The present study assessed comparatively the dimensional change of
four fluid-consistence elastomeric impression materiais (one addition silicone, two
condensation silicones and one mercaptan) using the headcap technique. A metal
cast (pattern) was made, enclosing two teeth with metal-crown preparation. On this
cast, with a 0,3-mm metal relief, were obtained the headcaps using Neelon's
technique (brush method). The impressions were carried out with a static-weight
press, where a strength of 39.2 N (newton) was pressing the trays over the metal
cast. The occlusal surfaces of the prepared teeth had cross-wise grooves. In the
extreme of each groove there were small points where the reading started. The
linear reading, in a comparing microscope, was initially done at the occlusal
surface of each teeth distinctly, so following it was read matching the points
between the two teeth. The results were statistically analysed and it followed that
there were no statistically significant differences.
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