Abstract
The purpose of this study was to clarify the characteristics of gnathofunction such as masticatory muscle activities and jaw position during playing wind instruments and to examine the load to temporomandibular joints (TMJ) and masticatory musucles during playing the instruments. The subjects were eighteen brass instrument players and twelve woodwind instrument players. Electromyograms (EMG) of masseter, temporal, orbicural oris and digastric muscles were recorded and distance between lower incisal points at intercuspation and during playing wind instruments was also measured. The obtained results were as follows:
1. During playing instruments, EMG activity in masseter and temporal muscles was extremely small in comparison with those during maximum clenching, while EMG activity in orbicural oris and digastric muscles was comparatively large.
2. There was no obvious change of EMG activity in each muscle when the sound volume in playing instruments was changed.
3. There was no obvious difference of EMG activity between brass instrument and woodwind instrument group in masseter, temporal and digastric muscles. However, brass instrument group showed larger variation of activity in masseter muscles among the subjects than that of woodwind instrument group.
4. Lower incisal point of woodwind instrument group moved to inferior direction in larger distance than that of brass instrument group. However, brass instrument group showed larger variation of direction in movement than woodwind instrument group.
The results suggested that the tension of masseter and temporal muscles and compressive load to TMJ are generally small during playing wind instruments. However, it is necessary to examine the influence of individual difference further.
