Analysis of Base Monomer Elution from 3 Flowable Bulk-Fill Composite Resins Using High Performance Liquid Chromatography (HPLC)

Abstract

BackgroundThe aim of this study was to evaluate the elution of BisGMA, UDMA, TEGDMA, and HEMA monomers from flowable bulk fill composite resins with different resin matrix compositions, polymerized in 4-mm-thick layers, into 3 elution media.Material/MethodsThree bulk-fill (SDR® (SDR), X-tra base (XB) and BEAUTIFIL-Bulk Flowable (BF)) resin-composites were tested. Cylindrical samples were immersed in 100% ethanol, 75% ethanol, and distilled water. The concentrations of the monomers were measured using the HLPC method (Agilent Technologies 1200 Series) after 1 and 24 h, as well as after 3, 7, 14, and 21 days.ResultsAfter polymerization of the tested resins, there was elution of the BisGMA, UDMA, TEGDMA, and HEMA monomers from the SDR and BF composites, but none of the tested monomers could be detected eluting from XB. The highest penetrations of the polymerized SDR and BF composites were observed in the 100% ethanol solution. This extraction medium eluted the highest amounts of free monomers. Some eluted monomers were not described in the composites Material Safety Data Sheets.ConclusionsThe elution of the residual monomers depended on the resin composition and the materials filler/resin matrix ratio. In composite materials, toxicity assessment should be carried out, and should consider both the material composition as given by the manufacturer, and also the residual monomers that elute from the polymerized material. The elution concentration and time of monomers from composites depended on the solvent used. The highest penetrations of the polymerized SDR and BF composites were observed in the 100% ethanol solution, and this extraction medium eluted the highest amounts of free monomers. The 75% ethanol was a more aggressive medium than water in terms of monomer elution from bulk fill composites.

The effect of pre-heating on monomer elution from bulk-fill resin composites

“…As another considerable finding, the present study showed that, various resin composites released different amount and types of monomers. According to this result, the second hypothesis was rejected, and this result was consistent with the results of other studies ( 19 - 21 ). Lempel et al reported different amounts of released monomers from bulk-fill resin composites ( 19 ).…”

“…Additionally, according to the manufacturer information, Bis-GMA does not exist in XB composite structure, also the results of this study confirmed that, this monomer was not released from XB composite. Łagocka et al in a study investigated the amount of monomer release from bulk-fill resin composites, and they showed that, any of the studied monomers such as Bis-GMA was not released from XB composite ( 21 ). Bis-GMA molecule is a monomer with high molecular weight, high capacity of hydrogen band and low molecular movement ( 26 ).…”

“…This monomer has a low molecular weight and also has an ethylene oxide group in its structure. This ethylene oxide group may cause an increase in the monomer reactivity, its mobility and release in the solvent ( 21 ). Though, Alshali et al ( 27 ), in a study showed that, TEGDMA, UDMA monomers were not released from XB composite in an aqueous environment, but in this study, the release of monomers from XB composite was shown to be detecTable in the ethanol environment.…”

Effect of food-simulating solvents on flexural properties of bulk-fill resin composites

“…ScF, and to a lesser extent XB and EXP, was less affected by solvents; however, some bulk-fills, particularly low-viscosity flowables such as VBF, FBF, and SDRF, were more susceptible to solvent attack, as indicated by a recent study reporting that XB released no monomers after storage in water or absolute ethanol [7]. The persistence of high flexural properties of ScF in solvents may be attributable to the presence of multivariant filler particles sizes, together with relatively high filler content that shortens filler spacing, thus delaying diffusion of plasticizing solvents [34].…”

“…In addition to these combined forces during mastication, solvent uptake can gradually damage restorations, as it is associated with subsurface cracking that may shorten its lifespan [6,7]. A previous study reported that a composite material with a low modulus of elasticity when placed in stress-bearing areas suffered greater distortion and marginal deterioration under masticatory forces [8].…”