A 3D analysis of mechanically stressed dentin-adhesive-composite interfaces using X-ray micro-CT

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Adhesive Dentistry

Background:

• Dentin bonding systems (DBS) are crucial for bonding restorative materials to tooth structure.
• Long-term stability of restorations depends on the seal at the tooth-restorative material interface.
• Limited 3D investigation techniques exist for non-destructive leakage assessment under mechanical stress.

Purpose of the Study:

• To analyze the properties of the dentin-DBS interface using advanced testing and imaging.
• To investigate the effect of mechanical cycling on leakage at the dentin-DBS interface non-destructively.
• To evaluate stress distribution within the dentin-DBS-composite interface.

Main Methods:

• Micro-tensile static and dynamic tests.
• Finite element modeling.
• X-ray computed micro-tomography with dual energy absorption and synchrotron beam light.
• Silver nitrate staining solution for leakage assessment.

Main Results:

• Multi-step DBS demonstrated significantly higher adhesive strength compared to other systems.
• 3D imaging revealed leakage primarily occurs radially along the dentin-adhesive interface.
• Dynamic tensile loading resulted in more diffuse staining penetration, indicating increased leakage.

Conclusions:

• Multi-step dentin bonding systems offer superior adhesion.
• Leakage predominantly occurs at the interface, highlighting the importance of interfacial integrity.
• Advanced non-destructive 3D imaging techniques are effective for analyzing interfacial behavior under mechanical load.