Effect of Treated Zirconium Oxide (ZrO2)Nanoparticles on the Color and Surface Properties of Interim Fixed Prostheses

Objective: Zirconium oxide (ZrO2) nanoparticles addition to interim fixed prostheses (IFPs) was suggested to improve the mechanical properties. However, the effect of ZrO2 on the color and surface properties of IFP was neglected. Therefore, this study aimed to investigate the effect of ZrO2 on the color, hardness, and surface roughness of IFP. Materials and Methods: Customized split-press metal molds were used for the fabrication of forty disk-shaped acrylics (10mm x 1.5 mm). The salinized ZrO2 particles were weighed using an electronic balance and added in concentrations of lwt %, 2.5wt %, and 5wt % of auto-polymerized acrylic polymer powder. Based on ZrO2 concentrations, specimens were divided into one control group without ZrO2 and three ZrO2 study groups 1 ZrO2, 2.5 ZrO2, and 5 ZrO2, respectively. A double beam ultraviolet-visible reflection spectrophotometer was the instrument used for recording the color measurements (CIEDE2000). The Microhardness and surface roughness (Ra, mu m) of all samples were tested. ANOVA test was used for data analysis (alpha = 0.05) Results: Notable changes were seen between the group containing 1% and the other two groups in Delta a*, Delta E-ab, and Delta E-00 parameters. Statistically significant differences were observed among the three groups for the Delta L* parameter. No notable changes were seen between the group containing 1% and the group containing 5% for the Delta b* parameter. The 1% group showed a statistically significant difference in hardness in comparison to the 5% group. For surface roughness, the 2.5% group presented statistically significant higher surface roughness as opposed to the 0% control group. Conclusions. The addition of ZrO2 in high concentrations resulted in a noticeable color change in IFP. However, the surface properties did not change hardness and roughness with ZrO2 addition except roughness increased with 2.5% ZrO2. Low ZrO2 addition did not result in a change in color and surface properties of IFP.