Effect of Graphene Oxide on the Acid Resistance of 3D-Printed Provisional Restorations Under Simulated Gastroesophageal Reflux Conditions.

Recurrent acidic exposure in patients with gastroesophageal reflux disease (GERD) accelerates the degradation of provisional restorative materials, whereas approaches to enhance the acid resistance of 3D-printed restorations remain inadequately characterized. This study aimed to evaluate the effect of graphene oxide (GO) incorporation on the surface properties and acid resistance of 3D-printed provisional restorative materials under simulated gastroesophageal reflux conditions. GO was synthesized using the Hummers' method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. XRD analysis demonstrated a pronounced shift in the characteristic peak (2θ) from 26° to 12°, consistent with an expansion of interlayer spacing after oxidation. FTIR confirmed the presence of oxygen-containing functional groups (hydroxyl, carbonyl, and epoxy), while Raman spectroscopy identified the characteristic D and G bands, confirming successful GO synthesis. Temporary Crown & Bridge resin (TC100) was modified with GO at six concentrations (0, 0.025, 0.05, 0.1, 0.5, and 1.0 wt %) using a planetary ball milling technique. Standardized 3D-printed specimens (n = 24 per group) were fabricated. Surface roughness and Vickers microhardness were measured before and after 45 h of immersion in simulated gastric acid (pH 2). Data were analyzed using one-way ANOVA and paired t-tests (α = 0.05). After acid exposure, the control group (0 wt % GO) exhibited significant surface deterioration, showing the highest surface roughness and a marked reduction in hardness (p < 0.05). Conversely, GO-modified groups demonstrated a concentration-dependent improvement in resistance to acid-induced degradation. The 0.5 wt % GO group showed the most favorable performance, maintaining both surface roughness and hardness with no significant difference from baseline values (p > 0.05). These findings indicate that GO incorporation enhances the surface integrity and acid resistance of 3D-printed provisional resins, with 0.5 wt % identified as the optimal concentration for minimizing acid-induced surface deterioration.