Compatibility of Dual-Cure Core Materials with Self-Etching Adhesives

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Established material incompatibility exists between self-etching adhesives and amine-containing dual-cure resin composites for core buildups.
• Amine accelerators in dual-cure composites can interfere with polymerization and reduce bond strength when used with acidic self-etching adhesives.
• Understanding these interactions is crucial for predictable clinical outcomes in restorative dentistry.

Purpose of the Study:

• To compare the dentin bond strength of various amine-containing and amine-free dual-cure core materials when used with self-etching adhesives of different pH values.
• To evaluate the influence of adhesive pH and core material chemistry on bond durability.
• To identify strategies for mitigating material incompatibility in core buildup procedures.

Main Methods:

• Extracted human molars were prepared, and specimens were assigned to groups based on dual-cure core material (amine-containing, amine-free) and self-etching adhesive pH (1.0, 3.0, 4.0).
• Shear bond strength was measured using a universal testing machine after 24-hour water storage.
• A comparative analysis included light-cured core materials and a reference light-cure only composite.

Main Results:

• Statistically significant differences in shear bond strength were found between adhesives, core materials, and their interaction (p < 0.01).
• A trend of decreasing bond strength with decreasing adhesive pH (pH 4.0 > 3.0 > 1.0) was observed for self-cured materials.
• Amine-free core materials exhibited higher bond strengths than amine-containing materials, particularly in self-cure mode. Light-curing enhanced bond strength for some materials.

Conclusions:

• A material incompatibility between self-etching adhesives and dual-cure resin composite core materials is confirmed.
• Lower adhesive pH negatively impacts the bond strength of dual-cure core materials during self-curing.
• Using amine-free core materials or employing light-curing for dual-cure composites can minimize or overcome this incompatibility.