Duration and sequence of muscular activation in dentate individuals and complete denture wearers during simulation of activities of daily living.

Occlusal support may influence muscular function during complex motor tasks. This study evaluated the duration and sequence of muscular activation of masticatory (temporal, masseter), postural head/neck (sternocleidomastoid, trapezius), postural trunk (rectus abdominis, paravertebrals), and low extremity strength (rectus femoris, gastrocnemius) muscles during simulation of activities of daily living (ADL) in edentulous women wearing complete dentures (n = 10) and in dentate women (n = 10). Electromyographic activity was recorded during tests of stand-up/sit down in the Chair, sit up/lie down in the Bed and lift/lower Bags. Occlusal support (dentures) had a significant effect on duration of muscular activation in the Chair Test: the masseter muscle activated longer with dentures during the standing movement. The masseter and sternocleidomastoid muscles showed significant alteration in their order of activation in non-denture-wearing women. For the Bed Test, dentures had significant effect for the gastrocnemius during the sitting-up phase and for the rectus abdominis during the lying-down movement. For the Bag Test, head/neck muscles were activated in a different order as a function of occlusal support. Anticipation of activation of the paravertebral muscles, rectus abdominis, and gastrocnemius was observed in dentate women compared with denture wearers. These findings suggest that occlusal support influences electromyographic activity of some muscles during simulation of ADL.