Purpose: The objectives of this investigation were to evaluate the effect of disinfection on surface quality and dimensional stability of more recent, reformulated vinylpolysiloxane (VPS) and polyether (PE) materials. Methods: Using ANSI/ADA specification 19 protocol, 40 impressions of a stainless steel die were made 20 of each material. 10 impressions of each material were immersed in 2% glutaraldehyde disinfectant and acted as control group. 5 impression of each group were poured with extra hard dental stone type IV and the other 5 with refractory die material. The wettability, dimension stability and hardness were measured for each sample. Results: There was general increase in wettability after disinfection of all groups. All groups exhibit shrinkage before disinfection in comparison to the standard mold After disinfection, the addition silicone showed shrinkage whereas the polyether exhibited expansion. The hardness of both die materials decreased after disinfection but it was statistically insignificant (P ≥ 0.05). Conclusion: Although moisture may not adversely affect the wettability and the dimensional stability of both impression materials, the evidence suggested that VPS was more dimensionally stable. The hardness of the resulting dies was adversely affected but not statistically significant by the disinfectant.