The purpose of this study was to evaluate the effect of the repeated nonthermal atmospheric discharge (NADC) exposure without peroxide or water on bleaching effect of cycling stained tooth and to evaluate surface roughness and microhardness of the enamel surface exposed by NADC. Specimens with 5×5mm were prepared from extracted bovine teeth. Staining with tea and exposure by NADC were repeated for five times and color was measured at each step. Other specimens were prepared and surface roughness (Ra) and microhardness (Vickers hardness) were measured after exposure by NADC. The repeated NADC exposure without peroxide or water showed bleaching effect for stained bovine teeth. The surface roughness was not changed by NADC exposure. The less microhadness was shown by NADC exposere.
Keywords: Microhardness; Nonthermal atmospheric discharge; Stain removal; Surface roughness.