Healing large bone defects, especially in weight-bearing locations, remains a challenge using available synthetic ceramic scaffolds. Manufactured as a scaffold using 3D printing technology, Sr-HT-Gahnite at high porosity (66%) had demonstrated significantly improved compressive strength (53 ± 9 MPa) and toughness. Nevertheless, the main concern of ceramic scaffolds in general remains to be their inherent brittleness and low fracture strength in load bearing applications. Therefore, it is crucial to establish a robust numerical framework for predicting fracture strengths of such scaffolds. Since crack initiation and propagation plays a critical role on the fracture strength of ceramic structures, we employed extended finite element method (XFEM) to predict fracture behaviors of Sr-HT-Gahnite scaffolds. The correlation between experimental and numerical results proved the superiority of XFEM for quantifying fracture strength of scaffolds over conventional FEM. In addition to computer aided design (CAD) based modeling analyses, XFEM was conducted on micro-computed tomography (μCT) based models for fabricated scaffolds, which took into account the geometric variations induced by the fabrication process. Fracture strengths and crack paths predicted by the μCT-based XFEM analyses correlated well with relevant experimental results. The study provided an effective means for the prediction of fracture strength of porous ceramic structures, thereby facilitating design optimization of scaffolds.

The aim of this study was to investigate the fracture behaviour of fissural dental enamel under simulated occlusal load in relation to various interacting factors including fissure morphology, cuspal angle and the underlying material properties of enamel. Extended finite element method (XFEM) was adopted here to analyse the fracture load and crack length in tooth models with different cusp angles (ranging from 50° to 70° in 2.5° intervals), fissural morphologies (namely U shape, V shape, IK shape, I shape and Inverted-Y shape) and enamel material properties (constant versus graded). The analysis results showed that fissures with larger curved morphology, such as U shape and IK shape, exhibit higher resistance to fracture under simulated occlusal load irrespective of cusp angle and enamel properties. Increased cusp angle (i.e. lower cusp steepness), also significantly enhanced the fracture resistance of fissural enamel, particularly for the IK and Inverted-Y shape fissures. Overall, the outcomes of this study explain how the interplay of compositional and structural features of enamel in the fissural area contribute to the resistance of the human tooth against masticatory forces. These findings may provide significant indicators for clinicians and technicians in designing/fabricating extra-coronal dental restorations and correcting the cuspal inclinations and contacts during clinical occlusal adjustment.