Resin-dentin interface of Scotchbond Multi-Purpose dentin adhesive

Area of Science:

• Dental Materials Science
• Biomaterials Interface Analysis
• Adhesive Dentistry

Background:

• Understanding the dentin-adhesive interface is crucial for durable dental restorations.
• Scotchbond Multi-Purpose (SMP) is a widely used dental adhesive system.
• Visualizing the dynamic application and interaction of adhesive components is challenging.

Purpose of the Study:

• To evaluate the interface between dentin, Scotchbond Multi-Purpose (SMP), and resin composite (Z100) using confocal fluorescence microscopy.
• To investigate the penetration and interaction of SMP primer and adhesive components with dentin tubules.
• To assess the formation of the hybrid zone and the adhesive layer at the interfacial region.

Main Methods:

• Novel confocal fluorescence microscopy techniques were employed for real-time observation.
• Components of the SMP adhesive system were labeled with fluorescent dyes.
• The application of primer and adhesive onto dentin, and the subsurface morphology, were studied.

Main Results:

• Ideal application showed primer and adhesive penetration into dentin tubules, forming a hybrid zone.
• Disruption of the primer layer by the application brush was observed, incorporating primer into the adhesive.
• Air thinning prevented primer delamination, while air stream application enhanced tubule penetration but increased adhesive thickness in irregularities.

Conclusions:

• Confocal fluorescence microscopy provides unique insights into the dynamic behavior of dental adhesives at the interface.
• Handling properties of SMP may be influenced by viscosity differences between primer and adhesive.
• Optimizing application techniques, such as air thinning, can improve interface integrity but requires careful consideration of adhesive thickness.