Purpose: This study aimed to examine the flexural strength, surface roughness, and surface hardness of heat polymerized denture base material incorporated with copper oxide (CuO) nanoparticles.

Materials and Methods: Forty heat polymerized acrylic resin specimens with the dimensions of (65x10 x 2.5mm) were prepared according to the manufacturer's instructions. The specimens were divided into four groups (n=10 each). Unmodified denture base material is the control group, the other groups were incorporated with 1%, 3%, and 5% CuO nanoparticles to the heat polymerized acrylic resin powder. The Universal Testing Machine was used to measure the flexural strength. A non-contact optical profilometer was used for surface roughness testing, and a Vickers digital testing machine to measure the surface hardness. One-way ANOVA test followed by Tukey's post-hoc test was used to compare different groups.

Results: A statistical difference was found between the nanoparticle-added groups and the control group regarding flexural strength. The highest mean value was observed for the 1% nano-CuO group. The surface hardness was significantly increased as compared to the control group. The surface roughness was not significantly altered except for the 5 % concentration.

Conclusion: Within the limitations of this study, it was concluded that the incorporation of CuO nanoparticles to heat polymerized denture base resin improved flexural strength. The highest strength was with the 1% concentration of the nanoparticles. The CuO nanoparticles addition also improved the surface hardness and did not affect the surface roughness in concentrations below 5%.