Quantitative Analysis of Surface Activation of Mastication-related Muscles in Individuals with Normal Occlusion Using Time-domain Parameters

doi:10.13701/j.cnki.kqyxyj.2026.08.012

Abstract

Abstract: Objective: To establish the time-domain reference range of the oral masticatory system for individuals with normal occlusion aged 18-30 years by synchronously monitoring four pairs of masticatory-related muscles. Methods: A total of 69 subjects aged 18-30 years with normal occlusion were included. Four pairs of masticatory-related muscles (including the anterior bundles of bilateral temporalis muscles) were monitored synchronously to establish the reference ranges of surface electromyography (sEMG) parameters and specific values under five mandibular movements. Results: The temporalis and masseter muscles were the main masticatory muscles, with the strongest activity in the maximal clenching position. The anterior belly of the digastric muscle showed obvious activity in the mandibular postural position to maintain mandibular stability. The sternocleidomastoid muscle was asymmetrically activated during unilateral mastication to maintain craniocervical stability, confirming its synergistic effect with masticatory function. Unilateral mastication presented a significant "chewing side dominance", and gender differences were observed in some EMG parameters (P<0.05). Conclusion: This study establishes the EMG reference ranges for multiple muscle groups and multiple movements in individuals with normal occlusion aged 18-30 years, clarifies the functional division of masticatory muscles, and provides a basis for the quantitative evaluation of oral masticatory system function.

Key words: surface electromyography, individual normal occlusion, masticatory-related muscles, occlusal stability, time-domain analysis

CHEN Shiman, HE Jiayue, LIU Yuxin, ZHANG Rui, LI Luoxin, GOU Xiaorui, WANG Mengyuan, SHEN Yufeng, ZHOU Zheng. Quantitative Analysis of Surface Activation of Mastication-related Muscles in Individuals with Normal Occlusion Using Time-domain Parameters[J]. Journal of Oral Science Research, 2026, 42(8): 708-713.

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