[Studies on bonding interfaces of two dentin adhesives by scanning electron microscopy]

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Adhesion Science

Background:

• Dental adhesives are crucial for restoring tooth structure.
• One-bottle dentin bond systems aim to simplify application while ensuring effective bonding.
• Understanding the microstructure of the hybrid layer is key to predicting bond durability.

Purpose of the Study:

• To investigate the microstructure and bonding mechanisms of two one-bottle dentin bond systems: Prime & Bond NT (PBNT) and Prime one Mirage (P-One).
• To compare the resin-dentin interfaces formed by these systems.
• To evaluate the effect of thermocycling on the bond interface microstructure.

Main Methods:

• Human molars were prepared and treated with either PBNT or P-One.
• Bonded teeth were subjected to microtensile bond strength testing and Scanning Electron Microscopy (SEM) observation.
• A subset of teeth underwent thermocycling (2400 cycles, 5-55°C) before analysis.

Main Results:

• Both PBNT and P-One formed a typical hybrid layer (3-5 microns) with resin tags penetrating dentinal tubules.
• A three-dimensional resin micro-network with lateral branches was observed.
• No significant differences in SEM images were found between the two systems or with/without thermocycling.

Conclusions:

• PBNT and P-One exhibit effective resin infiltration and create a complex resin tag network within dentin tubules.
• This microstructure, characterized by interlocking resin tags, enhances adhesion between dentin and the restorative material.
• The observed microstructure remained consistent after thermocycling, suggesting good interfacial stability.