Background <p>This study aims to augment the advantages of three-dimensional (3D) printed provisional restoration with a higher weight% (wt%) of nanofillers through evaluating the effect of simultaneous silanization and grafting reaction on the surface of mesoporous silica nanoparticles (MSN) and testing the effect of modification of 3D-printable provisional resin (3D-PPR) with surface treated MSN on its physicomechanical properties.</p> Methods <p>The surface of MSN was first silanized with (3-Aminopropyl) triethoxysilane (APTES) and then silanized MSN was grafted with methyl methacrylate (MMA). The surface modifications of MSN were characterized by transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) pore size analyses, fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Modified 3D-PPR specimens with 0.25, 1 and 3 wt% of silanized MSN (S-MSN) and grafted silanized MSN (GS-MSN) were printed and evaluated by degree of conversion, surface morphology, surface roughness, surface hardness, flexural strength, flexural modulus and fracture resistance.</p> Results <p>The simultaneous surface treatment of MSN decreased their agglomeration and enhanced their distribution within 3D-PPR. The modified 3D-PPR with GS-MSN showed a gradual enhancement in physicomechanical properties by increasing filler wt%, in contrast to modification with S-MSN only which showed a gradual decrease in physicomechanical properties by increasing filler wt%.</p> Conclusion <p>This simultaneous surface treatment of MSN opens the door for increasing MSN wt% into 3D-PPR to have the superior potential and efficacy for long-term provisional dental restorations.</p> Graphical Abstract <p></p>