Addition silicone and polysulfide impressions were disinfected without a loss in accuracy, whereas polyether impressions were adversely affected. The surface quality of dies was acceptable with disinfection and one disinfectant contributed to an improvement in surface quality compared with the control.A working cast-and-die system of improved dental stone used with cast dental restorations must provide dimensional accuracy, strength, and resistance to abrasion, and must reproduce surface detail. These impressions can act as vehicles of transmission and carry various types of microorganisms, which further cause diseases like Hepatitis B, C, HIV, Tuberculosis etc. This contamination and cross contamination of microorganisms can be prevented by disinfecting the impressions immediately after removing from the mouth and label them as disinfected.