Surface Electromyography (sEMG) – Functional Clench

The K7 electromyographic scan 11 clench test is able to record the patients ability (quality) to clench and recruit the masticatory muscles (temporalis anterior and masseter muscle groups are recorded). Higher sustained amplitude readings are a good indicator that the muscles are able to function.

Left window – The first to burst of EMG recordings show poor (low amplitude) muscles clenching recruitment when the patient clenches in their habitual occlusion. The third and fourth clench is with wet cotton rolls placed over the natural teeth. These measurements indicate masticatory dysfunction and also quantifies a patients level of functional impairment before treatment.

Right window – The same patient is able to show improvement muscle recruiting ability with the GNM orthotic and with cotton rolls used as a control. This shows improved functional quality and no functional impairment.

A reduction in SEMG amplitude during a functional clench test is a clear indication of a physiologic impairment.
There is a linear relationship between the strength of a muscle and the amplitude of the integrated EMG.

Reference Literature:

Liberson, WT. Dondey, M., Asa. M.M.: Brief repeated isometric maximal exercises. Am J Phys. Med., 41:3, 1962.
Soderberg GL, Cook TM. Electromyography in Biomechanics. Phys Ther. 1984; 64 1813-1820.

EMG Studies of Bite Force in Patients with Functional Disorders

There is evidence based on controlled studies that used extensive statistical test that maximal bite force and the electrical muscle activity during maximal bite in the intercuspal position are significantly weaker in patients with functional disorders of the masticatory system than controls without such disorders.

References:

Molin, 1972; Helkimo et al., 1975; Randow et al., 1976; Sheikholeslam et al., 1980; Moller et al., 1982; Sheikholeslam et al., 1982; Kydd et al., 1986.

Occlusion is the ACT of closing. One’s occlusion (bite) can be supportive toward functional health or it can be destructive toward physical functional impairment and dysfunction.

OPTIMAL FUNCTION and HEALTH vs. PHYSIOLOGIC IMPAIRMENT

“In a carefully controlled study of voluntary isometric biting forces at maximal and submaximal levels, Molin (1972) demonstrated that there were “progressively increasing force differences between the (control/healthy subjects and patients with mandibular pain dysfunction syndrome (MPD). The joint study conducted at University of Karolinska and University of Gothenberg in Sweden concluded that “the patients generally produced only one half to two thirds of forces produced by the control subjects.”

Reference:

Molin, C: Vertical isometric muscle forces of the mandible: A comparative study of subjects with and without mandifest mandibular pin dysfunction syndrome. Acta Odont. Scan., 30:485-499, 1972.

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