Abstract
Materials and methods:
Three groups of heat cured acrylic resin specimens were prepared; the first was Group C made of conventional heat cured acrylic resin, the second group was Group Ag where the acrylic resin specimens were incorporated with 5% Silver nanoparticles, and the third group Ti had its specimens incorporated with 5% Titanium oxide nanoparticles.
The specimens were tested for microbial colonization using direct culture and serial dilution methods. The specimens were then further tested for surface roughness.
Results:
There were higher bacterial counts in specimens of group C (control) 51.12±4.7198 than those with Ag nanoparticles 32.44±2.7701 and TiO2 nanoparticles 31.92±2.2159. The difference was statistically significant between the control group (C) and the Ag nanoparticles group and between the control group and the TiO2 nanoparticles group. However, there was a statistically non-significant difference between the Ag nanoparticles group and TiO2 nanoparticles group. Statistical analysis by ANOVA for repeated measures showed statistically non-significant difference between the three groups regarding the surface roughness.

Conclusions:
• Ag and TiO2 nanoparticles had a similar antimicrobial effect when added to PMMA.
• The addition of 5% of Ag and TiO2 nanoparticles has not affected the surface roughness of PMMA.