Effect of green tea-loaded chitosan nanoparticles on leathery dentin microhardness

[Abstract] The purpose of this study was to assess the effect of a chitosan-based nanoformulation containing green tea on leathery (remaining) dentin subsurface microhardness. Size distribution, polydispersity index (PDI) and zeta potential (mV) of nanoformulations were previously determined by dynamic light scattering (DLS). Human dentin specimens were exposed to Streptococcus mutans for 14 d. Soft dentin were selectively removed by Er:YAG laser (n=30) or bur (n=30). Remaining dentin was biomodified with chitosan nanoparticles (Nchi, n=10) or green tea-loaded chitosan nanoparticles (Gt+Nchi, n=10) for 1 min. Control group (n=10) did not receive any treatment. Subsurface microhardness (Knoop) was evaluated in hard (sound) and soft dentin, and then, in leathery dentin and after its biomodification, at depths of 30, 60 and 90μm from the surface. Nchi reached an average size of