The effect of adding graphene oxide nanoplatelets to Portland cement: Potential for dental applications

Assessing the Impact of Nano-Graphene Oxide Addition on Surface Microhardness and Roughness of Glass Ionomer Cements: A Laboratory Study

Background

Nanomaterials, including nano-graphene oxide (nGO), have emerged as promising modifiers for dental materials. Therefore, this study investigated the effect of incorporating nGO into conventional glass ionomer cement (CGIC) and resin-modified glass ionomer cement (RMGIC) on surface roughness and hardness.

Methods

Sixty disk-shaped specimens (2 × 6 mm) were divided into six groups: CGIC, RMGIC, CGIC with 1 wt.% nGO, CGIC with 2 wt.% nGO, RMGIC with 1 wt.% nGO, and RMGIC with 2 wt.% nGO. Surface roughness (Ra) and Vickers microhardness (VHN) were measured using a surface profilometer and Vickers microhardness tester, respectively. Statistical analysis employed the Kruskal-Wallis and Mann-Whitney tests (p <0.05).

Results

The microhardness of RMGICs significantly increased with 1% and 2% nGO (p=0.017, P=0.001, respectively), while CGICs showed a significant decrease in VHN with nGO incorporation (p=0.001). VHN values of all CGIC groups were significantly higher than those of all RMGIC groups (p=0.001). Mean surface roughness values for all CGICs were significantly higher than those of RMGIC groups (p=0.001). Within the RMGIC groups, mean Ra values of RMGIC + 1 wt.% nGO and RMGIC + 2 wt.% nGO groups decreased significantly compared to the RMGIC control group (p=0.001, p=0.001, respectively). Among CGIC groups, mean Ra values of 1 wt.% and 2 wt.% nGO/CGIC groups were significantly higher than the CGIC control group (p=0.016, p=0.001).

Conclusion

Incorporating nGO into RMGICs increased surface microhardness while reducing surface roughness, offering potential advantages for clinical applications. Conversely, adding nGO to CGICs increased surface roughness and decreased surface hardness. These findings emphasize the potential benefits of utilizing nGO in RMGICs and their implications in clinical practice.

The optical behavior of nano filled resin composite loaded with graphene oxide nanoparticles

OBJECTIVES

Assessment of the effect of incorporation of graphene oxide nanoparticles (GONPs), different concentrations into resin composite with different thicknesses on its color modulation.

MATERIALS AND METHODS

GONPs were prepared using the chemical reduction method and characterized using a transmission electron microscope and X-ray diffraction. The minimum concentrations of GONPs that provided the most effective antibacterial action (0.05 wt% and 0.2 wt%.) were prepared to be the concentration added to the tested resin composite. Calculations were done to find the required volume of the GONPs solution needed according to the mass of the resin composite. 70 nano-filled resin composite discs were prepared with 10 mm diameter × 3 mm height. 10 resin composite discs were prepared without GONPs incorporation and served as a control (G0). The other 60 resin composite specimens were divided into 2 equal groups (G1& G2) according to the concentration of the loaded nanoparticles in the specimens. Each group was divided into 3 equal subgroups according to the thickness of the resin composite containing GONPs; [T1: GONPs dispersed in the bottom 1 mm of the disc, while the top 2 mm of the disc was of resin composite only. T2: GONPs dispersed only in the bottom 2 mm of the disc and T3: GONPs dispersed in the total thickness of the disc (3 mm)]. ∆E values were calculated using a Vita Easy shade Spectrophotometer.

RESULTS

Incorporation of GONPs into resin composite induced significant color change and among all the 6 experimental groups, G1T1 group (of 0.05 wt% concentration GONPs dispersed only in the bottom 1 mm of the disc) showed a non-significant color change.

CONCLUSION

Dispersion of GONPs has a detectable effect on the color change of resin composite. Meanwhile, dispersion in low concentration for only the bottom 1 mm thickness of resin composite has an undetectable effect on its color.

Graphene-Based Materials in Dental Applications: Antibacterial, Biocompatible, and Bone Regenerative Properties

Graphene-based materials have been shown to have advantageous properties in biomedical and dental applications due to their high mechanical, physiochemical, antibacterial, and stem cell differentiating properties. Although graphene-based materials have displayed appropriate biocompatible properties when used in implant materials for orthopedic applications, little research has been performed to specifically test the biocompatibility of graphene for dental applications. The oral environment, compared to the body, varies greatly and must be considered when evaluating biocompatibility requirements for dental applications. This review will discuss in vitro and in vivo studies that assess graphene's cytotoxicity, antibacterial properties, and cell differentiation ability to evaluate the overall biocompatibility of graphene-based materials for dental applications. Particle shape, size, and concentration were found to be major factors that affected overall biocompatibility of graphene.

Evaluation of Cytotoxic Effect of Graphene Oxide Added to Mineral Trioxide Aggregate

Aim:

Recently, although studies have shown that biomaterials containing graphene oxide (GO) in biomedicine stand out for their positive effects, the effect of GO on dental tissues when used with dental materials is not well known. The aim of this study was an evaluation of the cytotoxic effects of GO on gingival fibroblasts when it is combined in two different ratios with Mineral Trioxide Aggregate (MTA).

Materials and Methods:

In this in-vitro study, a homogenous mixture of adding +0.1 weight (wt)% and +0.3 wt% GO to Angelus MTA was created (two experimental groups) and compared with pure Angelus MTA and negative control groups. The materials were mixed according to the manufacturer’s instructions, and Teflon molds were used to form 24 disc-shaped samples for each group. The samples were divided into groups according to the simple random sampling method. The cytotoxic effect of samples was determined on gingival fibroblast cells by using the MTT test, and total oxidant status (TOS) and total antioxidant capacity (TAC) kits in 24 and 72 hours. The data were statistically analyzed using one-way ANOVA and Tukey tests.

Results:

A significant difference was found between the material-applied groups and the control group at the TAC 24 and 72 hours and between the groups containing GO and the control group at the MTT 72 hours and TAC and TOS 24 and 72 hours ( p < .05).

Conclusion:

The addition of GO to MTA increased the dose and time-based toxicity and oxidant amount, and decreased antioxidant capacity.