Abstract
The present study was so designed as to evaluate the influences of the experimental occlusal interferences on masticatory muscles of children by means of electromyograms (EMG) on tonic neck reflexes.
Eight children, who were in Hellman's dental stage IIA, were examined. A metal overlay approximately 350, μm thick was capped on one side of the 2nd deciduous molar of mandible. The EMG of temporal and masseter muscles were then recorded sequentially, before and 7 days after placement and 7 days after removal of the overlay.
The results obtained in the present study were as follows:
1) All subjects except one complained of some unpleasantness for after placement of the metal overlay and none of them complained of pain.
2) Increased muscle activities ipsilaterally on the interference side, with the metal overlay, were found in 5 subjects out of 8.
3) In regard to the synchronism found in the EMG, onset of muscle activity on the interference side preceded that of the other side, and this tenden cy was likely to be prominent in the masseter muscle.
4) Influences of occlusal interferences on masticatory muscles evaluated both with amplitude and synchronism of muscle activity were found in 7 sub jects out of 8, and susceptibility against interferences may differ individually.
