Selective dentin etching: A potential method to improve bonding effectiveness of universal adhesives

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials Engineering

Background:

• Universal adhesives offer versatility in dental bonding procedures.
• Optimizing the interaction between adhesives and dentin is crucial for durable restorations.
• Phosphoric acid etching protocols significantly influence the resin-dentin interface.

Purpose of the Study:

• To investigate the impact of reduced phosphoric acid etching times on universal adhesive-dentin interaction.
• To evaluate the long-term bonding effectiveness of selective dentin etching protocols.
• To determine optimal phosphoric acid etching parameters for improved bond strength.

Main Methods:

• Selective etching of dentin with 32% phosphoric acid for varying times (3, 5, 10, 15s).
• Bonding with a universal adhesive (Scotchbond Universal) and evaluating micro-tensile bond strength and nanoleakage.
• Analysis of residual calcium content and SEM observation of hybrid layer morphology.

Main Results:

• Selective etching for 3s improved universal adhesive interaction depth and immediate bond strength.
• These improvements were maintained after long-term aging (thermocycling, artificial saliva).
• No significant differences in silver uptake or calcium content were observed compared to non-etched dentin.

Conclusions:

• Selective dentin etching with phosphoric acid for 3s enhances universal adhesive bonding effectiveness.
• This protocol improves long-term bond durability compared to standard self-etch or longer etch-and-rinse methods.
• Avoidance of prolonged etching times is critical to prevent adverse effects on the dentin substrate.