Fracture Resistance of Teeth Restored With Different Fiber-Reinforced Composites: A Comparative In Vitro Study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Restoring large posterior teeth with mesio-occluso-distal (MOD) cavities presents a fracture risk.
• Conventional nanohybrid composites may lack sufficient cusp reinforcement under occlusal load.
• Fiber-reinforced composites (FRCs) offer potential for improved mechanical properties and stress distribution.

Purpose of the Study:

• To compare the fracture resistance of mandibular molars with MOD cavities restored with different FRC systems and conventional composite resins.
• To evaluate the effectiveness of FRCs in reinforcing weakened tooth structure against fracture.

Main Methods:

• Standardized MOD cavities were prepared in 40 human mandibular molars.
• Restorations were performed using nanohybrid composite (control), or nanohybrid composite with FibraFill Dentin, Ribbond polyethylene fiber, or EverStick glass fiber.
• Fracture resistance was tested using a Universal Testing Machine until failure.

Main Results:

• All FRC groups exhibited higher mean fracture resistance than the control group (nanohybrid composite only).
• EverStick (2759.5 N) showed significantly greater fracture resistance than the control (1655.3 N).
• FibraFill Dentin (2371.1 N) and Ribbond (2057 N) also improved fracture resistance, though not always significantly compared to the control or each other.

Conclusions:

• FRCs significantly improve the fracture resistance of teeth with large MOD cavities compared to conventional composites.
• EverStick glass fiber provided the highest fracture resistance among the tested materials.
• FRCs represent a promising approach for reinforcing extensively damaged posterior teeth.