Effect of impression contamination on the accuracy of plaster model surface

: Macroscopic and microscopic examination of plaster models obtained from impressions with alginate mass Kromopan Super and silicone mass Dentaflex Pasta confirmed that leaving of saliva and blood on the surface of impressions causes uneven surface of plaster models. For ensuring sufficiently even surface of the model the impression should be cleaned immediately after its obtaining with water and a brush, or later on by immersion in 2% Na2SO4 solution.