<p>Graphene nano-sheets are one of the most recent and exciting subjects used to reinforce dental filling and various industrial applications. Poly-(methyl methacrylate) (PMMA) and synthesized graphene oxide (GO) were used to restore two types of dental fillings to fabricate dental filler nanocomposites using modified acoustic and sonication procedures. Morphology, structure, thermal, and ultrasound mechanical behavior, as well as cytotoxicity activity, were investigated. X-Ray diffraction (XRD) and Fourier-transform infrared (FTIR) showed a significant change in diffraction behavior and a strong interaction at the interface after adding PMMA and GO nano-sheets for dental fillings. Scanning electron microscopy (SEM) images demonstrated a considerable improvement in homogeneity after the contribution of PMMA within the excellent dispersion of GO in the dental matrix. GO's contribution revealed a critical enhancement in thermal stability of up to 65% using thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) also showed increase in glass transition temperature (T_g) after the restoration of dental fillings with PMMA and GO nano-sheets. After PMMA and GO nanomaterials contributed, ultrasonic mechanical velocity, compressibility, and elasticity modulus revealed enhanced values up to 50%, 75%, and 160%, respectively. The cytotoxic effect of calcium oxide (X-SUBSTANCES) against rat embryonic fibroblasts (REF) cells was up to 94.92% of the cell viability for restoration nanocomposite fillings. The findings notably improved the thermo-mechanical stability of promisingly developed longer-life dental fillings.</p> Graphical Abstract <p></p>