The purpose of this study was to investigate the influence of occlusal contact conditions during intercuspation on masticatory functions in patients with osseointegrated implants. Osseointegrated implant bridges were placed in 23 patients presenting with unilateral defects in the molar region. They were classified into 2 groups:an even occlusal contact (EOC) group, and a lower occlusal contact (LOC) group, on the osseointegrated implant bridge, according to the height of occlusal contact on the implant bridge, which was measured by the Addpicture system.<br/> We studied their mandibular kinesiographs (MKG) and electromyograms (EMG) of the masseter and anterior temporal muscles during unilateral gum chewing. We compared their dentate side with the osseointegrated implant bridge side, and the EOC-group implant side with the LOC-group implant side.<br/> The results were as follows:<br/>1. No statistically significant difference was seen between the implant and the dentate side on MKG of both groups.<br/>2. On EMG parameters of the EOC-group implant side during implant side chewing, the value of the coefficient of variation on the implant side was stable and very similar to EMG on the dentate side.<br/>3. On EMG parameters of the LOC-group implant side during implant side chewing, the value of coefficient of variation on the implant side was higher than that on the dentate side.<br/>4. On EMG parameters of the anterior temporal muscles during ipsilateral and contralateral side, the value of the coefficient of variation on the LOC-group implant side was higher than that on the EOC-group implant side.<br/> The results suggested that we should equalize occlusal contact heights in both molar regions, which could lead to the stability of masticatory movements for osseointegrated implant bridge placed in patients presenting with unilateral molar region, or it might affect on masticatory functions.<br/>