The Influence of Craniofacial Form on Bite Force and EMG Activity of Masticatory Muscle

The Influence of Changing Direction in Clenching on Magnitude, Direction of Bite Force and EMG Activity in Normal Face Group

Abstract

In this study, dentulous subjects in the normal face group were selected had been engaged in vertical and anterior clenching to measure the magnitude and direction of bite force as well as the EMG activity of masticatory muscles. The influence of changing direction between vertical and anterior clenching on the functions of stomatognathic system were analyzed.
The results were as follows:
1. The magnitude of bite force in anterior clenching was smaller than that of in vertical clenching at 25-100%MC.
2. According to the increase of bite force, the direction of bite force (θ) in vertical and anterior clenching was increasing.
The dircetion of bite force (θ) in anterior clenching was smaller than that in vertical clenching 25-100%MC.
3. The EMG activity per 1kgf of temporalis in anterior clenching was smaller than that in vertical clenching at 50-100%MC.
The EMG activity per 1kgf of lateral and medial pterygoid muscle in anterior clenching was larger than that in vertical clenching at 25-100%MC.