Distance alterations of dies in sagittal direction in dependence of the die material

The distance alterations between the first premolar and second molar in the sagittal direction were measured on complete arch models in two planes. Two dental stones, three resins, and silver-plating were used to make reproductions of a master cast under standardized conditions. Special emphasis was directed to the distinction between the right half of the model with teeth between the dies and the left side edentulous between the dies. The stones Die Keen and Fuji Rock showed the least distortion, identical bilaterally. The epoxy resins Blue Star E and Metapox exhibited a significant distinction between the right and the left sides. In addition to the pronounced distance reduction caused by polymerization shrinkage, a divergence between the dies and the model base on the side with teeth was measured. This phenomenon was also observed with polyurethane Blue Star P resin, but was less substantial. Silver-plating recorded a slightly greater reduction in distance between the dies than Fuji Rock. However, no significant differences were found between both sides.