Background: Sleep bruxism (SB) is an oral behavior characterized by high levels of repetitive jaw muscle activity during sleep, leading to teeth grinding and clenching, and may develop into a disorder. Despite its prevalence and negative outcomes on oral health and quality of life, there is currently no cure for SB. The etiology of SB remains poorly understood, but recent research suggests a potential role of negative emotions and maladaptive emotion regulation (ER). Objective: This study’s primary aim investigates whether ER is impaired in individuals with SB, while controlling for affective and sleep disturbances. The secondary aim tests for the presence of cross-sectional and longitudinal mediation pathways in the bidirectional relationships among SB, ER, affect, and sleep. Methods: The study used a nonrandomized repeated-measures observational design and was conducted remotely. Participants aged 18-49 years underwent a 14-day ambulatory assessment. Data collection was carried out using electronic platforms. We assessed trait and state SB and ER alongside affect and sleep variables. We measured SB using self-reported trait questionnaires, ecological momentary assessment (EMA) for real-time reports of SB behavior, and portable electromyography for multinight assessment of rhythmic masticatory muscle activity. We assessed ER through self-reported trait questionnaires, EMA for real-time reports of ER strategies, and heart rate variability derived from an electrocardiography wireless physiological sensor as an objective physiological measure. Participants’ trait affect and real-time emotional experiences were obtained using self-reported trait questionnaires and EMA. Sleep patterns and quality were evaluated using self-reported trait questionnaires and sleep diaries, as well as actigraphy as a physiological measure. For the primary objective, analyses will test for maladaptive ER in terms of strategy use frequency and effectiveness as a function of SB using targeted contrasts in the general linear model. Control analyses will be conducted to examine the persistence of the SB-ER relationship after adjusting for affective and sleep measures, as well as demographic variables. For the secondary objective, cross-sectional and longitudinal mediation analyses will test various competing models of directional effects among self-reported and physiological measures of SB, ER, affect, and sleep. Results: This research received funding in April 2017. Data collection took place from August 2020 to March 2022. In all, 237 participants were eligible and completed the study. Data analysis has not yet started. Conclusions: We hope that the effort to thoroughly measure SB and ER using gold standard methods and cutting-edge technology will advance the knowledge of SB. The findings of this study may contribute to a better understanding of the relationship among SB, ER, affect, and sleep disturbances. By identifying the role of ER in SB, the results may pave the way for the development of targeted interventions for SB management to alleviate the pain and distress of those affected.
Bibliographical noteFunding Information:
This study was preregistered at an independent institutional registry: the National Institute of Dental and Craniofacial Research (NIDCR)  of the National Institutes of Health (NIH). The authors thank the peer reviewers from the NIH involved in peer reviewing the study protocol (Multimedia Appendix 8). This work was supported by the NIDCR in part by grant R01DE026771 awarded to the principal investigator, JJG. The coordinating group includes AKA, ASB, JJG, Leah Harris, SDK, Hanqiu Li, SSL-G, Olivia Magaña, and Hannah Overbye. The steering committee consists of JJG, Clete A Kushida, GJL, and RM. The data management team consists of ASB and SDK. Study oversight is provided by NIDCR program officials (Dr Melissa Riddle, Medical Monitor Oversight Report-Quality Management Reporting Committee) and NIDCR Clinical Research Operations and Management Support. The authors thank research assistants Ella Becker, Alexander Bruckhaus, Yishu Chen, Victoria Costa, Isabel Gao, Addison Gills, Anusha Goyal, Rachel Hokanson, Rachel Huynh, Norhan Khafagy, Sewit Kidane, George Lausten, Gordon Luu, Olivia Magaña, Charlotte Ostrow, Priti Patel, Zoey Pham, Lorena Portillo, Yasamin Sadeghi, Sohrab Sami, Ann-Kathrin Schwientek, Purnima Seshadri, Elian Mateo Valencia, Michael Wicklein, Jocelyn Wilmore, and Sawyer Wisniewski for help with the data collection; Olivia Magaña and Yasamin Sadeghi for help with summarizing the literature; and Danny Nguyen for editorial support.
©Sylvia D Kreibig, Maia ten Brink, Ashish Mehta, Anat Talmon, Jin-Xiao Zhang, Alan S Brown, Sawyer S Lucas-Griffin, Ariel K Axelrod, Rachel Manber, Gilles J Lavigne, James J Gross.
- ecological momentary assessment
- emotion regulation
- heart rate variability
- rhythmic masticatory muscle activity
- sleep bruxism
- wrist actigraphy