Mechanical properties of polymer-infiltrated ZrO2 ceramic network improved by incorporation of SiO2 component

Abstract

Polymer-infiltrated ZrO₂ ceramic networks, due to their similar elastic moduli and hardness with natural enamel, have become a promising material for dental restoration. However, since the couple between ZrO₂ and resin is difficult, the poor interface bonding of ZrO₂/resin degrades the mechanical characteristics of polymer-infiltrated ZrO₂ ceramic networks. This study introduced SiO₂ into ZrO₂ as a scaffold to improve the coupling via the reaction of SiO₂ and silane coupling agents. The impacts of the SiO₂ concentration on the microstructures, the fracture characteristics, and mechanical properties of the porous ceramics and composites were investigated. The microstructures showed that ceramics and resins were bonded more tightly in PICNs with ZrO₂/SiO₂ scaffold than PICNs with pure ZrO₂ scaffold. The flexural strengths of the composites were significantly improved by the addition of SiO₂, which was attributed to the increased coupling degree. The composites with 20 mol.% SiO₂ as the porous ceramic exhibited the optimal mechanical properties, with flexural strength, elastic modulus, hardness, and fracture toughness values of 249.8 ± 24.3 MPa, 28.8 ± 4.0 GPa, 2.0 ± 0.2 GPa, and 2.6 ± 0.5 MPa·m^1/2, respectively. This study provides valuable information for the preparation of polymer-infiltrated ZrO₂ ceramic networks with excellent performance for dental restorations.