Physicochemical and mechanical properties of gallium oxide-, cerium oxide-, and graphene oxide-modified mineral trioxide aggregate: an in vitro study

BACKGROUND: Mineral trioxide aggregate (MTA) is widely used in endodontics for its excellent sealing ability and bioactivity. However, its prolonged setting time, challenging handling, and limited early strength restrict clinical efficiency. This in-vitro study evaluated the effect of incorporating gallium oxide (Ga₂O₃), cerium oxide (CeO₂), and graphene oxide (GO) nanoparticles on the physicochemical and mechanical properties of MTA. METHODS: Nanoparticles (1 wt%) were homogeneously blended with MTA powder before hydration. Eighty specimens were prepared and divided into four groups (n = 20 each): unmodified MTA (control), MTA + Ga₂O₃, MTA + CeO₂, and MTA + GO. Tests for setting time, dimensional change, solubility, and pH were performed on six specimens per group, while compressive strength was assessed using ten specimens per group, in accordance with ANSI/ADA Specification No. 57 and ISO 6876:2012 standards. Data were analyzed using one-way ANOVA with Tukey's post hoc test (p ≤ 0.05). RESULTS: All nanoparticle-modified groups exhibited significantly reduced initial and final setting times compared with control MTA (p < 0.001). Dimensional change improved in all modified groups at 24 h and remained consistent at 30 days. Compressive strength increased over time for all nanoparticle-modified cements, with CeO₂ + MTA and Ga₂O₃ + MTA showing the highest values at 30 days. Solubility outcomes were nanoparticle-dependent: Ga₂O₃ + MTA demonstrated the lowest long-term solubility, whereas GO + MTA and CeO₂ + MTA showed slightly higher early values. All formulations maintained an alkaline pH, with CeO₂ + MTA and Ga₂O₃ + MTA showing the highest levels. CONCLUSIONS: Incorporating 1 wt% Ga₂O₃, CeO₂, or GO nanoparticles into MTA enhanced setting characteristics, compressive strength, dimensional change, and alkalinity. Solubility changes were nanoparticle-specific rather than universally reduced. These findings indicate that targeted nanoparticle modification can improve MTA's physicochemical performance in endodontic applications. CLINICAL TRIAL NUMBER: Not applicable.