Improved dental adhesive formulations based on reactive nanogel additives

Current challenges in adhesive dentistry include over-hydrophilic bonding formulations,which facilitate water percolation through the hybrid layer and result in unreliable bonded interfaces. this study introduces nanogel-modified adhesives as a way to control the material's hydrophobic character without changing the basic monomer formulation (keeping water-chasing capacity and operatory techniques unaltered). nanogel additives of varied hydrophobicity were synthesized in solution,rendering 10- to 100-nm-sized particles. a model bisgma/hema solvated adhesive was prepared (control),to which reactive nanogels were added. the increase in adhesive viscosity did not impair solvent removal by air-thinning. the degree of conversion in the adhesive was similar between control and nanogel-modified materials,while the bulk dry and,particularly,the wet mechanical properties were significantly improved through nanogel-based network reinforcement and reduced water solubility. as preliminary validation of this approach,short-term micro-tensile bond strengths to acid-etched and primed dentin were significantly enhanced by nanogel inclusion in the adhesive resins. © 2012 international & american associations for dental research.