Monomer release from nanohybrid composites after bleaching

Abstract

The evaluation of the effect of bleaching on monomer release from two composite resins was performed by bleaching two nanohybrid composite resins Filtek Z550 and Tetric N-Ceram using two bleaching products Whiteness HP Maxx and Vivastyle. In total, 20 samples were made from each composite resin from which four groups were fabricated (two for each bleaching product). The samples were stored in a 75% ethanol solution, and the solutions were renewed after 1, 7, and 28 days. The monomer release was analyzed using high performance liquid chromatography. The data were analyzed using repeated measures analysis of variance and least significant difference multiple comparison test (α = 0.05). Monomers were found to be released from both composite resins. The amounts of monomer released were found to decrease over time (P < 0.05); however, the resins were not affected by bleaching, and the released monomers were well below toxic doses.

Effect of topical fluoride applications on residual monomer release from resin-based restorative materials

“…The effects of uoride application on the concentration of residual monomer release from restorative materials have remained a matter of curiosity. Material type [14], layer thickness [15], light-curing units [16], polymerization time [17], nishing and polishing procedures [12], bleaching [7], and chewing [18] may change the quantity of residual monomer release from resin-based restorative materials. Therefore, this research conducted to evaluate the elution of methacrylate-based monomers from three resin-based materials according to uoride application procedures over a month.…”

“…These restorative materials comprise organic matrices, llers, initiators, inhibitors, and plasticizers [6]. The main components of the organic matrix are cross-linking dimethacrylates, namely, bisphenol-A-glycidyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), and hydroxyethyl methacrylate (HEMA) [7].…”

“…Resins are polymerized due to converting monomers into polymers via photo or chemical processes [8]. Although resin-based restorative materials are considered very stable in structure, they cannot be wholly polymerized in the oral environment [7]. When the conversion of monomers to polymers is incomplete, unpolymerized monomers, also called "residual monomers," are released because of several external factors [2,9].…”

“…When the conversion of monomers to polymers is incomplete, unpolymerized monomers, also called "residual monomers," are released because of several external factors [2,9]. Monomer release from resinbased composites decreases the biocompatibility of materials [7] and has cytotoxic and genotoxic effects on speci c cell types [10]. It also negatively affects cell homeostasis [11].…”

“…Monomer release from resin-based restoratives has been evaluated in many studies [7,12,13]. However, to our knowledge, there are no studies investigating whether uoride applications cause monomer release.…”