Fabrication of superhydrophobic coating for preventing microleakage in a dental composite restoration

Superhydrophobic coatings were successfully fabricated by photo-crosslinked polyurethane (PU) and organic fluoro group-functionalized SiO₂ nanoparticles (F-SiO₂ NPs), and were introduced for preventing microleakage in a dental composite restoration. The F-SiO₂ NPs possessed low surface energy and the PU can not only improve the mechanical stability but also promote F-SiO₂ NPs to form multiscale structure, which could facilitate the properties of the as-prepared superhydrophobic coating by synergetic effect. The morphology and properties of the resulted superhydrophobic coatings with different PU/F-SiO₂ ratios were studied using ¹H NMR spectrum, fourier transform infrared spectra, scanning electron microscopy, atomic force microscopy and UV-vis spectrophotometry. The results showed that the superhydrophobic coatings with low PU/F-SiO₂ ratio (1:3) possessed excellent hierarchical papillae structure with trapped air pockets, high contact angle (160.1°), low sliding angle (<1°) and good transparency. Additionally, MTT experiments results certified the prominent cell viability and biocompatibility for clinical application. Based on its fantastically superhydrophobic property, the as-prepared superhydrophobic coatings effectively prevented water permeation in resin composite restoration evaluation. This research may provide an effective method to solve the problem of microleakage and will efficiently increase the success rate of dental composite restorations.