Implant-supported removable prostheses (ISrP) improve the quality of life, especially in patients who underwent mandibular reconstruction, but few studies have focused on the effect of ISrP in the fibular mandible on the function of the temporomandibular joint. The purpose of this pilot case series was to determine the usefulness of four-dimensional computed tomography (4DCT) images for the evaluation of differences in condylar movements with and without ISrP. Three patients who underwent ISrP following segmental mandibulectomy and free-flap reconstruction were evaluated. The participants were instructed to masticate a cookie during the 4DCT scan. The distance between the most anterior and posterior positions of the condyles on the sagittal view of the 4DCT images during the chewing of the cookies was measured and compared with and without ISrP. 4DCT revealed changes in the distances of condylar protrusion with and without wearing ISrP, but there were no obvious differences among the three patients. The 4DCT motion analysis was useful for the evaluation of the effect of wearing ISrP on condylar movements during mastication in patients with mandibular reconstruction and may become a useful objective evaluation method for the functional evaluation of ISrP.