: Cortically-mediated, unconscious but modifiable, responds to awareness training and biofeedback

Effective management starts with accurate identification of which type—or types—are present, then applies targeted interventions accordingly.