The purpose of this study was to evaluate the effect of disinfection protocol (Glutaraldehyde 2 % for 1 hour) of newly introduced polyvinyl siloxane (Express XT) impression material on the impression wettability and on the surface profilometry (surface roughness and ( surface hardness) of the produced stone cast (type IV extra hard stoneA total of thirty-eight impressions were made using Express XT impression material in specially fabricated trays. Nineteen impressions were left untreated for the control group, while other nineteen impressions were disinfected for the intervention group by Steranios 2% ECS by immersion disinfection technique . Both groups were used for measuring the contact angle, surface hardness and surface roughness. To evaluate the contact angle of the impression surface, a droplet of mixed stone in contact with the surface was measured to assess the effect of disinfection application on the surface wettability by DicoMesher software. To evaluate the surface hardness and surface roughness, impressions were poured using the dental extra hard type IV. The profilometer was used for measuring surface roughness and Surface Micro-hardness of the specimens was determined using Digital Display Vickers Micro-hardness.Concerning the contact angle: control group showed statistically significantly lower mean contact angle than intervention group. There was no statistically significant difference between the two groups for both surface roughness and surface hardness.Within the limitations of this study, The wettability of a regular body polyvinyl siloxane impression materials was affected by disinfection with 2% glutaraldehyde for 1 hour. The contact angle was increased after disinfection with 2 % glutaraldehyde resulting in poorer wettability compared with the contact angle of control group.Disinfection of a regular body polyvinyl siloxane impression materials with 2% glutaraldehyde had no effect on surface roughness and surface hardness of type IV fast setting dental stone materials.