Pain, tenderness and strength of human mandibular elevators

Area of Science:

• Biomedical Engineering
• Neuromuscular Physiology
• Dental Science

Background:

• Functional disorders of the chewing apparatus are prevalent and impact masticatory muscle function.
• Understanding the relationship between muscle strength and these disorders is crucial for effective treatment.
• Previous research has not fully elucidated the role of baseline muscle strength in the pathophysiology of these conditions.

Purpose of the Study:

• To compare the maximal electrical activity of the temporal and masseter muscles between patients with functional chewing apparatus disorders and healthy controls.
• To investigate whether differences in muscle strength contribute to the development or severity of these disorders.

Main Methods:

• Electromyography (EMG) was used to measure the mean voltage during maximal bite in the intercuspal position.
• The study included 39 patients with functional disorders of the chewing apparatus and 45 healthy controls.
• Statistical analysis considered factors such as sex, age, occlusal contacts, and pain.

Main Results:

• Maximal electrical activity of the masticatory muscles was significantly lower in patients compared to controls.
• This difference in electrical activity was primarily attributable to a lower maximal voluntary contraction strength in the patient group.
• Factors like age, sex, and pain presence did not fully explain the observed strength differences.

Conclusions:

• Weaker elevator muscles (temporal and masseter) in patients may be a predisposing factor for functional chewing apparatus disorders.
• Reduced muscle strength could make these muscles more susceptible to hyperactivity, potentially triggered by psychological factors or occlusal interferences.
• Stronger masticatory muscles in controls likely confer greater resilience against such hyperactivity and related disorders.