Zirconia particles were introduced into a methyl methacrylate monomer (MMA) liquid and polymethyl methacrylate (PMMA) beads during polymerization to develop novel bone cement substrates. Osteoblasts (bone-forming cells) were seeded at a density of 3500 cells/cm2 and were cultured on unmodified bone cements comprising of only PMMA, bone cements modified with micron ZrO2 additives, bone cements modified with evenly dispersed ZrO2 nano-additives, and bone cements modified with evenly dispersed ZrO2 nano-additives functionalized with 3-(trimethoxysilyl)propyl methacrylate for four hours and twenty-four hours. Cells were subsequently stained and counted. It was found that after four hours, osteoblast adhesion was significantly greater on bone cements containing unfunctionalized nano-ZrO2 and bone cements containing functionalized nano-ZrO2 as compared to unmodified bone cements with no additives. After twenty-four hours, osteoblast proliferation was shown to be significantly greater on all bone cements containing ZrO2 additives as compared to unmodified bone cements with no additives. Additionally, osteoblast proliferation was found to be significantly greater on bone cements containing unfunctionalized nano-ZrO2 bone cements and functionalized nano-ZrO2 as compared to bone cements containing micron ZrO2. Such data provided strong evidence of the increased cytocompatibility properties of PMMA with evenly dispersed ZrO2 nano-particles and, thus, these materials should be further studied for orthopedic applications.