Retenção ou "adesividade" do acréscimo de misturas de ZnO/Eugenol ao material já endurecido, nas moldagens de próteses totais [Title in english no available]

Abstract

ln the techniques for obtaining impressions of edentulous mouths with zinc oxide - eugenol impression materials it is common procedure to add newly mixed material to the already hardened impression in order to improve or "correct" the impression. It was our purpose to find out about the retentive or "adhesive" qualities of the above mentioned "additions" to the hardened material. To obtain this information weused a tensile strenght test in which the "added" material remained in the geometrical center of the test samples. As a comparison, test samples were also used, without added material. Five of the most widely used zinc-oxide/eugenol impression materials in Brazil were utilized throughout the experiments. The results, presented through Graphs and Tables, were statistically analysed. The addition of newly mixed material to already hardened material caused a reduction in tensile strenght values in all live impression pastes. This reduction, however, was not significant in paste "C"; it was significant (.05) in pasle "A” and highly significant (.01) in pastes,"B", "D"and "E”.