Investigations
1st investigations to order
clinical diagnosis
Test
The early clinical diagnosis of possible and probable bruxism is primarily based on non-instrumental approaches: history taking (i.e., structured questionnaires, interviews, and more general self-reported measures) and clinical examination (including a complete dental examination, an inspection of the cheek and tongue mucosa, and evaluation of the jaw muscles and temporomandibular joint).[1]
Clinical diagnosis does not allow for sleep bruxism and awake bruxism to be accurately distinguished.
Result
possible or probable bruxism
polysomnographic (PSG) study
Test
PSG shows the number of bruxism events per hour of sleep and is the definitive test for sleep bruxism (SB) diagnosis, but it has limited use due to high costs and very low availability.[1][81]
Patients with self-reports of severe bruxism, pain, poor sleep, and other significant sleep disorders (e.g., apnoea) may be candidates for a PSG evaluation with a sleep specialist.
Over 80% of people with severe bruxism are correctly identified by a PSG study.[49]
A SB event is defined as a contraction of the right masseter muscle exceeding 20% of maximum voluntary contraction (MVC). Based on its duration, an event can be classified as tonic (single EMG burst >2 seconds), phasic (3 or more bursts lasting 0.25 to 2 seconds), or mixed (a combination of the two types).
Result
positive for SB if: >4 bruxing episodes per hour of sleep; >6 bruxism bursts per episode and/or 25 bruxism bursts per hour sleep; and >1 bruxing episode with grinding noise
Investigations to consider
electromyography (EMG)
Test
Can provide evidence of both awake bruxism (AB) and sleep bruxism (SB) by recording the number of jaw muscle activities per hour during the sleep or awake state.
Diagnostic strategies based on single- or multi-channel ambulatory EMG recordings have been proposed.[78][79][80] A review of the diagnostic accuracy of portable EMG recorders, and validity testing showed that multi-channelled devices may be accurate even with a single-night use, while multiple nights with single-channel devices are required to achieve sufficient agreement with polysomnography (PSG)/SB diagnosis.[32][78][80]
Portable devices offer easier availability and lower-level technical equipment with respect to PSG; however, costs limit their full introduction into the clinical setting.
EMG can be used in patients with self-reported moderate to severe SB, excessive tooth wear, or repeated fractures/failures of dental restorations.
If limited-channel ambulatory EMG monitoring of people with SB is used (evaluates only facial muscles), care must be taken that other potential sleep disorders are not missed. Use of sleep disorder questionnaires, such as the Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index (PSQI) questionnaires, is advisable in this situation.
Result
cut-off criteria not established, but repeated measurements can provide insight into individual variations in EMG activity
ecological momentary assessment (EMA)
Test
Proposed as an alternative option to wake-time electromyography to achieve a definite awake bruxism (AB) diagnosis.
Involves repeated, real-time sampling of subjective behaviours and experiences about jaw muscle activities at certain time points during wakefulness (e.g., symptoms, affect, behaviour, feeling, cognition).[77][82][83] Allows patients to report the conditions of their jaw muscles such as: relaxed jaw muscles, teeth contact, teeth-clenching, teeth-grinding, jaw-clenching without teeth contact (i.e., bracing).
Progress in smartphone technology has opened up a new era for EMA, as data collection for clinical and research purposes can now be conducted using a tool that is already a part of daily life for a large percentage of the population.[82][83]
Result
appraisal of AB with current behaviours and experiences in real time (no established AB diagnostic criteria)
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