Improved dental adhesive formulations based on reactive nanogel additives.

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Polymer Chemistry

Background:

• Current dental adhesives face challenges due to over-hydrophilic formulations, leading to water percolation and unreliable bonded interfaces.
• The hybrid layer's integrity is compromised by water, affecting the longevity of dental restorations.
• Controlling hydrophobicity is crucial for improving the performance of dental bonding agents.

Purpose of the Study:

• To introduce nanogel-modified adhesives for enhanced hydrophobic character in dental bonding formulations.
• To investigate the effect of nanogel additives on the physical, mechanical, and bonding properties of dental adhesives.
• To assess the potential of nanogels in improving the reliability of bonded interfaces in adhesive dentistry.

Main Methods:

• Synthesis of reactive nanogel additives with varied hydrophobicity (10-100 nm particles).
• Preparation of a model BisGMA/HEMA solvated adhesive modified with nanogels.
• Evaluation of adhesive viscosity, solvent removal, degree of conversion, mechanical properties (dry and wet), and micro-tensile bond strength to dentin.

Main Results:

• Nanogel modification did not impair solvent removal by air-thinning, despite increased viscosity.
• Degree of conversion remained similar between control and nanogel-modified adhesives.
• Significant improvements were observed in bulk dry and wet mechanical properties, with reduced water solubility, due to nanogel reinforcement.
• Short-term micro-tensile bond strengths to dentin were significantly enhanced by nanogel inclusion.

Conclusions:

• Nanogel-modified adhesives offer a viable strategy to control hydrophobicity without altering basic monomer formulations or techniques.
• Nanogel additives significantly enhance the mechanical properties and water resistance of dental adhesives.
• This approach shows promise for improving the reliability and durability of bonded interfaces in restorative dentistry.