The aim of this study was to evaluate the changes in the masticatory functions of complete dentures before and after the insertion of a LOCATOR attachment. The mixing ability index with a two-colored paraffin wax cube was used to quantify masticatory performance. In addition, degree of satisfaction with the treatment was assessed using a visual analog scale. The mixing ability index for the implant-retained overdentures and the complete dentures were calculated (−0.03 ± 1.38 and −2.10 ± 1.57, respectively), as were the visual analog scales of the implant-retained overdentures and the complete dentures (8.9 ± 1.5 and 4.3 ± 1.7, respectively). The paired t test revealed significant improvements (P .001).