In vitro evaluation of the dispersion of nano-polylactic acid and nano-zinc oxide fillers in denture base resins using spectroscopic modalities

Polymethyl methacrylate (PMMA) is a widely used denture base material, but its mechanical and antimicrobial properties require further improvement to the diverse clinical situations. Nanoparticles such as zinc oxide (ZnO) and polylactic acid (PLA) offer promising enhancements through improved structural and functional integration. The aim of the study was to assess the molecular characterization and structural integration of PMMA modified with nano-ZnO and nano-PLA. This was an in vitro material characterization study. Forty samples were fabricated and divided into two groups: control (n = 20, unmodified PMMA) and test (n = 20, PMMA reinforced with 10% nano-PLA and 3% ZnO). A high-shear mixing technique was used. Molecular interactions were evaluated using Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS) estimated the nanoparticle dispersion and elemental composition. Qualitative analysis was used for statistical analysis. FTIR confirmed the inclusion of nano-PLA and nano-ZnO, with a broad absorption peak at 3500 cm-1 indicating increased polarity and hydrogen bonding. EDS analysis verified the presence of carbon, oxygen, and zinc, with uniform nanoparticle dispersion. Nano-PLA addition reduced crystallinity and nano-ZnO promoted crystal formation, indicating their functions in structural modification. The study confirmed molecular interactions and uniform elemental dispersion, with indications of reduced crystallinity. These findings suggest potential for further investigations into the mechanical and antimicrobial properties of this modified resin for clinical applications.