This in vitro study aimed to evaluate the bleaching efficacy and color stability of nonthermal atmospheric pressure plasma (NAPP)-activated 40% hydrogen peroxide (HP) and deionized water (DW). Methods: Two hundred-forty bovine enamel−dentin samples were stained with a coffee solution before bleaching. Samples were randomly divided into 12 (n = 20): (1) HP for 5 minute (HP-5), (2) HP-10, (3) HP-20, (4) Plasma-HP-5, (5) P-HP-10, (6) P-HP-5/HP-15, (7) P-HP-10/HP-10, (8) P-DW-5, (9) P-DW-10, (10) DW-5, (11) DW-10, and (12) DW-20. After bleaching, the samples were re-stained for 48 h using red wine. The color differences measured using a dental spectrophotometer after bleaching and after re-staining were reported as ΔE1 and ΔE2, respectively. The data were analyzed using Kruskal−Wallis and Mann−Whitney U tests (p< 0.05).@en

This in vitro study aimed to evaluate the effect of nonthermal atmospheric pressure plasma (NAPP)-activated hydrogen peroxide (HP) and deionized water (DW) on enamel microhardness and enamel surface morphology. @en