Relationship between myoelectric activity in masticatory muscles and bite force

Area of Science:

• Biomedical Engineering
• Neuroscience
• Biomechanics

Background:

• Understanding the relationship between bite force and jaw muscle activity is crucial for diagnosing and treating various oral and temporomandibular disorders.
• Electromyography (EMG) is a key technique for quantifying muscle activation during masticatory tasks.

Purpose of the Study:

• To investigate the relationship between varying bite forces and the myoelectric activity of the temporalis (anterior and posterior) and masseter muscles.
• To assess the linearity of this relationship and the endurance capacity of these muscles during sustained biting.

Main Methods:

• Five subjects exerted unilateral bite forces (50, 100, 200 N) on a bite fork placed between their premolars and molars.
• Ipsilateral and contralateral muscle activities of the temporalis and masseter were recorded using EMG.
• A subset of subjects underwent an endurance test at maximum bite force.

Main Results:

• EMG activity increased with increasing bite force across all tested muscles.
• The anterior temporalis muscle exhibited a linear relationship between force and EMG activity.
• The masseter muscle's EMG activity closely correlated with bite force during the endurance test, while contralateral muscle activity increased towards the end of the test.

Conclusions:

• Jaw muscle activation, particularly in the masseter, is force-dependent, with varying linearity across different muscles.
• The masseter muscle plays a significant role in force production and endurance during biting tasks.
• Further research can elucidate the implications for masticatory function and potential pathologies.