Preparation and fracture mechanism study of graded mechanics bionic resin-ceramic composites in prosthetic dentistry

This study aimed to develop mechanically biomimetic sodium aluminosilicate-based polymer-infiltrated ceramic networks (sa-PICNs) for abutment protection. Three sa-PICNs with varying ceramic framework porosities were fabricated by varying pressures (250‒300 MPa) and sintering temperatures (800 ºC‒850 ºC). Mechanical properties were assessed using Vickers hardness and three-point bending tests. The corresponding stress distribution and transmission path were analyzed using digital image correlation (DIC). Based on the obtained data, coarse-graining modeling were performed to further predict the mechanical behavior of nine sa-PICN models with porosities ranging from 10% to 51%. sa-PICNs with 25% (L group), 38% (M group), and 51% (H group) framework porosity were prepared. The L and M group exhibited Young’s modulus of 24.06 GPa and 17.98 GPa, respectively, similar to that of natural dentin. Vickers hardness of the L group (406.59 HV) was comparable to natural enamel (409.02 HV). The bending deformation was increased by at least 1.4 times after resin infiltration. Coarse-grained simulations revealed widespread cracking occurred with 10%‒15% porosity and enhanced crack resistance at 15%‒40% porosity. However, at 40%‒51% porosity, crack energy mainly dissipated through single large cracks. Predicted Young’s moduli modulus and fracture loads for 20% and 30% sa-PICNs were 29.16 GPa and 196.31 MPa, and 26.38 GPa and 174.63 MPa, respectively. sa-PICN with 20%‒30% ceramic framework porosity demonstrated biomimetic mechanical performance and improved crack resistance, suggesting their suitability for prosthodontic applications. Biomimetic materials can disperse occlusal stresses and provide enhanced protection for abutments in dentistry.