Introduction:
Acrylic resin is a material commonly used in dentistry, but restorations made with it are largely inhabited by bacteria or fungi. These microorganisms are the main cause of oral inflammation. Acrylic resins have been modified for some time with the addition of nanosilver, which has a strong antibacterial effect. Research is being undertaken to determine the appropriate concentration of nanosilver that will not reduce the mechanical properties of acrylic resin.

Aim of the study:
The aim of this work was to assess the effect of nanosilver addition on selected properties of acrylic material.

Material and methods:
Vertex Rapid Simplified acrylic thermosetting material was used for the tests. In each of the tests, the samples were divided into 5 groups, a control and 4 research groups, modified with silver nanoparticles from Sigma - Aldrich in weight concentrations: 0.01%, 0.05%, 0.3% and 0.6%. Hardness, impact strength, bending strength and compressive strength were tested.

Results:
The results obtained from the notched impact strength measurements indicate a significant improvement in the impact strength of all 4 groups of samples after adding nanosilver to them, additionally, statistical analysis showed statistically significant differences. The highest impact strength of 0.63 J/cm2 was observed for samples with 0.3 wt. nanosilver.

Conclusions:
Nanosilver in the concentrations used does not have a negative effect on the mechanical properties of acrylic material and can be used in the manufacture of dental prostheses due to its bactericidal and fungicidal effect.