Three-dimensional finite-element analysis of two ceramic inlay restorations with different cavity designs

The aim of this in silico investigation was to examine the influence of two ceramic inlay materials with different cavity designs on stresses in the inlay. Finite-element analysis and three-dimensional modelling were used to examine the stress in ceramic inlays resulting from a 250-N point load on occlusal surfaces. The adhesion properties and von Mises stress values in the enamel, dentin, ceramic materials and cement linings were simulated. Two ceramic inlay materials: porcelain ceramic (Empress II, Ivoclar Vivadent, Liechtenstein) and zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy), as well as two cavity corner designs: rectangular and rounded, were evaluated. The obtained von Mises stress results indicated that the maximum and minimum forces were concentrated in the enamel and dentin, respectively. The stress values in the dentin and inlay material were similar in the porcelain ceramic and zirconia ceramic groups. However, in the enamel, the stress values in the zirconia ceramic group were significantly lower than those in the porcelain ceramic group. Additionally, cavities with rounded corners were subject to significantly less stress compared to those with rectangular corners. Thus, the zirconia ceramic inlay demonstrated better performance under applied stress, based on the reduced stress values in the tooth structure. Cavities with rounded corners showed less stress than those with rectangular corners, which could be attributed to the enhanced stress distribution capabilities of rounded corners.