9 Influence of auditory stimulation on mandibular rest position : Analysis of jaw-closing muscle activity and electroencephalograms

Abstract

We attempted to clarify how the mandibular rest position is affected by psychological stress and by relaxation brought about by auditory stimulation. The jaw movements of 10 subjects were recorded with a mandibular kinesiograph (MKG) together with electromyograms (EMG) of the bilateral anterior temporalis and masseter muscles, and electroencephalograms (EEG) at Cz. White noise and relaxation sounds at 90 dB were used as auditory stimulation. We found that compared to the periods of silence or periods of listening to relaxing sounds, when the subjects were exposed to the white noise there was a significant decrease in the interocclusal distance at rest, while there were increases in both the jaw-closing muscle activity and the β wave constituents. We concluded that unpleasant stress, such as white noise, affected the mandibular rest position.