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Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation
Published on: June 14, 2014
Variation in masticatory muscle activity during subsequent, submaximal clenching efforts
F Lobbezoo1, J J R Huddleston Slater
1Department of Oral Function, Section Craniomandibular Disorders, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. f.lobbezoo@acta.nl
Journal of Oral Rehabilitation
|June 20, 2002
Summary
Variations in jaw positioning during clenching efforts partly explain differences in jaw muscle electromyography (EMG) activity. This effect is more pronounced at lower clenching levels, offering insights into muscle function variability.
Area of Science:
- Biomechanics
- Neuroscience
- Dental Physiology
Background:
- Previous studies noted significant variability in jaw closing muscle electromyography (EMG) during submaximal clenching.
- The reasons for this variability in muscle activation remain incompletely understood.
Purpose of the Study:
- To investigate the extent to which variations in mandibular positioning explain EMG variability in jaw closing muscles.
- To analyze the influence of clenching levels and stabilization appliances on this relationship.
Main Methods:
- Recorded electromyography (EMG) from jaw closing muscles in seven healthy individuals.
- Utilized a six degrees of freedom opto-electronic system to monitor mandibular position during three clenching conditions and three levels (10%, 30%, 50% MVC).
- Analyzed 90 EMG sweeps across repetitions and conditions.
Main Results:
- Variations in mandibular positioning accounted for up to 25% of the variance in jaw muscle contribution indices (P=0.000).
- The influence of positioning on EMG was weakly dependent on the clenching condition.
- The effect of positioning on EMG tended to decrease at higher clenching levels.
Conclusions:
- Coincidental variations in mandibular positioning partially explain EMG variability in jaw closing muscles during submaximal clenching.
- This relationship is particularly significant at lower clenching intensities.
- Understanding mandibular positioning is crucial for interpreting jaw muscle EMG data.
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