Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication. (December 2016)

• Record Type: Journal Article
• Authors: Pasinato, Fernanda; Santos-Couto-Paz, Clarissa C.; Zeredo, Jorge Luis Lopes; Macedo, Sergio Bruzadelli; Corrêa, Eliane C.R.
• Is Part Of: Journal of electromyography and kinesiology. Volume 31(2016:Dec.)
• Page Start: 88
• Page End: 95
• Publication Date: 2016-12
• Subjects: Surface electromyography -- Mastication -- Experimental jaw-muscle pain -- Masticatory muscles -- Neck muscles; Electromyography -- Periodicals; Kinesiology -- Periodicals; Electromyography -- Periodicals; Movement -- physiology -- Periodicals; Muscles -- physiology -- Periodicals; Électromyographie -- Périodiques; Cinésiologie -- Périodiques; Electromyography; Kinesiology; Electronic journals; Periodicals; 616.740757
• DOI: 10.1016/j.jelekin.2016.09.007
• Languages: English
• ISSNs: 1050-6411

Abstract

Abstract: The aim of this study was to verify the effects of induced masseter-muscle pain on the amplitude of muscle activation, symmetry and coactivation of jaw- and neck-muscles during mastication. Twenty-eight male volunteers, mean age ± SD 20.6 ± 2.0 years, participated in this study. Surface electromyography of the masseter and sternocleidomastoid (SCM) muscles was performed bilaterally during mastication of a gummy candy before and after injections of monosodium glutamate solution and isotonic saline solution. As a result, we observed a decrease in the amplitude of activation of the masseter muscle on the working side (p = 0.009; d = 0.34) and a reduction in the asymmetry between the working and the balancing side during mastication (p = 0.007; d = 0.38). No changes were observed either on the craniocervical electromyographic variables. In conclusion, experimentally induced pain reduced the masseter muscle activation on the working side, thereby reducing the physiological masseters' recruitment asymmetry between the two sides during mastication. No effects on SCM activity were detected. These results may partly explain the initial maladaptative changes underlying TMD conditions.