Pressed lithium disilicate glass ceramics: Microstructural characterization, in vitro and in silico nonlinear dynamic...

To evaluate the mechanical properties of lithium disilicates, and to assess the predictive capability of in silico models for biaxial flexural strength (BFS).

Specimens of four heat-pressed lithium disilicates (IPS e.max Press, Rosetta SP, LiSi Press, Vintage Prime Press) were obtained. Microstructural and crystalline evaluations, hardness, and fracture toughness were assessed. In vitro BFS was performed, and in silico nonlinear dynamic finite element analysis (FEA) for BFS was conducted. Weibull statistics were used to determine characteristic strength [σ₀] and Weibull modulus [m].

Different crystal sizes/shapes were observed depending on the material, while characteristic peaks corresponding to lithium disilicate and lithium phosphate crystals were revealed in all groups. Vintage Prime presented the highest fracture toughness, followed by Rosetta, LiSi Press, and e.max Press. Rosetta demonstrated lower σ₀ than Vintage Prime and LiSi Press, whereas e.max Press demonstrated similar values to all materials. Vintage Prime demonstrated the highest m among the materials. Similar load-displacement curves from in vitro and in silico BFS were obtained for all materials.

Vintage Prime exhibited higher fracture toughness and m compared to the other materials. The BFS and FEA results were consistent, reinforcing the FEA value as a complementary analytical tool for interpreting material behavior under controlled conditions.