Assessment of Monomer Release From Resin Composites Following the Use of Various Modeling Liquids

Abstract

Objectives

The chemical composition of resin composites and the use of modeling liquids may influence the release of residual monomer, potentially impacting biocompatibility. This in vitro study evaluated the effect of different modeling liquids on the elution of monomers from two resin composites.

Materials and Methods

Eighty disc-shaped samples were prepared using two nano-hybrid resin composites (Estelite Sigma Quick, Tokuyama; Harmonize, KERR) and three modeling liquids; Composite Wetting Resin (Ultradent, USA), Modeling Resin (Bisco, USA), and Modeling Liquid (GC, Japan) (n = 10). Resin composites were placed in four 0.5-mm increments into Teflon molds, and modeling liquids were applied with a brush between layers; control groups were prepared without modeling liquids. After polishing (Sof-Lex, 3 M ESPE), specimens were stored in 75% ethanol at 37°C. Release of UDMA, Bis-GMA, TEGDMA, and HEMA was quantified using a liquid chromatography–tandem mass spectrometry (LC–MS/MS) system (LCMS-8050, Shimadzu, Japan) at 24 h, 7 days, and 30 days. Data normality was assessed, and effects of resin composites type, modeling liquid, and time were analyzed using three-way ANOVA with Bonferroni post hoc testing (α = 0.05).

Results

Application of modeling liquid significantly reduced Bis-GMA release for both resin composites (p < 0.05). While TEGDMA release was significantly decreased in Estelite Sigma Quick groups (p < 0.05), no difference was observed in Harmonize groups. Modeling liquid applications increased total HEMA and UDMA release (p < 0.05). TEGDMA release in the Estelite Sigma Quick-control group was higher than the Harmonize-control group (p < 0.05).

Conclusion

The organic matrix of composite resins and the modeling liquids used influence the release of the tested monomers (TEGDMA, BisGMA, UDMA, and HEMA). The use of modeling liquid showed differences in monomer release according to the content of the liquid.

Clinical Significance

Modeling liquids may increase residual monomer release from resin composites, particularly shortly after polymerization. Clinicians should use these materials sparingly and in accordance with manufacturers' instructions to minimize potential biocompatibility risks.