Debonding from the denture base, poor resistance to tearing, and increase in hardness are some of the problems with denture liners. This research purposed to analyze the changes in mechanical characteristics of the tissue conditioner and the denture liner concerning the interaction of the material with the zirconium oxide nanoparticles (ZrO2-NPs). The surface functionalization of ZrO2-NPs was done using a silane coupling agent as a modifier for better integration of them into the denture liners. Then, they were added into acrylic- and silicone-based denture liner in two different percentages (0.5% and 1% by weight; respectively). The performed tests were tear strength, tensile bond strength, and hardness (Shore A). 0.5% and 1% of ZrO2-NPs added tissue conditioner test groups displayed statistically significantly lower tensile bond strength values than tissue conditioners without ZrO2-NPs (p < 0.001). However, the tensile bond strength results of all subgroups for soft denture liner were statistically similar (p = 0.239). In all of the test groups of tissue conditioner and soft lining material, the highest tear strength values were obtained in 0.5% ZrO2-NPs added test groups (tissue conditioner; 0.58 +/- 0.11 N and soft denture liner; 4.10 +/- 0.58 N). The shore A hardness results of both tested groups determined no meaningful differences (p = 0.100). All subgroups of the tested silicone-based denture liners had satisfactory and clinically adequate bonding strength to the base of the prosthetic.