[The materials properties of the stock for positioners--an in-vitro study. I. The elastic behavior].

The purpose of this study was to compare the physical and mechanical properties of materials for tooth positioners. 15 of these materials are in general use and four are experimental. Tensile strength at 20% elongation was observed and analyzed over a three-month period during which time the specimens were stored at 37 degrees +/- 1 degree C in an aqueous environment. The values of tensile strength covered a range from 24.9 MPa to 1.5 MPa depending on the particular material. Most of the materials displayed an increase in the module of elasticity over three-month period, but this increase was statistically significant in only one material (t-test, pmax < 0.00005).