EDTA-functionalized silica nanoparticles as a conditioning agent for dentin bonding using etch-and-rinse technique.

OBJECTIVE: This study investigated the possibility of using ethylenediaminetetraacetic acid functionalized silica nanoparticles (EDTA-SiO(2)) as a dentin-conditioning agent using etch-and-rinse technique to promote the durability of dentin bonding. METHODS: The SiO(2)-EDTA were synthesized by N- [(3- trimethoxysilyl) propyl] ethylenediamine triacetic acid (EDTA-TMS) and SiO(2) (50 nm), then characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The capacity of SiO(2)-EDTA to chelate calcium ions from dentin was examined by inductively coupled plasma-optic emission spectrometry (ICP-OES). The dentin surfaces conditioned with SiO(2)-EDTA were detected by field emission scanning electron microscopy (SEM), TEM and microhardness testing. For dentin bonding, dentin surfaces were adopted wet- or dry-bonding technique and bonded with adhesive (Adper(TM) Single Bond2) and applied composite resin (Filtek Z350) on them. The durability of dentin bonding was evaluated by mircotensile bond strength test, in-situ zymography and nanoleakage testing. RESULTS: FTIR, TGA and XPS results showed that SiO(2)-EDTA contained N element and carboxyl groups. SEM, TEM and microhardness results indicated that SiO(2)-EDTA group created extrafibrillar demineralization and retained more intrafibrillar minerals within dentin surface. In the dentin bonding experiment, SiO(2)-EDTA group achieved acceptable bond strength, and reduced the activity of matrix metalloproteinase and nanoleakage along bonding interface. CONCLUSION: It was possible to generate a feasible dentin conditioning agent (SiO(2)-EDTA), which could create dentin extrafibrillar demineralization and improve dentin bond durability. CLINICAL SIGNIFICANCE: This study introduces a new dentin conditioning scheme based on SiO(2)-EDTA to create extrafibrillar demineralization for dentin bonding. This strategy has the potential to be used in clinic to promote the life of restoration bonding.