Fiber reinforcement of a resin modified glass ionomer cement

Improving the Mechanical Properties of Glass Ionomer Cement With Nanocrystalline Cellulose From Rice Husk

This study aimed to evaluate the effect of incorporating nanocrystalline cellulose (NCC) sourced from rice husk on the mechanical properties of a commercial glass ionomer cement (GIC). NCC was isolated through acid hydrolysis, and its crystallinity, chemical structure, and morphology were characterized through x-ray diffractometry, Fourier-transform infrared spectroscopy, and transmission electron microscopy, respectively. Various concentrations of NCC (0%, 0.5%, 1%, and 1.5%) were added to reinforce the GIC matrix. Mechanical tests including compressive strength, flexural strength, hardness, and shear bond strength were conducted on the modified GIC samples. The addition of NCC resulted in increased hardness and shear bond strength values, with 1% NCC showing the highest values compared to other concentrations. However, there was no significant improvement observed in the compressive and flexural strength of the modified GIC. Failure mode test revealed a reduction in adhesive failure with the addition of NCC. Incorporating small amounts of NCC (0.5%-1%) suggests a promising and affordable modification of GIC restorative material using biomass residue, resulting in improved mechanical properties.

Effect of Graphene Oxide Nanoparticles Incorporation on the Mechanical Properties of a Resin-Modified Glass Ionomer Cement

The objective of this study was to evaluate the effect of incorporating different concentrations of graphene oxide (GO) nanoparticles on the mechanical properties of a resin-modified glass ionomer cement (RMGIC). A commercial RMGIC (Resiglass R, Biodinâmica) was modified by incorporating 0.1% and 0.5% (by weight) of GO into the powder's material. An unmodified RMGIC was used as a control group. Powder samples were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Specimens were fabricated and subjected to flexural strength (n = 15), modulus of elasticity (n = 15), Vicker's microhardness (n = 10), and surface roughness tests (n = 10). Data were analyzed using one-way ANOVA and Tukey's post hoc test (α = 5%). Experimental groups' powder demonstrated a homogeneous dispersion of GO. No statistically significant difference was observed in flexural strength (p = 0.067) and modulus of elasticity (p = 0.143) tests. The groups containing 0.1% and 0.5% GO showed significantly higher microhardness and lower surface roughness values (p < 0.001) compared to the control group. The incorporation of GO nanoparticles at concentrations of 0.1% and 0.5% improved the microhardness and surface roughness without negatively affecting the flexural strength and modulus of elasticity of an RMGIC.

Effect of E-glass fibers addition on compressive strength, flexural strength, hardness, and solubility of glass ionomer based cement

BACKGROUND

In dentistry, glass-ionomer cements (GICs) are extensively used for a range of applications. The unique properties of GIC include fluoride ion release and recharge, chemical bonding to the tooth's hard tissues, biocompatibility, a thermal expansion coefficient like that of enamel and dentin, and acceptable aesthetics. Their high solubility and poor mechanical qualities are among their limitations. E-glass fibers are generally utilized to reinforce the polymer matrix and are identified by their higher silica content.

OBJECTIVES

The purpose of the study was to assess the impact of adding (10 wt% and 20 wt%) silane-treated E-glass fibers to traditional GIC on its mechanical properties (compressive strength, flexural strength, and surface hardness) and solubility.

METHODS

The characterization of the E-glass fiber fillers was achieved by XRF, SEM, and PSD. The specimens were prepared by adding the E-glass fiber fillers to the traditional GIC at 10% and 20% by weight, forming two innovative groups, and compared with the unmodified GIC (control group). The physical properties (film thickness and initial setting time) were examined to confirm operability after mixing. The evaluation of the reinforced GIC was performed by assessing the compressive strength, flexural strength, hardness, and solubility (n = 10 specimens per test). A one-way ANOVA and Tukey tests were performed for statistical analysis (p ≤ 0.05).

RESULTS

The traditional GIC showed the least compressive strength, flexural strength, hardness, and highest solubility. While the GIC reinforced with 20 wt% E-glass fibers showed the highest compressive strength, flexural strength, hardness, and least solubility. Meanwhile, GIC reinforced with 10 wt% showed intermediate results (P ≤ 0.05).

CONCLUSION

Using 20 wt% E-glass fiber as a filler with the traditional GIC provides a strengthening effect and reduced solubility.

