Fourier-Transform Infrared Spectroscopy Analysis of 3D-Printed Dental Resins Reinforced with Yttria-Stabilized Zirconia Nanoparticles

<b>Background/Objectives:</b> This study investigates the chemical structure and molecular interactions in 3D-printed dental resins reinforced with varying concentrations of Yttria-Stabilized Zirconia (YSZ) nanoparticles, using Fourier-Transform Infrared Spectroscopy (FTIR) to assess the compatibility and bonding behavior at the molecular level. <b>Methods:</b> Three groups of 3D-printed methacrylate-based resin discs were fabricated: a control (0% YSZ), and experimental groups reinforced with 1% and 3% YSZ nanoparticles. Samples were produced using Digital Light Processing (DLP) technology and post-processed under standardized conditions. FTIR spectra were collected via ATR mode over a wavenumber range of 4000-600 cm^-1. Spectral differences at key wavenumbers (1721.16, 1237.11, and 929.62 cm^-1) were statistically analyzed using one-way ANOVA and Tukey's post hoc test. <b>Results:</b> FTIR spectra showed no significant shifts in the ester carbonyl band at 1721.16 cm^-1, suggesting the preservation of the core resin matrix. However, a statistically significant increase in absorbance at 1237.11 cm^-1 was observed in the 1% YSZ group (<i>p</i> = 0.034), indicating dipolar interaction. A distinct new peak at 929.62 cm^-1, corresponding to Zr-O vibrations, emerged in the 3% YSZ group (<i>p</i> = 0.002), confirming successful nanoparticle integration. <b>Conclusions:</b> YSZ nanoparticles enhance specific molecular interactions within methacrylate-based dental resins without compromising structural integrity. These findings support the potential application of YSZ-reinforced 3D-printed resins in durable, biocompatible permanent dental restorations.