Sex differences in masticatory muscle activity in healthy young adults

Abstract

Introduction. Several studies analyzed the gender differences in masticatory muscle activity. Previous scientific reports in­dicate the predominance of the masseter muscle activity in male subjects and the predominance of the temporalis anterior in women. However, there is a lack of studies analyzing the differences in the activity of the mandibular abduction muscles between men and women. 

Aim. The presented study evaluated the sex differences in activity within temporalis anterior, masseter, and digastric muscle 

in healthy young adults. 

Material and methods. Thirty-six healthy young adults aged 20 to 29 years (mean 22±2.6 years) were qualified for the presented study. The subjects were divided into two equal groups (n=18) in terms of gender. The masticatory muscle activity was recorded within the temporalis anterior (TA), the superficial masseter muscle (MM), and the anterior bellies of the digastric muscle (DA). Electromyographic activity was recorded in three conditions: at rest, during maximum voluntary clenching at the intercuspal position, and during maximum voluntary clenching with cotton rolls between teeth. 

Results. Significant differences in electromyographic activity between the male and female group were observed within rest­ing activity for the TA-R (Women: 1.98 µV vs. Men: 1.26 µV; p=0.000), TA-L (Women: 2.13 µV vs. Men: 1.33 µV; p=0.000), DA-R (Women: 2.17 µV vs. Men: 1.29 µV; p=0.001), DA-L (Women: 2.13 µV vs. Men: 1.37 µV; p=0.005). Moreover, significant difference in resting activity index was observed within left side (Women: -9.89 % vs. Men: 10.39%; p=0.037), and within right side during clenching with cotton rolls between teeth (Women: 9.83% vs. Men: 25.59%; p=0.016). 

Conclusions. Women represent higher resting sEMG activity within the temporalis anterior and digastric muscles than men. Electromyographic patterns may be influenced by gender at rest and during clenching tasks.