Properties of tonic episodes of masseter muscle activity during waking hours and sleep in subjects with and without history of orofacial pain

Abstract

Within the limitations of this study, it would be concluded that sustained TEs may have a correlation with orofacial pain and the intensity range of 7.5-25% MVC would be an important range for future clenching studies.

To what extent is bruxism associated with musculoskeletal signs and symptoms? A systematic review

“…Craniofacial pain (ie, presence of RDC/TMD painful TMD or tension‐type headache) was assessed in the study of Yachida et al, and there, no association was found between EMG events per hour and pain, while a positive association was found between the coefficient of variation from multiple night EMG recordings and pain. In the study of Mude et al, significantly longer mean EMG clenching durations and a higher EMG clenching‐associated temporalis muscle duty factor (ie, the sum of EMG clenching episode durations divided by the total recording time) were found in the pain group, compared to the non‐pain group. The authors found no differences for the number of EMG clenching episodes per night, EMG episodes per hour and mean clenching bite force between groups.…”

“…Chen et al used wrist vibrators for a 10‐day period to alert the participants of their study to report on non‐functional tooth contact while awake. On the other hand, Mude et al performed whole‐day EMG recordings of the masseter muscle in a group of participants reporting a history of pain or headache in the area of the masticatory system and a group without such history. Tonic episodes of muscle activity were measured for both sleep and awake states, and categorised based on duration, that is, sustained or short, and intensity, that is, percentages of maximum voluntary contraction (MVC).…”

“…Oro‐facial pain: The combination of RDC/TMD diagnosed myofascial pain and TMJ arthralgia was investigated by Glaros et al, and an association was found with “tension in jaw, face, and neck,” “proportion of time of tooth contact,” “intensity of tooth contact” and “effort”. Mude et al found that participants reporting pain showed a significantly higher incidence of sustained tonic EMG episodes (ie, episodes lasting > 13.65 seconds), than those without. In the same study, a significantly higher incidence and total duration of sustained, low‐intensity tonic EMG episodes were found in the pain history group.…”

“…In five studies, sleep bruxism was diagnosed with the aid of single‐channel EMG recordings. The study of Mude et al is described above. In the study of Baba et al, the masseter EMG activity of participants without, or with minor TMD symptoms, was measured for five nights .…”

“…Alongside with EMG frequency measures during sleep, such as number of episodes and bursts, it may be of value to investigate variables like background EMG activity, intensity, and amplitude of activity, variability of activity over time or the timing of activity during sleep, and their relation to musculoskeletal symptoms. A similar approach can be suggested for awake bruxism studies …”