AbstractObjective: The most common cause of clinical failures in all-ceramic dental restorations is crack formation in the veneering ceramic. The aim of this study was to determine whether graphene doping would change the characteristics of hardness and discoloration of the ceramic veneer surface.Material-Method:Thirty disk-shaped cores (10 mm in diameter and 0.8 mm in thickness) were prepared. Three different ceramic systems, IPS Empress (E) (Ivoclar Vivadent, Schaan, Liechtenstein), IPS e.max Press (EP)(Ivoclar Vivadent, Schaan, Liechtenstein), and Turkom Cera (TC) (Turcom-Ceramic SDN-BHD, Kuala Lumpur, Malaysia) were tested, each with n=8. The Vickers hardness and color difference (ΔE) values were measured before and after doping with graphene. Surface analysis was performed with XRD, XPS, and SEM. The Wilcoxon signed-rank test was performed to compare hardness values. The Kruskal-Wallis test was performed to compare ∆E values among all groups. The Kruskal-Wallis one-way ANOVA was used for the post hoc tests after the Kruskal-Wallis test (α=.05).Results: A significant difference was found among the groups and the mean values of ∆E (p = 0.002). According to the post hoc test results, this difference was found between TC and E groups (p = 0.002). Although graphene doping increased hardness significantly in group E, it was also found to decrease in group TC. The mean ∆E values indicated clinically noticeable (over the limit of 3.7) color change in all groups.Conclusions: Graphene doping may change the surface hardness of dental ceramics depending on the content of the ceramic. Similarly, depending on the content of the ceramic, it may affect its color to varying degrees. Graphene doping increased surface hardness only in group E but negatively affected the color of ceramic. Its application could be useful in the palatal region. Keywords: Dentalceramics; Color; Doping; Hardness