Dental fractures of the anterior teeth are a common form of dental trauma. Reattachment of fractured tooth fragment by means of self‐adhesive resin cement is currently compromised by the poor mechanical properties of these ceramics. Herein, we synthesized zirconium dioxide nanoparticles (nano‐ZrO2) using the Co‐precipitation approach and then mixing it in different concentrations (1.0, 2.0, 3.0, and 5.0 wt%) with the commercially available RelyX™ Unicem self‐adhesive universal resin cement (ARC) forming, nano‐ZrO2/ARC. Both the synthesized nano‐ZrO2 and nano‐ZrO2/ARC were characterized using a high‐resolution transmission electron microscope (HR‐TEM), field‐emission scanning electron microscope, X‐ray diffraction, and Fourier transform infrared technique. The HR‐TEM images revealed that the synthesized nano‐ZrO2 was spherical with a size of ~ 12 nm. The results showed that the addition of nano‐ZrO2 significantly enhanced the mechanical properties as fracture resistance, compressive strength, diametral tensile, and micro‐hardness values of the resin cement. The mixing 3.0 wt% of nano‐ZrO2 with ARC revealed the maximum improvement in the mechanical properties and, consequently, the resin's repair strength. Their incorporation with ARC up to 3.0% wt did not cause significant cell death than ARC alone. We believe that the information discussed here might be relevant to the stability of nano‐ZrO2‐modified resin cement and, therefore, to its clinical usage for fragment tooth reattachment, cementation of dental crowns, bridges, and bands.