Temporal patterns of bruxism behaviors: multiple day recording with portable electromyography

To assess inter-day variabilities and define temporal patterns of awake and sleep muscular activity during 72 h of continuous electromyographic (EMG) recording. 20 subjects used a portable EMG device for 72 h. Additional to the variables supplied by the instrument's algorithm, the number of grinding and of clenching episodes, per each hour of wakefulness and each hour of sleep, was counted. Number of grinding and clenching of episodes, per hour of sleep and wakefulness, were used in a mixed model analysis. For sleep grinding episodes, a linear temporal model showed a day-to-day increase indicating progressive elevation in grinding activity across measurement nights. For sleep clenching episodes, a basic model revealed a day-to-day increase and a linear decline across sleep hours. For awake grinding episodes, a linear temporal model revealed an hourly decline in grinding episodes, indicating decreased grinding activity throughout waking hours. No significant day-to-day variation was observed. For awake clenching episodes, a polynomial model revealed curvilinear patterns for both hourly and daily variations. Three days might be the minimum viable EMG monitoring period for comprehensive bruxism assessment. The distinct temporal signatures between sleep and awake bruxism, and between grinding and clenching, support the need for differentiated monitoring protocols. Standardization regarding EMG variables and minimum recording period should be considered for future studies. The complex temporal patterns of bruxism require multi-day observation to capture clinically meaningful patterns. Single-day assessments might miss critical temporal dynamics and underestimate the condition's severity and variability.