High-Performance Dental Composites Based on Hierarchical Reinforcements.

Area of Science:

• Materials Science
• Biomaterials Engineering
• Nanotechnology

Background:

• High-performance fibers like poly(p-phenylene-2,6-benzobisoxazole) (PBO) enhance dental composites but suffer from poor interfacial bonding.
• The inert surface of PBO fibers limits the mechanical properties of dental fiber-reinforced composites (FRCs).

Purpose of the Study:

• To develop novel hierarchical reinforcements for PBO fibers to improve the interface and flexural performance of dental FRCs.
• To investigate the interfacial bonding mechanisms and mechanical properties of modified PBO FRCs.

Main Methods:

• Constructed four types of hierarchical reinforcements: PBO-ZnO nanoparticles (NPs), PBO-ZnO nanowires (NWs), PBO-ZnO NPs-cage silsesquioxane (POSS), and PBO-ZnO NWs-POSS.
• Evaluated macroscale and microscale mechanical properties, interfacial shear strength (IFSS), and physicochemical characteristics.
• Assessed in vitro cytotoxicity using the CCK8 assay.

Main Results:

• PBO-ZnO NWs-POSS exhibited the highest IFSS (29.31 ± 2.40 MPa).
• The corresponding FRC achieved the highest flexural strength (925.0 ± 39.2 MPa) and a flexural modulus (39.39 ± 1.41 GPa) comparable to human dentin.
• Interfacial bonding involved mechanical interlocking, chemical bonds, hydrogen bonds, and van der Waals forces.

Conclusions:

• The PBO-ZnO NWs-POSS hierarchical reinforcement successfully enhanced IFSS and flexural properties in dental FRCs.
• This optimized PBO FRC demonstrates potential as a new option for endodontic posts.
• The study offers an interface design strategy for high-performance FRCs using advanced fibers in dentistry.