The association between sleep bruxism and awake bruxism

Thiprawee Chattrattrai received third place in the NVGPT publication prize for her article on the association between sleep bruxism and awake bruxism. The article, titled ‘The association between sleep bruxism and awake bruxism: polysomnographic and electromyographic recordings in women with and without myofascial pain’, is a part of her PhD thesis, ‘Sleep Bruxism: Associations and Comorbid Conditions’. A summary of her article is provided below.

Sleep bruxism (SB) is defined as masticatory muscle activity during sleep, and awake bruxism (AB) is defined as a masticatory muscle activity during wakefulness. SB and AB have distinct definitions based on their different characteristics. The gold standard for SB and AB assessment are polysomnography (PSG) and electromyography (EMG). This article aimed to assess the associations between SB and AB, and to investigate whether SB and AB are associated with different subtypes of activity—specifically, mainly grinding for SB and mainly clenching for AB.

This study included 122 female TMD pain patients and 46 pain-free controls. All participants underwent two-night PSG to assess SB and EMG to assess AB both at rest and during stress-related activities. The stress-related activities include a cold pressor test, a mental arithmetic test, a speech stressor test, and a reaction time/startle response test. The SB and AB events rates (measured as SB or AB event per hour) and EMG activity during SB and AB were analyzed.

This study found no significant differences in the event rates and EMG activity of SB and AB between TMD pain patients and pain-free controls. SB was primarily characterized by grinding activity, while AB was mainly clenching activity. The event rates and EMG activity of SB showed no association with those of AB, either at rest or AB during stress-related activity. However, muscle activity and event rate of AB at rest was positively associated with those of AB during stress-related activity. This suggests that individuals with AB may exhibit more AB during stress conditions.