title: Bite force and electromyograpy during maximum unilateral and bilateral clenching.
abstract: Maximum voluntary bite force has often been studied as an indicator of the functional state of the masticatory system. Bilateral, as well as unilateral, methods have been used to determine bite force. Only a few studies have compared the outcomes of both methods. The aim of this study was to measure bite force and jaw-muscle activity during bilateral as well as unilateral maximum clenching in a large number of healthy subjects, so that the results could be compared. In a group of 81 dentate subjects we observed an average bilateral bite force of 569 N. The average unilateral bite force was significantly lower, being 430 N (right) and 429 N (left). Masseter and anterior temporal muscle activities were also significantly lower during unilateral clenching as compared with bilateral clenching. The masseter muscles showed no difference in activity between the ipsilateral side and the contralateral side during unilateral clenching. In contrast, the activity of the anterior temporal muscle on the ipsilateral side was significantly higher than on the contralateral side. Thus, the change in the forces acting on the jaw during unilateral clenching compared with bilateral clenching leads to a different response in the temporal muscles than in the masseter muscles.
authors.affiliation: Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Center Utrecht, AB Utrecht, The Netherlands. a.vanderbilt@umcutrecht.nl
authors.forename: Andries
authors.initials: A
authors.lastname: van der Bilt
authors.forename: Anneke
authors.initials: A
authors.lastname: Tekamp
authors.forename: Hilbert
authors.initials: H
authors.lastname: van der Glas
authors.forename: Jan
authors.initials: J
authors.lastname: Abbink
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001732:Bite Force; D003799:Dental Stress Analysis; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D008875:Middle Aged; D009119:Muscle Contraction; D012737:Sex Factors; D018709:Statistics, Nonparametric; D013703:Temporal Muscle / Q000502:physiology*