Morphological evaluation of 2- and 1-step self-etching system interfaces with dentin.

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Microscopy

Background:

• Self-etching adhesive systems simplify dental restorations by combining etching and priming.
• Understanding the resin-dentin interface is crucial for long-term restoration success.
• Variations exist among 1-step and 2-step self-etching systems regarding their interaction with dentin.

Purpose of the Study:

• To evaluate and compare the resin-dentin interface morphology of two 2-step and two 1-step self-etching adhesive systems.
• To assess the penetration of resin tags into dentinal tubules using Scanning Electron Microscopy (SEM).
• To compare the performance of self-etching systems against a conventional etch-and-rinse system.

Main Methods:

• Class V cavities were prepared in human third molars.
• Four self-etching systems (AdheSE, Contax, Futurabond NR, G-Bond) and one etch-and-rinse system (PQ Clear) were applied.
• Samples underwent thermocycling, sectioning, demineralization, deproteinization, and SEM analysis.

Main Results:

• AdheSE, Contax, and Futurabond NR showed resin tag penetration into dentinal tubules.
• G-Bond exhibited a tight, thin junction with minimal resin penetration.
• The etch-and-rinse system (PQ Clear) produced the highest number of resin tags.
• A defined hybrid layer was observed with Contax and PQ Clear.

Conclusions:

• Most investigated self-etching systems demonstrated similar interfacial morphology with dentin, except for G-Bond.
• The degree of dentin interaction correlated with the acidity of the self-etching primers/adhesives.
• Self-etching systems generally formed fewer resin tags compared to the etch-and-rinse system.