Abstract
In this study, in order to investigate the association between frontal dentoskeletal form and the lateralized mastication index and masticatory EMG activity, the frontal form of 18 subjects who belonged to the normal face group was classified into left and right deviation groups, and the mechanisms of jaw function were analyzed by the lateralized mastication index and the asymmetry index of masticatory muscle EMG activity, and by investigating the associations by classifying the magnitude of bite force into 4 grades, the following conclusions were obtained.
1. Correlation between the asymmetry index of masticatory muscle EMG activity and frontal dentoskeletal form
Significant positive correlations were found in both groups in the posterior temporalis muscle with 100% MC for Me-ML, in the left deviation group with 75% MC for Me-ML, and in the right deviation group for the ∠Um-Um′. In the masseter muscle, there were significant positive correlations in both groups with from 50 to 100% MC for the ∠Um-Um′, 75 and 100% MC, respectively, for the ∠CG-Me, and 100% MC for Go-MLGo′ and Me-ML, and in the left deviation group, with 50% MC for Me-ML. Significant negative correlations were observed in the anterior temporalis muscle in both groups with 100% MC for the ∠Um-Um′ and Me-ML, and in the right deviation group with 75% MC for the ∠Um-Um′.
2. Correlations between the asymmetry index of masticatory muscle EMG activity and the lateralized mastication index
Significant positive correlations were found with 25% MC for the posterior temporalis muscle in the right deviation group and with 25 and 50% MC, respectively, for the masseter muscle in the two groups.
Significant negative correlations were found with 25% MC for the anterior temporalis muscle in both groups.
