Long-term bonding to eroded dentin requires superficial bur preparation

Area of Science:

• Dental materials science
• Adhesive dentistry
• Biomaterials engineering

Background:

• Dental erosion compromises dentin structure, potentially affecting the longevity of adhesive restorations.
• Effective bonding to eroded dentin is crucial for successful clinical outcomes and preventing secondary caries.

Purpose of the Study:

• To investigate how various surface preparation techniques influence the long-term bond strength of dental adhesives to eroded dentin.
• To compare the performance of a three-step etch-and-rinse adhesive with a mild two-step self-etch adhesive on prepared eroded dentin surfaces.

Main Methods:

• Dentin specimens were subjected to pH cycling to simulate erosion or left untreated.
• Five preparation techniques (pumice, air abrasion, silicon polisher, proxo-shape, diamond bur) were applied.
• Micro-tensile bond strength was assessed after 24 hours and 1 year using OptiBond FL and Clearfil SE Bond adhesives.
• Interface integrity was analyzed using stereomicroscopy, SEM, and TEM.

Main Results:

• Dentin erosion generally reduced bond strength, but preparation with a diamond bur minimized this effect.
• Long-term water storage significantly decreased bond strength, particularly for eroded surfaces.
• The mild self-etch adhesive (Clearfil SE Bond) showed better 1-year bond strength to eroded dentin compared to the etch-and-rinse adhesive (OptiBond FL).
• TEM analysis revealed degradation and silver infiltration at the interface of eroded dentin, indicating susceptibility to failure.

Conclusions:

• Superficial preparation with a diamond bur is recommended for achieving durable long-term bonding to eroded dentin.
• Minimally invasive preparation techniques are favored for preserving tooth structure while ensuring adhesive bond integrity.
• Understanding interface behavior is critical for developing more resilient adhesive systems for compromised dentin substrates.