The purpose of this study was to investigate and compare the EMG activities of both temporal and masseter muscles on cranoimandibular disorder patients with or without balancing occlusal interference.
On examining 33 craniomandibular disorder patients, 14 of them had balancing occlusal interferences, on the other hand, 19 subjects had not. They were examined for Helkimo´s Anamnestic index and Dysfunction index, and were given guestionnaires to check bruxism, clenching and unilateral chewing. The bioelectric processor model EM2(Myo-tronics Research, Inc., Seattle,U.S.A.) with the surface electrodes was used to record the EMG activities of both anterior temporal and masseter muscles of craniomandibular disorder patients without balancing occlusal interference.
The results were as follows.
1. There were no significant differences in Helkimo´s indices and number of oral habits between the group who had balancing interferences and the other group who had not.
2. There were no significant differences in EMG activities except balancing anterior temporal muscle(P<0.05) between two groups.
3. In balancing occlusal interference group, EMG activities of balancing masseter muscles were significantly higher than that of working side (P<0.005).
4. In the subjects without balancing occlusal interferences, there were no statistical differences in EMG activities between working and balancing masseter and anterior temporal muscles.
|