THE CONTRIBUTION TO THE STUDY OF M-TEMPORALIS AS 2 DIFFERENT FUNCTIONAL UNITS

Emg activity of anterior (TA) and posterior (TP) part of temporal musc le in retruded occlusal position (ROP) and maximal intercuspal positio n (MIP) was examined by surface electromyography on a 4 channel polygr aph with digital integrators incorporated in it. The recordings were m ade in a group of 35 individuals with natural teeth and in a group of 30 complete denture wearers. ROP activity was compared to MIP activity for each group. Activity of TP significantly increased (p<0.01) in RO P in the both groups. TA activity decreased in ROP although not signif icantly (p>0.05) in the group with natural dentition, while in complet e denture wearers TA activity significantly increased (p<0.01). When t he activity in retruded occlusal positions (ROP) was expressed in the percentage of activity in maximal intercuspal position (MIP), the grou ps were compared using F test, which revealed higher TA activity in RO P in complete denture wearers. It was concluded that TA and TP functio nally undertake different roles - TA being dominant in elevation of th e lower jaw and TP in retrusion. It is also supposed that TA activity depends on the occlusal scheme, i.e. on the number of molar teeth in c ontact and on the changes in vertical relation between jaws.