3D-Printed lithium disilicate-resin composites with bioinspired toughening radial-concentric architecture for dental restorations.

OBJECTIVES

Intrinsic brittleness is the main problem that leads to the failure of lithium disilicate (Li₂Si₂O₅) all-ceramic crown restoration. To overcome this, this study aims to: (1) Develop bioinspired radial-concentric Li₂Si₂O₅-resin composites that emulate the hierarchical architectures of horsetail grass and glass sponges to achieve biomechanical compatibility and improved damage tolerance. (2) Investigate the influence of key structural parameters-including shape factors (shafts and rings), ceramic volume fraction, and structural gradients-on mechanical performance.

METHODS

Bioinspired uniform Li₂Si₂O₅ scaffolds with tailored structural parameters-including radial shafts (4,5,6,7,8), concentric rings (2,3,4), widths (1.7 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.3 mm) and vertical gradient (1.7 mm-2.3 mm)-were fabricated by digital light processing 3D printing, and then infiltrated into dental resin for mechanical testing (compression and bending), finite element simulation and cytotoxicity testing.

RESULTS

Results show that the bioinspired architecture substantially enhances damage tolerance, increasing compressive work of fracture by 20.1% (35.7 MJ/m³) and bending-specific energy absorption by 31.5% (421.2 J/kg) relative to pure ceramics. Crucially, the bioinspired composite the composites achieve a tooth-like elastic modulus (8.38 GPa, -20.1%) and low density (2.04 g/cm³, -16.7%) for promoting favorable stress transfer and reducing stress shielding, while retaining sufficient compressive (∼762 MPa, -15.8%) and flexural strength (∼424 MPa, -20.5%) for dental applications.

SIGNIFICANCE: This work establishes a design paradigm for creating biomechanically compatible and damage-tolerant ceramic-resin composites, providing a material design strategy that may inform future development of durable dental restorative materials.