Clinical Features and Device-Based Sleep Bruxism: An Exploratory Study

Clinical findings are commonly used to assess sleep bruxism (SB), although their validity as indicators of SB activity remains uncertain. This cross-sectional and exploratory study investigated associations between device-based SB activity and clinical and physiological findings.

Fifty-nine healthy participants (33 men, 26 women; aged 24-40 years) underwent clinical and physiological examinations and two-night portable electromyography (EMG). Mean hourly EMG event frequency was analyzed continuously. Secondary analyses compared high-/low-frequency SB (HSB/LSB; ≥19/<19 events/h) and self-reported SB-positive versus SB-negative (SR-SB+/SR-SB-) groups.

In the primary analysis, no significant association was detected between mean hourly EMG event frequency and any clinical or physiological finding; the largest effect was for cheek bite marks (OR 1.35 per 10-event/h increase; 95% CI, 0.90-2.09). PPT (β = 3.46 kPa per 10-event/h increase; 95% CI, -6.35 to 13.27) and masseter muscle stiffness (β = 8.26 N/m; 95% CI, -4.71 to 21.24) were not associated with EMG event frequency. Secondary HSB/LSB analyses similarly showed no significant differences in clinical or physiological findings. In the self-report analysis, masseter muscle pain was associated with SR-SB+ status (OR 7.03; 95% CI, 1.22-133.8).

No significant association was detected between device-based SB activity and individual clinical or physiological findings in this exploratory sample. Clinical findings should not be used in isolation to identify SB activity.

Commonly used clinical findings may not reliably reflect current SB activity and should be interpreted together with patient history and self-reported symptoms.