Electromyographic study of activity of the masseter and anterior temporalismuscles in patients with temporomandibular joint (TMJ) dysfuction: Comparison with the clinical dysfunction index

ABSTRACT

Objectives: A comparison was made between the electromyographic patterns specific to patient with temporomandibulardisorders and that of normal healthy patients. Study design: Electromyographic tests were carriedout during rest and function of the masseter muscles and anterior temporalis muscles in a homogeneous groupconsisting of 95 patients for whom such pathology and its different degree of severity had been previously studiedby means of a Helkimo Test. The electromyographic exploration results were compared to those of a controlgroup consisting of 31 healthy subjects. Results: There were significant differences among patients with a differentdegree of clinical dysfunction, as well as between these and the control group. These differences were moreimportant during maximum effort clenching and mastication. During maximum effort clenching, differences inmasseteric activity were observed between control group and group III, between groups I and II and betweengroups I and III. Meanwhile, differences in temporalis activity were significant among all groups except betweengroups I and II. The multiple comparison analysis demonstrated the existence of significant statistical differencesbetween healthy subjects and patients with severe TMD. However, the linear combination of these electromyographic(EMG) variables led us to elaborate four linear functions that classify all subjects into four well definedgroups. Once extreme cases were eliminated, our EMG classification revealed an 80% match with that of theHelkimo Test. We thus conclude that in many cases, classification using electromyographic criteria matches thatestablished by the Helkimo Test (AU)

RESUMEN

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