PolyMethyl Methacrylate was a broadly known material in the medical and dental fields since its exceptional biocompatibility and easy manufacture, nevertheless, exhibits inferior mechanical properties. In the present study, several experiments were implemented to improve PMMA resin characteristics utilized for lower and upper prosthetic complete dentures by incorporating two various particles forms: nanoparticles of zirconia (n-ZrO2) and silver (n-Ag). These particles were applied as a fluid resin matrix to the polymethyl methacrylate (PMMA) cold-curing resin with various volume percentages of (0, 1.5, 3, and 4.5) weight percent. The composite prosthetic denture samples have been utilizing the (Hand Lay-Up) process in this project. This study was aimed to explore the impact of the selected volume fractions of (n-Ag & n-ZrO2) in nanoparticle size on tensile, impact, and biological characteristics of hybrid composite prosthetic complete dentures. The experimental aspect of this research involved conducting several biological and mechanical experiments, involving (impact, tensile, corrosion in saliva media and bacteria) tests. This research found that the values of most characteristics improved as the (n-Ag, n-ZrO2) particles' fractional volume in polymer composite materials increased, but antibacterial activity reduced