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Motor pauses in EMG activity during chewing and biting
Odontologisk Revy
|January 1, 1975
Summary
Chewing hard particles triggers jaw muscle inhibition via mechanical jaw stops. Crushing food initiates a distinct unloading reflex before tooth contact, indicating different origins for motor control during mastication.
Area of Science:
- Neuroscience
- Biomechanics
- Oral physiology
Background:
- Mastication involves complex motor control to manage varying food textures and resistance.
- Understanding jaw muscle inhibition mechanisms is crucial for explaining protective reflexes during chewing.
Purpose of the Study:
- To differentiate the origins of motor inhibition during jaw movements involving hard particles and brittle substances.
- To investigate the roles of mechanical jaw stops and unloading reflexes in masticatory muscle control.
Main Methods:
- Electromyography (EMG) patterns were recorded during experimental biting and chewing tasks.
- Subjects engaged in activities like biting hard particles and crushing brittle materials.
- Jaw movement and muscle activity were analyzed to identify patterns of motor inhibition.
Main Results:
- Biting hard particles or tooth tapping primarily caused muscle inhibition due to tendon and muscle stretching from mechanical jaw stops.
- Crushing brittle food induced an unloading reflex occurring before tooth contact, distinct from the hard particle response.
- Periodontal receptors and surface sensibility played a minor role in these observed motor inhibition patterns.
Conclusions:
- Jaw muscle inhibition during mastication arises from at least two distinct mechanisms.
- Mechanical jaw stops are key for inhibition when encountering hard objects, while unloading reflexes protect against premature jaw closure on brittle foods.
- The study highlights the sophisticated neural control systems governing chewing under different mechanical loads.