Potential of Nano-Gum Arabic on the Physical, Mechanical, Adhesive, Optical, and Biological Performance of Glass Ionomer Cement: A Comprehensive In Vitro Study

BACKGROUND: Glass Ionomer Cements (GICs) have limited strength, esthetics, and bioactivity. This study aimed to develop a nanoformulation of Gum Arabic (GA) and incorporate it into a commonly used GIC material to evaluate its effects on the cement's physical, mechanical, adhesive, optical, and biological properties. METHODS: GA was oxidized to introduce active functional groups. The resulting solution was atomized using a nanospray dryer to obtain nano-Gum Arabic (nano-GA) powder. Dynamic light scattering (DLS) analysis confirmed the nanoparticle size distribution. Nano-GA was incorporated into GIC (Medicem; Promedica, Dental Material GmbH, Neumuenster, Germany) at concentrations of 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 wt%. The effects of nano-GA addition on film thickness, water solubility (Wsol) and sorption (Wsp), diametral tensile strength (DTS), shear bond strength (SBS) to enamel and dentin, translucency parameter (TP), and contrast ratio (CR) were evaluated. Biological assessments were also conducted, including cytotoxicity, genotoxicity, and cell viability analyses. Data were statistically analyzed using one-way ANOVA and post hoc tests at a significance level of p < 0.05. RESULTS: The 8.0 wt% group exhibited the highest film thickness among all tested formulations, while the 2.0 wt% concentration demonstrated the lowest Wsol. Increasing nano-GA content up to 16 wt% reduced Wsp compared to the control (p < 0.05). No significant differences in DTS were observed among the 0.5, 1.0, and 4.0 wt% groups. Regarding adhesive performance, 2.0 wt% showed superior SBS to enamel, whereas the 1.0 wt% formulation achieved higher SBS to dentin. Optical assessments revealed that the 16.0 wt% group had the highest TP values, while the CR decreased with increasing nano-GA content. Biological evaluation confirmed that nano-GA addition up to 4.0 wt% exhibited no cytotoxic or genotoxic effects; however, cell cycle analysis indicated a slight increase in apoptosis at 4.0 wt%, whereas the G0/G1 phase percentage was highest in the 0 wt% group. CONCLUSIONS: Incorporating nano-GA into conventional GIC improved its physical, mechanical, adhesive, optical, and biological properties in a concentration-dependent manner. Optimal performance was achieved at 0.5-2.0 wt% nano-GA, enhancing strength, adhesion, and stability without affecting translucency or biocompatibility. Nano-GA up to 4.0 wt% was biocompatible, while higher concentrations induced cytotoxic effects. Thus, nano-GA is a promising additive for improving GIC performance at optimized concentrations.