Objective\ To investigate the electromyographic(EMG) characteristics of masseter and anterior temporalis during various jaw movements in skeletal Angle Ⅲ malocclusion in mixed dentition.\ Methods\ 38 children with skeletal Angle class Ⅲ malocclusion in mixed dentition were selected for study and 40 children with normal occlusion as controls. EMG activities of masseter and temporalis in various movements were recorded by a four lead electromyography.\ Results\ When mandibular was in its rest position, no differences were noted in EMG between the two groups ( t=0.026-1.123, P >0.05). The EMG activities of masseter and tempolaris in Angle Ⅲ group were lower than those in the control ( t=1.59-11.25, P <0.05).\ Conclusion The activities of masseter and anterior tempolaris recorded in EMG in children with Angle Ⅲ malocclusion show significant differences as compared with normal ones.
