The Effect of Tooth Clenching and Grinding on Anterior Temporalis Electromyographic Activity in Healthy Subjects

Abstract

The aim of this study was to determine the effect of tooth clenching and grinding on anterior temporalis electromyographic (EMG) activity. The sample included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance and 15 with bilateral group function. An inclusion criterion was that subjects have to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left and right anterior temporalis muscles. EMG activity was recorded during the following conditions: A. eccentric grinding from intercuspal position to the right lateral edge-to-edge contact position; B. clenching in right edge-to-edge lateral contact position; and C. concentric grinding from right lateral edge-to-edge contact position to intercuspal position. On the working side, EMG activity was not significantly different between conditions in both occlusal schemes. On the nonworking side, EMG activity was significantly higher during condition C than condition B in both occlusal schemes (mixed model with unstructured covariance matrix). When comparing by side, EMG activity was significantly higher during conditions A and B on the working side than on the nonworking side. However, there was no significant difference during condition C. EMG activity was significantly lower with canine guidance than group function on the working side (in all conditions) as well as during concentric grinding on the nonworking side. These results could explain muscular symptoms in the anterior temporalis muscles if the subject is experiencing parafunctional habits either while awake and/or sleep that exceed the individual's adaptation capability.

Nature of Occlusion during Eccentric Mandibular Movements in Young Adults

“…By passing these two, unfavorable occlusion can also lead to altered muscle activity and temperomandibular dysfunction. 1,6,17 Today there is no debate on these facts. However, as regard to various theories of occlusion, there are many concepts, controversies, propounded by various research workers from time to time.…”

Does breathing type influence electromyographic activity of obligatory and accessory respiratory muscles?

“…In several studies, EMG activity at rest , during chewing and during tooth‐clenching have been recorded in the elevator muscles, but little is known about the EMG activity of the respiratory muscles during these activities.…”

“…In several studies, EMG activity at rest (8), during chewing (9) and during tooth-clenching (10,11) have been recorded in the elevator muscles, but little is known about the EMG activity of the respiratory muscles during these activities. Some skeletal muscles are termed 'respiratory' muscles as they alter the dimensions of the thorax and bring about inspiration or expiration.…”

Signal to noise ratio of masticatory muscle activity of functional and non‐functional oral tasks

“…Similar observations have been reported earlier where parafunctional activities like teeth clenching and grinding did not seem to affect the EMG activity of the anterior temporalis muscle. 44 These observations are explained by some early observations that show that while the masseter is a muscle with several separate portions of superficial and deep muscles, the temporalis is a fan-shaped muscle with fibres pulling in different directions. Both these muscles have regional differences in fibre directions and therefore regional differences in muscle activation leading to different mechanical actions.…”

“…Several studies have measured the EMG activity of functional tasks such as chewing and non-functional tasks such as biting, clenching, and grinding of the teeth at the anterior temporalis and masseter muscle in both healthy volunteers and people with orofacial pain. 30,41,44 However, there are not many studies that have measured the muscle activity of a wide range of light to vigorous rhythmic and sustained oral tasks, especially taking SNR into consideration. Thus, our findings can either be partially compared or cannot be directly compared to the literature.…”