A Biomimetic Li₂Si₂O₅ Composite with High Energy Absorption for Endocrowns

Area of Science:

• Biomaterials Science
• Dental Materials
• Mechanical Engineering

Background:

• Endocrowns are minimally invasive restorations for endodontically treated teeth.
• Anterior endocrowns face fracture risks due to lateral forces.
• Replicating natural tooth mechanical properties is key for improved biomechanical performance.

Purpose of the Study:

• To develop a novel multilevel ceramic composite for endocrowns.
• To enhance the biomechanical performance and fracture resistance of dental restorations.
• To create a material with mechanical properties similar to human dentin.

Main Methods:

• Fabrication of a diamond-topology lithium disilicate (LD) ceramic scaffold via vat photopolymerization.
• Toughening the scaffold through potassium nitrate ion exchange (IE) and epoxy resin infiltration.
• Comprehensive characterization of mechanical properties (compressive strength, elastic modulus, toughness) using reference materials like Vita Enamic and human dentin.

Main Results:

• The ceramic composite achieved mechanical properties closely resembling human dentin.
• Optimized heat-treatment and IE processes yielded a maximum compressive strength of 217 ± 11.8 MPa.
• The material demonstrated a minimum elastic modulus of 3.7 ± 0.1 GPa and maximum energy absorption of 37.7 ± 1.9 MJ/m³.
• Enhanced toughness was attributed to microcrack aggregation, interface delamination, and macroscopic crack splitting.

Conclusions:

• The novel ceramic composite offers a promising solution to prevent stress-induced fractures in abutment teeth.
• This material's dentin-like properties can significantly improve the biomechanical stability of endocrown restorations.
• Further research into optimizing fabrication and clinical application is warranted.