Aim: This study was performed to examine the anti-microbial effect of different 
percentages of titanium dioxide and chitosan nanoparticles to heat cured poly methyl 
meth acrylate .Subjects and methods: 120 specimens of heat cure acrylic resin were 
grouped according to nano additives concentrations for testing anti-microbial effect. 
Results: the addition of chitosan nano particles to PMMA in 0.3% and 0.5% decreased 
the microbial biofilm formation in comparison to the control (PMMA without 
chitosan). the addition of Tio2 nano particles in concentrations 1% and 2% decreased 
the microbial biofilm formation more than the chitosan nano particles concentrations 
0.3 and 0.5. Conclusion: The addition of chitosan nano particles to PMMA in 0.3% 
and 0.5% decreased the microbial biofilm formation in comparison to the control 
(PMMA without chitosan). the addition of Tio2 nano particles in concentrations 1% and 
2% decreased the microbial biofilm formation more than the chitosan nano particles.
The higher concentrations of the chitosan and Tio2 nano particles resulted in stronger 
antimicrobial effec