Resin-based composites used in dentistry often possess undesirable characteristics. This study investigated the effect of two different nano-additive materials, namely aluminum oxide (Al2O3) and titanium dioxide (TiO2), on the mechanical, wear, and water sorption/solubility behavior of a commercial restorative composite used in dental treatments (Nexcomp Flow A2). The results showed that dental materials containing the introduced nano-fillers have a higher wear resistance than their neat counterparts. Correspondingly, the average diametral tensile strength values were improved from a value of 14.6 MPa to values of 26.6 MPa and 50.8 MPa when reinforced with TiO2 and Al2O3, respectively. It has been found that there is a significant relationship between the improvements in wear resistance and tensile strength due to the addition of nano-additives. Further, the water sorption/solubility of the pure composite was lower by 60% after introducing 1% wt. Al2O3 and by more than 80% when 1%wt. TiO2 was the reinforcement additive. Scanning electron microscope images of the tested samples on worn and unworn surfaces showed that the nano-additives helped carry the load subjected to the surface. After introducing nano-additives into the matrix, surface degradation, which may occur due to water uptake, was suppressed.