A self-etch bonding system with potential to eliminate selective etching and resist proteolytic degradation

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Self-etch (SE) dental restorations degrade over time, leading to limited lifespan and poor enamel adhesion.
• Hydrolytic, enzymatic, and fatigue degradation compromise the integrity of bonded restorations.

Purpose of the Study:

• To develop and evaluate a novel two-step SE system utilizing bis[2-(methacryloyloxy)ethyl]phosphate (BMEP).
• To enhance the stability and performance of bonded resin composite restorations on both enamel and dentine.

Main Methods:

• A two-step SE system with a BMEP-containing primer was formulated and compared to a commercial 10-MDP system (CFSE).
• Evaluations included enamel surface roughness, microshear bond strength (µSBS), microtensile bond strength (µTBS), nanoleakage, MMP inhibition, and cyclic flexural fatigue testing.

Main Results:

• BMEP primers increased enamel surface roughness; BMEP-free adhesives showed comparable or superior µTBS and reduced nanoleakage versus CFSE.
• BMEP-based systems demonstrated minimal matrix metalloproteinase (MMP) activity and comparable flexural strength and fatigue resistance to CFSE.

Conclusions:

• Incorporating BMEP into the primer achieved satisfactory bond strengths to enamel and dentine, potentially negating the need for selective enamel etching.
• A solvent-free, hydrophobic adhesive with BMEP confined to the primer minimized leakage and enhanced resistance to degradation and chewing forces.