Models of each combination were made with type 1, 2, and 3 gypsum, and a 5-way factorial design was used to analyze the data. Silicone impression materials and models made with plaster or other gypsum materials were likely to give superior results for this application. Silicone, polysulphide, alginate, and the gypsum modeling materials had a wide range of physical and handling characteristics. A study should be conducted to determine the best material/modeling combination for environments which depart from the norm. 22 references (Author abstract modified)