[Brain activities during maximum voluntary clenching with soft occlusal pad in healthy adults by functional magnetic...

Using functional magnetic resonance imaging (fMRI) to detect the cerebral cortical somatotopy during maximum voluntary clenching with soft occlusal pad in healthy adults. By comparing with the cerebral cortical activation during clenching with and without soft occlusal pad we try to detect the central mechanism of the rule of the occlusal pad.

Ten healthy subjects were selected and scanned by Elscint/GE 2.0 Tesla MR system. Block design was used and the movement pattern was maximum voluntary clenching with soft occlusal pad. The fMRI data were analyzed by SPM99 software and group map analysis was done.

The activation areas were found in bilateral or unilateral motor cortex, somatosensory cortex, prefrontal cortex, temporal cortex, premotor cortex, insula, frontal operculum, basal ganglia (putamen), parietal cortex and cingulate. Group map analysis showed activation in bilateral motor cortex, right somatosensory cortex, bilateral basal ganglia, and bilateral insula. The activation of left motor cortex was significantly higher than right side. Compared with cortical activation without occlusal pad, the motor and somatosensory cortex changed a lot.

The changes of the activation of motor and somatosensory cortex during clenching after wearing the soft occlusal pad might be the central mechanism of the rule of the occlusal pad.