effect of zirconium oxide -titanium dioxide nanoparticles on mechanical and physical properties of soft denture lining materials

This study sought to identify the effect of adding zirconium oxide and titanium dioxide nanoparticles on some mechanical and physical properties (hardness, roughness, and spectrophotometer uv-light absorption) of soft denture lining materials. for 3 experiments of this study, 315 specimens were prepared from soft liner by conventional methods (n of each experiment=105) and then divided into three groups as stated by the tests (roughness, hardness, and spectrophotometer color absorption); 15 specimens as a control group (pure soft liner), 45 specimens for nanoparticles as a two test group (reinforced with 2 wt %, 3 wt %, and 5wt % of zirconium oxide and titanium dioxide nanoparticles respectively. the mean hardness and surface roughness values of the soft-lining denture in the experimental groups of 2 %, 3%, and 5% of tinps and zrnps were significantly lower than the control group (p< 0.001). the hardness and surface roughness decreased significantly after adding nanoparticles, and the most decrease was seen in the 5% of both tinps and zrnps groups. the uv- light absorption values of the experimental groups were significantly higher than those of the control group (p< 0.001), and the maximum increase was seen was in the 5% of both tinps and zrnps groups.incorporating the tio2 and zro2 nanoparticles into soft liner improve the mechanical and physical properties; decrease surface roughness, hardness, and increased opacity of the liner material. this improvement was directly proportional to the concentrations of the nanoparticle.