Comparison of dentine-resin interface in total-etch and self-etching adhesives using electron microscopy

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Achieving a durable adhesive bond between dentine and composite fillings requires altering dentine's hydrophilic nature to hydrophobic.
• Dentinal adhesives have evolved significantly, with recent advancements including self-etching formulations.
• Understanding the structural integrity of the dentin/resin interface is crucial for clinical success.

Purpose of the Study:

• To compare the structural characteristics of the dentin/resin interface following the application of dentinal adhesives using both total-etch and self-etch techniques.
• To evaluate the morphology of the hybrid layer formed by different adhesive systems.

Main Methods:

• Four dentinal adhesives were tested: Single bond and Prime bond (total-etch), Prompt-L-pop Adper and Xeno III (self-etch).
• The dentin/resin interface was examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM).
• TEM analysis involved 16 teeth (4 per adhesive), while SEM analysis involved 40 teeth (10 per adhesive).

Main Results:

• All tested dentinal adhesives successfully penetrated dentinal tubules.
• A hybrid layer was consistently formed with demineralized intertubular and peritubular dentine for all adhesives.
• No significant morphological differences were observed in the dentin/resin interface between the total-etch and self-etch techniques.

Conclusions:

• The study suggests that both total-etch and self-etch dentinal adhesives effectively create a hybrid layer.
• The functional quality of the hybrid layer appears to be similar across the four adhesives evaluated, regardless of the technique used.