Electromyographic comparisons between clenching, swallowing and chewing in jaw muscles with varying occlusal parameters.

UNLABELLED: The aim of this study is to determine the influence of Angle molar class, presence of a posterior crossbite, anterior guidance, as well as gender in the muscular activity of the masticatory system in a population of healthy dental students.

STUDY DESIGN: Surface electromyography recordings are made for the masseter, anterior and posterior temporalis and digastric muscles; in three different tests: clenching at maximum intercuspation, swallowing and chewing.

RESULTS: The results obtained show that: men achieve a higher masseter activity at maximum effort than women. Women achieve higher values than men, for the digastric muscles in deglution. Angle class II show higher activity than other classes for the temporalis muscle in deglution, while class III show higher activity than other classes for all muscles in maximum effort. The anterior guidance does not cause significant differences. The presence of a posterior crossbite affects the behaviour of anterior temporalis and masseter muscles.

CONCLUSION: The results of this study show the influence of the occlusal parameters on the muscular activity of the stomatognatic system.