Effect of the unilateral loss of posterior occlusal support on masticatory function

Abstract

We examined electromyograms (EMG) of the masticatory muscles during unilateral gum chewing and tapping on the mandibular incisors using a Mandibular Kinesiograph on three subjects whose posterior occlusion was altered on one side. All three had full crowns on <567>^^^- on one side. Tests were carried out as each crown was removed in sequence starting from the distal. Loss of support at 7^^^- or <67>^^^- did not significantly change the EMG. However loss of <567>^^^- significantly shifted the tapping points to the deficient side and scattered them. In addition, this significantly increased the coefficient of variation in many of the EMG parameters. These results suggest that loss of unilateral posterior support adversely affects masticatory function.