Macroscopic and microscopic investigation of the viscoelastic behavior of dental resin-ceramic composite materials

This laboratory study aimed to evaluate the viscoelastic properties of dental resin-ceramic composite materials at both macroscopic and microscopic scales.

Two resin-ceramic composites, a polymer-infiltrated ceramic network (PICN) and a resin-based ceramic (RBC), were compared with a direct resin composite (DRC) and a feldspathic ceramic (FC). Macroscopically, a bulk compressive creep test was conducted to obtain strain-time curves. Creep behavior was modeled using the Burgers model. Dynamic mechanical analysis was performed to determine the dynamic moduli. Microscopically, high-resolution topographic profiles of the resin-based materials were acquired using atomic force microscopy (AFM). The creep deformation of the resin and ceramic components, respectively, was measured via AFM force-ramp tests. A finite element model was developed based on scanning electron microscopy images, and the Prony model was adopted to fit the creep curves obtained by AFM.

The PICN and RBC exhibited viscoelastic properties intermediate to the ceramic and the light-cured resin composite in the macroscopic tests. The Burgers model provided a good fit to the experimental data. AFM revealed that the creep behavior of the resin component was more pronounced in the PICN and DRC. The Prony series model demonstrated excellent agreement with the AFM experimental data. The macroscopic viscoelastic properties calculated by finite element method showed similar trends with the bulk compressive creep test.

The viscoelasticity of resin-ceramic composites lies between ceramics and light-cured resin composites, and microstructure of ceramic component dominates the creep resistance. By using atomic force microscopy with numerical simulations, the finite element method effectively links microstructural features to macroscopic viscoelasticity.