Effects of adding graphene oxide to composite resin: An in vitrostudy

Abstract

Composite resin has been extensively used as a direct restorative material to restore posterior teeth due to its low cost and more complete preservation of the tooth than conventional resin. Nanohybrid resins are a popular alternative due to their apparently better mechanical strength and aesthetic properties compared to conventional resins. However, their clinical performance is still under evaluation. Adding small amounts of graphene oxide (GO) could improve the physicochemical properties of these resins. Aim: The purpose of the current study was to evaluate the effects on the morphological and physicochemical properties of nanohybrid composite resins when GO is added to them. Materials and Method: Three kinds of composite resin (Universal Nanohybrid Restorer 3M Filtek Z250 XT) were evaluated: G0, without GO; G1, composite resin with 0.01 % GO; and G2, composite resin with 0.02 % GO. Surface morphology and physicochemical characterization were analyzed for all three groups. Data were submitted to analysis of variance, followed by post hoc Tukey’s tests at a significance level of p < 0.05. Results: The addition of GO did not modify the surface of the composite resin compared to the control. The peak of the GO spectrum obtained by FTIR was very small and almost imperceptible due to the close combination of graphene molecules with the rest of the material. Flexural strength increased significantly in group G1, but decreased in G2 compared to the control group. Both GO concentrations resulted in a significant increase in resistance to wear compared to the control group. Conclusions: The addition of graphene oxide did not modify the surface morphology of the nanohybrid compound resin evaluated. However, it did produce changes in mechanical properties: resistance to wear increased significantly at both concentrations studied, while flexural strength changed in a concentration-dependent manner. These results suggest that low concentrations of GO may contribute to improving certain physicochemical properties of nanohybrid compound resins.