Identification of a Sleep Bruxism Subgroup with a Higher Risk of Pain

Abstract

Sleep bruxism research diagnostic criteria (SB-RDC) have been applied since 1996. This study was performed to validate these criteria and to challenge the hypothesis that pain is associated with lower frequencies of orofacial activities. Polygraphic recordings were made of 100 individuals presenting with a clinical diagnosis of sleep bruxism and 43 control individuals. TwoStep Cluster analyses (SPSS) were performed with sleep bruxism variables to reveal groupings among sleep bruxers and control individuals. Participants completed questionnaires during screening, diagnosis, and recording sessions. Cluster analysis identified three subgroups of sleep bruxers. Interestingly, 45 of the 46 sleep bruxers with values below SB-RDC were classified in the low-frequency cluster. These individuals were more likely to complain of pain and fatigue of masticatory muscles than were the higher-frequency sleep bruxers (odds ratios > 3.9, p < 0.01). Sleep bruxers were distributed among three heterogeneous groups. Sleep bruxers with low frequencies of orofacial activities were more at risk of reporting pain.

Sleep Bruxism-Tooth Grinding Prevalence, Characteristics and Familial Aggregation: A Large Cross-Sectional Survey and Polysomnographic Validation

“…8,20 Subjects were young and healthy adults recruited by advertising in our dental clinic as well as our campus at the Université de Montréal and were selected based on a history of jaw discomfort, dental tooth wear or sleep partner complaint of SB, and tooth-grinding history (> 3 nights/week). Subjects were invited to spend 2 nights of polysomnography in order to confirm and validate the presence of sleep bruxism, the first night for habituation and the second night for diagnosis.…”

“…8,21 The following research criteria were used to validate the presence of SB: > 4 RMMA episode/h of sleep, > 25 EMG bursts/h of sleep and > 1 episode with grinding noise. The diagnosis of SB was confirmed in 111 subjects.…”

“…Diagnosed SB subjects were classified into 3 groups based on criteria established by Rompré et al 8 using SB-RMMA frequency. High (n = 27), moderate (n = 34), and low (n = 50) groups were defined using cluster analysis.…”

“…7 However, other studies have found that low levels of SB are more correlated with TMD than higher levels of SB. 8,9 It was also previously reported that as much as 70% of TMD patients with myofascial pain also showed evidences of rhythmic masticatory muscle activity (RMMA) upon clinical examination and ambulatory sleep recordings. 10 SB may co-occur with other sleep disturbances including sleep apnea, insomnia, and restless legs syndrome.…”

Effects of Botulinum Toxin on Jaw Motor Events during Sleep in Sleep Bruxism Patients: A Polysomnographic Evaluation

“…Morning jaw stiffness is commonly reported by the subjects with frequent RMMA episodes. 34,35 Morning symptoms are thought to be a form of post-exercise muscle soreness caused by intense jaw muscle contractions during sleep. 36 Thus the results might suggest that the subjects perceived less muscle fatigue in the morning in relation to the decreased motor activities during sleep.…”