Mechanical Properties and Ion Release from Fibre-Reinforced Glass Ionomer Cement

The aim of this study was to compare the mechanical properties and ion release from a commercially available resin-modified glass ionomer cement to a formulation reinforced by the addition of short glass fibres at various percentages. Methods: Three experimental groups were prepared by adding a mass ratio of 10%, 15% and 20% of short glass fibres to the powder portion of the cement from a capsule (GC Fuji II LC), while the control group contained no fibres. Microhardness (n = 12), fracture toughness, and flexural, compressive and diametral tensile strength (n = 8) were evaluated. To study ion release, readings were obtained utilising fluoro-selective and calcium-selective electrodes after 24 h, 7 days and 30 days (n = 12). The spatial distribution of fibres within the material was evaluated through scanning electron microscopy. The data were analysed using one-way ANOVA with a Bonferroni adjustment. Results: The findings suggest that elevating fibre weight ratios to 20 wt% results in improved mechanical properties (p < 0.05) in microhardness, flexural strength, diametral tensile strength and fracture toughness. In terms of ion release, a statistically significant difference (p < 0.001) was observed between the groups at the conclusion of 24 h and 7 days, when the fluoride release was much higher in the control group. However, after 30 days, no significant distinction among the groups was identified (p > 0.05). Regarding calcium release, no statistically significant differences were observed among the groups at any of the evaluated time points (p > 0.05). SEM showed the fibres were homogeneously incorporated into the cement in all experimental groups. Conclusions: Resin-modified glass ionomer enhanced with short glass fibres at a weight loading of 20% showcased the most favourable mechanical properties while concurrently maintaining the ability to release fluoride and calcium after a 30-day period.

Herbalism and glass-based materials in dentistry: review of the current state of the art

Half a million different plant species are occurring worldwide, of which only 1% has been phytochemically considered. Thus, there is great potential for discovering novel bioactive compounds. In dentistry, herbal extracts have been used as antimicrobial agents, analgesics, and intracanal medicaments. Glass-ionomer cement (GIC) and bioactive glass (BAG) are attractive materials in dentistry due to their bioactivity, adhesion, and remineralisation capabilities. Thus, this review summarizes the evidence around the use of phytotherapeutics in dental glass-based materials. This review article covers the structure, properties, and clinical uses of GIC and BAG materials within dentistry, with an emphasis on all the attempts that have been made in the last 20 years to enhance their properties naturally using the wisdom of traditional medicines. An extensive electronic search was performed across four databases to include published articles in the last 20 years and the search was concerned only with the English language publications. Publications that involved the use of plant extracts, and their active compounds for the green synthesis of nanoparticles and the modification of GIC and BAG were included up to May 2023. Plant extracts are a potential and effective candidate for modification of different properties of GIC and BAG, particularly their antimicrobial activities. Moreover, natural plant extracts have shown to be very effective in the green synthesis of metal ion nanoparticles in an ecological, and easy way with the additional advantage of a synergistic effect between metal ions and the phytotherapeutic agents. Medicinal plants are considered an abundant, cheap source of biologically active compounds and many of these phytotherapeutics have been the base for the development of new lead pharmaceuticals. Further research is required to assess the safety and the importance of regulation of phytotherapeutics to expand their use in medicine.

Reinforcement of resin-modified glass-ionomer cement with glass fiber and graphene oxide

OBJECTIVE

To evaluate the effect of adding glass fiber and graphene oxide to a resin-modified glass ionomer cement (RMGIC).

METHODS

Experimental RMGICs were prepared by adding separately and simultaneously glass fibers (5, 10, and 20 wt%) and graphene oxide (1, 3, and 5 wt%) to the powder of RMGIC with different ratios. The samples were examined under SEM and XRD. The surface roughness, flexural strength, Vickers microhardness, water sorption, and solubility were investigated. Data were analyzed using ANOVA and Tukey tests (p = 0.05).

RESULTS

Adding fiber and graphene oxide to RMCIS increased the surface roughness, flexural strength, and microhardness. The highest surface roughness value was obtained in the 20% fiber+5% graphene oxide adding group and the lowest in the control group (p < 0.05). The highest microhardness and flexural strength values were acquired in the 20% fiber-adding group and the lowest in the control group (p < 0.05). 10% and 20% fiber addition increased water sorption and solubility (p < 0.05). Adding 3%, 5% graphene oxide, and 20% fiber+5% graphene oxide reduced water sorption (p < 0.05). The highest water sorption was found in the 20% fiber-adding group and the lowest in the 5% graphene oxide and %20 fiber+5% graphene oxide-adding groups (p < 0.05). Graphene oxide alone and together with fiber did not affect the solubility (p > 0.05).

CONCLUSION

The results show that reinforcement of RMGIC with glass fiber and graphene oxide may improve the mechanical properties. But the glass fibers may cause more water sorption and solubility. Graphene oxide may decrease water sorption of RMGIC and fiber-reinforced RMGIC.

BNN/TiO2 nanocomposite system-modified dental flow resins and the mechanism of the enhancement of mechanical and antibacterial properties

Robust and antibacterial dental resins are essential for repairing the shape and function of the teeth. However, an ingenious way to achieve a synergistic enhancement of these two properties is still lacking. In this work, guided by molecular dynamics (MD) calculations, a boron nitride nanosheet (BNN)/titanium dioxide (TiO2) nanocomposite system was synthesized and used to modify the dental flow resin to enhance its mechanical and antimicrobial properties. The mechanical and antimicrobial enhancement mechanisms were further explored. The modified resin demonstrated outstanding performance improvement with 88.23%, 58.47%, 82.01%, and 55.06% improvement in compressive strength (CS), microhardness (MH), flexural strength (FS), and elastic modulus (EM), respectively. Moreover, the modified resin could effectively inhibit the growth of Streptococcus mutans (S. mutans) regardless of aging in water and the inhibition rates were more than 90%. In conclusion, the modified resin is expected to be an ideal restorative material for clinical applications.