Electrodiagnosis at median occlusal position for human subjects with mandibular joint syndrome.

~~Neuromuscular inhibitory effects were monitored in the temporalis and masseter muscles for ten patients with mandibular joint (MJ) syndrome. and ten control subjects with normal occlusions. Analysis of the electromyographic (EMG) silent period in the controls showed no significant difference between durations at median occlusal position, following placement of a maxillary acrylic occlusal splint, and during gum chewing. However. for the patients with MJ syndrome. there was an immediate decrease in their mean EMG silent-period duration upon placement of the splint from 19.23 msec to 15.52 msec. This shortened duration was the same with or without a splint after the pain symptoms had subsided. Precise occlusal adjustment of the dentition at the pain-free appointment resulted in a further reduction (10.83 msec) to within the range of the normal control subjects at median occlusal position. Inhibitory pauses during gum chewing showed similar treatment interactions but, during some chewing cycles. no silent periods were evident.