Molecular level evaluation on HEMA interaction with a collagen model.

ABSTRACT

OBJECTIVE: 2-Hydroxyethylmethacrylate (HEMA) diffuses in wet dentin and promotes adhesion during dentin priming and bonding. We have investigated the molecular level interaction between HEMA and a collagen model by using saturation transfer difference (STD) NMR. METHODS: The binding of HEMA to collagen was preliminarily investigated by suspending demineralized human dentin powders in a 4mM HEMA solution for 1h and measuring the decrease in the HEMA concentration on a spectrophotometer. The molecular level interaction of HEMA with atelocollagen, which was used as a collagen model, was investigated by STD-NMR spectroscopy. RESULTS: The HEMA concentration in the suspension did not change, indicating that HEMA did not bind to dentin collagen. This was confirmed by STD-NMR; when the atelocollagen resonance was saturated, no saturation was propagated to HEMA and no STD signals were detected. SIGNIFICANCE: The HEMA protons were not near the atelocollagen surface, indicating HEMA did not interact with atelocollagen. The collagen fibrils may be surrounded by water molecules in dentin/bond interfaces, which prevent the direct HEMA binding interaction.