Abstract
Electromyograms (EMG) were examined during tapping movements to determine the effect of local pressure on mucosa underlying free-end saddle partial dentures in 6 denture wearers. EMG of the bilateral anterior temporal muscles (Ta) and masseter muscles (Mm) were recorded together with Mandibular Kinesiograph motions. Four plate types of two different diameters and thicknesses were fastened to the basal sheet of the denture to apply pressure. The degree of local pressure was at a subtle sensation level.
There were significant variations in EMG time parameters and integrated EMG among the experimental conditions. Cycle time had no change, and EMG burst duration was extended under the experimental condition, so that the burst interval was shortened. The change of duration was influenced of burst duration preceding tooth contact. The coefficient of variance for EMG time parameters was higher than that of the control under the experimental condition. EMG activity outlasting tooth contact of Mm and Ta decreased. The ratio of Ta activity of before tooth contact to that of the control significantly changed, contralateral activity was increased and ipsilateral activity was inhibited.
The present data suggested that a compatibility of the denture base and the mucosa was clinically important.
