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Kato T, Higashiyama M, Katagiri A, Toyoda H, Yamada M, Minota N, Katsura-Fuchihata S, Zhu Y. Understanding the pathophysiology of sleep bruxism based on human and animal studies: A narrative review. J Oral Biosci 2023; 65:156-162. [PMID: 37086888 DOI: 10.1016/j.job.2023.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND Sleep bruxism (SB) is a common sleep disorder that affects approximately 20% of children and 10% of adults. It may cause orodental problems, such as tooth wear, jaw pain, and temporal headaches. However, the pathophysiological mechanisms underlying SB remain largely unknown, and a definitive treatment has not yet been established. HIGHLIGHT Human studies involving polysomnography have shown that rhythmic masticatory muscle activity (RMMA) is more frequent in otherwise healthy individuals with SB than in normal individuals. RMMA occurs during light non-rapid eye movement (non-REM) sleep in association with transient arousals and cyclic sleep processes. To further elucidate the neurophysiological mechanisms of SB, jaw motor activities have been investigated in naturally sleeping animals. These animals exhibit various contractions of masticatory muscles, including episodes of rhythmic and repetitive masticatory muscle bursts that occurred during non-REM sleep in association with cortical and cardiac activation, similar to those found in humans. Electrical microstimulation of corticobulbar tracts may also induce rhythmic masticatory muscle contractions during non-REM sleep, suggesting that the masticatory motor system is activated during non-REM sleep via excitatory inputs to the masticatory central pattern generator. CONCLUSION This review article summarizes the pathophysiology of SB and putative origin of RMMA in both human and animal studies. Physiological factors contributing to RMMA in SB have been identified in human studies and may also be present in animal models. Further research is required to integrate the findings between human and animal studies to better understand the mechanisms underlying SB.
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Affiliation(s)
- Takafumi Kato
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Makoto Higashiyama
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Ayano Katagiri
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Hiroki Toyoda
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Masaharu Yamada
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan; Osaka University Graduate School of Dentistry, Department of Dental Anesthesiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Noriko Minota
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan; Osaka University Graduate School of Dentistry, Department of Oral and Maxillofacial Surgery, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Sho Katsura-Fuchihata
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Yiwen Zhu
- Osaka University Graduate School of Dentistry, Department of Oral Physiology, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Imai H, Haraki S, Tsujisaka A, Okura M, Adachi H, Ohno Y, Yatani H, Kato T. A lack of specific motor patterns between rhythmic/non-rhythmic masticatory muscle activity and bodily movements in sleep bruxism. J Prosthodont Res 2021; 65:415-420. [PMID: 33281172 DOI: 10.2186/jpr.jpr_d_20_00012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Purpose The aims of the present study were to investigate the temporal relationships between jaw and bodily movements and clarify motor processes in the genesis of rhythmic masticatory muscle activity (RMMA) in sleep bruxism (SB).Methods Video-polysomnography recordings were obtained from ten subjects with SB (mean age: 23.4 ± 1.6 years) and ten matched normal controls (CTL) (mean age: 24.4 ± 3.2 years). RMMA and nonspecific masseter activity (NSMA) were scored in association with bodily movements in the leg, arm, head, and trunk using electromyography and video recordings. The relationship between oromotor episodes and bodily movements was assessed in terms of sleep stage distributions and temporal relationships. Cardiac changes preceding oromotor episodes in stage N2 were assessed.Results Approximately 80% of RMMA and NSMA were associated with movements in one or more body sites. RMMA and NSMA were more frequently associated with movements of the leg (70-75%) and arm (40-55%) than movements of the head (17-22%) and trunk (5-25%). The relationship between oromotor episodes and bodily movements did not significantly differ among sleep stages. Oromotor episodes and bodily movements did not show a consistent temporal pattern in the SB and CTL groups. Regardless of the temporal relationship between oromotor episodes and bodily movements, the mean heart rate significantly increased by 5 beats before the onset of oromotor episodes.Conclusions No specific temporal motor patterns were found between RMMA and bodily movements. RMMA and NSMA represent a repertoire of arousal-related autonomic motor responses during sleep.
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Affiliation(s)
- Hideto Imai
- Faculty of Nursing, Setsunan University, Osaka, Japan
| | - Shingo Haraki
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Akiko Tsujisaka
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Mutsumi Okura
- Center for Sleep Medicine, Department of Neurology Asahi University Hospital, Gifu, Japan.,Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Hiroyoshi Adachi
- Health and Counseling Center, Osaka University, Osaka, Japan.,Sleep Medicine Center, Osaka University Hospital, Osaka, Japan
| | - Yuko Ohno
- Department of Health Sciences, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hirofumi Yatani
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan.,Sleep Medicine Center, Osaka University Hospital, Osaka, Japan
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Zhong Z, Xu M, Zou X, Ouyang Q, Zhang L, Yu B, Wang K, Yao D. Changes in heart rate related to rhythmic masticatory muscle activities and limb movements in patients with sleep bruxism. J Oral Rehabil 2019; 47:170-179. [PMID: 31697853 DOI: 10.1111/joor.12900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 10/05/2019] [Accepted: 10/29/2019] [Indexed: 12/19/2022]
Abstract
Most sleep bruxism (SB) episodes are accompanied by an increase in sympathetic tone and heart rate (HR). To characterise heart rate (HR) changes in relation to rhythmic masticatory muscle activities (RMMAs) in SB patients, polysomnographic recordings were performed on 10 SB patients and 11 normal controls. The duration of movement events, amplitude and duration of HR increases, and time to reach HR peak associated with RMMAs and limb movements (LMs) were determined, and the relationships of the parameters of HR increases with types of movements and RMMAs were analysed. All of the parameters of HR increases associated with three types of movements (RMMAs, RMMAs + LMs and LMs) and masseter activities (phasic, tonic and mixed) were significantly different (two-way ANOVA, P < .001 for all) in both SB patients and controls. The duration of RMMAs/LMs was positively correlated with the parameters (SB patients: R2 = .24-.85, P < .0001; controls: R2 = .23-.68, P < .0001). The amplitude of HR increases was also positively correlated with respiration changes in the SB patients (R2 = .3258, P < .0001) and controls (R2 = .09469, P < .05). The proportions of phasic RMMAs associated with awakenings, microarousals and no cortical arousals were significantly different and so were the proportions of tonic and mixed RMMAs (Friedman's tests, P < .05-.001). The HR increases associated with RMMAs may be intrinsic to the cortical arousal response and autonomic activation, and differences in HR increases associated with different types of movements and RMMAs might be related to the changes in respiration and differences in cortical arousal levels.
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Affiliation(s)
- Zhijun Zhong
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang, China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, China
| | - Miao Xu
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang, China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, China
| | - Xueliang Zou
- Jiangxi Mental Hospital, Nanchang University, Jiangxi, China
| | - Qian Ouyang
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang, China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, China
| | - Ling Zhang
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang, China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, China
| | - Bin Yu
- Jiangxi Mental Hospital, Nanchang University, Jiangxi, China
| | - Kelun Wang
- Department of Health Science & Technology, Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark
| | - Dongyuan Yao
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang, China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, China
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