Mechanical properties of polymer-infiltrated-ceramic (sodium aluminum silicate) composites for dental restoration

Objective To fabricate indirect restorative composites for CAD/CAM applications and evaluate the mechanical properties. Methods Polymer-infiltrated-ceramic composites were prepared through infiltrating polymer into partially sintered sodium aluminum silicate ceramic blocks and curing. The corresponding samples were fabricated according to standard ISO-4049 using for mechanical properties measurement. The flexural strength and fracture toughness were measured using a mechanical property testing machine. The Vickers hardness and elastic modulus were calculated from the results of nano-indentation. The microstructures were investigated using secondary electron detector. The density of the porous ceramic blocks was obtained through TG-DTA. The conversion degrees were calculated from the results of mid-infrared spectroscopy. Results The obtained polymer infiltrated composites have a maximum flexural strength value of 214   ±   6.5   MPa, Vickers hardness of 1.76–2.30   GPa, elastic modulus of 22.63–27.31   GPa, fracture toughness of 1.76–2.35   MPa   m 1/2 and brittleness index of 0.75–1.32   μm −1/2 . These results were compared with those of commercial CAD/CAM blocks. Our results suggest that these materials with good mechanical properties are comparable to two commercial CAD/CAM blocks. Conclusion The sintering temperature could dramatically influence the mechanical properties. Clinical significance Restorative composites with superior mechanical properties were produced. These materials mimic the properties of natural dentin and could be a promising candidate for CAD/CAM applications.