Abstract
Dental nanocomposite resins have been proposed as potential restorative materials that are inevitably challenged with dynamic oral conditions. This investigation focused on the contribution of miscellaneous silane blends, used as coupling agents, to the ultimate performance of dental nanocomposite dimethacrylate resins. Herein, silica nanoparticles were initially silanized with functional/functional or functional/non-fuctional silane mixtures (50/50 wt/wt). Fourier transforms infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) verified the modification of nanosilica. The organomodified nanoparticles were then inserted into Bis-GMA/TEGDMA based resins by hand spatulation process. Scanning electron microscopy (SEM) findings revealed a broad distribution of fillers in the polymer network when reactive silanes and their corresponding blends were used. Furthermore, optical profilometry results showed that the presence of functional/non-functional mixtures can produce relatively smooth composite surfaces. Polymerization shrinkage was found to be limited upon the decrease of the degree of conversion regarding all the tested silane mixtures. The functional/functional silane blend assured the highest flexural properties and the lowest solubility after the storage of the nanocomposite in water for 1 week at 37 °C. The above experimental data could contribute to the proper designing of dental nanocomposite resins which may fit the modern clinical applications.
Highlights
Composite resins dominated as dental restorative materials especially due to superior aesthetics, better operability, and toxicity concerns associated with amalgam [1]
Dental restoratives are subjected to extremely dynamic conditions affecting their longevity such as high masticatory forces, pH and temperature variations, water sorption, bacterial attack, and enzymatic changes [2,3,4], while they are often challenged with polymerization shrinkage and marginal microleakage [5]
From the chemical point of view, dental composite resins mainly consist of methacrylate-based monomers like 2,2-Bis[p-(20 -hydroxy-30 -methacryloxypropoxy) phenylene]propane (BisGMA) and 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane (UDMA), co-monomers like triethylene glycol dimethacrylate (TEGDMA), reinforcing inorganic micro- and/or nanofillers, as well as organosilane compounds constituting the coupling agent between the polymer matrix and the reinforcing filler
Summary
Composite resins dominated as dental restorative materials especially due to superior aesthetics, better operability, and toxicity concerns associated with amalgam [1]. The bis1,2-(triethoxysilyl)ethane (BTSE) [13,24,35,36,37,38,39], bis-[3-(trimethoxysilyl)propyl]amine [37], bis-1,6-(trichloroxysilyl)ethane (BISET), bis-1,6-(trichloroxysilyl)hexane (BISHEX), and bis1,8-(trichloroxysilyl)octane (BISOCT) [40] are considered to serve as typical cross-linker silanes In such a way, the formed stiff siloxane films can hinder the diffusion of water molecules inside the network [13], increasing the hydrolytic stability of the composite resin. The concept is generally based on the combining effect of the high reactivity derived from the functional silane and the hydrophobicity attributed to the non-functional silane, resulting in a robust matrix-filler interface in the composite This technique offers improved handling properties of the uncured paste, a higher degree of double bond conversion during photopolymerization, better mechanical properties, and lower water sorption and polymerization stresses [33]. The gold standards of MPS, ACPS, and OTMS were preferred as control silanes, while the influence of the blend systems ACPSOTMS and MPS-ACPS in the physicochemical and mechanical properties was investigated for the first time
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
